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Very Hot Topic (More than 25 Replies) R65 Resurrection (Read 13323 times)
skippyc
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Re: R65 Resurrection
Reply #225 - 08/10/19 at 18:04:01
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Compression does rise with engine speed, oil and throttle Opening.
  
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TomHoldom
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Re: R65 Resurrection -Fork oil seal replacement
Reply #226 - 10/05/19 at 10:01:56
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Hello
Here's a quick update for anyone who has been following/helping my project....
My right hand spark fouling up turned out to be a blocked slow air jet on the carburetor - cleared and all running much smoother now!!
(also successfully moved onto French plates.....which hasn't boosted my performance....)

So generally pretty good, and next job is to replace my leaking fork seals for which I would appreciate some help.
I'm hoping to follow a video tutorial (for a R100CS fork seal replacement) see link
https://www.youtube.com/watch?v=s9AfQOrwEeY
which doesn't take the whole forks apart, just the following;
1/ front wheel off
2/ release dampener rod allen screw lower leg fastener
3/ slip off the fork lower leg
4/ pop out the old seal and replace
5/ put back together and refill with oil
does sound sound about right?

I have some Multi ATF which is described as equivalent to DEXRON III H. Should that be ok for the fork oil?
My haynes manuel says 190cc for each fork and also 30 - 40 Nm to torque up the  dampener rod allen screw...?

Any hints appreciated
  
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Barry
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Re: R65 Resurrection
Reply #227 - 10/05/19 at 12:16:22
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TomHoldom wrote on 10/05/19 at 10:01:56:
1/ front wheel off
2/ release dampener rod allen screw lower leg fastener
3/ slip off the fork lower leg
4/ pop out the old seal and replace
5/ put back together and refill with oil
does sound sound about right?


Yes, no need to remove the stanchions and risk losing alignment. 

If the Allen screw just spins then the damper rod is rotating and you may need to drop a socket on a long extension down from the top to hold the damper rod still while you undo the Allen screw.  An impact gun would certainly get it loose without having to do that.  Even just tapping the Allen key with a small hammer will sometimes shock the screw loose.  ATF may be a little thick but worth a try if you have some. 190cc is correct but I prefer to measure the level with a dipstick touching the top of the damper rod. From memory the Level should be between 20mm and 50mm but you can check that in Haynes.  You can tune the forks between that range as it is effectively changing the air spring when the forks are compressed.

Don't overtighten the Allen screw as next time it can mean that instead of coming loose the damper piston unscrews off the top of the damper rod.
  

Barry Cheshire, England 79 R45
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TomHoldom
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Re: R65 Resurrection - rotating damper rod...
Reply #228 - 10/06/19 at 08:06:09
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Hi Barry , I got the rotating damper rod!!
do you know the length extender I'll need to reach and the size of the socket to hold the top end of the damper rod bolt
I read somewhere that it was 13mm?
I have an extension that around 25cm....
  
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Barry
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Re: R65 Resurrection
Reply #229 - 10/06/19 at 08:36:55
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13mm is correct. As you will have to remove the top plugs and springs, the fork leg can be collapsed to reduce the length of socket extention needed. I can't give you an exact length but 25cm is in the ball park. I need to string a couple of shorter ones together.

Did you try to shock the Allen screw loose ?   Given that it's only pressure from the main spring that resists rotation of the whole damper rod, another option to try is to increase that pressure by compressing the leg by hand while trying to undo the screw. Not easy and possibly a two man job.
  

Barry Cheshire, England 79 R45
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TomHoldom
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Re: R65 Resurrection
Reply #230 - 10/06/19 at 09:36:02
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Hi Barry, thanks, thats I what I did - pushed up and then suddenly it decided to come undone.
Seal out and replaced, but now I find myself not being able to tight.....is there any chance that compressing the leg again may help - or would that only work once filled with oil again?

Could I fill with oil at this stage?

If not, I suppose I'll have to remove the 'top plug and springs' not sure what this is....is that the bit where I have to push down to remove the circlip and also be carefull to put back in the same position (damn, I was hoping to avoid all that.....)
  
