IndyYZ85 said:
Get your jetting right, 40:1 will still smoke and spooge.
My 05 was jetted really rich. I switched to 40:1 and spent the time to jet properly using the guide at the top of this forum. Took several hours but I'm very pleased with the throttle response and NO fouled plugs since it was done.
The spooge is still there, not as bad as stock, but still there none the same.
Once you rejet, using a new plug and clean filter, pull your pipe and silencer. You can use a small amount of desiel fuel to wash out the pipe and repack your silencer. Be prepared for a messy power valve when you do your first top end.
If you have riden quite abit with the stock jetting your pipe will have an excessive amount of spooge still in it. Getting the jetting right first and then cleaning the pipe will at least give you a clean ride for a few times out.
Several of the Heartland Spodes have riden my YZ and have commented how crisp the jetting and throttle response is now. I ride at around 670' above sea level. I'll check to see what jets I'm using but I believe I dropped two sizes on the main and the pilot with the clip 2nd from the top. I've thought about trying a different needle but have been satisfied with the overall charateristics of the stock needle. My dealer gave me 4 thin shim washers for the needle to be able to adjust the needle between clip positions but I ended up not using them.
PS: Make only one change at a time when jetting and buy several new plugs before you start. Read the jetting guide several times and then start doing the procedure. If works very well and you will be an expert on jetting your bike when it is all done.