F500 carbs

[Richard-6]

From the 2020 GCR
9.1.1. Formula 500 (F500) Specifications
14. Snowmobile Derived Engines
A. Carburetors: The induction system is restricted to two (2) 38mm Mikuni VM 38 round slide carburetors (except AMW). No modifications are permitted to the carburetor bodies. The use of any jets or jet needles is permitted. External carburetor jetting devices such as Mikuni Power Jet, Thunder PowerJet, Dial-A-Jet, IntelAJet, or other similar devices may be used, provided they are plumbed to the float bowl and body of the carburetor for which they are installed. Cockpit adjustment of external jetting devices is prohibited.


From here: http://thunderproducts.com/product/thunder-powerjet/
Thunder PowerJet $ 64.95 – $ 189.95


The Thunder PowerJet fits any size or brand carburetor. It is exactly what you need to achieve maximum performance with your engine. The TPJ improves performance by precise fuel metering with needle valve adjustment. Fuel distribution is improved by adding fuel through two sources instead of just one. This means more horsepower at any temperature or altitude. The TPJ gives you a range of over 10 to 12 jet sizes with precision external adjustment.




Is anybody using this new jetting stuff?




I am not a EFI expert. But here is some stuff from the GCR concerning 600cc motorcycle engines and the fuel metering system.


15. 600cc Motorcycle Engines
D. The stock ECU shall be used. The ECU fuel and ignition map may be changed. Devices that modify inputs to or outputs from the ECU (e.g., Power Commander) may be used. Stand-alone after market ECUs are not permitted.




It would appear that the motorcycle engines have an advantage over the snowmobile engines in the fuel metering area. If I understand 15 - D correctly, the ECU is adjusting the fuel into the engine based on inputs in real time.


But looking at 14-A, the adjustment of the jets by the driver, while the car is in motion, is prohibited.


Why not allow driver adjustment of the jets?

Photo of the Thunder Jet



Richard
reddevilsix@msn.com

[clint]

From the 2020 GCR
9.1.1. Formula 500 (F500) Specifications
14. Snowmobile Derived Engines
A. Carburetors: The induction system is restricted to two (2) 38mm Mikuni VM 38 round slide carburetors (except AMW). No modifications are permitted to the carburetor bodies. The use of any jets or jet needles is permitted. External carburetor jetting devices such as Mikuni Power Jet, Thunder PowerJet, Dial-A-Jet, IntelAJet, or other similar devices may be used, provided they are plumbed to the float bowl and body of the carburetor for which they are installed. Cockpit adjustment of external jetting devices is prohibited.


From here: http://thunderproducts.com/product/thunder-powerjet/
Thunder PowerJet $ 64.95 – $ 189.95


The Thunder PowerJet fits any size or brand carburetor. It is exactly what you need to achieve maximum performance with your engine. The TPJ improves performance by precise fuel metering with needle valve adjustment. Fuel distribution is improved by adding fuel through two sources instead of just one. This means more horsepower at any temperature or altitude. The TPJ gives you a range of over 10 to 12 jet sizes with precision external adjustment.




Is anybody using this new jetting stuff?




I am not a EFI expert. But here is some stuff from the GCR concerning 600cc motorcycle engines and the fuel metering system.


15. 600cc Motorcycle Engines
D. The stock ECU shall be used. The ECU fuel and ignition map may be changed. Devices that modify inputs to or outputs from the ECU (e.g., Power Commander) may be used. Stand-alone after market ECUs are not permitted.




It would appear that the motorcycle engines have an advantage over the snowmobile engines in the fuel metering area. If I understand 15 - D correctly, the ECU is adjusting the fuel into the engine based on inputs in real time.


But looking at 14-A, the adjustment of the jets by the driver, while the car is in motion, is prohibited.


Why not allow driver adjustment of the jets?

Photo of the Thunder Jet



Richard
reddevilsix@msn.com

Just FYI, there's currently no systems that will adjust the fuel on the fly for any of the motors in the class. All of the systems can record the fuel and make a suggestion as to what it should be changed to. The wording in the rules is precautionary for things that could be.

[ChristopherBernard]

I think what Richard is talking about is that the basic fuel injection system adjusts fuel realtime so why is it disallowed to adjust your carb realtime. Seems only fair considering the two strokes are running at a disadvantage not to mention the catastrophic results from running a two stroke too lean.
I would assume that to be one of the reasons many wouldn't want to run a two stroke. Getting the jetting right every time can't be easy.

