Author Topic: 1971 CB750 C/S sprocket cover question UPDATE  (Read 3138 times)

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Offline Mini Mo

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1971 CB750 C/S sprocket cover question UPDATE
« on: September 26, 2013, 09:13:50 AM »
Hi all-

First post here after following for a year or so.

After refurbishing several '76's and a '75 this is my first early CB. Among the varies differences in the later bikes that I've noticed, I see that this cover does not fit as tightly as it should. It has a piece broken off and needs to be replaced but in looking at the '71 microfiche and the later years there are different part numbers starting in 1973.

Maybe this is off a different year and that's why it's not as tight a fit? Can anyone tell what the differences are and will a later one fit.

Preview is not showing my photos so hopefully they show up in my post

Thanks
Steve
« Last Edit: October 03, 2013, 05:45:13 PM by Mini Mo »
750 K1 (Just finished)
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2) 750 K6's (Restored and sold)
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Offline 70CB750

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Re: 1971 CB750 C/S sprocket cover question
« Reply #1 on: September 26, 2013, 09:18:27 AM »
It looks like the cover is bent?  I would rather think they are all the same 69-78.

I can check for you between 1970K and 1978F if nobody pitches in.
Prokop
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Offline Mini Mo

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Re: 1971 CB750 C/S sprocket cover question
« Reply #2 on: September 26, 2013, 09:25:52 AM »
Thanks.

The cover is actually flush with the top of the case and trans cover. It has an equal amount of gap from top to bottom about an 1/8", like it is just not quite deep enough. The microfiches do show different part numbers. Don't know why
750 K1 (Just finished)
750 K4 (In Process of resto)
2) 750 K6's (Restored and sold)
750 K5 (Restored and sold)
'75 850 Norton Commando (Restored and sold)
'99 Triumph Tiger (Daily rider)

Offline Rookster

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Re: 1971 CB750 C/S sprocket cover question
« Reply #3 on: September 26, 2013, 04:40:50 PM »
The cover did change.  I had the same thing when trying to fit a 71 cover to a 75 engine.  The cover would not fit.  The depth of the mounting bosses are probably what changed.  Overall both covers looked essentially identical and I had a later cover so I just used that and didn't think anymore about it. 

Scott

Offline Dream750

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Re: 1971 CB750 C/S sprocket cover question
« Reply #4 on: September 26, 2013, 06:04:33 PM »
As Rookster pointed out, it’s the mounting boss length. 
 
Your K1 uses the pre-K3 long style mounting boss, pix show the long and short cover difference.
 
Once you have the correct cover, it should fit with no gap showing.

Offline Mini Mo

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Re: 1971 CB750 C/S sprocket cover question
« Reply #5 on: September 26, 2013, 08:01:52 PM »
Thanks for the replies back. Just pulled the cover off and it is the one with the long style boss. I do see a bit of a gap if I put a straight edge to the face where it meets the engine case. Almost looks like it has been filed. Does this look right?

If I hold the cover on with just the bottom screw the gap is pretty good. If I then tighten the upper screw it kind of distorts the cover and pulls that what I called filed area in and creates the gap. Interesting. Guess I'm on the hunt for another cover.
« Last Edit: September 26, 2013, 08:06:03 PM by Mini Mo »
750 K1 (Just finished)
750 K4 (In Process of resto)
2) 750 K6's (Restored and sold)
750 K5 (Restored and sold)
'75 850 Norton Commando (Restored and sold)
'99 Triumph Tiger (Daily rider)

Offline 754

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Re: 1971 CB750 C/S sprocket cover question
« Reply #6 on: September 26, 2013, 08:16:21 PM »
Where you said it looks filed, i think a washer goes there..
 Look at your gap .. The crack is wider on one end when you compare front to back..

...just say NO to crack........
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline cheftuskey121

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Re: 1971 CB750 C/S sprocket cover question
« Reply #7 on: September 26, 2013, 08:23:53 PM »
I'm pretty sure 754 is correct. I remember fitting a washer in there when I put my chromed cycle x cover on. its hard to fish a washer in there because you have to pinch it WITH the cover as you slide the bolt through and then kinda drop the washer and hope the bolt goes through it just right, but nonetheless the top bolt on my sprocket cover most definitely has a washer. hope that helps at all. good luck

Offline 754

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Re: 1971 CB750 C/S sprocket cover question
« Reply #8 on: September 26, 2013, 08:25:14 PM »
I think my 72 had it but not my 73 or later ones.
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline Mini Mo

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Re: 1971 CB750 C/S sprocket cover question
« Reply #9 on: September 26, 2013, 08:40:20 PM »
Again, thanks for the input. The washer makes sense and would take care of the gap issue. Just need to find an early cover without the BIG chunk busted off. Anyone out there willing to sell one?  :)

This is a great forum btw. Regret note posting my progress on several of my earlier projects
750 K1 (Just finished)
750 K4 (In Process of resto)
2) 750 K6's (Restored and sold)
750 K5 (Restored and sold)
'75 850 Norton Commando (Restored and sold)
'99 Triumph Tiger (Daily rider)

