CAM/ROCKER COVER DIFFERENCES

[kp]

Fellas,
After seeing the cam covers posted by Wayne and Mark it confirmed something I was told a long time back by "I canna remember Jimmy", that there were two types of cam/rocker covers fitted on the Sandcast and K0 series bikes. We now know that Mark's cam/rocker cover is a rare find so that now makes 3 different covers. Type A, B und (and) C. So here they are with Mark's cover heading the list (hope Mark didn't mind me stealing his photo)   with Wayne's Sandcast and my early die-cast cover pictured. Would also like to hear if your covers fit anywhere in the grouping as this will add to our knowledge base of all the changes throughout the whole sandcast production run. Yibida Yibida .............. that's not all folks  

Mark's VIN 97 Cover - Type "A"



Wayne's VIN 576 Cover Bottom Picture - Type "B" & KP's VIN 11970 Cover - Type "C"



Differences between K0 Type "C" Cover and Later Covers

[markb]

(hope Mark didn't mind me stealing his photo)

I don't mind a bit.  Very interesting observations.
Thanks,
Mark

[Steve Swan]

The information is fascinating as well as very professionally presented and important to know depending on how painstaking we are with correct detail.  Thank you, KP !

[kp]

Having seen Wayne's Rocker cover off Engine 748 and Mark's Rocker off Engine 100, I went looking to see what differences exist between covers. Previously I reported on the differences between the 3 covers including a 1975/76 cover I had in my spares box.
Well I removed the cover off my Sandcast Engine 1771 today and compared this with the cover off my Diecast Engine 11974. My Engine 1771 cover is the same as Wayne's cover so I'm assuming these are both original Sandcast Cam covers. I was able to have a much closer look at these two covers (I couldn't get a hold of Wayne's cover ) and the differences are significant. I have no idea why Honda changed these covers and I'm not going to speculate. Anyway here are the pictures identifying the differences for those interested.
Based on this info the easiest way for you to identify which type you have on your engine is to look at the thickness of the centre casting where the crankcase vent cap screws to the cam cover as shown in picture 3
I would be really appreciative if members can post on here and let us know what cover you have and what VIN/Engine number you have and let me know if the cam cover is original to your engine. All adds to the knowledge base  KP

[hondasan]

The major reason for the difference between the two covers will be to accomodate the later type cam carriers fitted from 1010338 onwards - the inlet rocker shafts are longer, requiring the cam carriers to be wider also, hence the "cut outs" and other internal differences noted by KP for the 11974 cover. The parts list provides part number changes for all these components - cam carriers, inlet rocker shafts, cam cover, breather cover.
Presumably the increased height of the cam cover between centre sealing faces also came about to enable the necessary internal clearance for the longer cam carriers to "fit".
It would be interesting to measure the height of the top (breather cover) to see if this has been reduced in height between the 1771 and 11974 motors (probably by about 4mm as per the increase in height of the cover) so that the overall height of the assembled motor is the same.

Wonder why they increased the length of the inlet rocker shafts? - must have been some perceived weakness in the set-up? That said #5298 is at 116,000 miles on the original (short shaft) components and running great.

Cheers - Chris R.

[kp]

That's great feedback Chris. Another part of the puzzle answered. KP

[kp]

The photos of the sandcast cover is already at the beginning of this thread and are common to all sandcasts with the exception of the very early VIN bikes The Breather covers for the sandcast bikes is taller than the later breather covers as well. Can't really add any more

[Don R]

So most sandcasts are more like the c or b type? Mine (ebay) seems to fall somewhere in between. it looks like early on top, newer inside. One should be a c, it's a K0 104xxxx diecast and one is supposedly a 10033xx series sandcast. I have a known K4 to compare to.
 I notice on both of my older ones the front of the cam chain tunnel is rounder than later covers. The K4 is more flat on the front.  I'll post some pics later. On the speedo drive inside there is a pad cast that is angled on the k4 and level the on the earlier.

[vnz00]

Don, Id say the majority of sandcasts had the type B.  5528 I restored had the correct rocker cover with three pairs of criss cross patterns, as shown in type B, and the correct breather cover/breather cover screw combination.

I was just checking my manuals as to when the rocker cover / breather cover combination changed early in K0 production which KP refers to above.  I have changes shown for the Rocker and Breather covers from Eng # 10338, which I thought was when the screw lengths for the cam cover changed (hence the rocker cover & breather cover heights).  HOWEVER the cam cover screws show a change from Eng # 7769 from 70 to 75mm for the rear screws, 50 to 56mm for the front screw.

If the parts manual is correct, it appears there may have been an extra production change in the rocker and breather covers not documented.  However I think it is quite safe to say that all later sandcasts at least, had the shorter breather cover screws.

[Don R]

 Thanks, I purchased a sandcast cover reportedly from 10033xx however it appears exactly the same as my 104xxxx I had previously considered swapping it for the chrome one on my 1005511. I'll go for the dechroming. They did a nice job on my test pieces. I test dechromed the same, later model parts just to see how well the shop did.
 This winter when I remove the chrome one to strip it I'll post pictures of all three.