Tin Derby Covers

[Kevin56]

G'day from the Australian Tropics,

I have two chromed derby covers for a 1969 XLCH fitted with a 1966 clutch. One cover is brand new in its 1966 box, correct part number (and yes it cost a small fortune). The other is a used one in usable condition from an eBay seller. They are both "ribbed" where they fit over the clutch cover (the dome). The intention was to use the 2nd-hand one during the initial 500 mile run-in phase when the engine is complete and bike gets on the road.

The new one has a higher ribbed area allowing plenty of clearance but the used one touches against the dome of the clutch and shows signs inside of wear caused by the outer edge of clutch cover chafing against it and a loose chain gouging part of it.

The difference in the height, measured on a flat workbench and using a spirit level and steel ruler is between 1/16" and 3/32" (or 2ml approximately). I wouldn't have thought that would have such a close tolerance. I and my engineer friend rebuilding the motor are curious if there were two different covers to suit different models? The used one also has an odd indentation along the top flange-lip where it is attached to the engine case.

I could still use it if I make a thin spacer plate out of a 2 ml sheet of aluminum and use a gasket on both sides of it. A few hours extra work to make it but how can you calculate the labour cost of love?

Can anyone shed any light on this used cover?

[Lisa]

I have a double sided cork gasket with a metal center that measures 85K NEW for this cover. I have one on my 69 XLCH and it doesn't leak one bit I had 3 of them all tol. They were sold years ago by I don't know who might be V Twin can't remember ? 4137834045

[wz507]

Cometic also makes a 0.060" thick AFM gasket for your application.

https://www.ebay.com/itm/Harley-58-69-Primary-Cover-Gasket-AFM-060-Cometic-C9317F5/401409258282?fits=Model%3AXR750%7CMake%3AHarley-Davidson&hash=item5d75db332a:g:gQwAAOSwke9aTXNB

[Ferrous_Head]

The indentation is for the extra screw used on XLR's.
I think some XLR's ran narrower clutches to get more ground clearance. But of course unless the primary cover was narrower too you wouldn't gain anything.

[wz507]

Thought this might also be of interest on the subject of the cover with one missing hole.

viewtopic.php?f=15&t=524&hilit=primary+cover

[Kevin56]

Thanks Lisa, Ferrous_Head and wz507, the mystery is solved!

My engineer friend suspected XLR. I will purchase one of the thicker Cometic gaskets. Its good to know the derby cover won't simply become a wall ornament. Thanks again

[riverdog]

Hi kevin, If I read you right , you have a brand new in the box OEM Harley Davidson ribbed primary cover with out the !0th hole and without an indent for one,
If so I wonder if you could put up a pic of the whole front of the cover, I think I have the same cover on my 62 but never believed it was stock, pic of the box would be nice too..
Thanks a lot
Bob

[Ferrous_Head]

I have a NOS one on my 66. Came in the HD box. It has the indentation. I no longer have the box it came in so can't tell you the exact part number for it.

[JerrryR]

Hi Fellas,
Here is a shot of my primary cover on my 68XLCH. I believe the bike is pretty much original paint which is my way of saying I think the tin primary is original OEM on the 68?

68XLCH OP.jpg (194.05 KiB) Viewed 12610 times

[riverdog]

hey thanks Jerry, that is my exact cover, except mine is black, I was led to believe that all OEM ribbed primarys had the indent, im glad to see there is still a good chance mine is Harley
even if the wrong year

Bob