Topic: chain cuts in alluminium front sprocket cover

[schetebibber]

Hi all,

My chain cuts in my frontsprocket cover . It is a CB750K7, with a 630 chain. My old chain did it, and my brand new chain do it
also.
I have the back wheel in-line, the chain seems to be in-line, in fact... everything seems to be in-line.

There are 2 things I'm thinking of,
- How is the front sprocket mounted? There is a "hub" on one side of the sprocket. Since the old sprocket was mounted with the "hub" on the engine/gear side i mounted the new sprocket the same way. Is this the correct way?
- a few months ago i replace the rearwheel bearings, I'm sure i mounted everything the correct way. But maybe there is something changed and the rearsprocket has changed position a little.





Is there anybody here who can tell me if these measures are correct?

frontsprocket = 29,7 mm
rearsprocket = 23,5 mm

thanks!

[Lumbee]

...how much of a "rub" are we talking here...a few thousands, or so bad you can't install the cover?  Did you change the size (number of teeth) on the front sproket?  The chain on my chop rubs a little, but not enough for me to sweat it...

[schetebibber]

Here's a pic of the sprocket cover. You can see the rub on it.

[Lumbee]

the pics not great, but I think that looks about like mine.  Maybe its possible the sproket cover was broken in the past, and a differnt sproket cover from a diff. year was put on it.  I think they were slightly diff. over the years.  Either way I don't think I'd sweat it.  That cover is aluminum (soft) and the chain is steel, so it'll eat its way to a comfortable spot in the cover.   

[Bob Wessner]

Does the K7 use a different method of locking the front sprocket to the shaft splines than earlier models?

[schetebibber]

Does the K7 use a different method of locking the front sprocket to the shaft splines than earlier models?

Yes. The K7 uses 1 bold in the centre of the sprocket.

Can it be that the K7 uses a different sprocket cover because it uses a 630 chain instead of the 530 on earlier models?

[Dusthawk]

Greetings,

First thing, check if there looks to be extra gap where the chain rides the sprocket.

If there is no extra gap, it sounds as if a previous owner put new sprockets and chain on but went to the 630 as opposed to the 530 size. My 71 CB750 utilizes a 530 and fits perfectly. I know the years are a bit spread out but I would think the size would be the same.

If there is a gap, you are running a 630 chain on 530 sprockets.

I hope this helps, and good luck,

Peace and Long Rides,

Jeff

[schetebibber]

Thanks all for your replies, the solution for this is the dimension of the sprocketcover as someone here also mentioned.
When the 630 chain was introduced with the K7 and the F2, the front sprocket cover got other dimensions..., and on my K7 there is an older model cover mounted.

Nothing wrong with my sprockets, chain and wheel, i just have to do a little tuning on my sprocket cover.