1979 CR250 Aluminum Swingarm Question

coffmaad
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coffmaad
Edited Date/Time 2/7/2016 6:10am
I am in the process of restoring a 1979 CR250 and when I purchased it, it had an aluminum swingarm on it. I have been researching to find out what brand my swingarm is with no luck. It does not have a manufacturer stamped on it anywhere and it closely resembles a Thor swingarm. I noticed that the chain tensioner setup is different though and it is also wider than the Thor around the axle/chain tensioner area. Can anyone help me out?









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AHRMA361
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AHRMA361 2/4/2016 6:38pm
2/4/2016 6:38pm
It totally has the "Thor" look to it.

I have never seen a PDI or U.S. Sports arm for a 79 CR250 so can't say for sure it isn't one of those.
newmann
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newmann 2/4/2016 6:42pm
2/4/2016 6:42pm
Those are Thor extrusions. No one else had anything similar that I am aware of. Were the ones sold through Fox any different than ones sold elsewhere? I know the DG, Pro-Fab, Ottow's and another one or two for the early CR125M's all looked like they were built by the same person with only minor differences.
newmann
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newmann 2/4/2016 6:49pm
2/4/2016 6:49pm
Does it have a letter and a few numbers hand stamped into the swing arm pivot area? My early Thor RM125 arms had S and a 3 digit number the 76-78 CR125's had H303 or similar 3 digit numbers.
coffmaad
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coffmaad 2/4/2016 7:44pm
2/4/2016 7:44pm
I have searched all over and can not find any stampings on it.

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FreshTopEnd
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FreshTopEnd 2/4/2016 7:53pm
2/4/2016 7:53pm Edited Date/Time 2/4/2016 7:55pm
VMX or other repop?

Very early Fox, before they did their own, might be the case. the Fox Arms used that sort of chain adjuster, which I think is common to some of the Euro bikes (Fox started with CZ's and Maicos at GP Cycles).
newmann
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newmann 2/5/2016 11:23am
2/5/2016 11:23am
Current repro Thor arms have more of a squared /boxed front area.



Karl's Thor replica doesn't look much at all like a Thor arm. No mistaking it as a KLP arm though.





LWC307
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LWC307 2/5/2016 9:37pm
2/5/2016 9:37pm
Could it be a Cross Up? They looked similar. Also there was FMF Godzilla arms but i think Thor made them for FMF anyway yes?
newmann
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newmann 2/6/2016 9:15am
2/6/2016 9:15am
Not a Cross-Up, their extrusions had sharper edges on them. And yes, FMF arms were provided by Thor.

coffmaad
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coffmaad 2/6/2016 8:30pm
2/6/2016 8:30pm
I wish it had some info stamped on it......oh well! I plan on sanding out the rough spots and trying to make it look new again with a fresh coat of clear anodizing. Thanks for everyones input as well!
Oldnslo
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Oldnslo 2/7/2016 6:10am
2/7/2016 6:10am Edited Date/Time 2/7/2016 6:11am
It is a THOR arm...No question about it...

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