Topic: Sprocket set on k7 is 41/15 with stock 630 chain. Need a new chain for next season, should I upgrade

[Pielz]

I was hoping to bump my ratio UP TO 3 from the 2.7 that IT IS. lol I think you misread what I said

[Pielz]

Thread has been sitting for a bit but I'm thinking of going with the 16T JTF338 front sprocket and the 48T JTR284 rear. Folks that know, will that work? I'm just trying to make sure before I order so I don't get it and realize I have to return it lol

Also how many links for the chain, think 102 would be good?

[Rosinante]

Resurrecting an old (8 months old) thread.  My K7 1978 CB750K needs chain and sprockets.  I would prefer to switch to the 530 chain/sprocket setup, and I just need to know how to ensure they will fit and function properly.  Since the 530 chain/sprocket is not stock, I cannot just order the "stock" setup.  How do I ensure there will be no problems with fitment and function - offsets - mounting holes, etc.?

Anecdotally, I was imagining my current sprockets are non-stock hotrod units with higher RPMs and more impressive torque.  I do not think that now.  I just looked at some specs showing about 4000 rpm at 55-ish mph.  This is how my bike performs now.  I am a little surprised the factory did not set these up for closer to 3500 or even 3000 RPM cruising at 60 mph.  That would be WAY higher gearing, it seems.  In related news:  I also notice these things will do a 14-second quarter mile.  Pretty impressive for forty year-old technology.

[Bankerdanny]

Resurrecting an old (8 months old) thread.  My K7 1978 CB750K needs chain and sprockets.  I would prefer to switch to the 530 chain/sprocket setup, and I just need to know how to ensure they will fit and function properly.  Since the 530 chain/sprocket is not stock, I cannot just order the "stock" setup.  How do I ensure there will be no problems with fitment and function - offsets - mounting holes, etc.?

Anecdotally, I was imagining my current sprockets are non-stock hotrod units with higher RPMs and more impressive torque.  I do not think that now.  I just looked at some specs showing about 4000 rpm at 55-ish mph.  This is how my bike performs now.  I am a little surprised the factory did not set these up for closer to 3500 or even 3000 RPM cruising at 60 mph.  That would be WAY higher gearing, it seems.  In related news:  I also notice these things will do a 14-second quarter mile.  Pretty impressive for forty year-old technology.

Other will chime in on this, but I know that Cognito Moto sells sprockets with the correct offset to run a 50 chain on a K7/K8

[Rosinante]

Thank you!  I am not finding this on their website but I have send them a question.

Please tell me this, if you know:  Would a chain and sprocket set from an earlier CB750 work?  I think the chain might need to be a little longer (later CB750s have longer swing arms, I think), but would the fitment of the sprockets be correct if I used sprockets from, say, a 1976?

[seanbarney41]

You want a cb650 front sprocket...generally 17 or 18 tooth with a 48 tooth rear for any year cb750...you like to accelerate and understand that these engines are perfectly happy at 7000 rpm all day on the freeway run 17.  You are old and boring and think you need lower revs at 55mph get an 18.  ha ha just kidding guys.  102 link 530 chain is long enough, might be able to get away with 100 link...I always buy long so it can be trimmed to correct length, but I have a cut off wheel on a die grinder and good chain tools...even so, I always buy a clip type master link.  The only hassle then, is you will have to buy it separate.

[seanbarney41]

the other alternative is getting any year cb750 front sprocket and mill the shoulder off one side...most front sprockets are case hardened though so warn your machinist that he is in for a challenge or a trip to the grinder

[Pielz]

I think I ended up with 16 in the front and 48 in the back. So one down in the front from I think what stock conversion would be if you're conserving the final drive ratio. I just wanted peppier lower end cause I hate highway riding and love zipping around the city. 102 link chain I believe as well. Bought a 104 and trimmed 2 links off. Worked really well and hasn't stretched more than a tiny tiny bit I'm the initial few miles. I've put 400 miles on this parts unlimited X-ring chain and I've had no issues at all.

Also 75 on the highway I'm sitting at 7000 rpm or so. So I don't have a ton of overhead but that's not speed I use anyway. I like to cruise the back roads

The sprocket numbers from JT sprockets were 16T JTF338 for the front sprocket and 48T JTR284 for the rear. Had the correct offset and bolt pattern I didn't have to mess with it at all. Although I did smooth the sharp edges of the sprocket teeth with a bench grinder wire wheel at the recommendation of hondaman. He said it helps with break-in wear if they're a cast type steel gear which my front sprocket is

[grcamna2]

Brent,Your 750 has a torque-curve which works best with a certain final ratio;with a lighter 530 chain and sprockets it may run well with a larger countershaft sprocket than what you think.The 750 has a long stroke and is well able to be short-shifted through the gears,plenty of mid-range on those engines.

[Pielz]

Brent,Your 750 has a torque-curve which works best with a certain final ratio;with a lighter 530 chain and sprockets it may run well with a larger countershaft sprocket than what you think.The 750 has a long stroke and is well able to be short-shifted through the gears,plenty of mid-range on those engines.

I was honestly thinking of trying out a 17 tooth front sprocket but wasn't exceptionally excited to buy another chain. Wonder if I could make my current chain work? Wonder if there's any risk in doing that? Cause I don't really want to spend another 100 bucks almost on a chain

[grcamna2]

Depends how close your rear wheel is to the front of the adjustment,a 17 is a very small amount and should be easily 'do-able'.