Hey everyone i have a question. my 02 400ex is now puffing smoke at startup. i have read in other post to use heavy oil like 20w50 I picked up 2 qt of castrol syntec blend 20w50. Is this stuff ok to use with my clutch? i was going to get mobil but when i got to walmart i forgot what i needed and just remembered the weight. any help would be great. thanks.

 

Thicker oil might help. Why do you want to run engine oil in your clutch. I've heard that it works from some and I've also seen where someone thought it was causing his clutch to slip. For an extra 2 bucks is it really worth it? Buy the honda trans oil.

Your 400ex is smoking on cold start up because of oil seeping by the valve stem seals. Common problem on 4stroke engines with some miles/hours on them. The seals contract when they are cold and expand when they are warm. When heat gets to the seals, they expand and seal off the valve stem from the combustion chamber.

 

You should be using an oil that is formulated to withstand the torture of a small high performance engine, such as Castrol 4stroke motorcycle/atv engine oil or any Honda equivalent. As far as smoking when its cold, sounds pretty normal to me. You may be running a little rich. As long as it stops immediatley after warming I wouldn't worry about it.

 

I am not going to run it in my clutch 4 strokes use the engine oil to lube the clutches. I will look for some oil for bikes and try that i also will look into it running rich. that would cause it to bog at take off right? i have a E series and i took 6 disks out and added a quiet core and havent rejetted since that would probly make it rich. thanks.

 

Some times a synthetic or thin oil will just get by the rings when its cold. You might need a re ring job.

 

This is a very good point. I would never put a synthetic oil in my engine. The best thing you could possibly do is change your oil frequently.