Changing the final drive ratio of a '78 GS 750

[Fast Doc]

I'm new, again. I was a member here for a season, but I was deleted because I did not post for 6 months, so some of you may recall me.

My Suzuki is a '78 GS 750 with a Vetter fairing and hard luggage with 38,000 miles on the clock. It looks good, runs great, and is otherwise all original.

It is stored all year, and comes out for my buddy to ride when he visits me from Kalifornia every year. We take a trip together, usually about 2,000 miles. Other than that, the bike is (properly) stored in the shop.

This year's trip to Yellowstone will be a lot of highway, in the 70 MPH range.

My '07 Gold Wing presents no problem, but I'd like to change the gearing of the old Suzuki to make it better suited for the highway drone. I realize this will affect its acceleration, but we can work with that.

What's the best way? Can I just get a countershaft sprocket with an extra tooth and adjust the real wheel forward?

TIA,

Bill The Fast Doc.

[Steve]

Assuming the chain and rear sprocket are still in good condition, adding one tooth to the front sprocket is the easiest way.
Should reduce operating rpm about 6%.

.

[Dave8338]

Larger on the front sprocket or smaller in the rear, or both. Figure out the ratio that you want and choose a sprocket(s) that gets you closest to that ratio.

[Fast Doc]

Any issues with chain clearance under the sprocket cover?

[Fast Doc]

I found this on Bike Bandit:

http://www.bikebandit.com/aftermarket-parts-list?d=1170244+1173059+2166390+2166526

I want to stick with the 630 chain for now, it's new, as are the sprockets. If I understand corrrectly, stock size countershaft sprocket is 15 and this would give me the options of 17 or 19. I assume the '37' and '39' are typo's (?).

Would the 17 be too big? Would it fit under the cover? would I need a longer chain? Would it still have enough power with two people and luggage aboard?

[tkent02]

Wear earplugs.
These engines were designed to spin.

[Fast Doc]

Well, to put it in perspective, this is my usual ride, so the GS seems too buzzy:





The GS is for my buddy to ride when he visits me every year. We always go for a couple of thousand mile tour. I look forward to it all year:





The GS also helps me remember my youth some, as I had an '80 GS 1100 ET that I rode all over the US and Canada. I had that bike for many years and 75,000 miles.