110cc mini dirt bike tuning

nvd20l · Jul 13, 2005

Hey guys,

I just bought a new 110cc dirt bike. And I have to say I love it. So much fun.

It is almost through it's first tank of petrol. I just want to know how to tune these things. Is it something I can do myself and is it very difficult?

Also, when backing off the throttle, the thing pops and splutters (like backfiring). Is this a normal thing to happen?

Thanks guys....

gazza2003au · Jul 14, 2005

the bike is new so the back fire and splattering wont be from the valves did u use old fuel? try premium unleaded and u dont need to tune the bike it has already been tuned u will notice a marking on the screw just leave it

nvd20l · Jul 14, 2005

I put brand new regular unleaded pump fuel in. The next tank I will use premium unleaded.

Thanks. I will see how this goes....

condog · Jul 14, 2005

The popping and backfiring on shut off is perfectly normal. It means the pilot jet is lean when the engine is still spinning fast, but youve closed the throttle off and its now operating only on the pilot jet.

Guys with WR250 and 450F's deliberately do a mod to the carbie to achieve that popping on deceleration, as it means the bike is lean and will have a great throttle response off idle and when you reopen the throttle.

You can get rid of it by going to a bigger pilot jet but that would be plain stupid as it will drastically affect throttle response and may even create bog. It will reduce abit as the engine wears in a bit.

If your worried about it too much especially during break in then turn your idle down a bit. That will help richen the bike at idle and al the way through to high revs. In fact most pros bikes wont idle cause they set it so low to get extra top end power.