FZRSupport: the FZROnline Archive

its a 94 yamaha fzr 1000 exup.

i recently rebuilt the top end due to low compression and smoking pretty bad. rode it for the first time a couple days ago and it wants to miss when riding. it seems like there is a excess amount of valve train noise. i took the valve cover off tonight and seen nothing out of the ordinary. i did find two tight intake valves when it had about 10 miles on a freshly shimmed head. it has some power but not anywhere close to what i feel its suppose to have. all four cylinders are above 200psi. all four plugs are a nice cardboard color. i have taken the carbs apart and i believe there clean. at idle there is a backfire through the exhaust. the exup valve is not installed at this time. does anybody see anything i am missing here? and help is appreciated.

coreo19 wrote:its a 94 yamaha fzr 1000 exup.

i recently rebuilt the top end due to low compression and smoking pretty bad. rode it for the first time a couple days ago and it wants to miss when riding. it seems like there is a excess amount of valve train noise. i took the valve cover off tonight and seen nothing out of the ordinary. i did find two tight intake valves when it had about 10 miles on a freshly shimmed head. it has some power but not anywhere close to what i feel its suppose to have. all four cylinders are above 200psi. all four plugs are a nice cardboard color. i have taken the carbs apart and i believe there clean. at idle there is a backfire through the exhaust. the exup valve is not installed at this time. does anybody see anything i am missing here? and help is appreciated.

Have you checked for spark on all the plugs? Can you check the header temperature on all 4 cylinders?

I going to assume you are taking it easy since you just put the motor back together BUT without the exup valve in there the bike will most likely have little or no power until 4000 rpm...then all hell breaks loose (I found that the hard way when I ran my 94 1k without the exup). You've clean the carbs but have you done a synchronization yet? What is the age of the fuel filter? Have you tried riding it with the reserve switch unplugged? I ask that because the fuel sensor (for lack of a better term) can possibly be stuck at the bottom the tank (which will cause cylinders 1&3 to turn off and on). Are you sure the timing marks were lined up when you put it back together?

i feel like i have ample spark. carbs are synched. the reserve switch has not been plugged up since the rebuild. and i am positive it is timed correctly. i will double check tonight though. once the bike hits right around 4 or 5 thousand it just wants to fall flat. it misses and has no power. and yes i took it very easy for the first 50 or so miles

There is a switch on the left hand side of the bike that acts as a reserve type switch for when the bike starts to run low on fuel, make sure that it is flipped in the right direction

it will put the bike into gas-saving mode and is not and actual gas reserve

i figured it out. i decided to go ahead and pull the intake cam off to re shim the two tight valves i had. when i pulled the buckets up i found the problem. some how the valve keeper? not sure what its actually called. the two little metal shims that hold the valve in. well one of them had came up a little bit. dont know how it happened or anything but i put it back together and it works fine now. thanks for your help

Nice. Glad it worked out

Lucky you. Good thing it diden't drop the valves!!!!!!!!!!!! yikes!!! Glad you got it sorted out.Enjoy

chefen2006 wrote:Lucky you. Good thing it diden't drop the valves!!!!!!!!!!!! yikes!!! Glad you got it sorted out.Enjoy

That as they say was a very narrow escape from a bad accident and a "cattle trucked " engine