Sprocket and Chain Replacement

[xmishx]

I just ordered a 530 series chain with appropriate sprockets. I was told by Sprocket Specialists that a 49 rear 18 front was going to run pretty close to stock for my bike. I'm not up on gear ratios, but I just counted the teeth on the rear that is on the bike now and it is only 38 teeth. I'm thinking this a huge jump to a 49 that SS is suggesting. Any thoughts? I do not know how many teeth are on the front sprocket that is on there now.

Also, since I'm pulling everything off to install the new components, is there anything else I should be looking into or replacing? Any thoughts would greatl be apprciated.

Ted
1978 GS1000 E

[80GS1000]

Stock sprockets on your bike are 15/42 front/rear for a gearing ratio of 2.8. The sprockets you're getting will give you a ratio of 2.72, which is pretty close to stock. They suggested that you get higher tooth count sprockets to keep your chain clearance good as a 530 sprocket of a given tooth count is smaller in diameter than an equivalent 630 sprocket. So, a 15 tooth count 530 sprocket is smaller than in diameter than a 15 tooth 630 sprocket etc.

Wouldn't be a bad idea to check and possibly regrease your swingarm and wheel bearings, and check your rear brake fluid if you're in the area anyways.

[Boondocks]

I just ordered a 530 series chain with appropriate sprockets. I was told by Sprocket Specialists that a 49 rear 18 front was going to run pretty close to stock for my bike. I'm not up on gear ratios, but I just counted the teeth on the rear that is on the bike now and it is only 38 teeth. I'm thinking this a huge jump to a 49 that SS is suggesting. Any thoughts? I do not know how many teeth are on the front sprocket that is on there now.

Also, since I'm pulling everything off to install the new components, is there anything else I should be looking into or replacing? Any thoughts would greatl be apprciated.

Ted
1978 GS1000 E

An 18T 530 sprocket is the same diameter as a stock 15T 630 sprocket. A 530 sprocket of the same diameter as a stock 42T 630 sprocket would have 50.4T , so I would go with a 50T 530 sprocket rather than a 49T. This would give you a sprocket ratio of 2.78, which is as close to the stock 2.80 as you are going to get.

[80GS1000]

You could also go 17/48 front/rear for a ratio of 2.82, which is what I did when switching to 520 chain. (http://www.slcelectronics.com/GS1000...1365-small.jpg)

[xmishx]

Thanks for your responses. I just feel better knowing that I'm in the ball park. I got the chain the rear sprocket, but the front sprocket was still being heat treated and I should be receiving that sometime this week.

Thanks also for the tips to address other things while I'm replacing the sprockets and chain. It was also brought to my attention I should replace the seals at both the output shaft seal and shift shaft. Where could I pick up these seals?

Thanks,

Ted

[Boondocks]

Thanks for your responses. I just feel better knowing that I'm in the ball park. I got the chain the rear sprocket, but the front sprocket was still being heat treated and I should be receiving that sometime this week.

Thanks also for the tips to address other things while I'm replacing the sprockets and chain. It was also brought to my attention I should replace the seals at both the output shaft seal and shift shaft. Where could I pick up these seals?

Thanks,

Ted

I don't know who gave you this advice, but if the seals are not leaking I would leave them alone.

[bradleymaynar]

With 38 teeth on the rear it sounds like your bike was set up to be a high speed bike on the straightline. I had a 16/41 set-up on my 1100 with a 630 chain. And while it was excellent on highway mileage, it tended to bog at take-off.

My suggestion, if your bike is basically stock, is to stick with a near-stock set-up on the drive line. If you're going to a 530 conversion, stick to the straight conversion. I think you'll notice a head-jerking difference at take-off speed.

Brad bt