tuning!! jet recomendation?

gilera runner 172
malossi 172
polini 30mm pwk flatside carb
pm tuning 360 pipe.
pm boost bottle
full circle crank
stage 6 air filter
malossi cdi.

thats the spec. just need a jet to recomend as it has a 135ml jet and it only runs for 10mins then backfires and dies. then have to wait 10-15 mins to start again. think its over fueling. any thoughts on jet size?? cheers

 

Hi. No reccommendations for jet size but if it backfires, it's too poor, not too rich. get a box of jets in the range of 120 to 150 and start with a big one. Then work down.

Good luck.

 

It doesn't backfire all the time just before it's about to die?

 

Could be a depression pump / fuel like/ float bowl thing. Not enough fuel is getting in the bowl so as soon as the bowl runs dry you get the 'poor' symptoms. I'd check all hoses, clean the carb & check the depression pump works (suck/blow on the air pipe & see if the fuel runs freely from the fuel pipe).

Good luck