Andy Morris's Ceramic Coating for Aluminum Engine Components

[Wayne]

i can't recall any lip. the face extending to lip (front visible periphery) is flat smooth surface.  Hard to fathom how a plastic chainguard could scratch into a smooth surface.

Looks like mark's 97 experienced the same fate Steve. I can't tell if the "lip" goes full circumference or not.

[vnz00]

This is not uncommon - #5528 had the same problem too.  If you still have the chain guard and look in the corresponding area you might find flakes of aluminum in the chain guard.  This no doubt would accelerate the wear.

It's a hard area to weld fill too- easily distorts.  I just opted to get a good second hand one. 

Regards,
Steven

[Wayne]

Thanks Steven
My parts list keeps growing and growing. 

[vnz00]

Just check with your local welder- the lip on mine was too thin, however if yours is solid enough on yours, you may be able to weld it.

There are differences in the sprocket carrier markings that I have noticed. Some are stamped, some are cast I believe.  It's always better to restore the part which came with the bike unless absolutely necessary to replace it.

[Wayne]

I'll have my welder have a look. Thanks. I would say from my pic this unit was "cast". Going to need a short chain guard now. Wore the heck out of it!!!

[vnz00]

Hi Wayne, check the underside of the carrier.  There are numbered markings.  I believe yours should be stamped, but later carriers, even those with the sepearate sprocket bolts, have the number cast (raised as opposed to stamped).

[Wayne]

Yep, it's stamped. "13". The 1 is stamped very bold and deep, the 3 not as much.

[Steve Swan]

If the groove worn by chain guard is not too deep, is it possible to turn off (matching the taper of plate) the groove, then polish to hide the turn marks ?

[Wayne]

The "step" goes from the good area at 4.30 MM down to 1.60 MM. Looks like I have about a 2.7 MM gouge. I would never have believed the chain guard did that until I looked at it.

[markb]

If the groove worn by chain guard is not too deep, is it possible to turn off (matching the taper of plate) the groove, then polish to hide the turn marks ?

That's what I'm going to try to do to mine.  I'll post results.
Mark

[UK Pete]

Mark is this part unique to the sancast or is a 69/70 K0 one the same?
If same its a no brainer to me replace would surely be much easier than all that machining

Pete

[Steve Swan]

Wow. that's deep. 

Outward appearance, i don't think there'd be any issue using a 69-70 or probably even K1. 

[Wayne]

Wow. that's deep. 

Outward appearance, i don't think there'd be any issue using a 69-70 or probably even K1. 

Yes, it was wearing away for a while. Wore the lip right off the chain guard. I'll have my welder/machinist see what he thinks before I replace the flange. Like Mark says, for everything that goes well with these things something seems to go wrong!

[hondasan]

Nearly every one I've had has had this problem to some degree. No doubt the presence of road dirt trapped in any oil, etc adds to the abrasive action going on between chainguard and sprocket carrier. I have usually manged to clean them up using various grades of emery cloth. Just takes time.
K1 uses the same part number item, so should be possible to find a better replacement if the wear is too deep - unless of course the worn one is unique to the bike by virtue of casting differences / marks, etc.

Cheers - Chris R.

[Wayne]

I don't know how unique my part is being "stamped" with number 13. (unlucky in this case) As you can see in the side view the wear is quite substantial. Way beyond polishing it out. It woul dhave to be built up and resurfaced. I contacted my machinist to see what he thinks.