Quick question to all the experienced mechanics on here please..?

[fastcat1977]

How often is it that an ignition coil bench test on the primary side and secondary side fine as far as resistance in ohms but actually turn out to be bad after all , how likely does that happen..? 1975 Honda cb750 has new points and condensers but when hooking up a timing light the left side flashing intermittent and the ride side light won't flash at all , I took that side that wouldn't flash by timing light out and grounded plug to the engine case and it has a light spark and very intermittent, this bike went from running great and parked to sitting two days then next time starting it up it ran like crap , craziest thing I've ever seen.

 

[Biebs]

Electric problems are always interesting. Bench testing a coil with a
Ohm meter for resistance is a static test - in real world use the coil is alive with electricity. Old coils can have cracks in the casing casing shorts to ground / frame. Running or testing in Dark sometimes tells all you need to know.

 

[fastcat1977]

Yes my timing light will not even pick up the firing from the right side coil , tested my light on a vehicle just to make sure it was working properly and it is , I get flashing from left coil but no flashing on right side , points gap are new and gaped properly and also new condensers

 

[fastcat1977]

Had to retard my timing so much that I had ran out of slot on the timing plate just to get it hitting on the F mark statically timing it , I knew this couldn't be right so I pulled the plate off and found the advancer had a broken ear that goes into the advancing cam , this is just another issue solved .

 

[brettp]

Good work finding that.

 

[Loose Chain]

Ya good catch. Did you find the broken piece? You don't want it floating around if you can help it. Clean and double check every connection while you are at it.

 

[Biebs]

I had a condenser that was bad on a car caused engine backfire and missing issue.
See you noted parts are new does not mean they are good. Never assume.

 

[drgnrdr750]

Was wondering if you were getting a spark from the plugs on the side that the timing light wouldn't work on.

 

[fastcat1977]

Was wondering if you were getting a spark from the plugs on the side that the timing light wouldn't work on.

Very very light spark and very intermittent, timing light will not even pick it up

 

[fastcat1977]

Ya good catch. Did you find the broken piece? You don't want it floating around if you can help it. Clean and double check every connection while you are at it.

The piece must have been chewed up long long time ago , didn't find any pieces , this is a customer's bike , I had it running great after valve adjustment, carb cleaning, oil change and the guy had resistor NGK plugs in it , I changed to the recommended non resistor NGKs and it ran perfectly no skipping or anything then after it set for a day an a half I went to crank it and it ran like crap , in my way of thinking it's like those resistor plugs might have damaged the coil then when i put recommended plugs in it ran with more voltage and finished off the already damaged and old coil possibly. I put new condensers and points and he has the new OEM coils on the way .I've been through this entire bike over every wire , nothing is skint or broken, looked even in head light and kill switch it's all in great shape , coil is only firing on the 1st plug that my timing light will pick up the no 4 fire is so very weak my light won't pick it up , and also very intermittent.

 

[fastcat1977]

I have the spark advancer gone in these pics , but does this look like the proper way to wire these condensers in ..? I doubled up the fibrous washer so that when tightened down really tight it couldn't dig into ground in anyway on the bracket. Does this look correct anyone please...? This is the way it was when brought to me , I only doubled up the fibrous washer for extra precaution.

 

[fastcat1977]

I had a condenser that was bad on a car caused engine backfire and missing issue.
See you noted parts are new does not mean they are good. Never assume.

I definitely saved the old ones but yes I know exactly what you mean, I experienced that many times

 

[fastcat1977]

I had a condenser that was bad on a car caused engine backfire and missing issue.
See you noted parts are new does not mean they are good. Never assume.

Some times or actually a lot of times , your 50 year old part works better than the new China junk most definitely

 

[Old_Crow]

Try swapping the coils and see if the problem follows the coil. If not, swap the condensers, looking for the same thing.

 

[fastcat1977]

Actually got new coils on the way OEM Honda coils but I saved old condensers and points cause they were original Japanese made and probably better quality im sure

 

[Stubro]

I have the spark advancer gone in these pics , but does this look like the proper way to wire these condensers in ..? I doubled up the fibrous washer so that when tightened down really tight it couldn't dig into ground in anyway on the bracket. Does this look correct anyone please...? This is the way it was when brought to me , I only doubled up the fibrous washer for extra precaution.

Yes they look correct.

This is on a K6 I have on the lift.

 

[Stubro]

Actually got new coils on the way OEM Honda coils but I saved old condensers and points cause they were original Japanese made and probably better quality im sure

New, Aftermarket points and condensers are not reliable. They tend to fail very fast.
Spend the extra and buy from Honda the point plate assembly if you need new points and condensers.

 

[fastcat1977]

Yes they look correct.

This is on a K6 I have on the lift.

I see you have yours a little different having the wire tabs separate but still on same threaded bolt , my wire tabs are together, you think it will matter...?

 

[Stubro]

Yes. Do it the way mine are