Can anybody out there in "Estrellaland" tell me how to adjust the carb ? The spark plug is a sooty black and not being stupid what does this mean-too rich ?
Any help on how to put it right would be very grateful.
Thanks
Jon

Hi! I'm solving the same problem, but additionally I have my carb wire broken. I can inform you when I solve my problem. If you wish I can reply onto your email, if so - send it to me via private message.

So, I'll try, but i don't know wether my English is sufficient...

First of all: Clean the spark plug (or (if you've got money) install a new one).
Next thing: Take a look at the Carb (right hand side). Youll find one BIG screw for setting the revs an a small one for setting the air-fuel mix. Leave the big one as it is and screw in the small one totally (caution, don't be too enthusiastic! Else you might crack the seal-ring...).
Then screw out 1 1/2 turns (1 3/4 if you've got a carb heating (Kawasaki says, but that's just bullshit, 1 1/2 will do!)).
Start the engine and warm it up completely (by driving, not by running the engine on the main stand).
After that, adjust the revs in neutral by turning the big screw, you left aside before.
Then go for another fast lap, look for a parking place or something and just pull the clutch and stop the engine.
Have a smoke or a piss or whatever and srew out the spark plug. Should be quite okay by now.
If it is a bit to dark, just screw in the tiny screw on the carbs right hand side abaout 1/4, if it's almost white, srew out about 1/4 and retry.
If the spark plug still is black, either your airfilter ist blocked or you're burning oil.
Point one means cleaning or replacing, point two means EXPENSIVE!!

Hope that will help!

Hallo Dünnling !!

There ain't anything wrong with your English,. you could get a job as an edjucator at tech stuff on English

If they don't fint anything wrong by your suggestions,. i would also suggest to check the float bowl heigt,..

it's easy done with a plastic tube on the stud for the draining screw at the botton off the float bowl cup.

the plastic tube should be about 30cm,.then open the screw and hold the tube to the side off the carburettor,.

the petrol level shall be betwen -05mm to +1,5mm measured at the cups joint surface to the Carburettor housing.

If it's out of range this can be bacuse off a sticking floatvalve or a sticking float.

so Mich and jonboylizard just hit the tools now

My best.
Kjell

Mille Diavolo !!

I forgot to log in !!


http://www.bj250.de/html/t13.html

A. Idle rev/speed adjust screw.

B. Pilot jet,.range adjust screw.

C. Float bowl drain Screw.

Best.
Kjell

Hi, I'm an owner with recently BJ250 1999. After several tests carburetor adjustments the symptoms are as follows: idle is good but the problem is that the bike stops each time at deceleration. Thorough cleaning of the carburetor has yet been made. The garage think we need to change carburetor. What do you think?

Thank's and sorry for my english (google traductor) I try to find the good place to put this message, is it ?

Tienno,
Belgium

I don't think that a new carburetor is necessary.
Check the valve clearance as decribed in Bad fonctionnement

I realise this is an old question but I just wanted to add some thoughts for anybody in the future.
I had a similar issue with the bike cutting out on deceleration.
The vacuum tube at the back of the petcock was installed by previous owner with fuel line and not a vacuum hose and has deteriorated, so I think that was reducing the amount of vacuum and reducing how much fuel was getting through the valve and into the float bowl. I am waiting on new vacuum hose to arrive to replace.

what I have found so far is that my float bowl was not filling enough so when I decelerated and the fuel moved forward in the tank it would cut out because the fuel level was dropping below the petcock tube, that is my assumption, this got worse the less fuel there was in the tank. Maybe changing to reserve as a trouble shooting step to see if it helps.

I would have thought that the float bowl should have enough fuel in it to last a little while.
If I remove the vacuum hose at the back of the petcock the engine will not start, float bowl empty I would think.

Just wanted to add that here to help some troubleshooting in the future.