Until recently, my bike worked like a clock. Recently i had to ride over rough terrain, with some sand on the road. Total mileage was 8-10 km. I got to the garage without any problems, but the next day when i ride to work motorcycle after 6rpm + loses power and starts to stutter.
When i return to the garage, i cleaned the air filter (it was decent sandy), carbs are completely washed and blew with compressed air, rubber membranes sprayed for softness with silicone, tank was cleaned also(HRC mod on fuel tap)etc. I have been assured that a problem with fuel delivery system, but anything from this hasn't brought results.
My numerous rides have shown interesting feature. After the motorcycle doesn't go about 3-5 hours, i can ride normally in a short distance(5-10 km).
Can you advise where to look further?.

Hi Eniac,
is the fault really definitely related to 6k rpm?
If so, I would suggest the speed restrictor has somehow failed.

The error starts in a range 5-7k RPM and to a red line. Still it is necessary to mention that my instrument panel was derestricted...

Have you unplpuged your speedo?

Theres a rev limit wire that comes from your cdi, this needs to be connected to a +12v source if its been disconnected/removed in any way, ie when you disconnect the speedo. Its a limp home mode that cuts 2 cylinders at around 5.5k to 6k.

Eniac wrote:The error starts in a range 5-7k RPM and to a red line. Still it is necessary to mention that my instrument panel was derestricted...

I suggest the join there has failed. After a little time running it heats up, goes high resistance and then cuts the limiter in because the bike thinks it's doing 180kmh

I run to check all my wiring loom...

Drunkn Munky wrote:Have you unplpuged your speedo?

Theres a rev limit wire that comes from your cdi, this needs to be connected to a +12v source if its been disconnected/removed in any way, ie when you disconnect the speedo. Its a limp home mode that cuts 2 cylinders at around 5.5k to 6k.

Thanks a lot, it have solved my problem