KH and early Ironhead parts interchange

[vexx]

I've picked up a parts bike that has a 56KH left side engine case and right side engine case from a 68XL. The engine has ironhead cylinders and heads. I'd like to begin gathering parts to build a KHK spec engine. I've read that some of the hardest parts to gather for a K engine are the cams and cam cover. I've found some places online that you can purchase cam lobes and reuse donor camshafts with lobes of your desired duration / lift. I know that I'll need a KH right side engine case for the side valve alignment but will I need a KH cam cover or can I use a cam cover from an XL. Is there a way that I can use XL cams with lobes machined for a KHK and use a cam cover from an XL?

[wz507]

XL cam gears are fine donors for receiving press-on lobes for use in a KH engine with a KH cam cover. The K cam covers are readily available (see links below), so may as well use one, then stock idler gear/shaft and generator fit-up are hassle-free.

https://tinyurl.com/49srz24n
https://tinyurl.com/2ns7jyac

Also, look in the technical section here on the forum under “Cam Covers” to see the various K and XL cam covers.

LR XL-KH cam gears.jpg (148.88 KiB) Viewed 65636 times

[vexx]

I've reviewed the technical section and visually I see very little difference between the K/KH cam covers and the XL cam covers. The only thing that sticks out is the grease zerk. Can you elaborate on the reasons that an XL cam cover wouldn't work on a K/KH mechanically?

[wz507]

I've reviewed the technical section and visually I see very little difference between the K/KH cam covers and the XL cam covers. The only thing that sticks out is the grease zerk. Can you elaborate on the reasons that an XL cam cover wouldn't work on a K/KH mechanically?

I did not say an XL cam cover wouldn’t mechanically work in your application. I suggested that it might be easier to employ all KH components rather than mix and match K and XL components that require additional machining for fit-up.

The right KH case is machined to attach an idler gear stud that is secured to the case via a screw through the stud that threads into the case. The idler gear is bushed and rotates on this fixed stud (same stud and gear used in all VLs and ULs). The cam cover is machined to receive and support the outer end of the stud.

The XL idler gear set-up is different, as the gear is not bushed, but rather, has a fixed shaft through it that rotates in bushings installed in both the right crank case and the cam cover. If you care to employ this idler gear set-up (shaft through idler gear) with an XL cam cover, you’ll have to machine the right KH crankcase to receive a bushing for the idler gear shaft.

[vexx]

Thank you for the very informative reply. It makes more sense to me to source the cam cover from a K or KH.

[Rubone]

The XL right case has staright bored tappet holes, the K/KH is angled. XL cams have flat lobes, K series are angled. The parts do not play well together...

[yard man]

I could be wrong, but in your search for a cam cover (someone explained it to me so I’m passing it forward) the difference in the area where the generator idler gear shaft rides is different making the cam covers non interchangeable.

[yard man]

The above picture is xl and this picture is

K/ kh. Again, could be wrong but this was what was explained to me, and it sucks to buy stuff and then have to buy something else .

[hayleyl]

Hello boys and girls - firstly - real men 'push' start their motorcycles (only joking, raced a few old buggers in their time) - use K model stuff with K model stuff. Mixing and matching only opens a can of worms. Having said that, worms are good for fishing. Cheers Hayley.

[Simon]

Ebay item 374942135860 is a K model RHS case, hard to tell if it's for a 900 but it looks as if it's notched for rod clearance - can't tell from the pics without my glasses. Not a bad price.
I have spare K cam covers I believe, as well as a spare set of KH cams if you can't find any locally.