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TomHoldom
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Re: R65 Resurrection
Reply #231 - 10/06/19 at 10:08:21
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still stuck on doing up that first side, but in the meantime have taken the other side apart to find quite messy splodge on what I think is the damper rod seat - see photo
Is this something disintegrated which needs replacing?
  

right_side_fork.jpg ( 494 KB | 5 Downloads )
right_side_fork.jpg
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TomHoldom
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Re: R65 Resurrection - inside lower fork leg clean
Reply #232 - 10/06/19 at 11:11:48
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Also, with the first side I took apart I hadn't noticed that the 'damper rod seat' (if thats the right name for the tube /disk piece which sits on the end of the damper rod) had come off with the lower leg, so I went ahead and replaced the seal.
Now having tapped the leg a few times and got the 'seat' to fall out its revealed a load of grime in that leg as well which needs cleaning out without buggering up the new seal (which all the grime will need to come past). Any suggestions on how to clean out the inside of the lower leg appreciated.

Lastly, I don't see any of the other items further up damper rod which are listed in my haynes manual (circlip, shim, valve housing, valve washer, perforated washer & buffer) or this all hidden further up the damper rod?
see Items 12 to 17 on the attached diagram.
My damper rod seat (item 18) is also a different shape....?
Thanks
  

haynes_diagram.jpg ( 1006 KB | 6 Downloads )
haynes_diagram.jpg
inside_lower_leg.jpg ( 492 KB | 5 Downloads )
inside_lower_leg.jpg
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Barry
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Re: R65 Resurrection
Reply #233 - 10/06/19 at 11:56:31
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Tom,   You should be able to tighten it again by compressing the leg. I know there is a torque spec but it only has to be tight enough for the leg not to fall off and tight enough for the oil not to leak past the washer.

To remove the top plug if you need to, push the plug down against the spring pressure until the wire circlip is exposed, dislodge the circlip with a small screw driver and fish it out. The plug will then pop up when you release it.

The damper rod seat is called the top hat for obvious reasons. Besides holding the damper rod central they are usually tapered if not as much as the illustration shows. The reason for this is that on full compression of the forks the tapered section of the top hat enters the valve body and restricts the flow of oil to act as a hydraulic bump stop.

The sludge may be what's left of the topping out bump stop which is item 12 in your illustration. They were originally made of black rubber and it's highly likely to have  disintegrated especially if the forks have never been apart before. The valve body assembly which you don't see comprises items 12 through to 17  and lives up inside the fork stanchion. Remove the large circlip item 17 and the valve body will drop out. It can be done with the main spring in place but be careful as the spring will push it out.

Might as well go the whole hog now having found the sludge.
  

Barry Cheshire, England 79 R45
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TomHoldom
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Re: R65 Resurrection
Reply #234 - 10/07/19 at 07:20:58
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Hi Barry, I'm going try again to get to grab a bit more by compressing the leg - at the moment its turning easily....

What about cleaning the grime out from inside the lower legs - its difficult to get out as its mainly near the bottom end with the narrower diameter - i.e. I can't just pull a rag through.
Is trying to out with water a possibility?
  
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Barry
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Re: R65 Resurrection
Reply #235 - 10/07/19 at 09:28:08
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I wouldn't wash it out with water, at least not in the first instance, perhaps a very hot water and detergent rinse to finish off. You need a solvent that will dissolve the crude. I'd use whatever you have to hand, paraffin,  diesel, or even white spirit.

If you are not intending to remove and inspect the valve body assembly to see if the topping out bushes are still there, then at least measure the length of damper rod protruding from the stanchions. If they are not the same length then one of the bushes has disintegrated for sure.  The bushes are intended to absorb the shock of the forks reaching full extension although there is also a hydraulic bump stop effect if the forks are working properly.  In the very worst case it's not unknown for repeated topping out shocks to shear off the damper piston.
  

Barry Cheshire, England 79 R45
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