Subject: Re: MC-Chassis Re: swingarm brace
> is what I had in mind.
> It may be a bit overelaborate, but then a Vmax can put out a fair
> amount of power.
I have a swingarm braced almost identically to your drawing on my
GS450 sidecar rig, it made an incredible difference. Before I braced
it the back end would hop around in slides making it hard to hold a
line, now it slides smoothly and controllably. I chose this design
because bent tubing offends what few engineering sensibilities I have,
and I don't have a tubing bender.
I used MIG welded box section mild steel tubing, probably .049. I
think I used 1/2" X 3/4" on the sides where I needed tire and chain
clearance, at the front of the swingarm it's 3/4 X 3/4. The chain run
was a bit tricky. The tubes that go to the rear of the swingarm are
welded to the axle dropout, it was even a fairly aesthetic solution on
the GS450. I assume the VMax has two rear shocks, if so you might get
better support if the shaft-side brace terminates at the lower shock
mount (bolted to the shock mount of course).
A lot of bikes put the battery above the front of the swingarm where
the bracing wants to go. I won't spoil the mystery and tell where I
relocated it to on my bike (it's not on the chair). It would have
been much more convenient to brace the swingarm under the bike, but I
wanted maximum triangulation and I needed the ground clearance for
One problem to watch out for is distortion when you weld near the
bearing races. I was really careful and welded a bit at a time,
letting it cool in between welds, but still wound up with too much
distortion. I guess a single thou is too much distortion as far as
the bearings are concerned, probably the right approach is to just
assume that you'll have to clean up any critical surfaces near the
Date: Tue, 22 Dec 1998 19:14:22 -0500 (EST)
From: email@example.com (Peter Alan Engelbert)
Subject: Re: MC-Chassis SA alignment
The most simple and precise fix would be to find a shop with a Compu-Trak
machine. They can verify and fix the misalignment.
>Thought I would post this again in hopes of some input.
>I have a Yamaha V-Max which scares the hell out of me when I hit a bump
>in the turns (typical). I have found that the SA pivot pins
>(overhung)are badly mis-aligned (in my opinion). The bike uses tapered
>I machined a 12" rod with threads on one end and screwed it in the SA
>hole on one side. It was 3/8" off on the other side. This seems
>rediculous.(factory) Is this common? How much off will effect the
>handling and flex? Suggestions on repair? My thoughts were to machine
>about a 2" diameter shaft the width of the bike, and internally thread
>each end to accept the SA pins. Cut out the old threads, align the bike
>with the new shaft in place, weld the new shaft in, cut out the middle
>section when done. This should yield perfect alignment. Hope this
>makes sense. Any help, opinions or suggestions appreciated.
>V-Max Technical List Administrator
>VMOA Northwest Director
Peter Engelbert: bc180@Freenet.Carleton.CA or firstname.lastname@example.org
Vintage Road Racing: it's never too late to have a happy childhood.
End of MC-Chassis-Dgst V1 #860
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