1978 UK GS1000 - 530 conversion

[Himble]

Hi folks,
A fellow club member with the abovementioned bike would like to convert from 630 to 530 without changing final drive ratio.
Can someone help please. My friend is not computer savvy, hence the request.

[Nessism]

Move up 3 teeth on the front sprocket then calculate how many teeth needed in the rear to keep the ratio stock. Failing that, the answer is in the archives since this is a common question.

[Himble]

Thanks Ed, will check the archives.

[Sandy]

Yes, 3 teeth on the front (18) will make the rear a 50T. That will keep the stock ratio as close as you can get (within a a couple of 1/100s while allowing for the proper diameter sprockets. If you're searching for proper fitting sprockets use the GS650E for reference. It has the same splines up front and same fitment in the rear as your GS1000 and you'll need the 6mm spacer for the front sprocket. Chain if I remember correctly ended up at 116 links, I just ordered a 120 and cut it as needed.

[Nessism]

Thanks Ed, will check the archives.

Andy,

630 chain means 6/8" between links and 3/8" width
530 chain means 5/8" between links and 3/8" width

page 1-4 of the factory manual (free download on basscliff's website) states the final drive is 15/42 (2.80 ratio)

Move up 3T to 18 front so the rear needed is 18 x 2.8 = 50.4, so round down to 50 just as Sandy states.

The stock chain is 96 links x 6/8" per link = 72" long

72" / (5/8) = 115.2 links, so move up to 116 for the new 530 chain.

[Himble]

Many thanks Sandy and Ed, greatly appreciated! I'll onpass your recommendations to my mate!