Topic: front sprocket compatibility

[rugger81]

I stopped at the local parts dealer to order a front 17 tooth 530 conversion sprocket for my 77 cb750K today, and the only ones they had listed in their parts books were 14 and 15 tooth jt sprockets.  They did, however, have a 17 tooth sunstar sprocket listed for the 77-78 f series.  The parts guy said the part is compatible because it's the same sprocket, does that sound about right?

[City Boy]

Be carefull.I think the 14 and 15 are 630 sprockets and the F 17 also.I believe you should look for 69-76 K or F sprockets which all used 530 chains.Standard over the years was 16-17-18.The  18 is preferred so the chain does not turn too tight a circle,although the far superior strength of todays chains should eliminate that issue.Rock On

[eldar]

Most prefer the 17 tooth front for 530 size.

[City Boy]

I should never have used "preferred" as I have no stats to back it up but was doing my best to cover the options available from Honda.So sorry.

[mystic_1]

The parts guy said the part is compatible because it's the same sprocket, does that sound about right?

That makes sense, if what you're saying is that he looked up sprockets for the two models and found that they used the same part numbers in his book.  This would not be surprising to me, based on what I'm seeing in the respective Parts Lists:

K1,K2   23801-300-315   Sprocket, Drive (17T)
K1,K2   23801-300-000   Sprocket, Drive (16T)
K1,K2   23801-300-010   Sprocket, Drive (17T)
K1,K2   23801-300-620   Sprocket, Drive (18T)

K4,K5   23801-300-620   Sprocket, Drive (18T)

F,F1   23801-300-010   Sproket, Drive (17T)


So the F and F1 take the exact same part number for the front sprocket that came stock on some early K machines.

So given the question "Are K series front sprockets compatible with F machines?" the answer seems to be yes, at least as far as fitting on the shaft is concerned.

mystic_1

[eldar]

City, sorry I was not correcting you. 18 was the preferred honda gear for a couple years but most swapped them for 17s as the 18s just did not work very well.

[moham]

18 was the preferred honda gear for a couple years but most swapped them for 17s as the 18s just did not work very well.

eldar, could you elaborate on the problems experienced? I just switched sprockets this weekend (have not got the new 530 chain on yet) and didn't come across any issues in researching before hand. I've still got time to change now before I get the chain back on (btw my bike is 78 750k) if there are issues with an 18/48 set-up...thanks in advance for the info...

[754]

18/48 was factory gearing for a few years.

[eldar]

It is not so much as "issues" but what seemed to happen was when cruising down the highway, mpg was reported to suffer and the bike had a hard time reaching higher speeds. Some of this had been covered by hondaman a few months back. He seemed to recommend going with 17/48 to get my off the line and better overall cruising. Of course it makes things a bit buzzier.

[James]

Have a look for yourself http://www.jtsprockets.com/52.0.html, also look here http://www.staniforths.co.uk/ the images of the sprockets are a bit blurry but you can just make out the sizes, and they list all the sprockets over a couple of pages.

Having a quick look it looks like you use the jtf331, but judging by the measurements and spacing of the splines you can use 550 sprockets (as well as others)

you would need sprockets jtf288 http://www.jtsprockets.com/61.0.html?&L=0&sel_artnr=JTF288,17 or jtf338 http://www.jtsprockets.com/61.0.html?&L=0&sel_artnr=JTF338,17, be mindful of the locking tab screw holes, how does yours secure,? a locking nut/bolt? do you have the groove on your output shaft for a locking tab?

[HondaMan]

The original 750K0 gearing ws 16T/45T, in 1969.

Before May of 1970, Honda changed this to 17T/48T with a small sheet metal guide over the countersprocket, in an attempt to guide broken chains away from the engine cases and crankshafts (expensive warranty repairs).

In 1971, starting with the early K2 models, the front sprocket went to 18T. All the K2-K6 came with 18T/48T from Honda.

I can't weigh in on the "F" models, or the K7-K8... 

[rugger81]

Yeah, you're right James, they at least use the same 630 sprocket.  I'm ordering a 530 conversion sprocket, but I would assume as long as they use the same type of front sprocket for the 630, they should be able to use the same type of sprocket for the 530 conversion. 

I'll go ahead and order the sprocket, thanks guys.

[James]

You're most welcome, I used the jtf288 on mine as I needed to move the chain over on my project (coming soon)