cdi or coils!!!

[mick355]

Guys do you think this is a cdi or coil problem on my 88 gsxr 750, I have really poor spark on all four cylinders, the plugs have only gone round the block a couple of times and now it wont start at all. First it fired on 1 and 4 eventually going on all four. Next day it starts on 2 and 3 before running on all four and now she wont go at all. When I remove the plugs and check the spark it seems week on all four but I find it hard to believe that both coils would be on the way out at the same time. Is there any real way to check the cdi boxes on these things??? Or is there anyone in melbourne with a good second handy.

[FIGHTERMC]

what color were the plugs when you took them out
also have you been driving the bike or just starting
it.wouldn't say both coils would go at once.

[mick355]

plugs were black and really wet. Had taken the bike for a short ride about a week before. But i have been having running dramas for a while

[latheboy]

Are you using summer or winter plugs ? if you got the wrong ones in for the time of year it'll never work like it should

[FIGHTERMC]

Bike will not run right or run at all if the plugs
are black buy new ones and try them.had this with my
blade and it was from starting it up and not riding it.

[Tone]

I get the same shit with my 89 750 Mick,it sits a while and runs shit in the city but after a good run at speed seems to clean out heaps and goes hard...until it sits around again.Checking sparkplugs has shown them to be in good nick but I've never checked the actual spark when I'm out on a run and the bike is going well.Just bought an engine analyser thing but am still to check the coils as I'm not completely sure on how to work the fucker...chinese manuals !!!
I get a gut feeling that fuelling is my problem but just had the carbs fixed and can't believe they've fucked out after so few k's.
Let us know if you find a solution.
Also FighterMC,what is the diff between starting and running the engine and going for a ride when the motor is essentially doing the same thing,did you find any reason for your bikes crappy running from starting it only? Cheers.

[Tone]

quote:Originally posted by mick355

plugs were black and really wet. Had taken the bike for a short ride about a week before. But i have been having running dramas for a while


Black and wet with oil would be fucked rings or valves wouldn't it?

[Booster]

Or fuel evaporating out of the carbs concentrating the crap they add to it

[cutcat]

There is a good place in Geelong to send your CDI for a check and/or repair. Its called Small Coil Rewind,in Edols Street ask for Bert. He can change the advance curve while he's there!(on some models)
Send your coils too.
Good luck.

[mick355]

Thanks for all the replys guys, just to add a few more points. Rebuilt the top end, new rings had the head done (seats cut, valves faced and new stem seals.) Replaced the emulsion tubes and needles, even found a place in the UK that sell the plastice needle blocks as they were shagged aswell. Standard jetting and checked the floats for leaks and reset. Standard exhaust. And replaced the leads with a set of 7mm DYNA leads. I'm sick of throwing money at this thing. Gone through three sets of plugs in the last few months. Every time i putt a new set of plugs in it runs ok for a few kays then the problems reappear.

How good is this guy in Gelong. I have heard a few dubious things about the guys in coburg and am a bit unwilling to sen the bits there

[alfiestorm]

quote:Originally posted by cutcat

There is a good place in Geelong to send your CDI for a check and/or repair. Its called Small Coil Rewind,in Edols Street ask for Bert. He can change the advance curve while he's there!(on some models)
Send your coils too.
Good luck.


Can these guys fix dyna2000 ignition boxes ? I have three that need repair have you got there contact number

mick355
it seems from my previouse experience that your cdi is fucked as I have worked on several bikes as yours with the same problem and only on one of them did it turn out to be the pick ups and on none were the coild fucked. I have found with coils they either work or they dont work.
Check all your earth connections are good aswell with no corrosion on the connection faces as this can have the same effect as you are having.
have fun and when you are about to smash it to fuck with a hammer sit back and have a beer :D

[Johnnie5]

quote:Originally posted by alfiestormI have found with coils they either work or they dont work.

have had coils that are intermittant

and also some that would fail once hot ,nce cooled would be ok again

[mick355]

alfistorm this things turning me into an alco. There's only so much vb you can drink before the hammer comes out but i'll check all the earths! Only other thing i can think of is the needle and seat is leaking but at $80 a carb its a bit rich. I only have a shitty multimeter but i cant measure any resistance between the poles and the outputs. Maybe i'm just being a redard. Don't think its the fuel tap cause the thank has been on the floor overnight and there is no sign of fuel on the floor.