[sathorp]

This rule change was submitted to the CRB with no verbage about in cockpit driver adjustment.
SCCA added Cockpit adjustment of external jetting devices is prohibited.

[Jnovak]

I understand the concern about not making the jetting adjustable from the cockpit. I have 2 thoughts:

1. If the jetting was cockpit adjusutable there would be, imo, about a 75% piston seizure rate in those cars

2. I can only discuss how the suzuki fuel injection system works. The driver cannot adjust the FI system from the cockpit. For example we can read the fuel variables between sessions and then adjust the fuel pressure between sessions in an effort to optimize the system.

If you want to have cockpit adjustment send your letters to the CRB.

[Marty Nygard]

I remember being at Brainerd a number of years ago and Dan Olberg had cockpit adjustable jetting for his Suzuki Water Buffalo powered DSR. The long straightaway gave him plenty of time to adjust (if some is good, more is better) and also plenty of time for him to bang out the pistons and hand polish the cylinder bores and pistons. I have to admit, I have never seen that bit of machining done by the light of a campfire before.
M

[Richard-6]

Just FYI, there's currently no systems that will adjust the fuel on the fly for any of the motors in the class. All of the systems can record the fuel and make a suggestion as to what it should be changed to. The wording in the rules is precautionary for things that could be.

Well that may or may not be true. Your team may not be using the closed-loop system but it certainly is available for the Honda CBR600RR.

Did a little studying up on the Honda CBR600RR and the ECU. It appears that additions to the engine ECU, such as the Power Commander, does allow the use of oxygen sensors to determine the best fuel to air ratio and can adjust to ratio while the engine is operating. Also the ignition timing is/or can be done on the fly, based on several inputs such a throttle position and RPM and others.

Here is a You Tube video explaining the various controllers that maybe used on motorcycle engines:
https://www.youtube.com/watch?v=EY8wv1xwQEA
Motorcycle Fuel Injection Controllers Explained - How They Work and What You Need



From the GCR below for 600cc motorcycle engines:
The stock ECU shall be used. The ECU fuel and ignition map may be changed. Devices that modify
inputs to or outputs from the ECU (e.g., Power Commander) may be used.


Not allowing the driver adjustable fuel mixture on the 2 cycle engines is a big handicap. For example, on Saturday, after practice, you check your data read out and adjust the fuel mixture accordingly. All goes well for qualifying in the afternoon on a warm sunny day, but come race time on Sunday, the weather has changed to cool and humid. Now, how to adjust the fuel mixture? Guess ? If your wrong on the guess, you either blow your engine or your dead slow.

With the ability to adjust the fuel mixture during the race, top performance can be obtained and give the 2 cycle powered car a chance to be competitive with the 4 cycle powered cars.

Richard

[clint]

Well that may or may not be true. Your team may not be using the closed-loop system but it certainly is available for the Honda CBR600RR.

Did a little studying up on the Honda CBR600RR and the ECU. It appears that additions to the engine ECU, such as the Power Commander, does allow the use of oxygen sensors to determine the best fuel to air ratio and can adjust to ratio while the engine is operating. Also the ignition timing is/or can be done on the fly, based on several inputs such a throttle position and RPM and others.

Here is a You Tube video explaining the various controllers that maybe used on motorcycle engines:
https://www.youtube.com/watch?v=EY8wv1xwQEA
Motorcycle Fuel Injection Controllers Explained - How They Work and What You Need



From the GCR below for 600cc motorcycle engines:
The stock ECU shall be used. The ECU fuel and ignition map may be changed. Devices that modify
inputs to or outputs from the ECU (e.g., Power Commander) may be used.


Not allowing the driver adjustable fuel mixture on the 2 cycle engines is a big handicap. For example, on Saturday, after practice, you check your data read out and adjust the fuel mixture accordingly. All goes well for qualifying in the afternoon on a warm sunny day, but come race time on Sunday, the weather has changed to cool and humid. Now, how to adjust the fuel mixture? Guess ? If your wrong on the guess, you either blow your engine or your dead slow.

With the ability to adjust the fuel mixture during the race, top performance can be obtained and give the 2 cycle powered car a chance to be competitive with the 4 cycle powered cars.

