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Chuey wrote:Even the difference between my '76 bike and my '83 and '84 bikes is surprising. Mostly, that is down to the clutch and transmission.

It is the rider that is the limiter on my bikes.

Did R90Ss come with the strengthened top tube? That would mean their frames were different than their contemporaries in the R90/6, etc., no?

Chuey

No, I mean yes. There is an insert in the top tube of the 90S frame. I have the tank off my 76 and from what I can see of it, the wall thickness appears to be greater than that of the tube. I don't remember if my 74 looks that robust or not?

I'm not aware of any difference between the frames used across the /6 range. Certainly the R90S frames were not materially altered between 1974 and 1976, although handling issues were addressed in '76 bikes with the introduction of closer tolerances within the fork components and a reinforced swingarm.

R90Steve wrote:[

No, I mean yes. There is an insert in the top tube of the 90S frame. I have the tank off my 76 and from what I can see of it, the wall thickness appears to be greater than that of the tube. I don't remember if my 74 looks that robust or not?

The "doubled" tube as used in later models (until the mono, which reverts to a single tube) is easily identified.
One can plainly see the "tube within a tube" when viewed from the rear where the tool tray would sit.
Also, along the sides of the outer spine-tube, holes were drilled through the outer tube
and then welded around their circumference in order to "structurally attach" the inner and outer tubes.

vanzeen is, as usual, right. All of the R90S had the double tube and later it was added to the rest of the /6. This is my second post saying the exact same thing.

How many times must it get posted?

Thanks for all the responses. It sounds like it will be a bolt in operation except for the electrical stuff under the gas tank. I'll use the /5 "simple" stuff, the /5 gas tank and drum brakes.

As for why, it' s b/c I feel my 75/5 frame is off kilter, and my simple measurements confirm that, plus looking at it from the front, and while riding, it is obvious that the center yoke has been twisted. Someone had a wreck on the bike only going 45 mph, and the handlebars took a direct side hit. They were 3 inches bent, and my guess is the rest of the force was taken by the frame. I had an expert look at it and he checked things out and concluded otherwise. But I already have a good /7 frame from a R100, which is a bike I never really cared for. So that's the story.

I agree with the comment or opinion that the 60/5 was a better feeling ride than one of the newer bikes. I recently rode the F bike, a GS, and was just not very impressed. Maybe it was the cylinders sticking out on the /5 that gives it a ride like no other.

rd1

My Early (reg Sept 75) R90/6 also has the double wall main frame tube.

When I rode an early 1200GS, I was amazed by the handling and brakes, much much better than the older bikes.

IMHO etc etc Charles

rd1 said, "As for why, it' s b/c I feel my 75/5 frame is off kilter, and my simple measurements confirm that, plus looking at it from the front, and while riding, it is obvious that the center yoke has been twisted."

Did you do the simple tests for a bent frame? Does it track straight? Is it neutral in corners? A twisted yoke doesn't mean that the frame is bent.

My website shows simple tests for a bent frame. Did you try using Google to find info?