- Sun Apr 21, 2019 4:40 pm
#9264
My Indian home market 350 Electra has suffered ongoing problems with fuel starvation. If I hold the throttle wide open for longer than about 30 seconds the bike misfires then stops. If I close the throttle for a few seconds it picks up and runs normally again. If I close the fuel tap when it begins to misfire the engine immediately dies and will not restart (insufficient fuel in the float bowl). If I turn on the fuel tap again and wait five seconds it starts first kick. I've tuned the bike a bit after the exhaust valve seat was replaced at just over 3,500 miles from new because the original one was soft; I've gas flowed head and retarded the inlet cam by the usual one tooth. It also has a cone air filter and a Gold Star silencer. I've adjusted the mixture using a 105 main jet and the richer slide produced by our hosts. The plug colour doesn't show excessive richness - I fitted a 100 as a first guess but had to go one size bigger still because the plug centre showed mixture weakness after carrying out some "plug chop" runs.
The bike will still do about 70 mpg so it's not losing fuel for any reason and there are certainly no fuel leaks.
I've tried a different design of tap (packaged as OE Royal Enfield in the Indian plastic packaging) and since gone through a process of removing its internal bowl filter and drilling out the fuel passages to remove any possible casting flash, so I doubt that's the root cause of the problem.
I tested for a blocked fuel cap breather very early on. The tank drains through either fuel tap at the same rate with the filler cap on or off so that's not a factor. I've also removed the OE inline fuel filter from the supply pipe - it's a plain pipe now. The tank is pristine inside, no debris or signs of rust at all.
I'm now suspecting the carburettor needle valve assembly - the bike has the OE Mikcarb 24mm carb.
Has anyone else found a similar issue? I don't think the bike would benefit from a bigger carb, it just needs better fuel flow to the existing one.
The bike will still do about 70 mpg so it's not losing fuel for any reason and there are certainly no fuel leaks.
I've tried a different design of tap (packaged as OE Royal Enfield in the Indian plastic packaging) and since gone through a process of removing its internal bowl filter and drilling out the fuel passages to remove any possible casting flash, so I doubt that's the root cause of the problem.
I tested for a blocked fuel cap breather very early on. The tank drains through either fuel tap at the same rate with the filler cap on or off so that's not a factor. I've also removed the OE inline fuel filter from the supply pipe - it's a plain pipe now. The tank is pristine inside, no debris or signs of rust at all.
I'm now suspecting the carburettor needle valve assembly - the bike has the OE Mikcarb 24mm carb.
Has anyone else found a similar issue? I don't think the bike would benefit from a bigger carb, it just needs better fuel flow to the existing one.
Built like a gun... could go BANG!