Richard

Let me start out by saying that if you want to send in a request to the CRB requesting that the two-strokes have cockpit adjustable "jetting" or for that matter fuel injection that can "tune itself" I will personally write in to the CRB in favor of it. With that said, you might want to do a little more research before posting about capabilities that doesn't exist LEGALLY. The power commander 3 or 5 doesn't have the capability to adjust fuel tables in real time. The ONLY thing they can do fuel wise is "suggest" a fuel map based on PREDETERMINED air/fuel targets that the person tuning the motor has to put in initially during installation . To simplify this I will say that if you want the air/fuel ratio to be at 14.8:1 throughout the entire rpm range then you would put 14.8 in each box for the autotune unit. Once you have run a session you can see what the autotune unit "suggests" and decide whether or not you want to "accept" the "suggestions" . There's reasons for this that I don't care to go into it especially given the fact that you've "researched" this particular thing (meaning you've done your best to understand it) and still don't understand it. IF IT WAS THIS EASY WE WOULDN'T HAVE TO SPEND $2000.00 AT MINIMUM EACH TIME A RESTRICTOR CHANGE IS IMPOSED ON THE MC MOTORS.If you do manage to find a unit that will work on a GSXR, CBR,or R6 that does what you're claiming I will gladly apologize. Until then please try not to post things that you don't understand. It only gets other people excited that doesn't know what's going on as well. Before you know it restrictions start being put in place simply because one doesn't nor ever did have a clue about performance advantages. Here's a link for your continued research https://www.youtube.com/watch?v=AOi9NHRv7jE

[Richard-6]

Let me start out by saying that if you want to send in a request to the CRB requesting that the two-strokes have cockpit adjustable "jetting" or for that matter fuel injection that can "tune itself" I will personally write in to the CRB in favor of it. With that said, you might want to do a little more research before posting about capabilities that doesn't exist LEGALLY. The power commander 3 or 5 doesn't have the capability to adjust fuel tables in real time. The ONLY thing they can do fuel wise is "suggest" a fuel map based on PREDETERMINED air/fuel targets that the person tuning the motor has to put in initially during installation . To simplify this I will say that if you want the air/fuel ratio to be at 14.8:1 throughout the entire rpm range then you would put 14.8 in each box for the autotune unit. Once you have run a session you can see what the autotune unit "suggests" and decide whether or not you want to "accept" the "suggestions" . There's reasons for this that I don't care to go into it especially given the fact that you've "researched" this particular thing (meaning you've done your best to understand it) and still don't understand it. IF IT WAS THIS EASY WE WOULDN'T HAVE TO SPEND $2000.00 AT MINIMUM EACH TIME A RESTRICTOR CHANGE IS IMPOSED ON THE MC MOTORS.If you do manage to find a unit that will work on a GSXR, CBR,or R6 that does what you're claiming I will gladly apologize. Until then please try not to post things that you don't understand. It only gets other people excited that doesn't know what's going on as well. Before you know it restrictions start being put in place simply because one doesn't nor ever did have a clue about performance advantages. Here's a link for your continued research https://www.youtube.com/watch?v=AOi9NHRv7jE

Why are you yelling?

There's reasons for this that I don't care to go into it especially given the fact that you've "researched" this particular thing (meaning you've done your best to understand it) and still don't understand it

Now there you go again, you don't know what I know or don't know. Implying that I am not as intelligent as you puts this discussion on a whole different level.

Richard

[clint]

Why are you yelling?



Now there you go again, you don't know what I know or don't know. Implying that I am not as intelligent as you puts this discussion on a whole different level.

Richard

Actually, I'm not yelling. Just making sure you see the points. In any case, if you had been asked to change restrictors 5 times in 6 years at $2000.00+ each time I'm pretty sure you too would be a little loud .Since you're implying that I don't know what you know, maybe you can help everyone reading this post figure out what you do know. So far, everything you've posted I've taken at face value. The things you've posted thus far hasn't had any validity to them. So, please help everyone out by posting the rest of what you know. BTW, it wouldn't have taken very much at all to take this conversation to "a whole different level". Currently it's at the crayon and coloring paper level and I don't see it getting past that unless someone else joins in that bothers to do meaningful research.

[Richard-6]

OK, I agree with you about the Power Commander not doing fuel to air adjustments in real time.

However the ECU coupled with the Power Commander does give the 4 cycle engine an advantage over the 2 cycle engines in other ways.

It's just to bad that the CRB did not allow the new fuel jet adjustment on the 2 cycle engines to be adjusted by the driver.

