CBR400 nc23 1986 poor at low revs HELP!

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watmb01
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CBR400 nc23 1986 poor at low revs HELP!

Post by watmb01 » Wed Sep 13, 2017 4:26 pm

Hi, I am new to the forum and am trying to get my CBR back on the road after 10 years.
Bike runs smooth after 6000rpm thro 14000, but uneven from tick over to 6000. So awkward in towns.
I have had carbs off cleaned bowls, jets & re-set floats. New filter & cleaned out fuel pump as there was debris in bowls.
Sounds a bit like is running on 3 cylinders and no.3 exhaust (from right to left when sat on bike) is defo cooler than the others when revving on stand. Have swapped plugs seems to stay with 3. Pull off lead & splutters a bit but not straight stall like if I disconnect another lead, so is high idle hiding poor running on 3?
Also when last on the road i remember balancing carbs & compression testing showed low on one cylinder (cannot remember which one!) could this cause this issue ? If so can I get around it?
Any ideas would be appreciated.

dunkenb
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Bike owned: Cbr400rr nc29 type8 NSR250
Location: West Midlands
Re: CBR400 nc23 1986 poor at low revs HELP!

Post by dunkenb » Tue Sep 19, 2017 8:27 pm

Check the o-rings on the mixture screws haven't perished . :o

watmb01
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Re: CBR400 nc23 1986 poor at low revs HELP!

Post by watmb01 » Sat Sep 23, 2017 3:03 pm

Thanks. All O rings are intact. But pointed me in the right direction regarding pilot circuit.
Pilot jet blocked! Running sweet again now.


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