Foot pegs

I noticed something was weird with the foot pegs on day one. They were both free but would not drop under their own weight. I had other things to fix and they were working just fine so I did not mess with them until last night. They are made out of the same 9/16″ diameter steel bar stock that every Nethercutt and Rokon I have ever owned are made from. They are retained with short 3/8-16UNC set screws which does not seem very positive. All my other bikes have short bolts that can be locked into position. The set screws were loose when I went to remove them. The first screw came out kinda lumpy like it was side loaded. When it cleared the notch in the foot peg the peg popped out about 1/4″. Turns out there was a heavy die spring between the foot pegs. I put a green MK1 foot peg in the picture for comparison. New one on me. Not sure what purpose the die spring serves.

Prototype 4a, 4b

I see a lot of similarities between this bike and the number 5 bike that I am working on. It looks like it has the same wheels, sprockets, brake and front fork as number 5. The gas tank matches the number 5a picture. The bike I have has a fine thread gas cap like what my MK1s have. I suspect this cap is a quarter turn cap similar to the Stants on our MK3s and MK4s. The cap seems a bit flatter than the Stant so it might be an earlier version. I suspect my bike has a later MK2 gas tank because I do not see any green under the yellow paint.

I see 3 cables and a clutch actuating lever on the Albion side cover so I suspect this bike has a hand clutch in addition to a fluid drive like my bike has.

The slots in the drum wheel fill plug and the miter cap screw are both clocked the same as my number 5 bike. The front miter cap on my bike is clocked differently from the 5a picture but the drum wheel fill plug is clocked the same. The muffler looks very much like what is on my number 5 bike. Looks like my muffler has had the outlet moved from what would have been straight to the rear on the number 4 bike to straight to the rear on the my bike. I suspect this is the same muffler and they robbed parts from the number 4 bike to build my bike.

This bike has the Engray-Maico engine and the right side shifter. The shifter handle appears to be bent forward a bit maybe in an attempt to facilitate foot shifting. The clutch cover is big enough to go over an engine mounted fluid drive. It looks like the driver sprocket is outboard of the fluid drive instead of inboard like number 5.

Prototype 3a

This bike is very similar to 2a and 2b. The rims, handlebars, black sprockets and vertical foot pegs seem to be a match. The big difference is the German Engray-Maico minibike engine. Possibly this engine was swapped into the 2a frame.

The clutch cover looks too small to have a fluid drive mounted on the engine. Maybe this bike had a fluid drive mounted on the transmission. The Engray-Maico puts out 16 HP. The other side of the Engray-Maico engine looks nothing like the 2a and 2b pictures.

Prototype 2a, 2b

I think these 2 pictures are of the same bike. 2a is dated 1959 and was taken by Eleanor Fehn. Jim Cavanaugh stated that there was at least one JLO powered bike before he started working for Nethercutt. According to magazine articles the JLO LK101L , page 2 (MK1 engine) was not introduced until 1962 so I think this engine is a JLO L101L that is the basis for the LK101L kart engine. One of my MK1s has a L101L dated 1958 so these were available in the correct time frame. The L101L was only available with a Bing 19 constant depression carb that has a float. The carb has to be mounted horizontal and 2 of the L101Ls that I purchased were set up with the cylinder vertical and the carb at a right angle to the cylinder. Pictures 2a and 2b look like they have the cylinder mounted vertical. the rims look the same as 1a and 3a. I named these rims X on my spreadsheet.

Prototype 1a

We believe this is Charlie’s first prototype. His wife Eleanor is riding it in 1958. His patent drawings follow this design very closely. I can’t tell what engine is in it but the miter boxes look like off the shelf industrial units. His patent references a 1948 patent that features a belt driven fluid drive mounted on the transmission. I think the same wheels or same design wheels were used on bikes 1a, 2a, 2b and 3a. I see 3 different wheels on the 6 prototype variations. I called them X, Y and Z on my spreadsheet.


