GPX250R Issues

[pervert]

Hi all, first post. :cool:

I just bought a 1988 Kawasaki GPX250R yesterday, 24,000kms on the clock.

I have a couple of concerns, first is it doesn't run!!!

I bought the bike off a guy who lives in the country (about 1 1/2 hours from Dunedin), when I got there the bike hadn't been pre-warmed or anything, and it started and ran great! I was really happy with it and bought it.

Drove it back to Dunedin (all highway running, except for a stop at the gas station where it idled fine), but when I started slowing down for roundabouts and the likes it started coughing a bit at low revs. When I pulled into my driveway it just died, then wouldn't restart.

Now, if it's cold it will start OK, but then as soon as you try and ride it, it just dies. When I start it again the only way to keep it running is to give it full gas, and it just thumps away barely running at less than 300RPM, and as soon as you try and ride it off or let some gas off it just dies again and takes ages to restart. On the rare occasion I can get it to ride out the gate, it dies everytime I stop and really doesn't want to go again!!!

I'm guessing its a carby issue, but any further help would rock!

Also, I am aware these have a bit of a bottom end knock when cold, but mine is shocking, it just clunks away...is this normal?

[bobsmith]

uhhhh is the choke on??? it sounds like you left the choke on, some bikes with the choke on doesn't like to start at high temps.... sorry if it's obvious but you didn't mention how experienced you are so have to try with little things...

[pervert]

No, the choke isn't on. If you use the choke at anytime (hot or cold) it just dies.

As far as bike mechanics go I can strip and rebuild my pit bike in my sleep, and car mechanics are a piece of piss...but I haven't worked on a roadbike before...

[Anaru]

From what you have describe it sounds like you may of lost one of the cylinders.

First of all check that you have a spark going to both cylinders. Secondly, move on to the air and carb side of things, clean and ensure everything is as it should be. Thirdly, check compression in both cylinders if you still haven't resolved the problem. Failing all of those, take the bike to a mechanic.

[pervert]

From what you have describe it sounds like you may of lost one of the cylinders.

That, is a fucking good suggestion...it does seem like that!

I will check that tonight...:cool:

[ZeroIndex]

check the coils.. mine needed 2 when i got it..

[pervert]

I just started it from cold and it went OK, as soon as it started to warm up the idling problem appeared again, with it eventually stopping and refusing to start again without ticking along at 300rpm before dying...:Pokey:

[imdying]

That is doesn't like the choke from cold sounds a bit suspect. Are the airbox rubbers securely attached to the carbs?

[pervert]

That is doesn't like the choke from cold sounds a bit suspect.

I thought so too...


Did some further testing tonight, the bike starts well from cold, and you can ride it perfectly in open road traffic and it performs excellently except for a bit of a miss around 3000-4000rpm. But as soon as you need to stop, the revs drop back to about 3000rpm, then slowly fall until the bike stalls.

Once it has stalled, you can't restart it until it has cooled right down unless you crash start it. It just fires, but can't build up enough revs to keep running when using the electric start.

[ZeroIndex]

I thought so too...


Did some further testing tonight, the bike starts well from cold, and you can ride it perfectly in open road traffic and it performs excellently except for a bit of a miss around 3000-4000rpm. But as soon as you need to stop, the revs drop back to about 3000rpm, then slowly fall until the bike stalls.

Once it has stalled, you can't restart it until it has cooled right down unless you crash start it. It just fires, but can't build up enough revs to keep running when using the electric start.

drops back to 3000rpm? what does it idle at? should be idling at 2000rpm, here's what i had to do when i got my gpx: new coils, valve clearances, carb tuning (and a few other things that i can't remember).. when i got it, it idled at 4000rpm, and would occasionally die and take a while to restart..

[pervert]

What did the valve clearances and coils cost you?

[ZeroIndex]

What did the valve clearances and coils cost you?

not sure of the exact costs of each individual costs, just check at your local bike mechanic..