And in response to Jay's assertion that having the driver adjusted jets would result in more burnt pistons, I have a box full of burnt pistons that would disagree with that statement. All of these melted pistons were the result of setting the jets on Saturday eve and then racing the next day. Sometimes it works, got a bunch of trophies to show that and sometimes it doesn't, got a box full of burnt pistons for that.

Richard

[sathorp]

The only way to change the F500 rules is to write letters to the CRB. You either have to accept the F500 rules the way SCCA writes them or write letters to the CRB to change the F500 rules.

[clint]

OK, I agree with you about the Power Commander not doing fuel to air adjustments in real time.

However the ECU coupled with the Power Commander does give the 4 cycle engine an advantage over the 2 cycle engines in other ways.

It's just to bad that the CRB did not allow the new fuel jet adjustment on the 2 cycle engines to be adjusted by the driver.

And in response to Jay's assertion that having the driver adjusted jets would result in more burnt pistons, I have a box full of burnt pistons that would disagree with that statement. All of these melted pistons were the result of setting the jets on Saturday eve and then racing the next day. Sometimes it works, got a bunch of trophies to show that and sometimes it doesn't, got a box full of burnt pistons for that.

Richard

It doesn't give it a performance advantage. It only lessens the amount of expertise one would need to optimize it once you've figured out how to operate the power commander and auto tune. If you ask Brad, tuning the two-stroke is much easier than dealing with the MC stuff. Then again, Brad knows what he's doing so it's going to come easier to him than most. If you ask the other 99.5% of the guys trying to tune the two stroke, its a pain and most only get it right half of the time at best. If you do happen to get it right on the motor side then you still have to match the CVT to the HP for that hour. There's no advantage to the MC motor performance wise if both tuners know how to tune their own respective motor. It is easier to run more consistent for the average joe when dealing with a MC motor simply because it's fuel injection and the gear box doesn't have the variables the CVT does. To me, that's what's appealing to the MC motor. If I knew how to tune the two stroke and CVT I would be racing one of those instead. I don't, so it's wishful thinking but if I were offered the chance to run a 593 setup prepared and tuned at the track by Brad I would be back in a two stroke in a heart beat.

[clint]

OK, I agree with you about the Power Commander not doing fuel to air adjustments in real time.


It's just to bad that the CRB did not allow the new fuel jet adjustment on the 2 cycle engines to be adjusted by the driver.



Richard

I stand by my comment. If you write in to the CRB for this I will support it and I'm sure that atleast 90% of the class will as well. I know 7 drivers right off the bat that will write in to support this. You should write the letter and post the letter number so we will have a reference number to put with our letters.

[Dan McMahan]

OK, I agree with you about the Power Commander not doing fuel to air adjustments in real time.

However the ECU coupled with the Power Commander does give the 4 cycle engine an advantage over the 2 cycle engines in other ways.

It's just to bad that the CRB did not allow the new fuel jet adjustment on the 2 cycle engines to be adjusted by the driver.

And in response to Jay's assertion that having the driver adjusted jets would result in more burnt pistons, I have a box full of burnt pistons that would disagree with that statement. All of these melted pistons were the result of setting the jets on Saturday eve and then racing the next day. Sometimes it works, got a bunch of trophies to show that and sometimes it doesn't, got a box full of burnt pistons for that.

Richard

When we were running 2 stroke, I went to grid with a jet card in one pocket and an air density meter in the other. Not unusual to be changing jets at the 5min. We smoked quite a few, if you aren't on that edge , you aren't up front.

[sathorp]

When we were running 2 stroke, I went to grid with a jet card in one pocket and an air density meter in the other. Not unusual to be changing jets at the 5min. We smoked quite a few, if you aren't on that edge , you aren't up front.

The current new 2-Stroke Carb Rule allows these jetting changes to be made on grid by the pit crew at the 1 to 0 minute mark. One system also allows infinite adjustment instead of discrete jet changes. If you need a ½ jet size you don’t need to decide to go to a bigger or smaller jet.

http://thunderproducts.com/thunder-products-intelajet/

[Dan McMahan]

The current new 2-Stroke Carb Rule allows these jetting changes to be made on grid by the pit crew at the 1 to 0 minute mark. One system also allows infinite adjustment instead of discrete jet changes. If you need a ½ jet size you don’t need to decide to go to a bigger or smaller jet.

http://thunderproducts.com/thunder-products-intelajet/

No longer have to do that.............Bike motor.

[sathorp]

No longer have to do that.............Bike motor.

