Topic: sprocket setups cb500

[hymodyne]

Is anyone running a 17 tooth front and 37 rear tooth sprocket on a cb 500 engine?
I'm interested in how the change affects performance.
I've read the threads on the gear ratio differences between the 500 and 550. This is an overbored 605 cc engine with a 650 cam and a Mrieck porting job.

hym

[bryanj]

dont forget there was a primary ratio change as well 500 to 550 so overall ratio is similar

[hymodyne]

A hotter cam is supposed to increase the RPMs my engine can produce. The change in gear ratios increased the number of RPMs the 550 motor required to produce the same speeds as the 500 motor. So, if I stick with the 17t stock front sprocket and go with a 37t rear on a modified 500K motor, will the aggregate result be O? If that's the case, what can I expect if I keep the stock 34t rear in place after having made the mods to the engine mentioned above?

Hym

[bryanj]

With a "hotter" cam you WILL need a bigger back sprocket as although you get more power at higher revs you get less at low revs. From memory a CB500 four with a Yosh street cam needed, i think, 38 tooth rear and extra ignition advance and we still found that 5th gear was an overdrive where you lost speed and it was a dog off the line

[TwoTired]

Inside the engine, the primary chain reduction ratio was 2.000 on the Cb500, and 3.063 on the CB 550.  With the stock sprockets on each bike, the 500 had a final drive ratio of 2.000, and the 550 had 2.176 ratio.

If you put a 37T sprocket on your 500 your engine will turn LOTS faster at cruise than a Cb550.  I wouldn't want to cruise on the freeway with the engine winding that high.  But, maybe for drag racing or the stoplight grand prix, it would be fun.

Cheers,

[hymodyne]

what then is a more ideal sprocket set up, front and rear for an engine like mine with the 500's primary drive ratio?

hym

[TwoTired]

What is your goal?  Lowering 0-60 times, or increased top speed?

Do you care about engine longevity?  Time between top end jobs? 

Lower gear ratios make you grin more while throttle twisting, but frown more at overhaul time.

Cheers,

[hymodyne]

I'm interested in making this latest rebuild and overhaul last for a while.

I plan do some touring and highway riding on the bike; nothing too fast- (80mph+) I'm too old for that stuff anymore...

hym

[hymodyne]

do I have any other options besides a 37 or 34 tooth rear sprocket?

[bryanj]

From Honda no, but others make different. Check out 450 and 500 twin as they use the same rear hub

[hymodyne]

thanks Bryanj,
Do these bikes have the same gear ratios?

hym

[bryanj]

Cant answer that one mate, 17 tooth was fairly standard as a front sprocket but not sure about rears, try one of the on line parts people, personally i find Motogrid is easiest to use and there site has a number comparison as well.

[paulages]

sprocket specialists can make anything you want. there are several gear calculating utilities out there that will tell you your RPM at any given speed with any given gear ratio. type "gear calculator motorcycle" or something similar into google and you'll come up with some.

[hymodyne]

http://cgi.ebay.com/ebaymotors/Rear-Sprocket-39t-Honda-CB450-CB500-Twin-CB-450-500-New_W0QQcmdZViewItemQQcategoryZ35600QQihZ006QQitemZ160225953642QQrdZ1QQsspagenameZWDVW
Anyone use this size on their 500/550?

hym