I ordered a replacement 530 chain for a '76 RD400 cut to stock RD400 length from Economy Cycle
The chain was cut to 96 links and it's too short. The chain I replaced is 98 links. Can someone help me figure out where I went wrong here? The rear sprocket is has 38 teeth, if that helps at all. Even with the rear wheel all the way forward, I'm 2 links from being able to connect the ends of the chain.
Rob
Easy answer, you got an rd350 chain length.
Quote from: Striker1423 on October 11, 2020, 04:42:52 PM
Easy answer, you got an rd350 chain length.
Nope, according to Economys site the 350 is cut to 92 links and the 400 to 96 links.
Do you still have the stock swingarm?
Quote from: rodneya on October 11, 2020, 07:20:03 PM
Quote from: Striker1423 on October 11, 2020, 04:42:52 PM
Easy answer, you got an rd350 chain length.
Nope, according to Economys site the 350 is cut to 92 links and the 400 to 96 links.
Do you still have the stock swingarm?
It was a barn find, so... Yes? As far as I know.
Did you count the links, maybe it was cut wrong?
Quote from: 1976RD400C on October 11, 2020, 08:53:46 PM
Did you count the links, maybe it was cut wrong?
Yep. Old chain: 98. New chain: 96
I have found 96 in several places, including the parts diagram. But then I see 98 in posts like https://www.aircooledrdclub.com/smf/index.php?topic=51468.msg404047#msg404047 and I don't know what to think
Does it have the proper adjusters allowing the axle to move all the way forward in the oval holes in the swing arm? :umm:
Just throwing this out there but could there be some confusion between the number of links with a 520 vs a 530 chain?
Quote from: 1976RD400C on October 11, 2020, 09:24:31 PM
Does it have the proper adjusters allowing the axle to move all the way forward in the oval holes in the swing arm? :umm:
The wheel is all the way forward, yeah
Quote from: Jspooner on October 11, 2020, 09:34:07 PM
Just throwing this out there but could there be some confusion between the number of links with a 520 vs a 530 chain?
All of the chains I see on economy's website say 96 links for the rd400. 520 and 530 alike.
Quote from: ElFuegoBlanco on October 11, 2020, 09:14:57 PM
Quote from: 1976RD400C on October 11, 2020, 08:53:46 PM
Did you count the links, maybe it was cut wrong?
Yep. Old chain: 98. New chain: 96
I have found 96 in several places, including the parts diagram. But then I see 98 in posts like https://www.aircooledrdclub.com/smf/index.php?topic=51468.msg404047#msg404047 and I don't know what to think
96L is correct for RD400 (USA 1A1 & 2V0 and for CAN 1A1 & 3J7)
THE TECH LIBRARY »TRANSMISSION - CLUTCH - FINAL DRIVE (http://www.2strokeworld.net/forum/index.php?topic=66.msg19620#msg19620)
Not sure what model that post on the A/C site is referring to because the UK/EU 1A3 & 2R9 also uses a 96L.
Maybe post some pictures of what your parts look like.
I'm not sure what pictures would be helpful. If you have any suggestions, please let me know.
Rob
That swingarm doesn't look stock.
Should look like this. Notice the axle slot plates
https://www.ebay.com/itm/Yamaha-400-RD-RD400-Used-Swingarm-1976-1977-ANX-B-54/154129701988
https://www.ebay.com/itm/1977-YAMAHA-RD400-REAR-SWINGARM-SUSPENSION-ARM/312174166393
This is very interesting. I have an RD350 and bought the 92L (520) chain from them, and it was 2 links too short as well, even with the adjusters cranked all the way forward. I'm returning it and getting a 100L chain and cutting it to my needs.
(https://i.imgur.com/svefDHK.jpg)
(https://i.imgur.com/sL9z6q4.jpg)
RD250/350 is 92L
RD400 is 96L
520/530 are same length only width is different. 400 swinger is 1" longer.
Quote from: SoCal250 on October 12, 2020, 02:54:14 PM
That swingarm doesn't look stock.
Should look like this. Notice the axle slot plates
https://www.ebay.com/itm/Yamaha-400-RD-RD400-Used-Swingarm-1976-1977-ANX-B-54/154129701988
https://www.ebay.com/itm/1977-YAMAHA-RD400-REAR-SWINGARM-SUSPENSION-ARM/312174166393
I don't quite understand what you mean. I'm not seeing the difference you're referring to between the ebay swing arm and mine.
The swing arm measures just shy of 20 1/4" (best I can measure while installed, anyway) and the rear sprocket is right around 8".
I have a stock 400. 96 links. Swing arm from center of grease fitting to the end is 18 to 18 1/8"
The shock mount to the axle cut out is where the difference exists.
(https://i.ebayimg.com/images/g/IfUAAOSwXRJfd7rx/s-l1600.jpg)
Quote from: scully on October 12, 2020, 04:13:56 PM
The shock mount to the axle cut out is where the difference exists.
(https://i.ebayimg.com/images/g/IfUAAOSwXRJfd7rx/s-l1600.jpg)
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
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
Always amazes me when I see prices on 400 swingarms.
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.
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.
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