Just got out the workshop i am put my ace engine back into my yzf750 frame "again"

Plz help when the key in turned on the rev counter the needle goes up the scale and then back down this happens when the engine is running as well.

"the fuel tank is not on at the moment i am running the bike on a mower tank" could this be the problem.

well mate put the tank on or wirer it up..

i'd say the clocks are electrical so i'd

be more likely be that cause..

couple of mates work for yamaha

so if your still stuck in next few days i'll

see they can help..

afaik the thunderace has set fault issues which are shown by the rev counter, as you say go up and down....each different for various faults.

cheers guys sorted

6 rpm is a fuel pump fault

9 rpm is exup servo fault

Last spring when I just had bought my YZF, I had a similar fault after first time I washed it. When I turned around the key the nedle jumped up and stopped on 15000 (the engine was not started). When I then started the engine it stabilized on the right RPM, but it was jumping up and down some times. I opened it, but could not see any water, but spendt a few minutes with an hairdryer, before I put it together again. After that this has never occured again, so I guess that a little bit of humidity can give symptoms like that.

from what i remember thin happens when uve got a sticking exup valve.

well mate put the tank on or wirer it up..

i'd say the clocks are electrical so i'd

be more likely be that cause..

couple of mates work for yamaha

so if your still stuck in next few days i'll

see they can help..

i am having the same problem it goes up to eight yhen back down to o then back up to 3

i am having the same problem it goes up to eight yhen back down to o then back up to 3

8000rpm indicates a problem with the fuel level indicator circuit

Check the wiring connector that goes to the tank.