www.zxrworld.co.uk

hi ive got 1990 zxr and engine runs sweet starts from cold no problem. went out last night and was ok then a chose a particularly tasty piece of road and chewed the neck off her when i came to a junction she died and whould not start, left her while having smoke and kicking tyres fired straight up, again on another stretch of road gave it the beans topped out and when slowing for bend she cut out. managed to get fired up on slow down took it easy all the way home and she was fine. she seems to only cut out when i ride at high revs for a while i.e bendy roads about 5 miles ridden hard any ideas???

Blocked fuel tank breather

If you have the kit or are near a garage, get a compression test done...

possibly the fuel pump.

Cloud Wolf wrote:If you have the kit or are near a garage, get a compression test done...

And that would prove what???
The bike starts fine from cold, That would rule out low compression.
A tight valve could be the issue addmitedly, this would only take out one pot though and not kill the engine and by the time you have got the kit out of the way to do a compression test, the engine would have probably cooled sufficiently for a tight valve clearance to upen up again.
My guess is fuel starvation or an overheating elec component, Whatever the issue is it is taking out all four pots, Therefore look for what has an input on all 4 cylinders. Fuel.... Pickup ... CDI... Earths.

my guess is a partially blocked fuel filter, if the fuel doesnt flood straight through its not enough for flat-out running, the pump will get hot and the carbs will run dry.

i had a completely blocked tank breather on my spare L tank .. it sucked enough air past the cap for it not to be a problem

if it was the pump it probably wouldnt restart, at least not that soon as they take a while to cool down again after getting hot enough to stop

i have a some what similar problem.
i will take the bike out and ride for about 20 miles, then at a junction, it just goes dead, and will not refire for about 15 mins. the regulator gts super hot, i.e. you can't touch it its that hot. i think this is my problem because its like the battery looses all its power (ITS A BRAND NEW BATTERY), but after say 20 mins, its full of beans again, and kicks into life. i think its defo an electrical ove heating issue you have, like me.
what is everyone elses rectifier like for heat. i know they get hot, and when with my mate on his nc 3 we tested and mine was hotter.
i know the nc has an issue with the burning out, so could this be our problem too?
whats your thought on this being the problem?

i've got a spare rectifier if you want it, its fine as long as you don't put your lights on.

lol, where do you live, as i may try it, with no lights on and ee if it cures the problem

redditch mate, would be fine to test in the day.

if its getting that hot, its because of a fault elsewhere that's causing it to have to work too hard.

thanks for all the response i am gonna start with fuel breather and pump and let you know cheers

zimm, what do you think it will be then, the coils or something else.....
i am confused as to what it will be. i thought, it may be getting old ( 20 years) and just need replacing.
now im a little confused.
i think i will stick a new one on, that i know works, and go from their. the next stop is the coils and ht leads.
just to clarify, l model coils will fit the h model bike?

coils are interchangeable aye ..

check the generator .. thats what creates the current the reg/rec deals with to charge the battery etc ..

have you checked the voltage across the battery terminals at both idle and ~4k ? shouldn't exceed 14.4 ..

I get a bit lost with leccy stuf tbh, metal/spanners/geometry is more my end of the spectrum.

have you checked the voltage across the battery terminals at both idle and ~4k ? shouldn't exceed 14.4

Zimms right, it shouldn't exceed 14.4v but it should be around there. A 12v battery on vehicles is not 12v. If your getting 12v when the engine is off then the battery may not even have enough juice to turn the engine over to start.
So the voltage across your terminals whilst the bike is running should be at least 13-14v to show that it is being charged by the reg/rect and generator properly. If its less than 13-14v try it with a different reg/rect, if that makes no difference, i'd suspect the generator.