Author Topic: Sprocket cover rubber chain guide  (Read 690 times)

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Offline Kickstart

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Sprocket cover rubber chain guide
« on: November 23, 2013, 10:40:52 PM »
I don't know what it's officially called, but it's that black hollow wedged shaped piece of rubber that's on the back side of the sprocket cover.  I call it a chain guide as the chain has clearly rubbed into mine.

Are these still available to purchase? (I don't think they're even on the parts fiche).

It looks like mine has been turned upside down at some point (as there are wear marks on both sides).  Is the one side molded to help guide the chain (mine seems to be)? I might ask my friend to try to make me one out of Teflon or something, but I want to make sure I get the original dimension correct.

Thanks,
Chris
- Chris
75' CB750F Orange flake (rider)
75' CB750F Blue (Project)
75' CB750F Painted black (Project)
No Reserve Racing #171 AHRMA

Offline Kickstart

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Re: Sprocket cover rubber chain guide
« Reply #1 on: November 26, 2013, 03:43:00 PM »
bump... anyone have any info on these - suggested replacements?

Thanks,
Chris
- Chris
75' CB750F Orange flake (rider)
75' CB750F Blue (Project)
75' CB750F Painted black (Project)
No Reserve Racing #171 AHRMA

Offline lone*X

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Re: Sprocket cover rubber chain guide
« Reply #2 on: November 26, 2013, 03:56:12 PM »
Something there by accident?  Something the PO tried to quite down chain rattle with?   Looks like a short section of radiator hose.   Never seen anything like that stock.
Lone*X  ( Don )

75 CB550K1  
VTX1800C for two up cruisin.
Several others have come and gone but whose keeping track.
52 years on two wheels and counting.....
"The best safety feature of any motorcycle is the one God put between your ears.  It's also the least utilized"

Offline Kickstart

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Re: Sprocket cover rubber chain guide
« Reply #3 on: November 26, 2013, 05:13:52 PM »
All of my 75 CB750F bikes have it...

Hmm... I have newly acquired K2, I'll take a look and see if it has one.
- Chris
75' CB750F Orange flake (rider)
75' CB750F Blue (Project)
75' CB750F Painted black (Project)
No Reserve Racing #171 AHRMA

Offline mitchie

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Re: Sprocket cover rubber chain guide
« Reply #4 on: November 27, 2013, 07:40:49 AM »
All of mine have had them....  Whats wrong with that one?  worn right through?
I would try the rad hose Idea with a heat gun.

Offline Kickstart

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Re: Sprocket cover rubber chain guide
« Reply #5 on: November 27, 2013, 02:10:58 PM »
This one isn't that bad, but the one on my other bike is worn pretty badly.

Just interested in replacement options.  Is the purpose of this part just support the chain?

I wonder if I could make a better than original part... I could make it out of Teflon... that's good for an extra 5hp, right?  :)
- Chris
75' CB750F Orange flake (rider)
75' CB750F Blue (Project)
75' CB750F Painted black (Project)
No Reserve Racing #171 AHRMA

Offline Johnie

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Re: Sprocket cover rubber chain guide
« Reply #6 on: November 27, 2013, 02:24:25 PM »
The purpose is if the owner does not keep the chain adjusted it keeps it from wearing on the alumimun brace. All my 750's came with it. Never needed to replace any.
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Sprocket cover rubber chain guide
« Reply #7 on: November 27, 2013, 02:35:09 PM »
Also helps to keep the noise down from metal on metal. Do not think they are available from Mr Honda.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline Kickstart

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Re: Sprocket cover rubber chain guide
« Reply #8 on: November 27, 2013, 02:58:01 PM »
I don't think that's an aluminum "brace" where this slides over.  At least not serving a structural purpose for the sprocket cover.  There is some purpose for it being there (the aluminum and the rubber sleeve). 

Intuitively, it does seem like it would have something to do with mitigating a problem with a slack chain, but what's the situation/problem Honda was providing a solution for?

Why is it important to put a chain support (or divider) there?
- Chris
75' CB750F Orange flake (rider)
75' CB750F Blue (Project)
75' CB750F Painted black (Project)
No Reserve Racing #171 AHRMA

Offline MCRider

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Re: Sprocket cover rubber chain guide
« Reply #9 on: November 27, 2013, 03:20:44 PM »
IIRC, there is a part of the cover that "stands out" the cover from the cases. The screw goes through it. Without it you wouldn't get a clean cover to cover fit. The black grommet then mitigates noise from a slack chain rubbing on that standout. At one end of the wheel travel, I forget which, the problem is worse, but just for the moment the wheel is at that extreme.

Again, IIRC, it can't be used if you drop the CS sprocket a tooth,as the chain will slide on it constantly and it isn't meant for that. Just occasionally.

Working from memory. I do know they exist and I throw them away as one thing more I don't need to worry about.   ;D
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."