Topic: Where can I get a 630 to 530 chain conversion kit?

[blackhog02]

It looks like the  PO of my 78 CB750 did a home made conversion from a 630 to a 530 chain.  The front sprocket he used seems to be kind of micky moused onto the drive shaft.  It has the OEM single bolt and washer to hold it on to the drive shaft but the sprocket is too thin or needs a spacer because it has way to much free play on the shaft.  The sprocket he used takes the plate with two screws but the drive shaft does not have the grove for the plate.

Anyone know where I can get a proper 630 to 530 conversion kit?

[MRieck]

Check out the JT Sprocket website. I don't know the address off hand but a quick search should do it.

[blackhog02]

Found the site at http://www.jtsprockets.com/ but i did not find anything on conversions.  It looks like a realy good site for OEM replacements.

[the_genrl]

whats wrong with the 630 chain?  arent they supposed to be stronger?   cause, ya know, bigger number=better right?

[frostypuck]

Actually, the front sprocket will always have side to side free play on the shaft. As far as I know, sprockets don't come in thinner or thicker sizes, when I did the conversion on my '78 750K (now sold) everything went together very well without spacers, at least on the front. The rear wheel needs to be spaced slightly.
The reason that most people I know of that have done the conversion is because a 630 chain on a '70's vintage 750K is overkill. Also the ratio's Honda came up with for the sprockets make it less quick than the pre-77 bikes. Therefore, when I did the conversion, I simply used the pre-77 sprocket set up, and used a large washer as a spacer to push the rear wheel to the left slightly to make everything line up. Also, the price difference between 630 chain and sprockets and 530 chain and sprockets, and the easier availability of a 530 chain/ master link made the decision  an easy one. And if you need just a little more persuasion, the whole set up probably weighs 5 lbs less than the 530.
P.S., you didn't buy your '78 from someone in SC, did you? Just in case it was mine from a couple years ago.
Chris in Boston

[blackhog02]

I pulled out the metal ruller and I would say there is almost 1/8 of an inch that the sprocket travels on the main drive shaft.  Not sure but with that much travel it seems like the chain could jump off the sprocket with a sudden move or slap of the chain.   I have a 75 CB500t a 77 CB550 and a 82 GS850 none of them have anywhere near that much movement on the front sprocket.

I picked up the bike from a guy in NC he only had it for a short time. the PO used some silicon between the sprocket and the washer to take up the space.  I think a sprocket plate that normally fits into the grove on the drive shaft would work as a spacer to tighten things up between the washer and sprocket in this set up but I am open to any ideals.

Bart

[Terry in Australia]

Sprockets DO come in different widths to suit different applications, the sprocket on my Suzuki GS1000S is maybe 20mm wide, at the hub. (inbuilt anti-vibration damper)

As I said in a previous post mate, that set-up on yours is "bodgie". 1/8" is far too much side play!

If the sprocket is a good fit on the splined shaft, take it to JT sprockets (or a good bike accessory store) and buy one in the correct width to maintain chain alignment, or it'll flip the chain off, and that's just nasty!  

[the_genrl]

what ratio do you guys run?  It says im at 2.73.  would going to 2.87 or 2.93 really make that much of a difference?  or would it just make my gas mileage worse. 

(sorry to kinda throw this into your thread, blackdog)

[MRieck]

what ratio do you guys run?  It says im at 2.73.  would going to 2.87 or 2.93 really make that much of a difference?  or would it just make my gas mileage worse. 

(sorry to kinda throw this into your thread, blackdog)

It will make a difference. How much depends on the CB model as there are different final drive gear ratios. In general you will improve acceleration and increase RPM at any given speed.

[blackhog02]

Found a guy at the local bike salvage shop that also has a same year cb750 and can help me.  I was going to go by today but could not get off work in time.  He can also order a conversion sprocket but the smallest he can get is a 17 tooth.  the OEM is a 15 and it currently has a 16.  Would a 17 tooth be too big

Thanks for all of the feedback.