What did the sprocket come off from? Any mods to make it fit? How many teeth? Will it line up with motor sprocket when installed? I still want to change mine to chain so I can get some top end out of it. 80mph and redlined doesn't get it!!!!If I can come up with something other than the German kit I''l go for it in a heartbeat. The German kit would give me chain drive, but it only slightly changes the top end speed. Maybe 2-3 mph. Not worth the money. If going from a 152.5 main jet to a 155 or bigger jet doesn't get me any more top end, it's back to changing to chain and sprocket ratio's.
What I'm really trying to do is get less rpm at 80mph.

What is the ratio of your front and rear sprockets?

Hutch, I think the best you can do is goto bikebandit.com and get a 17 tooth front for a gs550 spoke wheel 1980 and a 40 tooth rear for the same year and model.  You can play around with spacers to see what will work best for alignment.  This will give you a 2.35:1 ratio.  Can't find a way to go taller than that, but that's pretty tall.  I'm interested to see how this whole thing pans out

Disclaimer:  Since I haven't personally done the mod I can't verify this will work, but lots of folks seem to think it's close to a "bolt-up" operation.

Here's a handy tool to get ratios & rpms for the changes: http://www.kaila.net/tl125/gearing.html
As for the lube, I've read a lot of good reviews on Dupont Teflon Mult-Use dry wax lubricant, which you can find in most hardware stores for about 1/2 the price of chain lube at the stealership.

Quote:

How well does your bike accelerate now in 2nd gear?  No matter what you do, it won't be worse than that...

17/47 would be a pretty small change, you'd get that much from a rear tire change if you stuff a 150-90-15 back there, not even a 10% change.  Most of the "overdrive" kits found on scootworks.com feature a final ratio between 2.2:1 and 2.56:1.  That seems to be the sweet spot for most v-twin cruisers looking for a "highway gear."  

But....that's just my 2 cents and probably not worth as much    Keep us posted how the project goes.

Here is the break down:------------------ (new ratio)
(stock ratio)--------------------------------17/45 sprocket
50@3111-------------------------------50@2799=312lessrpm
60@3733-------------------------------60@3359=374rpmless
70@4355-------------------------------70@3919=436lessrpm
80@4977-------------------------------80@4479=518lessrpm
90@5600-------------------------------90@5040=560lessrpm
100@6222---------------------------100@5600=622lessrpm
105@6500---------------------------105@5850=650lessrpm

That leaves the new ratio with 650RPM left until the red line, and you are already doing 105mph.
SOUNDS GOOD TO ME. Now if it works in the real world is another story.Since my motor will be running at lower rpm most of the time I think I will stick with my 152.5 main jet and see what happens with the chain conversion.I should get a lot better gas milage(60+?). I know the engine won't wear out as fast, with fewer rpm's for the same distance.I'll just keep playing with rear sprockets until I get a good compromise of acceleration and less RPM at 80mph. For anyone in terested. For every tooth that you add or subtract on the rear sprocket, you will have a change of 2.5% in your speed and rpm. For every tooth you add or subtract on the front sprocket it is about a 5-6% change. A 44 tooth rear sprocket would even be better, if one could be found. That would be nearly 600RPM less at 80MPH

Savage_Greg wrote on 12/31/69 at 16:00:02:

I like the pun there Greg, RUSTY CHAIN, The biggest sprocket that will fit is probably the 17. I suppose that is why the germans chose it. A 530 chain should be the right one if I remember correctly. Yeah that is what I like about chain, no shock removal, no cover removal, no pulley removal, just put in nuetral and feed it through, insert master,adjust, tighten axle,BACK ON THE ROAD.