RD400 chain length confusion

1976RD400C · October 12, 2020, 03:59:18 PM

I have a stock 400. 96 links. Swing arm from center of grease fitting to the end is 18 to 18 1/8"

scully · October 12, 2020, 04:13:56 PM

The shock mount to the axle cut out is where the difference exists.

ElFuegoBlanco · October 12, 2020, 04:43:48 PM

Quote from: scully on October 12, 2020, 04:13:56 PM
The shock mount to the axle cut out is where the difference exists.

Ahhh. I see what you mean now! It is definitely a different shape. Not having any history of the motorcycle has made this process a bit of a challenge. Thanks for pointing this out.

Quote from: 1976RD400C on October 12, 2020, 03:59:18 PM
I have a stock 400. 96 links. Swing arm from center of grease fitting to the end is 18 to 18 1/8"

Thanks for this! That would definitely explain the problem.

I guess the next question is whether to stick wallpaper the this unknown swingarm or try to find a replacement RD400 one.

Thanks for all the help once again.
Rob

SoCal250 · October 12, 2020, 04:48:23 PM

Your axle plates appear to be longer and the distance between shock mount bolt and axle is much greater (even when your axle is all the way forward)

Best comparison image I could find quickly. My 1A1 400 is not here so I couldn't go out and shoot a picture.
Compare with other stock 400 images and you'll see the difference.

EDIT: Rob, while I was writing this post I see you already found the diff

RDFL · October 12, 2020, 06:26:31 PM

Always amazes me when I see prices on 400 swingarms.

Hawaii-Mike · October 13, 2020, 03:40:45 PM

If the swingarm works, why not buy a longer chain and use what you have? Many people like to extend their swingarms anyways.

If you want a used RD400 swingarm and can't find a good price let me know. Joe Spooner might be a better source if he has a spare.

ElFuegoBlanco · October 14, 2020, 10:58:44 AM

Quote from: Hawaii-Mike on October 13, 2020, 03:40:45 PM
If the swingarm works, why not buy a longer chain and use what you have? Many people like to extend their swingarms anyways.

If you want a used RD400 swingarm and can't find a good price let me know. Joe Spooner might be a better source if he has a spare.

I was thinking the same thing. As long as the rear fender works and the shocks aren't affected, I'll just suck up the costs of buying a new chain. If a replacement swinger was cheaper, I'd just go that route, though.

ElFuegoBlanco · October 14, 2020, 06:23:41 PM

Huge thanks to John at Economy for helping me out getting the right part. It's such a relief dealing with top notch vendors like them.

Rob

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RD400 chain length confusion