Author Topic: Aluminum swingarm quest  (Read 4630 times)

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Offline 85RZwade

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Re: Aluminum swingarm quest
« Reply #30 on: September 05, 2020, 09:22:51 AM »
Thank you all for chiming in! This thread has produced some GREAT information  :patriot:
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Offline sav0r

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Re: Aluminum swingarm quest
« Reply #31 on: September 05, 2020, 11:25:06 AM »
Between the members here couldn't we do a run of aluminum swing arms?

I could machine the dropouts, shock mounts, chain guard bung, and the butt joints on the tubing. Somebody will have to bend the tube, do the welding, and machine the front tube to fit bushings. A jig should also be made.

I'd a guess that a minimum run of like 5 or 6 would be required, but given that this thread continues to march on that should be doable?
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Offline 85RZwade

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Re: Aluminum swingarm quest
« Reply #32 on: September 06, 2020, 08:14:25 AM »
Oh, my. This has just taken a tantalizing turn... I would be in for an RD350 arm for sure.
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Offline sav0r

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Re: Aluminum swingarm quest
« Reply #33 on: September 06, 2020, 07:18:23 PM »
With fall just around the corner this is really the perfect time, IMO, to organize a project like this. If anybody is interested, either in purchasing an arm, helping fab, or both, send me a PM. Let's try to get it going.
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Offline m in sc

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Re: Aluminum swingarm quest
« Reply #34 on: September 06, 2020, 07:27:38 PM »
and heat treating to be done correctly.


Offline RDFL

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Re: Aluminum swingarm quest
« Reply #35 on: September 06, 2020, 07:49:17 PM »
Why reinvent the wheel, like I said in another thread someone with the equipment and skills could do what ever needs to be done, added to the motolanna and sell them.

Offline m in sc

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Re: Aluminum swingarm quest
« Reply #36 on: September 06, 2020, 07:58:06 PM »
i agree. a motolana arm modded for an rd ready to bolt in would be very useful and prob way cheaper.

or

4130.


 :whistle:

Offline sav0r

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Re: Aluminum swingarm quest
« Reply #37 on: September 06, 2020, 08:17:37 PM »
If I was going to design an arm for myself I'd use a thin wall 4130 that's slightly smaller in ID than the stock thick wall tube. I'd bend it, then flatten it slightly in the press so that the oval shapes thick section would be oriented laterally. This would make an arm that was both lighter and stiffer than the stock arm. For what though? There's no real reason to do it, so I've not done it. And I personally prefer the look of the round tube swing arm.

People seem to like that retro/monoshock look though.

As for heat treating, given the loads a twin shock arms sees, it simply isn't needed. Though I do agree it would be ideal.
« Last Edit: September 06, 2020, 08:19:09 PM by sav0r »
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Offline m in sc

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Re: Aluminum swingarm quest
« Reply #38 on: September 06, 2020, 08:28:42 PM »
should on the aluminum, just good practice. But as said, prob not needed.

Offline rodneya

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Re: Aluminum swingarm quest
« Reply #39 on: September 06, 2020, 09:19:05 PM »
i agree. a motolana arm modded for an rd ready to bolt in would be very useful and prob way cheaper.

or

4130.


 :whistle:

Only problem is Motolana does not offer longer lengths

Offline oxford

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Re: Aluminum swingarm quest
« Reply #40 on: September 06, 2020, 10:37:41 PM »
Only problem is Motolana does not offer longer lengths

How long are you looking for?  Pretty sure they are +1 for a 400 and would be +2 for a 350.

Offline rodneya

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Re: Aluminum swingarm quest
« Reply #41 on: September 06, 2020, 11:00:35 PM »
Only problem is Motolana does not offer longer lengths

How long are you looking for?  Pretty sure they are +1 for a 400 and would be +2 for a 350.

Motolana arm is for a SR500, not and RD. It is 1/4 inch longer than the RD350 arm according to the internets.

Offline m in sc

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Re: Aluminum swingarm quest
« Reply #42 on: September 07, 2020, 08:08:45 AM »
im pretty sure nathan told me his was a bit longer than that on his 350. .02

Offline rodneya

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Re: Aluminum swingarm quest
« Reply #43 on: September 07, 2020, 01:03:47 PM »
Dimensions for the Motolana that I found posted online a while back. No guarantee they are accurate.
length to mid adjustment 18.25"
Pivot spread 8.28"
axle spread 7.25"

Offline oxford

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Re: Aluminum swingarm quest
« Reply #44 on: September 07, 2020, 01:36:50 PM »
Based on this picture I see 18.5” from pivot to axle.

I have a 400 arm on my bike and it measured around 16.5” from pivot to axle. 

Nathan reported the moto lanna to be 1” longer than stock 400. 

I have no real idea on what is what other than what the arm on my bike measures.