DJ,
This is one where I will probably ramble too much, but here it goes.
Since the final drive ratio is the same it does not make that much
difference, I would rather have the five speed on a pure street bike though.
Harley four speed cases have replaceable tappet blocks. When they wear,
buy new ones and drop them in. Five speed cases have them cast in, and as of
yet there no fix.
Four speed cases have a bigger cam chest that allows you to run larger
cams easily. On five speeds, you have to run cams with a smaller base
circle, and remove metal in the cam chest for lobe clearance.
Four speed outer clutch hubs have the alternator magnets glued in the back
of them and ALL of them come lose, and sometimes get caught between it and
the altenator (ouch!). There is a real good fix for that though.
Five speeds are belt driven, and the belt does not tolerate the abuse
like a chain, nor offer the large selection of final drive ratios.
If you are building from scratch, buy S&S Sportswear cases with a
four speed front, and a five speed rear. I would (and am) start with a four
speed Evolution sportswear, but really when it is all is said and done,
either can be made to work.
For what it is worth, I am rebuilding a 88cubic inch 1986 Evo Sportster,
and have been through alot of the roadblocks you might encounter.
Dale "chief" Thomas
-----Original Message-----
From: DJ <speed@gloenterprises.com>
To: land-speed@autox.team.net <land-speed@autox.team.net>
Date: Friday, December 31, 1999 5:21 PM
Subject: 4 or 5 speed
>In planning my motorcycle construction I have the option of using a 4 or 5
>speed transmission, I plan on reaching approx 140 mph, is there any
>advantage over one or the other since both give exactly the same ratio in
>high gear? Or will it not make much difference?
>
>
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