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The KHRM post

PostPosted: Mon Feb 26, 2018 6:28 am
by xlh59
Hi All,

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
I assume that the "cam kit" also included the KHK type cylinders so that the KHRM with cam kit would get the same "engine treatment" like the KHK -- which makes much sense from a production point of view.
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!

Re: The KHRM post

PostPosted: Mon Feb 26, 2018 10:07 am
by Dirty dave
Hi ! I have a 1955 Khrm too . It’s been I a box way to long maybe this post is the push I need to start to get it done .

Re: The KHRM post

PostPosted: Mon Feb 26, 2018 10:24 am
by EKHKHK56
That's neat info. :) I have one frame, and one KRM frame. It's a 54, never had tabs for side covers. And KRM 53.The last one I saw at the auction appeared to have the big KRTT brake package. It was white, beautiful. One of the ones that went with several Ks about 3 years ago at Mecum? Fellow had a large K collection. But who knows, could be wrong or optional.

Re: The KHRM post

PostPosted: Mon Feb 26, 2018 12:25 pm
by wz507
xlh59 wrote: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
I assume that the "cam kit" also included the KHK type cylinders so that the KHRM with cam kit would get the same "engine treatment" like the KHK -- which makes much sense from a production point of view.
Still not clear to me is which valves (and valve springs) the KHK cylinders would get -- KH or KR?

The title of the above subsection is “Cylinders, Cams and Heads”, which begs the question in my mind, what heads did they use on these engines - KR head or the ubiquitous KH type head?

KHK cylinders were fit with 1-13/16” (1.813”) valves, so if these were used on KHRMs, that would be the valve size. The few images I’ve seen of KHRM engines all have the long thin (KH type) valve cover, which only accommodates the long small dia KHK type spring. The KR dual spring set requires the short fat (large dia) KR valve cover. Since the KHRM was a long stroke engine, having considerably lower operating speed range than a KR, the stock KHK spring would be sufficient to control valve motion.

Re: The KHRM post

PostPosted: Mon Feb 26, 2018 3:22 pm
by EKHKHK56
KHK springs are just less coils, and shorter -32 instead of -52 # The KHK will turn 6 no problem. But it torques out around 5.

Re: The KHRM post

PostPosted: Mon Feb 26, 2018 3:25 pm
by xlh59
... a nice start for this post.
@Dave: the parts in your boxes would be of big help. Get started! :D
@Erik: what neck vacting does your frame has? 52, 52A or 55?

About the heads:
I dont think the KHRM used KR heads, as it just does not go together with the KH or KHK cylinders/cams. But another aspect: You can find KHRMs with cast finish outside and polished heads. Another sign that the customer had the option between KH and KHK top end. And propably 3hp extra would not make a signifikant difference in a desert race ..

The "big diameter" heavy duty race shocks bikes seem to be very "low" ... as if the shocks would be only 13,5" in lenght?

Re: The KHRM post

PostPosted: Mon Feb 26, 2018 6:17 pm
by thefrenchowl
1953 KRMs and 1954 KHRM have special cylinders... Nothing to do with race specs, just special cause they have the fins on the right hand side milled a certain way to clear the HUGE Wico vertical magneto. If you submit your supposed KRM/KHRM cylinders photos, I can tell you if they have been milled by the factory or after they left the factory by an owner fitting a Wico on a K or KH...

In 1955, the Fairbanks-Morse appears, so std KH cylinders for these last KHRM.no need for milling fins out.

Apart from that and the magneto, KRM and KHRM engines are just street engine, no race bits inside. The tin covers were added by owners on KRM, not at the factory. Even the KRTTs in these early days had the cast alloy 3 bolt cover. 54 seems to be the start of the tin cover on KHRMs...

How do they breathe without a gene? Good question that I have pondered for more years than I care to name... I personnally have fabricated a number of rotating oil slingers out of the 2 ends of a gene and a shortened shaft in between. If you run without the slinger, all the engine oil will find its way out the breather in about 50 miles, done it, tried it, won't work...

When KRM/KHRM ordered with KK or KHK cams, same cylinders as above, but std K or KH heads milled to clear extra lift. The KK or KHK tune up doesn't involve cylinder work, just head work...

Joe Leonard was givem a KHRM as a reward for his 1955 number 1 plate, so the AMA class C guys must have raced wherever there was money to be made, the Class C schedule wasn't that heavy in these years, 1954: 18 races, 1955: 17 races. 1956: 7 races, 1958: 10 races for the number 1 chase...

Frames... K and KR frames at the beginning... difficult to say... I've seen both frames used on KRM. It's as easy to pinch a K frame before brazing all the uselessbits on so they could mount the horse shoe oil tank. but as easy as pinching a KR frame if one was in stock.

You can believe they were made in batches, personnally, I doubt it...

To finish, one 55 original, never touched, somewhere in Ca... (they must have had spare front cylinders, that's one for a 1954 Wico bike)

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Patrick

Re: The KHRM post

PostPosted: Mon Feb 26, 2018 6:23 pm
by mikeslemmon
the heco shocks I have are 14 1/2 " maybe other sizes as they were used on open wheel coilover race cars

Re: The KHRM post

PostPosted: Mon Feb 26, 2018 7:50 pm
by EKHKHK56
I have several cylinders with factory machined fins for KRM KHRM

Re: The KHRM post

PostPosted: Mon Feb 26, 2018 9:56 pm
by Simon
Here is the brochure for the 54:

54 KHRM.jpg
54 KHRM.jpg (136.9 KiB) Viewed 9504 times


and the 55:

55KHRM.jpg
55KHRM.jpg (222.41 KiB) Viewed 9504 times


Not sure if the shocks are Heco - I'll need to check. The Heco were used on 63 onwards XLRs I believe. From memory the big shocks were a Canadian brand, which I'll confirm shortly.

Joen Leonard's KHRM:

$_57 (3).JPG
$_57 (3).JPG (252.52 KiB) Viewed 9504 times