I put together a picture with the best shots I could find of the prototype bikes. Best I can figure there were at least 6 substantial variations. I am working on the number 5 variation.

I tried to put together a spreadsheet to make some sense out of all the variations.

I talked with, e-mailed and messaged Jim Cavanaugh about the old bikes before he passed away. This Word document is a tabulation of his Rokonworld message board posts with a few pertinent ones thrown in from Orla and others. Jim was the only hands-on guy we could contact to get info on the old bikes. The pictures and info I got from him were used to put the spreadsheet together. I am sure there are some mistakes.

Military testing

Charlie Fehn’s invention was submitted to at least 3 U.S. military tests for evaluation for use as a NTV (Narrow Trail Vehicle) in South East Asia. I found records of 5 such tests running from November of 1960 to June of 1963. If the information that Jim Cavanaugh gave me is correct then this bike was used in 2 of these tests. He said there was one West bend powered bike built before Nethercutt switched to the JLO powered MK1s.

I have complete copies of RAVE I and RAVE II and 6 pages of the Swamp Fox II Volume III report. RAVE stands for Remote Area Vehicle Evaluation. Best I can figure RAVE I was part of Swamp Fox II. Swamp Fox II testing covered a lot more than just vehicles. There are 10 volumes that include medical and aircraft evaluation. They were testing in Panama to simulate conditions in Southeast Asia. Since the Swamp Fox II report is still restricted I have submitted a FOIA request to obtain the rest of it. We will see.

Fairbanks Morse Recoil Starter

The FM recoil needed a rebuild because it slipped and retracted very slowly. Part of the rebuild was to strip the paint and get it down to bare metal like I suspect it is in the factory photo. I thought there would be gold paint underneath but the entire engine has no paint under the yellow except the carb which is Hunter green. Since I want to use the FM to start the bike I decided to look in my box of FM goodies to see what was there. I quickly found an unpainted FM housing that came from my 82006 powered chainsaw which spins the wrong way. FM recoils are built to be reversible so I used that. 82001 recoil at top, 82006 recoil bottom left and 58011 recoil bottom right. I used parts from all 3 recoils.

All 3 of these recoils had the old style friction washers with round bores. I swapped the old friction washers out for the newer more positive style with 2 flats in the bore. I also put a new 2 stroke rated starter rope on the recoil.

I knew there was a notched FM cup on a 58011 engine that was laying around somewhere. I was always curious to try that to see if it was more positive then the smooth bore cup. ( I hate FM recoils FYI)

I used a new nut and tightened it up with my impact wrench. They are supposed to be torqued to 35 foot pounds.

I used flat head bolts to center up the recoil starter since the FMs do not self center and many times drag on one side. I also used the handle from the 58011 FM starter since it is wide enough to get 4 fingers on not 2 like the original. (My right hand middle finger pops out of joint real easy.) I prefer the mitten handle yankers but that would not look correct.

I replaced the flat heads one at a time with the correct Pan head screws.

Ignition Timing

I popped the flywheel off to retard the timing since this engine wants to rip my fingers off. I was going to put new points in but the ones that are in there look brand new and are correctly gapped. I backed off the ignition timing a 1/16th of an inch, re-lubed the cam wick and sanded the surface rust off the flywheel magnets and coil fork. The original WICO coil looks good except for yellow paint on the primary wire so I will use it instead of replacing it with a new coil. The engine pulls and kicks over easier now but is still harder than I want since I am old, have a rotator cuff injury that is still healing and my right middle finger comes out of joint easily. I want to use the recoil to save wear and tear on the one way bearing in the fluid clutch.

Kill Switch

I noticed 2 small holes on the left side of the handlebars. The end of the kill switch wire ended there so obviously there used to be a kill switch there. Doh

Both of my MK1s have clamp-on kill switches where the strap is bolted around the bar. I measured the bolt pattern and it was the same. I purchased an old style switch and wired it up. My newer style switch would not be correct.

Perfect fit.