Longer shocks = chain fouling

[nighthog]

Hi all, on my '82 I fitted 340mm / 13.5" Hagon shocks to both improve the damping and to raise the rear a little, helping with the handling. That's all been just fine, but it has reduced the chain-swingarm clearance just enough enough so the chain chews up the grease seal at the end of the swingarm and can even dig into the swingarm itself a little. And yes, I do try to keep it correctly tensioned.

I've tried various ways to protect that area but with no success. I'm currently fettling a TX750 swingarm to replace the standard one and would like to address this before fitting it - I know others have used longer shocks to good effect so must also have had to deal with this issue.

If anyone has an elegant solution to this I'd be delighted to hear about it! Thoughts?

Cliff

 

[arcticXS]

On my 77 model, I have/ had the same issue. I ended up making a plastic bushing that fit over the swingarm bearing tube. A more properly designed chain slider, as found on many newer bikes would of course be better.
The actual root cause of this problem, is the primary drive ratio, that forces the use of very small rear sprockets. Other road bikes often have 37-43 tooth sprockets, that lift the chain away from the swing arm. So the ultimate fix is a new set of primary drive gears, from Ivan Hoey, Heiden or Smedspeed.

 

[nighthog]

Thanks, and changing the primary drive gears is no doubt the best fix, but I'm looking for something considerably cheaper! I was hoping there may be a chain slider for another bike that could be simply modified and fitted, for example.

 

[arcticXS]

Thanks, and changing the primary drive gears is no doubt the best fix, but I'm looking for something considerably cheaper! I was hoping there may be a chain slider for another bike that could be simply modified and fitted, for example.

Unfortunately there aren't many round tube swing arms that came with chain sliders. It is possible the XT500 had something.

 

[atom4488]

Sounds like you need a chain slider, as found on almost all dirtbikes these days. Between Amazon, eBay and whatever other favorite online vendors you may have, you should be able to find a slider that could be adapted. I have often used plastic cutting boards, as found at your local household goods retailer, as a source of plastics for such purposes. The material, whether nylon or whatever its actual composition is, can be readily cut, machined, bent/molded and drilled. Time to get creative!

 

[Wingedwheel]

Would a chain tensioner help hold it off the swingarm?

 

[jpdevol]

I glued a piece of red rubber sheet on top of the swingarm. Set-up is 13" shocks and 32T rear. Chain doesn't rub at rest, but obviously makes contact while running - works good.

 

[MrBultaco]

I don't know if you could use this Bultaco part...it might work. Shipping from the UK would be expensive though.

https://www.inmotiontrials.com/product/sherpa-top-chain-slipper-198a199a-onwards/

 

[nighthog]

Thanks, all. That's given me some good ideas

 

[gggGary]

Radian

 

[gggGary]

https://www.ebay.com/itm/115509211799

 

[arcticXS]

Out of curiosity, is there any weight difference between OEM XS650 swing arm, and the Radian swing arm?

 

[Jim]

Out of curiosity, is there any weight difference between OEM XS650 swing arm, and the Radian swing arm?

@MrBultaco just put one up for sale. Maybe he could weigh it for us while he has it handy. Tom?

A little more exposure for your ad....

https://www.xs650.com/threads/radian-swingarm-hammerhead-shocks-for-sale.63248/#post-773604

 

[MrBultaco]

12.4 lbs as pictured...in post

 

[nighthog]

Thanks, Gary. I'll see if that's available in the UK, looks ideal.

 

[gggGary]

Thanks, Gary. I'll see if that's available in the UK, looks ideal.

I'll see if I can get out to the shed of ill repute, check the fit on an XS swing arm

 

[gggGary]

Since no one asked.
stock XS swing arm vs Radian arm with same amount of parts attached
stock 10.05 KG
Radian 9.95 KG
I just stuck the guard on the XS arm should be easy enough to make an attach point. Some enterprising soul could 3D print a guard?
Note how the radian rectangular tubes are thicker (taller)at the pivot, chain wear on the radian arm behind the hard rubber guard.
It's slightly longer about 1/2" 13mm
The radian axle is 17mm the whole length, the XS650 20mm, necked to 17 at the thread. It's straight forward to open up the radian axle slots, adjusters to accept the 20mm axle.
Radian arm has a plastic chainguard, prolly lighter than the XS steel chainguard.


Key words; radian custum swing arm swingarm pivot shaft axle fit install modify compare dimension size length width height.

 

[5twins]

I run shocks that are about 13.25" (337mm) long and don't have any chain rubbing issues, so that could be another option - get shorter shocks, lol.

 

[nighthog]

Thanks, Gary. That slider looks just the job, just need to drill and tap one hole in the swing arm to secure it. IF I can find one .... over here, UK and EU, Yam parts suppliers don't even list YX models so maybe the Radian was a US-only bike. I'll keep looking ...

 

[arcticXS]

I'm pretty sure you're correct, the Radian was US market, or at least not on the European market. Same as the Nighthawk models from Honda, CSRs from Kawasaki, and most likely several others, Honda SL from early 70s comes to mind