Coils?

[Vetteman761]

Hey guys, I bought my bike few years ago, since then replaced motor, but before I had replaced the motor It had a problem with stumbling when taking off like cutting out, Replaced the coils and it seemed to take care of it, ok then replaced motor and after x amount time now its doing same thing, HAd bought some cheap ones on ebay for like 60 bucks for 4, thinking I happen to get some bad ones? I tested them, and they are all within range, but is it possible they all would test out fine, but when they get hot they might not be? thought to myself maybe My bike happen to run better with the so called new coils maybe my ecu is bad but from what I gather on here those rarely do ever mess up... any advice appreciated

 

[Mr Brown]

More likely to be plugs than coils. Have you pulled them?

 

[Vetteman761]

have not but will check them out in morning , they have been replaced though last year, but will still give em a look

 

[Kiwi Rider]

@Vetteman761 Yeah man, ALWAYS start at the plugs as first port of call when there is a misfire issue.
Then coils, and then work back through the harness to infectors and sensors, ground connections, battery terminals, etc, etc. the ECU is at the end of the chain when checking this type of issue.

 

[Berlin Germany]

spark plug replacement - an unpleasant story:

some years ago , a buddy replaced the 4 spark plugs at his bike for new ones as part of normal maintenance - "success"?
the bike didn't start anymore. (he tried to start the motor directly after the replacement)
amazed eyes - old spark plugs back in - bike started again.
brand new plugs all bad?
seemingly.
so he went back to the dealer, exchanged the new spark plugs that had just been bought there for new ones, installed those and the bike started.

what did i personally learn from it and what were the consequences (for me)?
if I replace spark plugs, that are still working, with new ones, I always keep these "old" plugs (as a kind of backup) in case I get new plugs that the bike does not start with.
then I would screw these "old" ones in to exclude (or find) this possible but very very rare error by faulty plugs.

a little true story (just by the way)
from across the pond

 

[Berlin Germany]

another general thing:

when ever you change coils at gen1´s
strictly pay attention to the article number / color of the stickers
the gen1 got two different kind of coils (at least here in europe)
and those generally shouldn´t be mixed (experience of a very good buddy)

if you look at the different resistances, it will become relatively quickly clear.
the spark pattern, however, could look different, which then might lead to a different, possibly worse, engine running.
it does not matter which 4 coils you install - the main thing is that they are identical (sticker color / art. no.).

´99-´02 coils (black sticker)

´03-´07 coils (blue sticker)

 

[fns]

Fresh Spark plug and the proper gap is really important. Along with good gas

 

[Vetteman761]

Thanks guys for the advice, checked the plugs and they are all fine but , did notice some seepage around my head gasket in a few places thinking my compression might be off a bit, gotta test it here when I can

 

[Mr Brown]

Post pics of your plugs if you have a chance. I can't see two sets of coils being bad and plugs looking fine...

 

[Vetteman761]

Here is some pics of plugs, also did a compression check on motor, albeit engine was cold , had fresh battery and got 50 psi 130 psi 50 psi. And 50 psi. Those are in order from 1-4 cylinders, i dont see how it runs like that , no obvious signs of coolant in oil or smoke out exhaust, just the small oil seepage around head gasket,

 

[Mr Brown]

Put new plugs in it. Those are not useable.

 

[Berlin Germany]

(...) compression check on motor, (...) got 50 psi 130 psi 50 psi. And 50 psi. Those are in order from 1-4 cylinders, (....)

hell what - sorry - nonsense values.
the lowest values (cold), following the manuals, are :
at gen 1 - 130 psi / max. diff. 28 psi
at gen 2 - 142 psi / max. diff. 28 psi

I conclude that you did not open the throttles 100% during the check.
picturally said - if the motor can´t breath there is nothing to get compressed.

 

[Vetteman761]

hell what - sorry - nonsense values.
the lowest values (cold), following the manuals, are :
at gen 1 - 130 psi / max. diff. 28 psi
at gen 2 - 142 psi / max. diff. 28 psi

I conclude that you did not open the throttles 100% during the check.
picturally said - if the motor can´t breath there is nothing to get compressed.

They were fully open

 

[Vetteman761]

Put new plugs in it. Those are not useable.

Really? All my years I thought thats not a bad burn for a plug, but will throw some in it, still doesnt address my compression issue but one thing at a time

 

[Mr Brown]

Those look like they've been struggling to fire. The porcelain should be visibly white, and it's not. Maybe I'm wrong, but plugs are cheap.
Recheck your compression, making sure you did it correctly is free.