[alfiestorm]

quote:Originally posted by Johnnie5


quote:Originally posted by alfiestormI have found with coils they either work or they dont work.

have had coils that are intermittant

and also some that would fail once hot ,nce cooled would be ok again



You are correct I forgot to mention this point but i do believe with this particular problem that the cdi is the major suspect in this case. If I am wrong cover me in chocolate and chuck me to the lesbians please :D

[mick355]

anyone in the easten suburbs of melbourne with a spare cdi they want to unload?

[FIGHTERMC]

quote:Originally posted by Tone

Also FighterMC,what is the diff between starting and running the engine and going for a ride when the motor is essentially doing the same thing,did you find any reason for your bikes crappy running from starting it only? Cheers.

Tone i just wanted to see if he was just starting the bike
every few days and not driving it as this will cause
the plug to blacken and fuck up but he has a bigger problem
than this.
rgds
fightermc

[Tone]

Cheers FMC...looks like my cdi has had the dick also!

[Johnnie5]

based on the descriptions i ould be inclined to look at the cards for flooding

when you take out your black plugs and find a weak spark , have you plugged a new plug in and checked the spark ?

you have rebuilt the top end, have you tried a compression test to be sure ?

[mick355]

replaced the plugs this arvo with some new hotter and single electrode ones. She fired up straight away put the spark still seems a little weak and the plugs still came out a little blackish. Comp test is fine, and about the only thing i haven't replaced in the carbs is the float/needle assembly. Was holding off on that alittle cause there $80 per carb. Maybe when it sits for a week or so it is flooding and rooting the plugs.

[Benz]

Have you checked the plug caps? Usually there is a 5k resistor inside them, behind the screw.
My bike was misfiring and running on 2, then wouldn't go at all at one stage, changed out the plug caps, and the problem was solved. Rust gets inbetween the resistor terminal ends, and weakens the spark.
Might not be your problem, but its an easy check.....good luck.
Could also be a weak battery....or no/not enough charge,or possibly bad connections in the loom.
Hope this helps!

[loosebruce]

Not using Shell Optimax innit are you?
Checking plug caps, pickup gap, earths etc won't cost

[alfiestorm]

cover me in chocolate and chuck me to the lesbians please

[mick355]

BENZ ive changed the leads to dyna ones if that make any difference. Don't think they have any sort of resistor in them. But the leads never fixed the problem. I did have CALTEX VORTEX in it as i've never had any dramas using it in my two strokes unlike optimax and bp premium, but just drained the tank and put bog stock unleaded in

[mick355]

just went out to the shed and checked the old plug caps. All are showing 10k+ resistance, Could this have damaged the coils or cdi? and now that im running dyna leads and caps does this mean i need to use dyna coils and non resistance type plugs. I changed from the std JR9c plug to D8EA yeasterday and it seems to have made an improvment.

[hooligan]

I had a similar prob with mine. Every now and then it'd drop 2&3, I'd let it cool down and she'd be fine again. Tracked down (after replacing everything with dyna) to the stator coils.
But I'm a chef, not a mechanic, so i could be wrong.

[Benz]

Mick, Check that you have 13.8 DC battery voltage or thereabouts with the motor running at roughly 3k .You should see the increase in voltage on the meter as you idle up. Any less than this means you have a charge problem, and that would explain the weak spark.
With a low battery my slabby 11 motor won't run, but it will crank over.
Charged to 13.8, it starts and idles instantly.
A new set of Dynas will improve overall engine performance anyway, from what I've been told , they will work well below 12volts too....in total loss systems, on dragbike engines.
Might not be the problem, but its another thing eliminated!

[mick355]

Benz. brand new battery last weekend cause i was thinking along the same lines. Will probably do the dyna coil thing anyway just for peace of mind. After all she's nearly 20 years old now and that pretty damn good out of a set of coils. Just hoping the cdi is still sweet. Will ring small coil rewinds tomorrow and have a chat. Only pain is getting the bits to Geelong

[honda boy]

quote:Originally posted by loosebruce

Not using Shell Optimax innit are you?
Checking plug caps, pickup gap, earths etc won't cost


Guy's - don't intend to change the intent of this thread but what's wrong with Shell Optimax?

[cutcat]

Optimax has a bit of a reputation of making engines run a bit rich and fouling plugs.

Alfie that number for Small Coil Rewind in Geelong is 03 52788454.

Mick, I just post 'em my parts and they post 'em back.