Author Topic: Fork Internals AS3  (Read 218 times)

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Offline evan_calgary

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Fork Internals AS3
« on: October 08, 2019, 03:34:01 AM »
Hi all,

After a long time sitting I am putting the AS3 front end back together.

I've got 200 parts and the 125 ones which isn't helping.

Do the 125 internals have any sort of damping rod that is supposed to go in them? 

I can see a smaller inner tube in the bottom of the lower but the RD200 forks have tube with a mushroom head that reaches much higher towards the top of the fork.

Want to make sure this goes together proper.

Also, I am in need of some fork springs for the 125.  Does anyone have some? I appear to have potentially misplaced the 125 springs :(

Offline Barnett

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Re: Fork Internals AS3
« Reply #1 on: October 09, 2019, 08:39:52 PM »
Very basic construction, yes lower leg has vertical internal tube sprouting from the bottom of the leg. The damper rod is just a hollow tube with a welded bush on the end, i.e. piston. A little way up is a groove on the tube for a circular spring clip, this is the end stop on full extention, i.e. makes contact with the top bushing housed in the top of the bottom tube and secured by the chrome gland nut. The spring fits inside the damper rod of course, then a thick plain packing washer and small diameter rolled steel preload tube about 1 1/2" long. A thick O ring fits onto the top of the fork tube and seals it against the underside of the top crown casting, secured by the chrome fork top bolt.
The gland nut houses the oil seal, which interestingly has no circlip or retention ring to keep it in, just a tight fit. on the underside of the nut is a large diameter sealing o ring and the thin wall steel bushing which should fit snugly in the top of the lower leg and around the damper rod or fork tube.
So a very basic construction but work very well and give a plush ride!
Yamaha 1974 RD125 (AS3) fully restored 2018 on road
Kawasaki 1977 z650 B1 on road
Yamaha 1972/3 U.S. early RD350 ongoing project.

Online Astute Greaser

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Re: Fork Internals AS3
« Reply #2 on: October 13, 2019, 01:49:03 PM »
Hi all,

After a long time sitting I am putting the AS3 front end back together.

I've got 200 parts and the 125 ones which isn't helping.

Do the 125 internals have any sort of damping rod that is supposed to go in them? 

I can see a smaller inner tube in the bottom of the lower but the RD200 forks have tube with a mushroom head that reaches much higher towards the top of the fork.

Want to make sure this goes together proper.

Also, I am in need of some fork springs for the 125.  Does anyone have some? I appear to have potentially misplaced the 125 springs :(

Will these do
https://www.ebay.co.uk/itm/Genuine-OEM-Yamaha-RD125-200-Front-Fork-Springs/153674156710?hash=item23c7b18aa6:g:8PIAAOSwGRNdmfEE