Busa not starting when hot

[seekoei]

so hi guys.
bought me a 99 busa about 2 months ago. got 40000km on the clock and is in relatively good condition.

BUT when i get it up to temp and park it in the garage, exactly 40 min later (not 10\30 min) it wont start up again.
motor spins up as always but doesn't take. so when u lift the tank up i hear bubbles cumming up into the tank
and then starts up fine there after.

So here's what i found. some how a airlock is created in the fuel pump... (u can hear the pump is dry and not pumping anything)

i checked : the fuel tank + cap breathers.
: that there is no blockages\kinks in the fuel line
: the fuel pump (took it apart, didn't have to clean anything. looks like a new pump.)
: cleaned all the filters (wasnt dirty)

otherwise the bike goes great. no problems while riding. and only does this when warm and parked in a warm ish environment...
a bit embarrassing when u out with ur mates and u first have to lift the tank before it starts....

HELP!!!

 

[MLSDUKE1]

Just give me the bike, I'll figure it out..... Honestly though, if your getting an airlock, change the pump

 

[SoCal Blur]

Have you tried cracking the throttle just a little when starting it warm/hot?

 

[Argilbertson]

My initial guess right off the bat is ignition coils. At least on cars, a faulty ignition coil can cause inability to start when hot, since the coils cannot generate enough voltage. Just a thought.

After reading back through the OP, it sounds like there is a fault in the fuel return system that's bleeding air...I believe this was endemic of the external 99-2000 fuel pumps (Just following logic here, so please correct me if I'm wrong), which is why they changed to the in tank pumps on the 2001+.

 

[dadofthree]

to the oRg Vapor lock maybe. I've heard of people relocating the fuel pump on early models or putting a beer coozy around the pump to insulate it from engine heat.

Not an expert, but one should be along soon. Best of luck

 

[seekoei]

@dadofthree - thx, ya insulation was my next move. we'll see how that goes...

@SoCal Blur - no use... the pump's not pumping anything. did try it though. but as soon as u lift the tank slightly and run the pump she starts

 

[micbusathens]

??? Fuel pressure regulator ?....https://www.hayabusa.org/forum/busa...-hayabusa-fuel-pump-issue-finally-solved.html

 

[GsxrBots]

Bike is junk. I'll give you $50 for it, and pick it up tonight. PM me your address..