Offline 754

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Re: 1971 CB750 C/S sprocket cover question
« Reply #10 on: September 27, 2013, 10:18:25 AM »
I hope to hell there is not 30 bikes among the forum members with these mounted wrong.. Will check the KO parts book later, it should show the washer.
 I think, i used to hold my pointer finger over the washer with bolt flush, then try to get into place without dropping it. ..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline Mini Mo

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Re: 1971 CB750 C/S sprocket cover question
« Reply #11 on: September 27, 2013, 11:18:21 AM »
Well this picture tells a lot. Notice the chain guard and the shape. Looks like it fits right where the notch in the cover is. This explains the gap. I guess if you don't have the guard you use a washer instead!
750 K1 (Just finished)
750 K4 (In Process of resto)
2) 750 K6's (Restored and sold)
750 K5 (Restored and sold)
'75 850 Norton Commando (Restored and sold)
'99 Triumph Tiger (Daily rider)

Offline Dream750

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Re: 1971 CB750 C/S sprocket cover question
« Reply #12 on: September 27, 2013, 11:32:31 AM »
I think so too. Going from memory here: 
 
If your K0 or K1 had the (optional) inner case protector fitted, then the sprocket cover would need a relief added to allow for proper clearance and fitment of the case protector. Once the inner case protector was removed and the modified cover was not replaced, then a washer was needed to make up the gap difference.
 
The early K0/K1 parts book dated 10/70, does not show a washer. Pic #1
 
The later K0 to K4 parts book dated 01/74 does show a washer. Pic #2
 
You can see the case protector in both examples, the washer/no washer requirement is not gospel. Just depends if it’s needed for a good cover fit.


Offline 754

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Re: 1971 CB750 C/S sprocket cover question
« Reply #13 on: September 27, 2013, 03:06:38 PM »
First off KO did not use protector till 26,***
 , and if it is used, I am not clear if it extends up to the cover.
 I forgot to che ck serial number range for the washer ,but there were 3 different covers in  use by the end of KO...approx 44,8**.
I believe my 72 had washer and no protector.

Checked my book that goes to K1 ..washer came into use at #44,806.... Dont know till when ..maybe end of K2.
« Last Edit: September 27, 2013, 07:43:47 PM by 754 »
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline Mini Mo

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Re: 1971 CB750 C/S sprocket cover question UPDATE
« Reply #14 on: October 03, 2013, 05:43:43 PM »
I know this post is a week or so old but I wanted to give an update and FYI:

Bought this from a fellow enthusiast in Reno. Noticeable difference in the castings. Maybe a later model. Not correct for my '71 but I won't tell anyone. BTW it fits perfectly now.

Anyway, just something to look for if replacing this part.
750 K1 (Just finished)
750 K4 (In Process of resto)
2) 750 K6's (Restored and sold)
750 K5 (Restored and sold)
'75 850 Norton Commando (Restored and sold)
'99 Triumph Tiger (Daily rider)

Offline Mini Mo

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Re: 1971 CB750 C/S sprocket cover question
« Reply #15 on: October 03, 2013, 05:44:53 PM »
2 more angles
750 K1 (Just finished)
750 K4 (In Process of resto)
2) 750 K6's (Restored and sold)
750 K5 (Restored and sold)
'75 850 Norton Commando (Restored and sold)
'99 Triumph Tiger (Daily rider)

Offline 754

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Re: 1971 CB750 C/S sprocket cover question UPDATE
« Reply #16 on: October 03, 2013, 07:29:20 PM »
Way less work to use the washer..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline Mini Mo

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Re: 1971 CB750 C/S sprocket cover question UPDATE
« Reply #17 on: October 03, 2013, 08:22:56 PM »
If I didn't have that BIG chunk out of the back of the original I would have just used the washer  :)
750 K1 (Just finished)
750 K4 (In Process of resto)
2) 750 K6's (Restored and sold)
750 K5 (Restored and sold)
'75 850 Norton Commando (Restored and sold)
'99 Triumph Tiger (Daily rider)

Offline kbart1

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Re: 1971 CB750 C/S sprocket cover question UPDATE
« Reply #18 on: February 09, 2015, 06:55:16 PM »
on my '70 KO the engine # is CB750E-1021777 so according to frank it never had the case protector. I am wondering if for safety sake I should fit one? would it fit this case. the cover is totally flat on the surface that mates to the case so there is no relief there for the protector OR washer. would one fit this motor???

thx
kent

Offline 70CB750

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Re: 1971 CB750 C/S sprocket cover question UPDATE
« Reply #19 on: February 10, 2015, 03:12:29 AM »
I had one on my K0, took it out and afaik somebody in Australia now has it on his period correct bike.

Running modern chain and making sure your battery drain does not drip on the chain makes almost 100% guarantee that the chain will not brake.

Prokop
_______________
Pure Gas - find ethanol free gas station near you

I love it when parts come together.

Dorothy - my CB750
CB750K3F - The Red
Sidecar


CB900C

2006 KLR650