GSXR missfiring and dying

[GROOMER]

Hi guys and girls :-)
I have an '88 Suzuki GSXR250 jap import, and these bikes are well known for having bad coils.
Recently the bike started missfiring at high rpms, and also at very low rpms.
A few short rides after, one coil completely died. So I sourced some Honda? second hand coils, put them on today, and the bike ran better than it has since Ive owned it. UNTIL...around 30mins riding it started missing at high rpms (15-17,000rpm) and also from low rpm take offs.
As I rode nicely home, it would miss anywhere after 9k, and now the bike hardly wants to start. Sometimes it will start fine and rev out quite well, but other times it wont start at all, or will continue to miss badly.

Has anyone come across this or know of anything to help> PLEASE? :-)

P.S. There is spark at all four leads still.

Thanks,
Adam

[inlinefour]

Its a pity that you did not get the rest of the bike that went with the Honda coil (PT).
No sorry I have not ever heard of this before and would be inclinded to take into a dealer to get the problem resolved, good luck.
:wari:

[MSTRS]

I recall a thread lately on this very problem. Think it was a GSXR250 as well. search for it - there may be some resolution there for you.

[Slingshot]

I had a 89 GSXR250RR. I had heaps of problems.

If the problems happen more often when it's wet it's probably the plug caps, I had to replace mine cause they weren't the right impedence and if water got down around the spark plugs it created all sorts of problems.
I may also be the carbs, I had to have the needle valves replaced.

[FROSTY]

couple of things spring to mind. First that ya CDI is faulty and only faults when it gets hot. -This is gonna sound reallly weird BUT. Take ya CDI unit out -2 plugs and a screw i think and bung it in the freezer for an hour or so.
Haul it out plug it in and see if the problem has dissapeared. If it has -go ride for an hour and see if it ciomes back.
The other possibility is ya could be dealing with a fucked charging system.
Hook up a car battery to ya bike and see if the problem goes away

[Malc]

I had an '87 Suzuki Impulse 400cc years back, similar type of bike with a 4 cyl that made no power under 8000rpm...
Mine had a very similar problem, it revved out to redline ok when hot, but it wouldn't run under about 2000rpm at all when warm....and wouldn't start until it had sat for half an hour or more to cool down. Bloody frustrating.
It was the coils, a known problem for the Impulse back then. I totally solved it by purchasing coils off a 1990 (I think) GSXR750, virtually bolt straight on.
In your case it could be the same, and its probably going to be the quickest fix time wise..if you can "borrow" a couple of coils off someone to try..
Just an idea..but it does sound remarkably like mine did...Good luck!

[GROOMER]

Thanks for your help so far guys...Me and my mate (an auto sparky) replaced the coils with honda ones. They seem to be sparking, but may not have enough voltage under load, so we figured it MAY me the CDI. So I might give the CDI unit the freezer a go :-) I'll go and try to strat the bike now after its been sitting overnight and se how she goes. Also, the voltage at batt terminals while running at 5000rpm (as per manual) is around 13.5v which is supposedly satisfactory.

Please keep any suggestions rollin' in :-)

Cheers
Adam

[GROOMER]

UPDATE... I started the bike cold this morning and it ran perfectly. Kept riding tilll things got warm and waited till the missing came back. Got straight home, and the bike died. I ripped the CDI box out and stuck it in the coldest part of the freezer, after 10-15 mins it was already cold to touch, so chucked it on the bike and it ran sweet again!
I thought maybe it was coincidence and that the "whole" bike had cooled down, but I remembered yesterday it would take at least 45-60 mins before the bike would fire again on its own.

Good luck to me to find a "good" CDI box :-)

Thanks for your help guys, appreciate it!

[Slingshot]

Just install one of those portable chilly bins that plug in, then install the CDI inside that.:2thumbsup
You'll be able to keep the beers cold as well!

[Motu]

Another trick along the same line as Frosty's freezer job is to spray the CDI unit with something to cool it down real quick - I use brake cleaner,but you can get special freeze it stuff,maybe a CO2 fire extingisher,that way you will isolate it much faster.

[FlyingDutchMan]

UPDATE... I started the bike cold this morning and it ran perfectly. Kept riding tilll things got warm and waited till the missing came back. Got straight home, and the bike died. I ripped the CDI box out and stuck it in the coldest part of the freezer, after 10-15 mins it was already cold to touch, so chucked it on the bike and it ran sweet again!
I thought maybe it was coincidence and that the "whole" bike had cooled down, but I remembered yesterday it would take at least 45-60 mins before the bike would fire again on its own.

Good luck to me to find a "good" CDI box :-)

Thanks for your help guys, appreciate it!

Holy shit! waiting for it to get cold enough to touch? Sounds like like someone forgot to take heat into account when designing the thing!

[GROOMER]

Holy shit! waiting for it to get cold enough to touch? Sounds like like someone forgot to take heat into account when designing the thing!

What I said was it was cold TO touch, not cold enough to touch.

[Sniper]

Its a pity that you did not get the rest of the bike that went with the Honda coil (PT).
No sorry I have not ever heard of this before and would be inclinded to take into a dealer to get the problem resolved, good luck.
:wari:


Honda, why do you write an answer to a thread you dont have any answer to??? :brick:

[FlyingDutchMan]

What I said was it was cold TO touch, not cold enough to touch.

Whoops, my dyslexia strikes again :Oops:.

[geoffm]

Wayne Gum (?) at ERD in auckland makes replacement black boxes for the impulse - should work on the 250 as well.
Geoff