CBR250RR spluttering at low revs

Finch- · L Plate Warrior Joined: 02 Oct 2007 Karma :

Well lads,

Bought a cbr there 3 weeks ago. few problems with it.

Theres a hole in my petrol tank, a tiny one, but im getting a new one anyway.

At 1-4k rpm the revs are catching and spluttering, mostly in 1st gear.

Also my fuel tap is broken, its stuck on !

Loads of people have said clean the carbs, which I agree, but is there any other small things I could try first ?

Jamie S · World Chat Champion Joined: 28 Dec 2006 Karma :

Give the carb a good clean and stick a new set of spark plugs in it.

Thumbs Up

Robby · Dirty Old Man Joined: 16 May 2002 Karma :

Is this hole near the top of your petrol tank?
and fuel tap stuck to on, or res?

Either way theres a fair chance that the problem is water getting into the fuel. A dash of meths in the tank will absorb any water in there, you also need to plug that hole. Use araldite or something until you can afford to replace the tank.

Finch- · L Plate Warrior Joined: 02 Oct 2007 Karma :

Cheers lads, yeh ill book it in to have the carbs cleaned and plugs changed. The neighbour next door reversed into it and put a dent in the tank anyway (was happening before this though) so ill be gettin a new one in the next week or so.

No the hole is by where the seat presses against the tank and im pretty sure its stuck on, on. theres no markings on the switch. The hole is plugged i think, looks like rust or somthin plugged it?

Robby · Dirty Old Man Joined: 16 May 2002 Karma :

Pop some meths in the tank before you book it in for any work - FYI jamie is 14 and knows fuck all about bikes, but like to post on every single thread in the workshop forum.

Also worth giving the HT leads (the leads going to the spark plugs) a good spraying with WD40.

The fuel tap should rotate to on, res, and off.

Your bike sounds a bit neglected too, which means you'll probably have a fair few problems with it. The carbs are likely a bit gummed up, but some decent fuel cleaner (not redex) and a few tanks of brand name super unleader may shift the crud. Getting the carbs out and cleaning them will cost a few quid on that bike because access is so tight.

Finch- · L Plate Warrior Joined: 02 Oct 2007 Karma :

Whats the best stuff then to mix with the petrol to clean the carbs?

Ah no there the only two problems I have with it, it was lying up for a while

TUG · World Chat Champion Joined: 12 May 2007 Karma :

he means you'll run into more problems with it in the future, just as with any bike, mine had been neglected pretty badly and i've done alot of work on it, just keep a vigilant eye on it so when something does or doesnt crop up you can fix it before it becomes too much of a problem.
does it only splutter in 1st gear? or all?
____________________
Haz ER-5, innit!

Finch- · L Plate Warrior Joined: 02 Oct 2007 Karma :

No all gears, below 4.5krpm. Yeh ill keep an eye on her, not the best with bikes at all, not mecanically minded lol

TUG · World Chat Champion Joined: 12 May 2007 Karma :

nothin like owning a bike to get the mech head on, well sounds like its a carb problem, had alot of them with mine Rolling Eyes

i once had a blocked jet that caused alot of spluttering but the bike still pulled ok until about 4-5krpm.
if you want to get a mechanic to check it out or someone who knows or do it yourself, have you got a manual for the bike??
____________________
Haz ER-5, innit!

bish777 · World Chat Champion Joined: 11 Nov 2004 Karma :

I would suggest replace all of the float valves and gaskets in the carbs, then investing in a new fuel tap.

Whats likely is the combination of tap and worn float valves means the thing will run too rich at the bottom end creting the rough running you describe.

Also check the float heights are correct.
____________________
GSXR1100J