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The 2-Stroke Garage => Turning Wrenches => Topic started by: Membername on April 30, 2019, 12:10:42 AM

Title: Swing arm assembly RD400C
Post by: Membername on April 30, 2019, 12:10:42 AM
I'm finally re-assembling my RD400C, and I really appreciate all of your help to get the project this far.  Two pictures of the progress are below. 

So I think I remember reading on the aircooledRDclub forum that the swing arm should fall slowly down under its own weight (without shocks of course) when tightened correctly.  Does this sound right?  Because when I torqued it to 40 foot lb (36-58 is the spec I believe) it did not fall down under its own weight.  It does move when I move it but it stays in position otherwise. 

Is this normal?

Thanks,
Karen
Title: Re: Swing arm assembly RD400C
Post by: Yamaha 179 on April 30, 2019, 07:51:58 AM
I have always followed the advice you mentioned reading on the air cooled forum; done that for years. Did you replace the bushings with bronze inserts?  That wouldn't make any difference, just asking.
Lyn Garland
Title: Re: Swing arm assembly RD400C
Post by: Dvsrd on April 30, 2019, 08:25:39 AM
Do you have all 3 steel sleeves/ spacers installed? Generally, the total length of all 3 sleeves needs to be slightly more than the width of swing arm with bushings installed. That means you cannot end up having the frame "pinch" the swing arm.
Title: Re: Swing arm assembly RD400C
Post by: Membername on April 30, 2019, 10:31:04 AM
The order I have stuff installed on the left side, from outside to inside goes:

Zerk, bolt, rearset, frame, metal cap, thin spacer, 2nd thin spacer

The right side goes (again outside to inside):

Zerk, bolt, tabbed washer, rearset, frame, metal cap, thin spacer

I didn't put in new bushings.   I do have all three of the steel sleeves installed.

So you guys are able to get 38 foot lbs and the swing arm falls slowly?  This is without the tire in correct?

I greased the bar but maybe I need to grease under the cap? 

Title: Re: Swing arm assembly RD400C
Post by: Organicjedi on April 30, 2019, 11:16:12 AM
I torqued mine to 45lbs and it would still fall under it's own weight. I'd advise you toss out the nylon bushings and get a set of bronze bushings if they are not already in there.

A trick with the bushings is to put them in the freezer for several hours or overnight before install.
Title: Re: Swing arm assembly RD400C
Post by: m in sc on April 30, 2019, 11:27:15 AM
yup. and after  afew rides after everything settles in, repeat the test. you'll probably be re-torquing.  :twocents:
Title: Re: Swing arm assembly RD400C
Post by: Membername on April 30, 2019, 11:53:02 AM
After more reading on the aircooledRDclub site, I think I should remove one shim and try it again.  Can anyone confirm this is the correct way to go?  Also I will look into the new bushings but as Lyn said I don't think this would cause this problem.  Probably need them regardless.

Thanks,
K
Title: Re: Swing arm assembly RD400C
Post by: Organicjedi on April 30, 2019, 01:42:34 PM
My 400D has 3 metal tubular spacers and two dust caps that go on the shaft. I have no shims.

Title: Re: Swing arm assembly RD400C
Post by: m in sc on April 30, 2019, 01:50:20 PM
make sure there is no paint/powederoat on the frame where the cups sit.  and yeah, lose the nylon bushing, they suck.

Title: Re: Swing arm assembly RD400C
Post by: Membername on May 09, 2019, 09:59:08 PM
I removed one shim (so now there is one shim on each side), and it falls slowly just as it should under the proper torque.  Thanks for your help!

K