lucky enough, I was the one to buy the KHRM cases that Mike from this forum offered ... I was in the process to rebuild a 55KH I bought more then 10 years ago, but the cases needed so much welding, that I took the chance to buy these very nice unmolested cases from Mike (thanks again Mike!) ...
So now I think its time to collect information on the KHRM and I think it might be good to collect all information in one post here. Thats why this post will have many questions and many different "chapters" -- I hope thats OK.
Customer:
I think the first important question is, who was the potential customer of the KHRM, as this might shade light on where and how the KHRM was assembled. From my point of view its not very likely, that a "professional" racer or KR customer would buy a KHRM, as the desert races take a lot of time without any points in any championship. I am not sure about the price money at that time, but I am pretty sure it was not relevant. So my assumption is, that the KHRM was ordered from privateers that would race 1-3 races a year and would like to ride the KHRM once in a while on the street. Saying this, I would assume that the KHRM was assembled like a factory build KHK and not in the race department.
Engine Cases:
Obviously the cases are "normal" KH cases with roller bearings and cam bushings. The bushing shoulders are "notched" just like the bushings on my KH (not sure if this was a KHK modifications for high lift cams, as my KH was raced hard). The only real difference towards the KH/KHK cases I can spot is the additional threads for the tin primary cover.
It makes a lot sense, to not use ball bearings in that engine, as in desert races the mechanic is not maximum on the other side of the track! Reliability is an essential aspect of a desert racer.
Also it seems, that the KHRMs were assembled in batches, as in 55 there are a few bikes with 12.. serial numbers and with 22.. serials. The 12.. bikes have a trap door, -54 belly numbers and no transfer valve, whilst the 22.. have -55 belly numbers and a transfer valve.
Cylinders, Cams and Heads:
From the factory timing instructions its clear that the KHRM was available in (at least) two versions:
- With standard cams -- same timing as KH
- With cam kit -- same timing as KHK
Still not clear to me is which valves (and valve springs) the KHK cylinders would get -- KH or KR?
Frame:
From the KHRMs I have seen (besides one 55KHRM in real all others on pictures only!) I can spot three types of frames. On the 55KHRM I have seen in real the frame is an early K frame with -52 (not welded) neck casting. The frame has not the additional lug on the right lower tube, so I dont think its a racing frame. Then there is the -52A frame without reinforcement tubes and the -55 with reinforcement tubes. As late 55 KHRMs seem to have the -55 neck and early 55 the -52A neck, I dont think the KHRMs used racing frames. Rather the frames were not equipped with the tabs for the oil tank and tool box. I could never spot the additional tab on an KHRM ... My KH came in a -56 frame with the tab, A6 manufacturing code.
Brake linkage and skid plate:
I think these two parts are the only unique part for the KHRM. What irritates me, is that the brake pedal holder is mounted on the left foot peg mount and on one of the tin cover bolts. So the left foot peg mount needs a threaded hole in it. Generally I fond it very weired to use the standard foot peg mount on only one side (right) ...
Other:
- Shocks seem to be heavy duty or the big race shocks
- high level exhaust pipe
- rear fender is a short pre 55 fender (without cutout) and seems to be unique to KRM and KHRM, later then XLCH
- steel rims in 18" or 19" with standard hubs (no -R hubs)
- standard gas tank
- which carburetor? I assume the M53A1?
- no speedo
- lights optional as add-on
- How the hell did the breather tube work without generator?
I will keep this post updated with pictures from my build, but usually I am slow with building due to family and work ...
Thanks for reading!