TT-Portal

Hello
I'm having some issues with my carburator, it backfires everytime i let go of the gas. The air/fuel screw has been adjusted to what the manual says it should be and the idle is also okay.
It started happening some time ago and i dont know why it does it. I had it dynoed a few days ago sadly without lambda sensor but it only made 27whp. Which seems to low.

Does anyone know why or have an idea of what it may be.

Video link of issue https://streamable.com/iadzan
Dyno graph link https://imgur.com/a/eQUorb9


Thank you alot - Thomas C.

Mangels Englischkenntnissen: Vielleicht kann es jemand übersetzen?

Ich habe das Problem auch, alles Mögliche versucht, keine Fehler gefunden.
Meine Lösung:
Ich habe die Leerlaufgemisch-Einstellschraube ca. 8 Umdrehungen heraus gedreht.
Damit läufts!

ndugu hat geschrieben:Mangels Englischkenntnissen: Vielleicht kann es jemand übersetzen?

Ich habe das Problem auch, alles Mögliche versucht, keine Fehler gefunden.
Meine Lösung:
Ich habe die Leerlaufgemisch-Einstellschraube ca. 8 Umdrehungen heraus gedreht.
Damit läufts!

Übersetzung / Translation:
" I had the same problem as you, tried everything but couldn't find the reason.

My solution:
I adjusted the idlemixture screw 8 turns out. Now it's running!"

Viele Grüße
Felix

Thanks!

Thank you alot, i will try

Hi Thomas C

have you already checked the "intake rubbers" I dont know the english expression for the rubbers between the carburator and the cylinder.
If the vulcanization dissolves the engine will get "wrong air" this can cause the backfire and also the poor performance.
If she sucks in the wrong air, she is also too lean, which you may also see in the "picture" of the spark plug.
The idlemixture screw 8 turns out could works against too lean mixture but dont solve the root cause.

One possibility to test it is with brake cleaner -spray it on the rubbers if there is a difference in the engine speed they are leaking.
Don't try to glue them I also thought that it works and did the work 2 times.

Hey Thomas
Check the exhaustgaskets.
A leaky gasket between outletport and header can also cause backfire.