topping out forks

[blacklav]

Hello all,
I have a 1977 D model. I have just replaced fork stantions and springs, what a difference, but the forks are now topping out badly. Its a big thud of metal to metal.

I notice some other models have a spring on the Damper body to stop this. The manual of my model doesn't show this.

So how do you stop it.

I didn't notice it before as the springs were that soft they never pushed the forks upright anyway.

Any help much appreciated

chris r


Read more: http://xs650forum.proboards.com/thread/3261/topping-out#ixzz37udnLVey

 

[Brian902]

Fork oil weight might help by upgrading to 20w or 30w.

And using real fork oil not motor oil.

Check you local dealer or 20w as a start.

It should help slow the rebound, but probably will not eliminate the thump.

If you have spacers in the top of the forks above the springs you can either reduce the length or eliminate.

Sounds like your springs are too strong.

 

[blacklav]

Thanks Brian.
I`m using 20-30 oil which the manual states.
I've just looked at the old stanchions, at the bottom there is a fitted sleeve which contains a very small and weak spring. This I removed but it wont fit into the new stanchions as they already have a non removable sleeve fitted but no spring.
I have now removed the forks and fitted a rubber grommet of 5mm thickness to the damper, this has stopped the metal to metal banging and seems to be working fine.
Its a worry as these stanchions were from Jerry Heiden and for my model so why the difference I don't know. I will have to send a message to Jerry about them.

Thanks

chris r

 

[5twins]

The '77 tubes were the 1st year of the 35mm forks and had those removable parts in the bottom. All later tubes had the parts crimped in place. I don't think that little spring you found in there is for top out protection, I think it's part of the dampening control. It spring-loads a "floating" ring that the damper rod moves through .....

If you could find a pair, you can add the later top out springs to your '77 forks .....

You will lose a little bit of travel and lower the forks slightly but you hardly notice. In fact, many of us lower the forks slightly by raising the tubes in the trees 1/4" to 3/8". This lowers the front end slightly, more firmly planting it and giving a bit better "feel".

 

[blacklav]

Thanks for that 5trees,
It looks like they have sent me the 78 on forks. If the grommet I fitted stops working I`ll have to get some springs or cut a short length of the old ones.
regards
chris r

 

[5twins]

That's probably all that's available. I don't think anyone makes a copy of the '77 tubes with all those removable parts. It was probably a cost cutting measure on Yamaha's part to "simplify" the tubes after '77. Something else of note, you may have noticed the oil holes in your damper rods were beveled. That didn't happen any more after '77 either.

 

[itsatoy]

5trees, lol.

 

[5twins]

Yep, must be that warm beer, lol.