Motorcycle Forum banner

1 - 5 of 5 Posts

·
Registered
Joined
·
17 Posts
Discussion Starter #1
1980 CB750F - does anyone know what the air gap is supposed to be for the ignition pickup, and can you explain how to set ign. timing?
 

·
Registered
Joined
·
12 Posts
First of all there is no gap adjustment on your pick-up coils. But, if you want to adjust your timing you really should have a good manual. There is a timing mark on the plate behind the coils. It has a small "s" then a large "F" and then a #1 going from left to right looking at it, and then it has a "T" the "f" is the actual timing mark. You can either use a timing light which is best or you can use what they call static timing. Timing is correct if the narrow projection on the lefthand pulse generator (pickup coils) that aligns with the projection on the rotor. When these two are lined up the "f" mark should also be lined up with the pointer. It is much easier when you are actually looking at the pics in the book. I would definitely not get a Haynes manual or Chiltons manual Get a Clymer Manual or an original Honda Shop Manual. If you need any help I can send you pics.
 

·
Registered
Joined
·
17 Posts
Discussion Starter #3
actually, I got it all figured out already. I managed to find a link on here to a manual for it.
 

·
Registered
Joined
·
1 Posts
First of all there is no gap adjustment on your pick-up coils. But, if you want to adjust your timing you really should have a good manual. There is a timing mark on the plate behind the coils. It has a small "s" then a large "F" and then a #1 going from left to right looking at it, and then it has a "T" the "f" is the actual timing mark. You can either use a timing light which is best or you can use what they call static timing. Timing is correct if the narrow projection on the lefthand pulse generator (pickup coils) that aligns with the projection on the rotor. When these two are lined up the "f" mark should also be lined up with the pointer. It is much easier when you are actually looking at the pics in the book. I would definitely not get a Haynes manual or Chiltons manual Get a Clymer Manual or an original Honda Shop Manual. If you need any help I can send you pics.
Hi, I had my 81 cb900c running yesterday but today it won't start. It backfires and sounds like the timing is way off. How could that happen. Anyway I would like to check the ignition timing and would greatly appreciate the pictures that you had offered. Also, any advise on why the timing could have gotten off would be helpful.
 

·
Registered
Joined
·
49 Posts
Hi, I had my 81 cb900c running yesterday but today it won't start. It backfires and sounds like the timing is way off. How could that happen. Anyway I would like to check the ignition timing and would greatly appreciate the pictures that you had offered. Also, any advise on why the timing could have gotten off would be helpful.
Good news is the timing on your CB900 works the same way as described above. Being that this thread was started 11 years ago, and the OP and the others who answered have low post counts, I doubt they will reply. So that being said... the advise is sound and the Clymer or OEM manuals are best. EBay or Amazon are good places to look.

As for things that can be the cause, I would check the timing tensioner first. If it went loose then one of the cams or the crank could have jumped a tooth. Even if it didn’t jump a tooth a loose tensioner can throw off the cam timing. Check the points to make sure they are still gapped and aligned properly. And lastly if your carbs are dirty and causing the engine to run really lean that can cause a popping in the exhaust that will sound like a back fire. Exhaust leaks will do that too.
 
1 - 5 of 5 Posts
Top