Frontera cutting out

[sadlotus]

Evening all.

Riding the Frontera round the fields today, all was fine til I opened it up - good for a couple of hundred yards then it cut out.

Started immediately. then good for another coupla hundred yards. Then cuts out again. If I pootle along the bike will go on forever.

Felt like fuel starvation. Took the carb off and all looked good, felt like a sticky float valve but all looked good.

Then... spotted a split in the 'rubber' manifold connector. 

Question: would this air leak give the symptoms? Would have thought the bike would rev up or cut out at low revs but ticks over smoothly forever.

Thoughts?

[section swept]

A massive air leak will kill the engines performance. An air leak after the carb will weaken the mixture so much that you will find the engine produces little to no power. Tape up the split to prove the point but dont rely on the tape as a cure. 

[sadlotus]

Thanks SS, I’m getting plenty of power. Not sure the split mount is even affecting the running. It’s as if full throttle uses all the fuel in the float bowl, then refills by the time I come to a halt and kickstart. Starts first kick. Carb’s off now getting a blow through, new mount ordered. 

I do drain all petrol out when I put it away including draining the carb.  So may be some dried fuel on the float needle? Hopefully a clean up will fix it.

[twinnshock]

Have you checked the Air vent in the fuel tank filler cap? 

If blocked can cause fuel starvation similar to what you describe.

Stuart

[sadlotus]

Thnks Stuart... good idea.

Will check