Big twins are fantastic to ride, with great gobs of torque available at low rpm. The downside, of course, is vibration. A 650 or 750cc parallel twin vibrates enough to affect my vision: I literally have to squint hard when reading road signs to keep my eyeballs from bouncing up and down. Norton attacked this problem by hanging the engine in rubber mounts. The ‘Isolastic’ system eliminates vibration above
3,000 rpm, but sometimes 2,000 rpm is more appropriate—like when you are trolling along, squinting your eyes, trying to read the road signs. In 1973, Yamaha produced the TX750 which uses chain driven balancers within the bottom end to quell vibes. Kawasaki followed suit in 1976 with the KZ750B1. Both of these bikes offered the performance of a big bore vertical twin without the inherent vibration issues.
AWESOME! But with both of these bikes nearing 50,00 or  more miles, problems have begun to surface with the internal chain drive for the balancer weights. The Yamaha received a factory update back in the day: new crankcases incorporated an eccentric balancer shaft pivot to allow the balancer chain tension to be adjusted as it stretched over time. The Kawi uses an automatic, cam chain type, ratcheting tensioner. Modern bikes use gear driven counterbalancers.

 

During a tour this year the KZ750 twin oil light began to flicker at idle speeds. It still ran fine and sounded normal. I replaced the oil pressure switch to no avail. Next, I plumbed in an oil pressure gauge which showed 25psi at 4,000ropm where 48psi was specified. Hmm. The bike still seemed to sound and run normally. Next, I removed the oil pan and discovered a one inch diameter, slightly flattened, needle
bearing lying in the bottom. The motor was removed from the frame, the clutch and alternator sides were stripped, and the engine was flipped upside down. Once the crankcase was opened up, we could see that one of the 4 balancer shaft bearings had come out of its race somehow. Everything has a downside: mechanical engineering, like life, always involves compromise. So now we scour the internet for the parts needed to make repairs. This is an unusual and  omplex engine. Many hours and dollars will be needed to make it right again. Is it worth effort and expense? Financially no but emotionally yes.

 

The brown R100/7 was special. It has one of the tightest, best running engines of all the airheads that RetroTours has run. The handling and brakes also were much better than average. A major wreck took out a guard rail, the front end, and the frame, plus many, many related parts. I have already found and purchased most of the needed bits. All that remains is a week of wrenching to assemble everything.

 

The Moto Guzzi V50 is light and nimble, and oh so characterful; it is always one of the favorites. This year the rear main seal began leaking so badly that we had to hang an oil deflector in front of the rear tire to make it possible to limp it to a generous friend’s house, where it was exchanged for a loaner that enabled us to complete our tour. Years ago, I had the engine and trans out for a clutch replacement. I
remember that the job is rather fiddly: awkward/difficult. Now I need to do it all over again.

 

I purchased a 2002 SV650S recently. It was cheap but needed a lot of work. I have been working down the punch list while riding it. It is a very enjoyable bike that I would consider putting into RetroTours, but at just 21 years old, maybe it’s too new. What do you think?

 

I won’t bore you with other fleet projects but be assured that we will be busy over the next few months. In addition to mechanical repairs, ride reports for the past season will begin to post to the website in January. I hope you will enjoy reading about the rides of 2023 and consider joining a tour in
2023.

 

Wishing each and every one of you a Happy Holiday season, a Healthy New Year, a great Upcoming Riding Season, and much Peace, Joy, and love.

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IT’S TRUE. Old motorcycles are fun!

 

RIDING old motorcycles brings you back to a place that’s a bit slower and simpler. RetroTours can take you there. We’ll tend to all the details. You just show up, ride, and feel young again! Roll back the years. Revisit your youth.

RETROTOURS....a great gift anytime. Open ended action adventures on classic bikes.

Just go to www.retrotours.com, click on ‘Gift Certificates’, and follow the easy steps.