Has anyone had any problems setting up an R6 rear shock?

[mkane]

For the $$ they are nice unit's.

[mike YPVS]

yes, very nicely made.

[JonW]

Nice! Love the excel rims as well, what bike is that? an AC?

[mkane]

^^^^^^^^^400

[RuZty]

Okay, on Max preload mine sags 10mm under the bikes weight and another 30 with me on it, I'm around 220, well past my glory days. My bump stop is slightly deteriorated but only from age, there is no sign of contact, even though I ran preload in the middle for a long time.
In North America all our ebay R6 shocks generally come out of the US, versus yours from the UK/Europe. I also notice that when I buy clothes in the US or order food at a fast food place I have to go down a size from what I normally get at home. I will let you draw your own conclusions as to any correlation this observation might have as to how OEM spring rates may vary by market.

[mike YPVS]

Well, you only have to read the posts to see that it works for some but not for others

Just wish I knew why?

[JonW]

I agree Mike, thats the strangest thing. You would think it would universally be an issue, or not. Did you have any luck finding out if there was an issue with your R6 unit?

I actually have another r6 unit in my spares, sadly its a right palaver to pull the F1 shock and try the 2nd unit or I would.

The only other uncommon denominator would be if the suspension on the RD/RZs is subtly different... Mine is on an 85 with the box section swingarm. John (Silvers) is on an 86-on with the same swingarm. Now then, are the ->85 and 85-> frames the same in this area? I guess the question is, did Yamaha sell the same shock for both bikes? hmm...

[silverstrom]

The part numbers are only slightly different with one being 51L and one being 31K, the rest of the number is the same. From what I can see the shocks on both 85s are identical. I keep thinking that the only way you could crush the R6 stop would be a very weak spring from many, many miles of use, an internal defect, loss of oil/nitrogen, the shock was previously modified, or the linkage on the bike isn't right. There are many 85s, both US and F1 using the 99-02 R6 shock and I haven't heard of any issues. Whatever Mike's shock problem is, it seems to be isolated.

[mike YPVS]

Ok, here's the latest!

The shock was taken to the shock specialist yesterday, the spring was removed and tested. it was rated at 9.2, standard is around 9.3 so no problem's there. the damper was checked and was found to be ok. like Trev (the specialist) said, even if your damper had no internals it still sits on the spring, the damper is purely for damping the spring.

Why it didn't work I am not sure. My bike is an "85" F1 model, all the linkages were fine, but I fitted new bushes anyway. The new shock as put everything back to where it should be, which also proves the bike is fine.

I noticed that with the R6 shock fitted it did drop quite a lot when I sat on it, but did'nt check the loaded sag until later. At this point it proved to be very soft as I later found it was dropping 107mm when I sat on it. This was with the R6 shock set on a mid pre-load setting. While it was set like this, I did take my wife on the back for a few miles and I am assuming the extra weight on the bike was when the bump stop got crushed. Before you ask, no she is not an heavyweight, she only weighs about 9 stone.

It was later when I did some measuring that I jacked up the preload to full, but I couldn't get the loaded sag to less than 60 odd mm, which is still too much as I was after about 35 to 38mm.

All I can say is that everyone with an R6 shock fitted should check their loaded sag measurement, as finding out it's too soft while hitting a pot hole in mid corner is a sure way to put yourself in the hedge.

[RuZty]

Bizzare, I got 30mm off the stand and another 35 with me on it set right in the middle for preload.

[mike YPVS]

Bizzare, I got 30mm off the stand and another 35 with me on it set right in the middle for preload.

Not sure what you mean by that, do I read it that you have a 65mm drop when you sit on it?

[mike YPVS]

For anyone who is not sure what static and loaded sag is, or how to measure it. I found this one the internet, really good!

http://www.gostar-racing.com/club/motor ... set-up.htm" onclick="window.open(this.href);return false;

[RuZty]

Bizzare, I got 30mm off the stand and another 35 with me on it set right in the middle for preload.

Not sure what you mean by that, do I read it that you have a 65mm drop when you sit on it?

Yes.

[mike YPVS]

so yours is too soft!

you should be looking at 35mm total drop with you sat on it.

Jon, did you manage to measure yours with you sat on it?


I might add, that I have now ridden the bike with the new rear shock and it handles fantastic. Which goes to show my original YPVS shock was tired, and the R6 was too soft. The new rear shock has quickened up the steering and the bike is now very "flickable" and holds it's line very well.

I guess having a soft rear shock would let the bike drag it's arse on the floor and turn the geometry into something like a cruiser.

[JonW]

not yet Mike, I need to either wait until a mate who understands biking comes round, or suffer the sneers of the mrs when asked to perform such tasks... hmm...