Is my swingarm original?

[Oddjob]

Hey, I'm not planning to die for 40 years yet Bryan, what do you mean by they'll last you out 

TBH I'm just doing this for the increased handling they give, not really doing it for longevity. 

[Bryanj]

Ken, we both know that if greased like Honda said the originals would last forever. Its people expecting grease to last the 4 years it takes to do 1500 miles!
Like the Ford escort owner who was surprised his cambelt broke at 30,000 miles but it was 7 yrs old. Nobody reads the OR bit in the service scedule book!

[alexdecker]

I live in Copenhagen, Denmark! Will try and see if I can find some in the German eBay!

[K2-K6]

The bushes have an irony in that the better you make them technically and with tightened tolerances, then they are more likely to give a problem in torsion. The material is a competent solution if everything stays aligned in use.

Issue comes from shock performance, specifically matcing exactly as a pair. Any mismatch during higher speed compression (that's damper shaft speed, when the bike is loaded and you drop into a dip) and one arm compresses faster than the other, putting the pivot into torsion which then locks it on the pivot. The rear wheel then tracks to a different line than the front as it cocks sideways momentarily giving that rear wheel steering feel.

These frames where often blamed but they aren't bad at all, if you try to shift one on a jig they take quite a tonnage to move them.  The swingarm is another matter though, and why many tried bracing on them to improve resistance.

The biggest illustration when riding them in contemporary era was if you had a pillion on there and running through a corner when you went through a dip, they would certainly show you then what it's about.
The problem is with the shock, but it promotes response in pivot, needle rollers are the correct solution for that.

[philward]

I have read that a lot of the top classic CR750's raced in the US use standard swingarms as they don't flex - box section swing arms where maybe an incorrect solution to the swing arm bush problem - the replacement swing arm would come with replacement bushes i guess which solved the problem. Take your point on the matching damper/spring being an issue though

[K2-K6]

The 750 and 500/550 arms are very different in construction, one from the other.

The 750 is a true monocoq concept with the skin taking load in most direction, and really quite a clever design too.

The 500 relatively is poor, with roughly three tubes welded together and additional skin bracing stuck on top. They haven't even welded it where it probably needs it (internally near where the tire wall is) but then if they did that it's bad practice in fatigue teams from having a continuous weld that would possibly crack at that point. It's got the appearance of significant compromise in pure engineering integrity. Definitely looks cost compromised.

The 750 is a far more elegant solution, and in all reality a "box section" in it's own right.

[deltarider]

I don't know what I've done wrong, but my swing arm still doesn't show play. I don't think I've greased it more than maybe 7 times in 140.000 km and some of my attempts have not even been succesful... Could the modification the model CB500K2 (ED, F, G) had, have anything to do with it? For a picture scroll down in: https://www.honda4fun.com/faq/generali/400-cb500-differenze-tra-k0-k1-e-k2

[K2-K6]

I don't know what I've done wrong, but my swing arm still doesn't show play. I don't think I've greased it more than maybe 7 times in 140.000 km and some of my attempts have not even been succesful... Could the modification the model CB500K2 (ED, F, G) had, have anything to do with it? For a picture scroll down in: https://www.honda4fun.com/faq/generali/400-cb500-differenze-tra-k0-k1-e-k2

Yes but you build your roads smooth on your country and much of Europe too  we don't do that here 

[McCabe-Thiele (Ted)]

Ken, we both know that if greased like Honda said the originals would last forever. Its people expecting grease to last the 4 years it takes to do 1500 miles!
Like the Ford escort owner who was surprised his cambelt broke at 30,000 miles but it was 7 yrs old. Nobody reads the OR bit in the service scedule book!

Interestingly most car cam belt failures on modern cars are due to either tensioner wheels failing or severe oil contamination of the belt. The Volvo ones are changed at something like 100k miles or every 10 years. Inevitably the cost involves changing the tensioner wheels at the same time.