cbr250rr idle < <

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26-12-2009, 07:35 PM
Moey.C

cbr250rr idle < <

hey guys had a look at a cbr250rr 2day and im pretty keen however at idle the revs are a bit jumpy. they dont settle at one spot. it dosnt idle from 2k for 4k or nothing but just under 2 to just over 2. when the bike is revved say to 4000rpm there is no jumpyness and everything is fine, no flat spots etc.

the owner said the previous owner had put in cbr400 cams or something like that. definantely said there were bigger cams. and the bike has a yoshi pipe. just wondering if a tune would fix this idle and if the cause of the idle is the bigger cams..

also wat else could this problem be.

cheers. moey :thumbsup:
27-12-2009, 01:12 AM
rayb3na_

why does it have to be a problem? lol thats how my bike idles and its fine unless theres something wrong with my bike too its very subtle it kinda just wavers over that spot correct?
27-12-2009, 01:16 AM
rpm boy

Was the choke on? Shouldn't be idling that high anyway bigger cams should still hold idle ok but I don't think the 400's cams are bigger even to the extent to make the idle as erratic as you explain... Could be plugs
27-12-2009, 11:34 AM
Moey.C

Quote:

Originally Posted by rayb3na_

why does it have to be a problem? lol thats how my bike idles and its fine unless theres something wrong with my bike too its very subtle it kinda just wavers over that spot correct?

lol nah this isnt that subtle u can clearly hear the idle hovering around. but yes it does just waver around the correct spot. iits not toooo bad but sounds owrse than urs

Quote:

Originally Posted by rpm boy

Was the choke on? Shouldn't be idling that high anyway bigger cams should still hold idle ok but I don't think the 400's cams are bigger even to the extent to make the idle as erratic as you explain... Could be plugs

and no the choke was used 2 start it up but then was fine. my bro thinks it could be the plugs too
27-12-2009, 11:42 AM
SHOGUNOVDDRK

has it been serviced recently?
27-12-2009, 11:50 AM
jdm_kid

just re adjust the idle cable, or use the timing gun
29-12-2009, 10:19 PM
c0LL1n

HAHA wtf putting CBR400 cams in a cbr250rr not sure if they are capable of taking the high rpm of that motor.
the bike should rev at about 1.5k rpm or there abouts, if choke was on the bike would not idle that high since it is restricting the airflow which would result in too much fuel into the mixture.

on idle, quicly rev the bike to say 5krpm then let go of the throttle. if the revs drop low(below idle) then pick up again it means the bike needs a tune as it is running to rich.