CBR250 RR running like dogS**T

**TALEB TYRES** · 08-02-2009 01:26 AM

Hey guys,

got a mc22, had it for a few months now, left it sitting for about a week or two, only runing it for a few minutes every few days so it wont die out.

But now the thing is just missfiring like crazy.

Can hear it on idle, and runs like it has no guts at all.

Im still new to bikes so would appreciate any input or experience anyone has had with this problem and bike.

Im thinking maybe sparkplugs, but they were changed < 3 months ago.
could be carb problem i dont know.

( another factor i just though of, i last filled up with bp ultimate, but thats all i use for my skyline, funnily enough i used to fill up the bike with vpower with no probs, but that used to give my car the shits).

**bennjamin** · 08-02-2009 09:20 AM

spakplugs might be gummed up/fouled. Syphon the tank and put a full tank of normal 91 or 95 RON unleaded. If not fixed replace or clean sparkplugs

Will the bike struggle to rev past say 4 or 5k? (miss ALOT)
Next up , check under fairing fuse box (located in the nose , near the HORN) and check the fuses. A fuse maybe gone and causing electrical issues.

**dogcrapau** · 08-02-2009 11:34 PM

not running and when running for a bit every now and then causes easy sparks fowl
it happened to me when i put it away during winter last year.
just replace ur sparks. i dont think fuel will cause u to misfire, it will make the bike run crap but not misfire. just buy some new sparks or pm me i bought 2 boxes in the past and other shit which may help ur bike if needed.

**TALEB TYRES** · 09-02-2009 02:30 AM

Ok thanks for the help guys,
Ill replace the sparkies n check fuses this week when i get a chance, hopefully its that easy, though i heard changing them is a bit of a bitch.

Yea the bike still revs all the way up, but constant missfire.(especially bad at low revs when tryna take off from lights etc)

**mekros** · 09-02-2009 05:05 AM

give your carbies a good cleanout too, your jets in the carbies could be blocked.

**hisoka** · 09-02-2009 08:51 AM

yep as mekros said, you need to give the carbies a good clean.

you can buy carbie cleaner spray from super cheap and shop like that.
i just use wd40 and deagreaser at the same time lol. but i think carbie spray is better.

after you clean the carby put fresh fuel through it.

before you try all of this try and run new plugs.

if none of this works your air flow ratio maybe incorrect.

does the bike start first time everytime ?

**CONAN** · 09-02-2009 10:54 AM

I would change the spark plugs first and see how you go...

If that doesn't work give the carbs / jets a clean.

**lookingforboost** · 10-02-2009 09:34 AM

My CBR did this and it was one of the spark plugs i replaced them all was about $25 bucks and cleaned the carbys out at the same time has ran sweet ever since, you have to take them for a ride they hate just sitting there being started as stated above they fowl the plugs up really quickly.

**N1nj4R1d4h** · 12-02-2009 10:01 AM

I used to ride a ninja and this same thing happened to mine. I changed spark plugs, cleaned out the carbie, changed leads and so forth and after doing all these, problem still persisted. After doing a bit of ringing around, it turns out that its the CDU unit. Bike ran fine after changing it.

Maybe u should check your bikes cdu unit if problem still persists. CDU unit is usually located towards the rear of the bike beneath the left rear fairing. its a small black box. Hope this helps.

**TALEB TYRES** · 12-02-2009 03:48 PM

well i was about to start ripping her apart, then i noticed that one of the pipes was cold compared to the other 3, so i changed that plug as i could tell it wasnt firing,
and problem gone!(cbf changing the other three still havent done 1000k on them)

thanks for all the replies theres alot of great advice here, im sure it will come in handy next time.

btw make sure you have a 16mm thin/tube socket if your planning on doing the sparkies.

now to clean out the indicator switch for that laggy right indicator...