I have no interest in arguing about F500 engines with anyone. I SURRENDED IN THE F600 section below.

[Jnovak]

I think that the 2 stroke combination is about 5 to 10 times more complex to get ir optimized. Compared to the MC package.

I am preparing a letter to the FSRAC & CRB that imo will greatly reduce the complexity of optimization of the 2 stroke package.

Now back to one of the issues wrt the bike motors.

Clint McMahan remaps his ecu for every restrictor change and i have no doubt that this proviides a, imo, a relarively minor power advantage. We do it a bit differently and i am very confident that it works and the total cost is very low.

When I retire from my involvement In F500 i will publically share what i have learned!

[Tom Grossmann]

Jay correct if I'm wrong but wouldn't it be possible with modern electronics to have a self adjusting power jet set up for a two stroke? This would stay within the rules as they are written.

[Jnovak]

Jay correct if I'm wrong but wouldn't it be possible with modern electronics to have a self adjusting power jet set up for a two stroke? This would stay within the rules as they are written.

Tom, i am sure this could be done. How to make it commercially available is the issue imo.

Great idea Tom!

[Richard-6]

Jay correct if I'm wrong but wouldn't it be possible with modern electronics to have a self adjusting power jet set up for a two stroke? This would stay within the rules as they are written.

Tom - I believe you are correct in that assumption. The rule states "the jets will not be driver adjusted". Doesn't say that they can't be auto-adjusted by a mechanism.

However, as I understand it, there is a problem with O2 sensors not lasting long when used in 2 cycle operation. It may be possible to just use the EGT readings for feedback into the mechanism.

Richard

.

[allof6]

Change the rules to allow cockpit adjusting. A dial-a-jet system similar to what is used in the midgets and sprints could be used.

Get rid of the CVT and go to a multi-disc dry or wet clutch set up that utilizes chain and sprocket.

These are both obtainable for the two strokes.

So here is my question(s). How many 2 strokes would actually make the investment to upgrade?

The short comings existed before the MC powered cars so why all hubbub against the 4 strokes?

You're always going to have the haves and have nots.

[clint]

Change the rules to allow cockpit adjusting. A dial-a-jet system similar to what is used in the midgets and sprints could be used.

Get rid of the CVT and go to a multi-disc dry or wet clutch set up that utilizes chain and sprocket.

These are both obtainable for the two strokes.

So here is my question(s). How many 2 strokes would actually make the investment to upgrade?

The short comings existed before the MC powered cars so why all hubbub against the 4 strokes?

Your always going to have the haves and have nots.

Now this is a great idea!

[Richard-6]

Change the rules to allow cockpit adjusting. A dial-a-jet system similar to what is used in the midgets and sprints could be used.

Get rid of the CVT and go to a multi-disc dry or wet clutch set up that utilizes chain and sprocket.

So you're suggesting that the 2 cycle guys use a single speed vs the 4 cycle Close-ratio six-speed ?

Doesn't sound like a fair fight to me.

Richard

[Jnovak]

Change the rules to allow cockpit adjusting. A dial-a-jet system similar to what is used in the midgets and sprints could be used.

Get rid of the CVT and go to a multi-disc dry or wet clutch set up that utilizes chain and sprocket.

These are both obtainable for the two strokes.

So here is my question(s). How many 2 strokes would actually make the investment to upgrade?

The short comings existed before the MC powered cars so why all hubbub against the 4 strokes?

Your always going to have the haves and have nots.

I did a ton of research into gearboxes for 2 strokes about 10 years ago and the proposal was knocked down. You could try again but the lowest cost at that time was about $2500 to install on one of our engines. Forget it!

If you want to shift buy an MC engine and figure out how to install it or buy an existing car that has one already!!!

I have converted about 10 cars and i bet Clint and his Dad have done more!

[allof6]

I did a ton of research into gear boxs for 2 strokes about 10 years ago and the proposal was knocked down. You could try again but the lowest cost at that time was about $2500 to install on one of our engines. Forget it!

If you want to shift buy an MC engine and figure out how to install it or buy an existing car that has one already!!!

I have converted about 10 cars and i bet Clint and his Dad have done more!

Theres nothing in my statement that that says anything about putting a gearbox on the two stroke. I suggest you reread it.

PS I already own a MC engine car!

[Richard-6]

Change the rules to allow cockpit adjusting. A dial-a-jet system similar to what is used in the midgets and sprints could be used.

