Very confused....help please

[93trident]

Hi all I am having problems with my ignition coils. I was still having slow starting (the bike cranks over normally but seems slow to fire) so I did the tune up as mentioned in the manual (carbs,valve clearance plugs etc)
Bike ran fine but next day after a wee 100mile run it still had the fast cranking but slow starting symptom.
I had a pair of new dynatek 3 ohm type coils and silicone leads so I thought it was a worthy upgrade and may help me more than hinder. After fitting i started the bike but there was fuel but no spark to the 2/3 . So I thought i had done something while rewiring and re did them(nothing was wrong). They all fired but bike ran like crap with high rev back fires.
I removed the dyna coils and put the originals back on and now it's cool on 1, cold on 2 and 3/4 run normally still fast crank but slow firing. I have no idea how 1 and 2 are not working as they are different coils.
Anyone had this problem?
Thanks

 

[Hammerandspanner]

Hi all I am having problems with my ignition coils. I was still having slow starting (the bike cranks over normally but seems slow to fire) so I did the tune up as mentioned in the manual (carbs,valve clearance plugs etc)
Bike ran fine but next day after a wee 100mile run it still had the fast cranking but slow starting symptom.
I had a pair of new dynatek 3 ohm type coils and silicone leads so I thought it was a worthy upgrade and may help me more than hinder. After fitting i started the bike but there was fuel but no spark to the 2/3 . So I thought i had done something while rewiring and re did them(nothing was wrong). They all fired but bike ran like crap with high rev back fires.
I removed the dyna coils and put the originals back on and now it's cool on 1, cold on 2 and 3/4 run normally still fast crank but slow firing. I have no idea how 1 and 2 are not working as they are different coils.
Anyone had this problem?
Thanks

I had the same problem, gave up with the dyna coils and reverted back to standard ones. What do the plugs look like on 1 and 2?

 

[93trident]

Thanks for reply. The plugs are cylinder 1 OK and cylinder 2 a bit lean. Cylinder 3 a bit lean and cylinder 4 OK. Re checked shims all within tolerance. Cylinders 1 and 2 are still playing up. When I swap leads nothing changes, new plugs the same the only thing I haven't checked is compression as my kit didn't cover our plug thread size so I have a new test kit coming this week.
Hopefully the problem might show it's face then. If not I will be back on here for answers. Cracking site with cracking members. Thanks again for reply.

 

[Hammerandspanner]

Thanks for reply. The plugs are cylinder 1 OK and cylinder 2 a bit lean. Cylinder 3 a bit lean and cylinder 4 OK. Re checked shims all within tolerance. Cylinders 1 and 2 are still playing up. When I swap leads nothing changes, new plugs the same the only thing I haven't checked is compression as my kit didn't cover our plug thread size so I have a new test kit coming this week.
Hopefully the problem might show it's face then. If not I will be back on here for answers. Cracking site with cracking members. Thanks again for reply.

 

[Hammerandspanner]

Good luck! Let us know how you get on. Such a frustrating problem!

 

[93trident]

Good luck! Let us know how you get on. Such a frustrating problem!

Yeah I will post when I am sorted or not

 

[93trident]

I am leaning towards a fuel problem now after the compression test today. My first readings went like this on a cold engine test. But this numpty forgot to hold throttle open
1) 100,100 then 125 with oil added
2) 130, 130
3)120, 120
4) 120,120
Then I remembered I had to hold the throttle wide open so redid the test on a cold engine again.
1) read 175 then dropped to 150 and stabilised at 150 I presume after the oil had been scraped off the bore.
2) 150,150
3) 150,150
4) 160,160.
In my mind those figures look quite good. I have swapped leads, plugs and those first 2 cylinders still were cold. Because they are controlled by 2 different coil packs my guess is fuel carb side as the shims are all within tolerance and compression is good. I will report how I fixed the problem so it might help another member

 

[plantguy]

Hi all I am having problems with my ignition coils. I was still having slow starting (the bike cranks over normally but seems slow to fire) so I did the tune up as mentioned in the manual (carbs,valve clearance plugs etc)
Bike ran fine but next day after a wee 100mile run it still had the fast cranking but slow starting symptom.
I had a pair of new dynatek 3 ohm type coils and silicone leads so I thought it was a worthy upgrade and may help me more than hinder. After fitting i started the bike but there was fuel but no spark to the 2/3 . So I thought i had done something while rewiring and re did them(nothing was wrong). They all fired but bike ran like crap with high rev back fires.
I removed the dyna coils and put the originals back on and now it's cool on 1, cold on 2 and 3/4 run normally still fast crank but slow firing. I have no idea how 1 and 2 are not working as they are different coils.
Anyone had this problem?
Thanks

Check my post in this thread.

https://www.cb750.com/threads/cdi-ignition-module.9296/