RS 125 Not reving past 8k rpm even though derestricted

[Walshie]

Hi,

I bought a rs 125 as a project and was told it was derestricted, it has a br10 plug and the bridge cut on the cdi, but it will not rev past 8,000rpm.

I haven't had a close look as yet as i've only just got the engine back together after rebuilding, initially i am thinking that the powervalve is not opening?

before i started ripping it apart again i wondered if anyone could point me in the directions of things that could be causing this prob.

Cheers
Chris

[Kickstart]

Hi

The CDI mod has zero effect on peak power or it revving out. It affects the 5000~6000rpm range and does nothing outside that.

Even with the power valve not opening I would expect it to rev beyond 8k in the lower gears, although not particularly usefully. However the valves can stick, especially if run around at low speed too much (like running in after a rebuild.....). Also check the valve is in the right way up (the angled end of the valve should be parallel with the ground / top of the exhaust port, NOT parallel with the side of the barrel).

All the best

Keith
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[Walshie]

Apologies I forgot to mention that this is when the bike is in neutral, (not sure if this will make a difference or not?)

I have literally just put the engine back in the bike yesterday after the build, i don't know what it was running like before as i bought it with a seized piston.

I haven't had chance to ride the bike yet as I am just spraying the fairings at the minute so can't get it on the road yet.

Thanks again for the hlp

[Kickstart]

Hi

In neutral there is no load. Shouldn't have a problem revving out fully with very little throttle (Possible if it is the latest bike there may be an ignition cutout if it think it is in neutral, but never heard anyone mention that).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Walshie]

Cheers Keith, I've just had a bit of a thought, maybe abit of topic though.

My throttle cable snapped, so to rev yeterday i was just pulling the cable that goes into the carb up. Not thinking that the oil pump is also linked to the throttle cable further up.

Could the lack of 2stroke getting into the chamber affect this? additional friction etc.

....hopefully not done any damage to the cylinder wall, although it was only running a couple of mins.

[Kickstart]

Hi

Err, I would expect lack of oil to make little difference to the performance right to the point where the engine started to seize. At least you will still get some oil though.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing