Cbr250rr, full throttle stall.

[pukana,BLAH!]

Have run a few searches but not come upon anything similar.

Have got a Cbr250rr '92 and it is giving me some trouble.

-Under Idle the revs are jumpy.
-Strong gasoline smell.
-WOT will stall the engine.
-Can not get enough revs for a hill start, only allows part throttle.

Have talked to the mechanic at the Honda dealership on Barrys point road, He seemed to think that it my Float valves needed replacing.

I am guessing that it is running too rich, My plans were to strip the carbs clean them and balance them.

What do you guys think?

Any help is appreciated.

[The Pastor]

yep sounds about right.

[vagrant]

You may have a stuck or worn needle valve, allowing fuel to flood the float chamber at the base of your carb.

These are opened and closed by the floats, to keep a balanced amount of fuel in the carb.

The floats can also get damaged or worn, allowing fuel inside them, making them into a sinker, which will also allow the bowl to flood.

Or it could be simple like a bit of crap caught in one of the valve seats.

Have a google for a manual for your bike to assist you in getting the carbs off and the set up sorted.

you are onto it with your fault finding and plan.

[t3mp0r4ry nzr]

take it to the pros and get them sort it. Twin carbs that are a pain in the arse to get at is not a friendly place for a noob thrown in the deep end trying to sort a complex prob out.

It will cost you some dollars but will be well worth it in the end

[vagrant]

Manual here if you want it. (think it's the right model)

http://pdftown.com/Honda-CBR250-Service-Manual.html

let us know what you decide, or how you got on?

[FROSTY]

dude how did this problem apear?
Is it a sudden thing or has it slowly got worse over time?

[pukana,BLAH!]

Right so Ive pulled the carbs apart and removed what I could cleaned with a dergreaser and rinsed in petrol. The most noticable problem is that the rubber boots at the base of the carb have perished. And after taking them off some of the rubber broke off. I have ordered some from Japan.
Would these be the sole cause of my problem as they are not sealing?

Also the brass seats for the float needle valve look like someone has taken a flat head screw driver and placed the head in the hole in order to remove them. The damage is not where the needle seats, so I don't think any fuel could seep past it.

The pilot screws were way out of synch, with some being half turns from seated and some being 2 1/2 - 3 turns. According to many sources for my model of cbr250rr the correct setting from factory is 1 3/4, so I set them all to that.

Unfortunately I had put the vacuum tube to the tap on the drain hole and not the vacuum valve inlet, and ran the battery flat turning it over.

Thanks for any help youve given and I appreciate the link to the manual. i will keep you all posted and any more comments/ideas are still apreciated.

[geoffm]

Right so Ive pulled the carbs apart and removed what I could cleaned with a degreaser and rinsed in petrol. The most noticeable problem is that the rubber boots at the base of the carb have perished. And after taking them off some of the rubber broke off. I have ordered some from Japan.
Would these be the sole cause of my problem as they are not sealing?



The rubber boots will be a cause of some of your problems - an air leak will lean out the mixture and cause all sorts of weird behavior. Fix this first before you fiddle with anything else.
You can buy aftermarket float valve kits which are much cheaper than OE, although just at present I can't remember the name of the supplier.
Geoff