Dear Readers: Knowing when to stop is as important as knowing when to start. After 11 years, I think it’s time for me to hang up my wrenches. In that 11 years, the idea of a classic motorcycle has moved forward. Unfortunately, my limited knowledge has not moved forward with it. My whole world is the ’60s and ’70s bikes, and I know little about the ’80s onward.
I’ve enjoyed my time writing for you all, and it has been a pleasure to meet some of you at events.
I have truly enjoyed my years of association with the magazine, Richard, Landon, and all the folks at Motorcycle Classics who have helped me with material and information along the way. — Keith Fellenstein
Tire balance issues
Q: I have a 1973 Triumph Trident T150V with modern Dunlop K81 TT100 tires from 2016. I recently had a rear tire go flat. I decided to replace both the tube and the rear tire (new K81 TT100) since the tread was worn in the middle but not on the edges. The front tire seems fine so I didn’t replace it. I noticed the front wheel had weights on it and that it had been balanced. The rear tire had no weights. The manuals I’ve read seem to imply that the rear tires don’t need to be balanced. I would like your opinion on the need to balance the rear tire and if you think a local motorcycle shop would be able to do this with an original rim. Also, the new rear K81 tire seems a little taller than front K81, but both are the exact same model Dunlop tire. Is that an issue?
Scott Hassell/via email
A: Your apparent tire size difference between front and rear shouldn’t cause you any issues. As for balancing the rear tire, all of my bikes have both tires balanced, and have since I got them. It may have been common to only balance the front tire since you will feel the imbalance more strongly through the handlebars than the seat. It certainly can’t hurt anything to have both tires balanced, and any bike shop should be able to accommodate you.
No spark issues
Q: I have an old 1979 Suzuki 850GS that I am trying to bring back from the dead. I can get dash lights on by jumping it from another battery, but the bike only turns over. It seems to have lots of compression, just no spark. Thanks for any leads possible.
Benny Hamilton, Jr./via email
A: Well no spark at all indicates a system failure rather than a component failure such as a bad coil. However, for completeness, I’d start at the plugs and work my way back. New spark plugs are never a bad idea when troubleshooting ignition problems. Testing the coils is easy enough too, if you have a volt meter. The primary resistance should be about 4 ohms, and the secondary resistance should be about 15 thousand ohms. Also check the fuse box. The ignition fuse should be 10-15 amps. Old fuses sometimes look good but are bad, so replacing the fuse would be a good thing regardless of how it looks. Cleaning the breaker points should be done too. Many times a lack of spark can be traced to corroded points that act as insulators. Another possibility is the kill switch may have become corroded and is breaking the ignition circuit. You can bypass everything and feed the coils directly by running a jumper from the battery to the Orange/White wire that feeds the coils. Ideally you’d have a fuse in that jumper, but if you’re careful you can do without. Good luck!
Suzuki X6 Hustler troubles
Q: Hi Keith, I’m a long-time subscriber to Motorcycle Classics and I always look forward to getting it and reading your column. I am an avid X6 Hustler fan having bought my first 1966 Hustler in May 1967, a week after my 16th birthday. I still have it, I still ride it, and I love it. Over the years I have obtained three other 1966 models. The last Hustler was a true barn find. When I turned the engine over by hand I was pleasantly surprised that it had excellent compression. I bought it, and after tearing it down two years ago it is now a complete bike once again, having received a modest restoration. Two months ago when it was time to start the bike, I was amazed when it started readily on the third try. Here’s the problem: It didn’t take long to realize that it was only running on the right cylinder. Checking things over it had spark and fuel, and the timing is right on the money. The points and condensers are new. I am at my wit’s end with this problem. What am I missing? Thanks for your great magazine and your time.
Jimmy Stock/via email
A: One thing that always crops up with 2-strokes is the condition of the crank seals. If the crank seal for the right cylinder is bad, there will not be enough pressure build up to move the fresh gas charge to the combustion chamber. You’d still see decent compression of the top end, but the bottom end would leak out.
Comstar feedback
A: A final word from the original correspondent who asked about tubeless tires on Comstar wheels. — Keith
Hi Keith and all my Brothers of the Two Wheels! I feel I have to let you all know, I didn’t run tubeless tires on my Comstar wheels. After a little more research and a conversation with the local shop where I get my tires I decided not to try it. If Honda wanted them to be tubeless they would have been from the start. I had new Metzler tires and tubes installed and they are great. Thanks to all that commented!
Rick Poole/via email
Cimatti 100 feedback
Q: As always, we appreciate reader input on questions and answers that come up in this column. Reader Tom Willis has some info to share regarding the Cimatti 100 question from a past issue.
A: In the May/June 2019 issue a reader asked a question about a Cimatti 100. I have recently acquired a C100. It does not have a title, so I am not sure of the year, but I did get a factory parts and repair manual. The timing should be set at 7/64-inches BTDC in reference to Mr. Quisenberry’s question. I have found other questions on the internet like mine but not many answers. Perhaps I could share my technical data with others who would have pictures or information to help me with my restoration. Thanks.