The short comings existed before the MC powered cars so why all hubbub against the 4 strokes?

First of all, the way the F440 started and then transitioned into the F500 was that it always used the snowmobile CVT clutch/gearing system. And all was well in the world.

Then, about 7 years ago, came along those who were dissatisfied with the kingdom of 2 cycle engine racing. They wanted to shift for themselves. They wanted springs and shocks and bigger tires and they wanted it now!

So with the cooperation of the SCCA Board of Directors and the CRB, now suddenly, all that was well and likeable, was cast aside and the motorcycle engine was shoved down the throat of the 2 cycle family. And that is how it still stands today.

I will not regurgitate what happened over the last 7 or more years. If you are really interested, I'm sure you can use the search feature on Apex to find what you are looking for.

It has been repeated over and over again that the CVT system is less efficient than the geared transmission of the motorcycle. Even if the disparities of the carbureted 2 cycle engine were to be balanced out, the transmission issues would still put the CVT system at an disadvantage.


Richard

[Jnovak]

Theres nothing in my statement that that says anything about putting a gearbox on the two stroke. I suggest you reread it.

PS I already own a MC engine car!

I mis-understood

[clint]

First of all, the way the F440 started and then transitioned into the F500 was that it always used the snowmobile CVT clutch/gearing system. And all was well in the world.

Then, about 7 years ago, came along those who were dissatisfied with the kingdom of 2 cycle engine racing. They wanted to shift for themselves. They wanted springs and shocks and bigger tires and they wanted it now!

So with the cooperation of the SCCA Board of Directors and the CRB, now suddenly, all that was well and likeable, was cast aside and the motorcycle engine was shoved down the throat of the 2 cycle family. And that is how it still stands today.

I will not regurgitate what happened over the last 7 or more years. If you are really interested, I'm sure you can use the search feature on Apex to find what you are looking for.

It has been repeated over and over again that the CVT system is less efficient than the geared transmission of the motorcycle. Even if the disparities of the carbureted 2 cycle engine were to be balanced out, the transmission issues would still put the CVT system at an disadvantage.


Richard

You should learn from your oversights above. At least show people you're either trying really hard to be factual or just be honest and tell everyone you're not capable of making a factual post. Btw, however it's shaken out over the years neither powerplant has won two consecutive years.

So unless you're saying that you don't want parity (ya know, a two stroke winning every other year at the runoffs) I would refrain from saying the CVT is at a disadvantage when the proper tuning, driver, and handling setup is put together.

[Jnovak]

First of all, the way the F440 started and then transitioned into the F500 was that it always used the snowmobile CVT clutch/gearing system. And all was well in the world.


Then, about 7 years ago, came along those who were dissatisfied with the kingdom of 2 cycle engine racing. They wanted to shift for themselves. They wanted springs and shocks and bigger tires and they wanted it now!


So with the cooperation of the SCCA Board of Directors and the CRB, now suddenly, all that was well and likeable, was cast aside and the motorcycle engine was shoved down the throat of the 2 cycle family. And that is how it still stands today.


I will not regurgitate what happened over the last 7 or more years. If you are really interested, I'm sure you can use the search feature on Apex to fine what you are looking for.


It has been repeated over and over again that the CVT system is less efficient than the geared transmission of the motorcycle. Even if the disparities of the carbureted 2 cycle engine were to be balanced out, the transmission issues would still put the CVT system at an disadvantage.


Richard

I am sorry Richard but you do not have a f**king clue how it happened so i suggest that you just shut up.

[Richard-6]

I am sorry Richard but you do not have a f**king clue how it happened so i suggest that you just shut up.

I really doubt that your are sorry with the language that follows the "I am sorry"

Richard

[Tom Grossmann]

Back to the cockpit adjustable jetting; as actual jetting changes take all of 10 minutes one could make jet changes 10 minutes before going to grid. I can't recall an instance when road racing a two stoke bike where the weather changed enough that being able to adjust it on track would have made a significant difference. Feel free to disagree.

[dc]

I'm going to make one public warning to everyone involved that if tempers and confrontational posts are not avoided, there will be forum bans dished out—and no one wants that at all. Please keep it civil.


Jay, to the penalty box.

[Jnovak]

I really doubt that your are sorry with the language that follows the "I am sorry"

Richard

That was not an apology!

[Dan McMahan]

I have no interest in arguing about F500 engines with anyone. I SURRENDED IN THE F600 section below.

