Long story short the bikes been running fine. It’s been sitting about the garage recently and its developed a problem when it’s started up. Problem: The bike tried to bog down and dies when revved hard. If you release the throttle it will regain its composure and return to idle. Also the front cylinder is running as it should and the rear isn’t. I checked the exhaust headers using a thermometer. Front is hot, rear is not so hot. Things I’ve done: I noticed the crank position sensor had cracked where the wire comes out. So I replaced this with an aftermarket one from a fiat tipo. No change. So far I’ve tried: -swapping plugs between front and rear. -Tried swapping the coils between front and rear. -Checked the compression both cylinders are 120psi cold -I set the bleed air screws to 3/4 front and 1 1/4 rear the bike appears to run better But no major changes Other details: The fuel pump primes and I've changed the filter recently. I’m thinking it’s a fuel issue as I have spark and compression. I’m going to try blowing out the manifold with the injectors to see if there’s dirt in the lines. Any ideas would be greatly appreciated.
could be the fuel if its been sitting modern fuel goes off .........could be a sticky injector you could drain the fuel and put in fresh fuel and try that easy to drain there is a drain plug on the tank rear left also fresh fuel could go for shell v power bit better fuel might help
Thanks for the reply. Its got me thinking what’s the symptoms of a dying fuel pump and is there a way of testing it? The tank had rusted through at one corner and I repaired it with an ethanol resistant tank sealer. That’s also when I changed the filter but I noticed the pump is before the filter with a small mesh bag on the intake. Small particles of rust could still pass through.
I had similar but not exactly the same rough running which was found to be a rusty connector on TPS ?
I had a similar problem when i got mine and it turned out to be the fuel filter was dated 2000 same one it had at birth and rust and crap blocking the mesh filter at the bottom, cleaned out the crap and sorted, worth a look they are known for rusting in the tank and overlooking fuel filter!!
Update I checked the resistances of the injectors both about the same. I also disconnected the return pipe and noticed it was completely dry. It clicked to me that there wasn’t enough pressure to overcome the regulator set at 3 bar. I also noticed that front injector gets the fuel first then the rear. Making me further think it was being starved. So I took the tank cap off and noticed sediment at the bottom of the tank. I took the pump out and seen that the body was all rusted. I replaced the pump with a new one and instantly noticed that there was fuel coming back through the return after a few primes. Bike started up first time runs really sweet now. TLDR So basically the fuel pump was slowly on its way out. I thought these things either worked or didn’t
Yes. Im wanting to believe most of it’s came off of the metal fuel pump body. The whole inside of the tank has been sealed in the past as the corner closest to the seat had began to leak through. I don’t see any rusty spots. I’m guessing because of the weird shape of the tank water can collect in places and rust the tank out.
