Topic: cb750 Sprocket options (630 chain)

[uptworedline]

stock 78 cb750Fss

well I searched and searched on the forum to no avail for the answer to my question.
I see a lot of people up/down grade to the 530 chain from the stock 630 chain. well i'd rather not do that since my chain is new and increase the number of teeth in my front sprocket, or if available, reduce the number in my rear sprocket using my chain. i do a lot of highway driving, so i'd rather just have low low rpm.

so my question is (since I have a 14 in the front i think and 43 in the rear), where can I get perhaps a 17/18 front or low-30 rear sprocket to fit my 630 chain?

TIA!

[uptworedline]

so...does this option not exist?

[kghost]

Apples and oranges as far as the 530 and 630 goes....

5 and the 6 refer to chain pitch....as in 5/8 and 3/4...so each individual link is different...630 being longer.

So the tooth count is important to each type.

[uptworedline]

but are there any sprocket options similar to what i'm looking for with the use of the 630 chain in the

[kghost]

Dunno bro......

Just pointing out that 530 is different teeth count wise than 630.

I converted a rear Supersport wheel to 530 for use on my cafe build....

Thats fairly straight forward but I guess of no help.

Look on the bright side.....If you go out and find an answer you'll be the 630 chain guru.

[754]

Search motorcycle sprockets online and see what you find..

 Or walk into any bearing/power transmission supplier, pick a blank rear sprocket of the wall with a tooth count you like, and machine to fit.

[eurban]

www.sprocketspecialists.com will either have or can make whatever you want.

[uptworedline]

^^thanks man, that place has everything. not much of a selection for front sprockets in my case, but plenty for the rear. now i have to decide what sprocket i want between 30 and i think 51.

how low would a 31-32-33 bring me?

[upperlake04]

  A gearing calculator - http://www.dropbears.com/u/utilities/gearing.htm

[754]

driven
________   = ratio
driver

[uptworedline]

hey thanks guys, found a different gearing calculator earlier which worked great. so i bought the 32 tooth rear, we'll see how it goes.

another question, is there a maximum front sprocket i can run? like if i go to big will the chain rub on the crank case? what size does this? tia

[ev0lution7]

stock is a 15 front 41 rear... for the "K" it goes pretty good are you sure you want a 31 thats quite a "JUMP"

[uptworedline]

stock is a 15 front 41 rear... for the "K" it goes pretty good are you sure you want a 31 thats quite a "JUMP"

wait stock is 15 and 41 on a 78 750f? i don't have a k, but now i'm confused. and 32 is actually what i bought

[ev0lution7]

oh sorry didnt catch that you have a "F" mine is a "K" its a 77  i have 15 / 41 i dont remember what the "F" is but it still seems like 32 in the rear is a small sprocket in the rear?

[ekim98]

 I doubt that a stock 77 750k will pull a 32 tooth rear sprocket very well. It will be hard on the clutch on take off and probably never really get into the upper rpms where the real power is with that gearing. Gas millage should be good tho, since you won't be rideing it very hard, but it will probably bog out alot.

[upperlake04]

,,wait stock is 15 and 41 on a 78 750f?

 14-43 is stock.  Quick to accelerate but buzzy at  highway speeds nearly 5000rpm @ 100kmph (63mph).  The 15-41 dropped the rpm to about 4600rpm which is more comfortable  but I should have picked the 15-38 which would be about 4200rpm at that speed.  Next set.

[uptworedline]

,,wait stock is 15 and 41 on a 78 750f?

 14-43 is stock.  Quick to accelerate but buzzy at  highway speeds nearly 5000rpm @ 100kmph (63mph).  The 15-41 dropped the rpm to about 4600rpm which is more comfortable  but I should have picked the 15-38 which would be about 4200rpm at that speed.  Next set.

i was thinking about a front sprocket as well, but figured i could save some money and make the drop with all one sprocket (the rear). we'll see how the sprocket does if i dont like it i'll buy like a 37 or something

[754]

You may not be using 5th much, and when you change back you will need another chain...

Most change the front, as they wear out more often and you can change gearing without always having to change the chain.

[uptworedline]

You may not be using 5th much, and when you change back you will need another chain...

Most change the front, as they wear out more often and you can change gearing without always having to change the chain.

however only 14 and 15 front are offered for me and 15 would make only a small difference not enough what i'm looking for

[754]

Are ytou talking what you think you need or want to do..

Vs..

Wether the motor can handle the gearing change you are proposing..

Generally 1 tooth on the front is equal to approx 3 on the back.

Good luck...

[uptworedline]

Are ytou talking what you think you need or want to do..

Vs..

Wether the motor can handle the gearing change you are proposing..

Generally 1 tooth on the front is equal to approx 3 on the back.

Good luck...

so the motor won't be able to handle it? well i just looked at it this way, JT sprockets offers up to 18 front for my bike i think, and coming from 14 up to 18 in the front is about a 12 tooth difference in the rear. my rear being 43, a similar option would be to reduce it to 32 or so, making the same gearing difference. i didnt think it would affect that much as far what the motor can handle. this is what i want to do. motor can't handle that?

[Gordon]

this is what i want to do. motor can't handle that?

I don't think you'll be at all happy with the outcome.  That's a huge gear ratio change going from the stock 0.326 to your proposed 0.438.  Starting from a standstill with that ratio will probably be similar to starting up in 2nd gear with your current set-up. 

You'll have to slip the clutch a lot and you'll be lugging the engine on a regular basis, neither of which are good things.  I also expect that gearing will significantly hurt your fuel economy.  Gearing up, to a certain extent, can increase fuel efficiency, but go too far and it starts getting worse. 

[uptworedline]

this is what i want to do. motor can't handle that?

I don't think you'll be at all happy with the outcome.  That's a huge gear ratio change going from the stock 0.326 to your proposed 0.438.  Starting from a standstill with that ratio will probably be similar to starting up in 2nd gear with your current set-up. 

You'll have to slip the clutch a lot and you'll be lugging the engine on a regular basis, neither of which are good things.  I also expect that gearing will significantly hurt your fuel economy.  Gearing up, to a certain extent, can increase fuel efficiency, but go too far and it starts getting worse. 

thanks for the info gordon. well, i already ordered that sprocket but i should probably buy another (bigger) one. what would you suggest as a rear tooth count for my situation? tia