Where is the argument? I just made a statement that I no longer have to deal with carbs. Just my preference with no push on anyone to change over. I would like to see the 493/494 get on par with the 593. I would also support FI for the 2strokes.

[sathorp]

Where is the argument? I just made a statement that I no longer have to deal with carbs. Just my preference with no push on anyone to change over. I would like to see the 493/494 get on par with the 593. I would also support FI for the 2strokes.

I'm gun shy and I don't want to start more infighting! I have nothing against the MC engine or any of the drivers. I met Clint at Mid-Ohio in 2015. He was cordial friendly and answered all of my questions. I helped him move the yellow banana boat. At the time I was interested in purchasing that car.

In my mind the MC cars & drivers are not the problem and have never been the problem. A 115 hp de facto Standard or Target was set in this class by the 2014 Runoffs Wining car that was powered by a Rotax 593 engine that was Over Revved to 8800+ rpm. The MC Engine was then match to this 115 Hp de facto Standard or Target. The MC drivers didn’t create the de facto 115hp standard or target for this 8800rpm+ Over Revved 2-Stroke Hunk of Junk that breaks crankshafts and destroys crankcases. But the MC cars have to compete against the cars powered by this de fact Rotax 593 115hp @ 8800rpm+ Engine standard or target. So, they didn’t cause or create the problem and all the infighting. So quit blaming them!!!!

The MC Engine has the power to match this de facto Rotax 593 115hp 8800rpm+ Hunk of Junk Engine. The 494/493 & the low cost Rotax 593 Engine with the 25mm all make 105-106hp @ 8200 Rpm they can’t compete with the Rotax 593 115hp 8800rpm+ Hunk of Junk Engine standard or target.

I’m fed up and sick of what’s gone on in this F500 over last 5 years because of this Rotax 593 115hp @ 8800rpm+ Hunk of Junk Engine. In my mind the creator of this Rotax 593 115hp @ 8800rpm+ Engine Hunk of Junk caused the problems, created the problems, for his own personal self-interest.

Therefore, I do not support, and I will not support Jay Novak in this class under any circumstances. He’s still trying to protect his de facto 115 hp standard or target. The sooner Jay Novak retires from any involvement in the F500 class the better, he’s the problem, he’s not the solution.

[Daryl DeArman]

From the 2020 GCR
9.1.1. Formula 500 (F500) Specifications
14. Snowmobile Derived Engines
A. Carburetors: The induction system is restricted to two (2) 38mm Mikuni VM 38 round slide carburetors (except AMW). No modifications are permitted to the carburetor bodies. The use of any jets or jet needles is permitted. External carburetor jetting devices such as Mikuni Power Jet, Thunder PowerJet, Dial-A-Jet, IntelAJet, or other similar devices may be used, provided they are plumbed to the float bowl and body of the carburetor for which they are installed. Cockpit adjustment of external jetting devices is prohibited.


15. 600cc Motorcycle Engines
D. The stock ECU shall be used. The ECU fuel and ignition map may be changed. Devices that modify inputs to or outputs from the ECU (e.g., Power Commander) may be used. Stand-alone after market ECUs are not permitted.

Maybe those in the class could look to mistakes / unintended consequences of other classes that had similar rules in the past.

"Stand-alone after market ECU's" aren't really stand-alone after market ECU's when they rely on the stock ECU for their power and ground for example.

If that engine will not run without the stock ECU, that stock ECU is being utilized and the "stand-alone aftermarket ECU" is obviously not "standing alone". When does that aftermarket stand alone ECU become a stand alone ECU and when is it just modifying inputs/outputs?

As to tuning on the fly in the MC engine, what's to prevent somebody from installing a potentiometer in their O2 output circuit so that the ECU sees a slightly higher/lower voltage? Depending if they want to go slightly richer/leaner than what their current fuel map tables dictate?

I'd urge the community to consider allowing cockpit adjustable jetting/metering circuits on 2 stroke cars before the result is that you need a controller, a stepper motor, some additional sensors and a programing degree to be competitive. Alternatively, I guess somebody could make a cockpit adjustable device that modifies INTERNAL jetting

10 year old kids in 2 stroke karts learn what to do with high speed/ low speed needles to tune on the go. There aren't going to be a whole bunch more stuck motors It's not only about getting the jetting correct for the conditions at the start of the race, it's about getting the jetting optimized for off the corner and end of the straights, perhaps with a CVT that's not as critical as it is with a single gear and centrifugal clutch.

