Smoking at idle

[Coochas]

My FM has gotten increasingly smokier at idle. It looks like oil smoke.
I checked the spark plugs and they were pretty black.
I changed the plugs and the problem was instantly cured. After a few starts the car is smoking again at idle.
Is my mixture too rich? Is it the quality of the oil being injected? I did just change my oil but my guess is that it hasn't even reached the carbs at this point.

[mikey]

Check compression. Apex seals perhaps? Do you have hard starts?

[Coochas]

Check compression. Apex seals perhaps? Do you have hard starts?

It's starting OK.
Do you know the normal compression range for our motors? Racing Beat has a protocol for using a standard compression gauge and looking for any differences in oscillations suggesting a bad seal.

[Coochas]

I just looked at their protocol and it suggests 90-120 for peripheral ports. I'll warm it up tomorrow and then check compression.

[mikey]

When using a standard gauge I record video of the gauge during cranking at 60fps and play it back slow motion. Easy to see where the bounce occurs each oscillation then.

search google images for your engine with "compression test" after. Find a chart like this:

[mstephenson51]

As far as the smoke....

Get with Moses and get the Oil Metering Pump Block Off Kit. then you switch to using Premix oil like dirtbikes. This will lube the engine better than those crappy metering pumps.

You might be a little rich too, but these are supposed to be pretty rich, and keep gunning it every 30 sec or so to keep it cleared out so you don't foul plugs.

But yeah you will have some smoke always. and if you go to premix oil you will have a little more.

[Coochas]

Thanks for the replies guys.
I did some compression tests with a standard tester and the numbers didn't look right. I called Daryl Drummond who told me that using a regular tester isn't going to give good results. I told him what was going on including the fact that the power was good. He thought that it could be a dirty needle or high float level. I also spoke with Bruce Lawrence who recommended some minor changes in my jetting (more lean) given the humidity right now.

The smoking seems to be much less since I changed the oil and I'm still wondering if I was injecting crappy oil to burn.

I'm at NJMP in a few weeks so we'll see!