Tach jumps at 9000rpm?

[black and silver twin]

first I want to say this is my first new topic post so be please be gentle. I have gotten lots of info from previous posts and found most everyone to be very helpful  but this latest one has me stumped and I can find no old posts on this.

I bought a 07 gs500f with 1200 miles two months ago and I love it. I have since put 1500 more miles on it for a total of 2700. It has given me no problems so far and makes a dyno proven 40 whp bone stock. I get 66 miles per gallon average and have taken it above 110mph many times. today though i noticed somthing on my 225 mile trip, every time i rev up to 9000 rpm the tach jumps DOWN to 8700 then back to the correct rpm. It happens very fast and is hardly noticable but i never saw it before so i want to catch this before it turns bad. my bike has an electric tach (fancy) so sayeth every one on this forum, also i checked my self. it only happens once per trip above 9000, in any gear, never below 9000, and if im realy flogging it it doesn't happen till 9400. it acts as if the tach shuts off for a fraction of a second but the lights dont flicker. and lastly if i rev to 9500 and hold it it does it ONCE then not again till the rpms drop then go back up. any info will help

[LOUiE]

do you notice any power difference?  does the bike lag or bog down for a sec?  or is it strictly in the tach?

[ivany]

Uhm...9000 is getting pretty close to valve float territory isn't it? I think that you should not be taking it that high on a regular basis...

[Big Shot]

Uhm...9000 is getting pretty close to valve float territory isn't it? I think that you should not be taking it that high on a regular basis...

Sry but, there's absolutely nothing wrong with going above 9k at any and every time you want to provided your motor is in good working order...


Man or mouse? - Bob!

[black and silver twin]

the engine keeps singing furiously with no hiccups, it just the tach. i dont really like running the motor hard like that alot but i was cruisin with some friends on kawi 636, superhawk, and a kz1000, it was all i could do to keep up, untill the road got twisty then i passed all but the 636. it was a great day.

[black and silver twin]

also on the dyno the valves didnt start to float till 10000. my dumb ass accidentally reved it to 11500 on the first pull, the valves vere chattering and the power shut down past 10500. i will never rev past 10000 again i usualy shift at 9800 it puts me at 7900 in the next gear, right at the start of the power band.

[Bluehaze]

this has happened to me as well.  i have a gs500f 08.  It has stopped happening for now. I hope it is not bad for the motor.   i do end up around 9-10k some times..    it jumps between 7-8  or 8-9.. not all the time.. but it has since stopped since i contacted the dealership. so i didnt even bother bringing it to them.. since it stopped doing it on its own.   so i am hoping this is nothing bad.