Hey guys im a little stumped on this one and hoping someone wiser has some places to start.

ive had a new fuel pump, carb rebuild and setup, plugs, coils and ht leads, within 3 months and was just fine on a 40 mile round trip to get a new MOT.

i took the bike out t'other day and about 6 miles away and about 50-60 mph 5th gear it started to struggle, had i not just filled up it was the sort of struggle that id normally reach down and flip to reserve and head to a petrol station!. So definatley the symptoms in my opinion of fuel starvation, loss of power, then loads of power when i open throttle and then no power and then dies, the temp guage was about 1/4 so not really even where it normally is (1/2 on a ride like this). i sat about 10 mins, and then started up again, and turned around to head home. about 3/4 way back it did it again, if i let the revs fall below 2k it would just stall out.

ive followed a few tests around the fuel relay and pump flow and this all seems fine, its a new fuel filter too so cant see that being blocked but if it were id have expected the fuel flow test to have been bad. but it was about 1l pm so i think that exceeds minimum spec.

its had new coils and wires and iridium plugs not long ago (not that thats a reason to not be an issue). and now im a bit stuck. a friend suggested his did similar and was due to a 10A fan fuse but mine is fine, although come to think of it the fan didnt come on but maybe it wasnt warm enough too. is there a test? it was pretty free moving. is there a temp cut-off or sensor somewhere or is this not a thing that could cause this?

any help grately appreciated.

Zach

 

The next time it does this, open the fuel cap. If the bike starts running better, then you have a pinched hose.

 

Thanks Hamlin for such a fast reply, i checked the hoses this afternoon and no pinching, is there a way to check the breather hose? is there a 1-way valve and would a little compressed air sort that? trouble is i have 1 key and cant take key out of tank if its open, i have no idea why but ive tried

 

There shouldn't be a valve there. I think the easiest (and safest) thing to do is have a 2nd key made. It can be a very bad day if something happens to your sole key.

Short of; I would pull the tank and run compressed air up through the hoses/tubes.

 

thanks muchly, ill get a new key/lock set this one is the original and has seen better days anyways theyre pretty cheap

ill have a look at gettign the tank off, need a big jerry though so ill go shopping as a full tank in there and no where to put it.

ill stop back in a couple of days when ive done it thanks Hamlin