Another Jetting Question


I have a question about jetting my bike. I am new to this and wonder if someone experienced can give me a few ideas.

Temp is 17 degrees celcius. Humidity 77%. I am 70-200m above sea level.

My bike is a stock 2001 WR426F - only mod is that I´ve removed the airfilter box cover. I´ve not touched the carb settings so its stock european setup.

My problem is that when I run at 1/3throttle the bike runs uneven. When I release the trottle after hard acceleration it backfires. If I release the trottle slowly there is less or no backfire. When I removed the cover for the airbox there is more backfiring but less uneven run on 1/3 throttle.

I´ve mounted a Trailtech Vapor to the bike and it says that watertemp is around 61 degrees celcius while riding on the street.

All answeres will be appreciated.

It seems you are lean on the needle. Try raising the needle (go richer) and you should see an improvement.

You may even see some improvement going to a larger mainjet too. Try a 168 or 170.

Thanks. I´ll try this asap. I´ve also ordered a JD Jet kit, hope this will improve things.

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