Sprocket sizes?

Gotta old Gs 450 with a front sprocket of 16t and a rear of 42t. I've got the repair manual and all it shows is how to change them. Does any body know where I can find a bigger front and a smaller rear (don't we all). I'm getting new crankcase covers for both sides of it and thought I'd do the sprockets as I install the covers. It hauls great a** on the freeway at a steady 75mph, and still has throttle left, I just want to give it more on the higher end so it dosn't have to work so hard those speeds.
Sprocket sizes?
1 tooth smaller on the front is the same as 3 teeth bigger on the back..%26amp; visa versa..





so I would suggest that you go 1 bigger on the front %26amp; leave the rear untill youve tried it..





changing the rear is easy if you want to go more later..





sprockets can be purchased from a local engineering supplier that specialises in chain drives..





quite often you will have to drill the mounting holes yourself..





just clamp the old to the new %26amp; drill through to get them in the right place...





as an after thought... reducing the revs of the motor at 75 MPH.. can mean the motor is actually working harder...even though it is not reving as hard...





what you should aim for is to get the motor reving at the right RPM so that it is producing the maximum power ..





I think you will get better MPG.. but may lose some top end speed.. %26amp; definately lose acceleration..





It is very hard to say definately.. so could be just a case of try it %26amp; see...





hope this helps...
Sprocket sizes?
You don't necessarily want to change the size of both of them, you could step down one tooth in the rear and it will make a difference of about 500 rpm on the freeway. If you step down more than one tooth, you're not going to have enough adjustment on the chain and you'll have to remove a link. There are tons of them on Ebay, here's a 41 for the rear:


http://stores.ebay.com/K-D-Vintage-ReCyc...





Anytime you change sprockets, you need to replace both sprockets and chain at the same time. If you put an old chain on a new sprocket, it will wear unevenly and give you a much shorter life.
Reply:It might still have throttle left but you will destroy your acceleration and have to work your clutch harder off the line. Ask an experienced mechanic at your local workshop for their opinion. Two teeth on the rear is all most road bikes will take comfortably.
Reply:Sorry, Easygoin, front sprockes are splined to the tranny shaft, have to be made for the bike. Rear sprockets have to have the center hole cut to the proper size, and then mounting holes drilled. Some also have offsets, but not many. By far best to buy sprockets made for the bike. Standart commercial sprockets are normally not heat treated,bike front sprockets are. Also, the old GS450 will not poll much more gear, you would have him in 4th all the time. At 75, it is not working too hard now, go up on front, down a couple on rear, and it will be running very hard at any speed.





Tomcotexas.
Reply:I would only go down one on the rear and those are sometimes available at the dealer.