Need some help. Does anyone know where I can find an ignition coil for a 1970 ct1b I am restoring? Looking for original part or a new replacement part that will work. The original part number according to Yamaha is 248-83210-11-00. Just looking for a source. Thanks

You might check with DEET?  He may have new ones.

I could look and see if I have a used one...  I might.  But DEET would be my first choice. 

It isn't a part that tends to go out often...  are you sure you need one?

Beware of the new coils on ebay...  many stories here of people getting bad ones.  And several stories of people finding and fixing the real problem and only getting spark when they went back to original coil they thought was bad. 

Emgo makes a decent universal one (24-71532) I've had luck with but you'll have to make a mount and the early CT is a little harder to do that on than the later bikes.



 

Thanks for the info Mark. I am one of those that bought one on eBay. lol Installed it and it ran for about 30 seconds and then quit. I tested the coil I installed with an ohmmeter per the Yamaha shop manual and it appears the primary side of the coil is bad. The magneto has been rebuilt, new coils, points and condenser. When I bought the bike it wasn’t running and it didn’t have the origional coil. The one I bought on eBay looked correct for this application but maybe it was the wrong coil. If you have an original you would like to part with let me know how much. If not, do you know how I can get in touch with Deet to see if he may have one? This has been a 7 year restoration project of the first motorcycle I ever owned and I would like to get it up and running soon. Thanks

DEET's email is yamaha(at)nc(dot)rr(dot)com

Of course replace (at) with @ and (dot) with a period

I found a used one, I will test it with my meter tomorrow.

I'm sure new aftermarket coils are blamed many times when the problem lies elsewhere. Sellers must dread people coming back with 'Faulty'. Seller has no real way of testing the coil i guess. I'd love to have a box of returns to try on a good running bike. I could be wrong of course & have only ever bought a few but without issue. Even my lawnmower coil & box combined. I bought the cheapest one & had mount holes too close together so 'in desperation' i elongated the holes until it fitted & gapped it to a hacksaw blade for airgap. Started first pull & never looked back--still good years later.

Thanks Mark, let me know if it checks out. 

RT325, I'm going by the reports on here where someone installs a new coil when they don't have spark...  then cleans the points or whatever...  still no spark...  then in desperation installs the original coil they took off and they have spark.

Coils are so simple you wouldn't think this would happen but it does.  Not sure why.  Maybe specs are too far off on some of the replacements out there or something?  I've only used original and the Emgo and found that these old bikes are pretty tolerant of ignition coils...  points or CDI doesn't seem to matter.  And it's rare to see a bad original coil in my experience except the AT 12 volt battery ignition systems do sometimes burn up the coil when someone leaves the key on and engine off.

Correct me if I`m wrong but a 248 coil would be for an AT1 12v. I just installed an EMGLO coil on a CT1c.All you have to do is drill out one of the mounting holes to 6mm and mount it in the normal spot. Works just fine.
Capt Dave

All good Mark. Burning up coils reminds me of my Bucket Racing days when someone left the battery connected on a honda CB125 4 stroke after finishing his race. After a short while there was plastic dripping on the head followed by smoke. Turned out he was running a 6 volt battery coil with a 12 volt battery thinking Better Spark haha--or maybe it was but not for long. Be a hell of a draw on the battery i'm guessing.

Just wanted to say thanks for all the reply’s to this post. I found another coil off a salvaged bike. Works great I have spark now and the engine started. Running a little rough. Will have to fine tune then it should be ok.