high revs low speed???????????
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Please can you post items for sale or wanted in the correct For Sale section. Items / bikes for sale here will be removed without warning. Reasons for this are in the FAQ. Thanks
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blackduck
- Settled in member
- Posts: 35
- Joined: Fri Feb 04, 2011 9:05 pm
- Bike owned: cbr400rrj
- Location: ireland
high revs low speed???????????
seriously worried
went for spin this evening and when on way home i thought god its reving high, must not be in 6th. looked at the speedo....14000 rpm at 80kph ( 50 or so mph)!!!!!!!!! pulled in and at idle speed it was 4000rpm!!!!! when i set off it was at the normal 1300-1400 rpm. adjusted idle speed down to 2500 and it was about to conk out. any ideas? have a spare working engine but dont want to be stripping bike when we have such glorious weather.
anyone come across this before? no smoke or overheating while riding but did crawl home to keep revs at 11000 rpm. throttle releases fully when let go. hope it is something simple
cheers guys
went for spin this evening and when on way home i thought god its reving high, must not be in 6th. looked at the speedo....14000 rpm at 80kph ( 50 or so mph)!!!!!!!!! pulled in and at idle speed it was 4000rpm!!!!! when i set off it was at the normal 1300-1400 rpm. adjusted idle speed down to 2500 and it was about to conk out. any ideas? have a spare working engine but dont want to be stripping bike when we have such glorious weather.
anyone come across this before? no smoke or overheating while riding but did crawl home to keep revs at 11000 rpm. throttle releases fully when let go. hope it is something simple
cheers guys
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blueflag
- Site Supporter
- Posts: 145
- Joined: Thu Nov 19, 2009 1:43 pm
Re: high revs low speed???????????
Sounds odd. Slipping clutch? But that doesn't explain the fast idle. If you're sure you were in 6th it HAS to be the clutch, probably.... 
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blueflag
- Site Supporter
- Posts: 145
- Joined: Thu Nov 19, 2009 1:43 pm
Re: high revs low speed???????????
Just a thought, sorry if it sounds like a silly question but was it revving high or was the tacho just reading high?
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Davez29
- Site Supporter
- Posts: 1268
- Joined: Sun Aug 03, 2008 8:38 pm
- Bike owned: NC29 forever
Re: high revs low speed???????????
Things to check right away would be all cables, maybe ones slipped, perhaps springs and linkages on cables and carbs stuck open, carb screws fell out, maybe. What would happen with a loose carb jet/emulsion tube if it was loose or fell out? Tell us how you get on.
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dunkenb
- Regular Member
- Posts: 560
- Joined: Wed Jun 03, 2009 9:39 pm
- Bike owned: Cbr400rr nc29 type8 NSR250
- Location: West Midlands
Re: high revs low speed???????????
What do your plugs look like? the revs on my 250 start rising like that just before it goes on reserve (running lean from fuel starvation) so could be blocked fuel line or filter or tank filter? Or blocked breather?? 
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blackduck
- Settled in member
- Posts: 35
- Joined: Fri Feb 04, 2011 9:05 pm
- Bike owned: cbr400rrj
- Location: ireland
Re: high revs low speed???????????
too be honest found nothing wrong. lifted tank, filter housing and even removed carbs to check they valves were returning to normal position with throttle cable. everything fine. new air filter was still spotless.Durka Durka wrote:Things to check right away would be all cables, maybe ones slipped, perhaps springs and linkages on cables and carbs stuck open, carb screws fell out, maybe. What would happen with a loose carb jet/emulsion tube if it was loose or fell out? Tell us how you get on.
was a bit concerned about clutch but not sure. adjusted cable before i went for spin. everyting fine now last couple of weeks. have ordered new push and pull along with clutch cable to be on safe side.
thanks for everyones input