[Jnovak]

I'm gun shy and I don't want to start more infighting! I have nothing against the MC engine or any of the drivers. I met Clint at Mid-Ohio in 2015. He was cordial friendly and answered all of my questions. I helped him move the yellow banana boat. At the time I was interested in purchasing that car.

In my mind the MC cars & drivers are not the problem and have never been the problem. A 115 hp de facto Standard or Target was set in this class by the 2014 Runoffs Wining car that was powered by a Rotax 593 engine that was Over Revved to 8800+ rpm. The MC Engine was then match to this 115 Hp de facto Standard or Target. The MC drivers didn’t create the de facto 115hp standard or target for this 8800rpm+ Over Revved 2-Stroke Hunk of Junk that breaks crankshafts and destroys crankcases. But the MC cars have to compete against the cars powered by this de fact Rotax 593 115hp @ 8800rpm+ Engine standard or target. So, they didn’t cause or create the problem and all the infighting. So quit blaming them!!!!

The MC Engine has the power to match this de facto Rotax 593 115hp 8800rpm+ Hunk of Junk Engine. The 494/493 & the low cost Rotax 593 Engine with the 25mm all make 105-106hp @ 8200 Rpm they can’t compete with the Rotax 593 115hp 8800rpm+ Hunk of Junk Engine standard or target.

I’m fed up and sick of what’s gone on in this F500 over last 5 years because of this Rotax 593 115hp @ 8800rpm+ Hunk of Junk Engine. In my mind the creator of this Rotax 593 115hp @ 8800rpm+ Engine Hunk of Junk caused the problems, created the problems, for his own personal self-interest.

Therefore, I do not support, and I will not support Jay Novak in this class under any circumstances. He’s still trying to protect his de facto 115 hp standard or target. The sooner Jay Novak retires from any involvement in the F500 class the better, he’s the problem, he’s not the solution.

Frankly I am surprised that you think that $6000 is thought to be a lot of money for an engine package capable of winning the Runoffs. So i will break down the cost. I think it was a good deal.

Included. Remember new 593 complete were no longer available at that time. In other than this words to build a new engine you had to buy all the parts needed to assemble a complete engine plus all the time and labor involved.

Parts purchased:
New crankcase
New crankshaft
New cylinders
New pistons
Fasteners
Seals

Fabricate a new tuned pipe
Fabricate a new exhaust manifold
Rebuild carburators
Rebuild both clutches
Supply 3 matched clutch belts
Install everything in the car
Also supply 3 sets of weights

Dyno and jet the carbs etc

Now please note that 115 hp was really just 1 hp more than the test data supplied to get the 593 engine approved. So 114 hp is Ok but 115 is not fair?

Anyway we had to work very hard to get the jets and clutches right at the track

many thanks to Brad Hulings for building us a great motor that never missed a beat and a huge thanks to Brian Novak for the super drive to be fastest in EVERY SESSION and led every lap of the Race. Btw we had to modify the pipe every day for the first 3 days because we were over sound as were others

So the long and short of it is that we got a bargain at $6000. IMO

[sathorp]

Frankly I am surprised that you think that $6000 is thought to be a lot of money for an engine package capable of winning the Runoffs. So i will break down the cost. I think it was a good deal.

Included. Remember new 593 complete were no longer available at that time. In other than this words to build a new engine you had to buy all the parts needed to assemble a complete engine plus all the time and labor involved.

Parts purchased:
New crankcase
New crankshaft
New cylinders
New pistons
Fasteners
Seals

Fabricate a new tuned pipe
Fabricate a new exhaust manifold
Rebuild carburators
Rebuild both clutches
Supply 3 matched clutch belts
Install everything in the car
Also supply 3 sets of weights

Dyno and jet the carbs etc

Now please note that 115 hp was really just 1 hp more than the test data supplied to get the 593 engine approved. So 114 hp is Ok but 115 is not fair?

Anyway we had to work very hard to get the jets and clutches right at the track

many thanks to Brad Hulings for building us a great motor that never missed a beat and a huge thanks to Brian Novak for the super drive to be fastest in EVERY SESSION and led every lap of the Race. Btw we had to modify the pipe every day for the first 3 days because we were over sound as were others

So the long and short of it is that we got a bargain at $6000. IMO

10 Hours - Crickets Chirping and Forest Ambience

https://www.youtube.com/watch?v=NOfVUBLKYQE