Carbon deposits

[indapit]

Can anyone tell me why or how carbon deposits accumulate in the compression chamber. Is it throttle control, gas type, gasket leaks......????

I'm doing a top-end rebuild on a CRF250R '04 because of valve issues. Took apart the top-end and noticed a lot of carbon deposits on the valves and especially the piston. Seems like this could be why I was having valve issues.

Thanks in advance.

[triplebike]

I know that on street bikes (Kawasaki Vulcan's) the problem is due to either using to high of a octane fuel (using premium when regular is factory recommended) or logging the engine & not winding it out often enought. There is a sure fire cure for it ( as long as you use the recommended octane fuel) & thats a product called "SEAFOAM". Just add a once or so to every other tank of gas and you'll not have a problem with carbon build up again. I use it in every gas powered vehicle I own. It really is a great product. It's a little hard to find, but most NAPA part stores carry it or can get it. I found it in a " ADVANCED AUTO PARTS" store in Philadelphia. They make a few different products. It's also a great fuel stabilizer to use when your bike is down for the winter, or for a extended period of time.

[creeky]

Here is an informative web site www.aati.com.au/hirth/how_to_read_pistons.htm