Tool Box

I found 4 Bondo filled holes in the rear fender. Earlier I had noticed what looked like a tool box behind the seat on pictures 3a, 4a and 5b. I decided to go ahead and purchase a 1950s vintage road flare box now that I have a better resolution picture of 5b. I am not certain this is the correct box but it is the closest thing I could find. I bolted it up to the existing holes. I wanted a tool box to carry tools and a spare #35 primary chain.

Seat mount

The seat mount is quite different than later bikes. It is made out of C channel steel and is welded to the rear fork stays since there are no braces going up to the rear rack. Rear stays are also missing on the #2, #3, #4 and patent bikes. They are probably also missing on the #1 bike but the picture is not clear enough to tell. The spring mounts are moved outboard compared to later bikes. The front mounts are 3/8-24 UNF nuts just like the later bikes.

Fuel valve

Since the gas tank was swapped at some point and I suspect is a newer MK2 tank I am not certain that the BSA EWARTS fuel valve is original. The higher resolution FOIA picture that I now have does look correct except it is on the left side not the right side. Complicating matters further is that the valve came apart about a month ago and I lost the plunger, retaining screw, most of a tank of gasoline and my son’s fancy leather boots. Below is the best picture that I could find of the original unit. I suspect I could find the plunger with a metal detector since I know roughly where it fell out.

A new BSA cork lined plunger was easy to find. The retaining screw was not. I finally found the correct 6-40 threaded screw in a gun shop. The retaining screw is too long but I have equipment that can make stuff shorter. Hopefully cork is rated for Ethanol. The new plunger is plated. Not sure if it is chrome or Cadmium.

The fuel outlet threads are 7/16-19. This might be an obsolete JIS -3 thread. The tank threads appear to be G1/8-BSPP which is another obsolete Whitworth thread. There was a Phenolic fiber washer between the tank and valve.

Edit: The phenolic washers showed up and are a perfect fit. They are .062″ thick which is about .020″ thicker than the original washer but that is what worked on the right side of the tank. Since I want to match the SFII picture that shows the valve on the left side I will have to sand the washer to get the valve to clock correctly on the tank. The G1/8-BSPP straight threads will not correctly accept 1/8-27 NPT tapered plugs without chasing the threads with a pipe tap on the right side. I still need to shorten the retaining bolt.

Rear axle

Since I pulled the rear drum wheel it made sense to take a peak at the rear axle. As I expected since the frame is 3/4″ wider than all MK models from 1962 to present the rear axle is also 3/4″ wider. So that makes it 10″ long by 5/8″ in diameter.

The axle came out real easy despite the rust. The spacer on the left is what retains the rear brake drum dust cover in place against the frame fork. I was surprised to see R10-2RS bearings instead of the wider 1623-2RS bearings used in MK1, MK2 and MK3 15″ drumwheel bikes. It was bent by about 1/16″ right where it came out of the bearing on the brake drum side. I used a 2 ton arbor press to straighten it. I did not have to lay into the press very much so I suspect this longer unsupported axle is a weak spot. If it bends again I will look into upgrading to 3/4″ axles. I put cheap wheel barrow grade bearings and a 3/4″ axle in my good MK1 4 years ago and they are still holding up quite well.

The rust cleaned up on my ScotchBrite wheel. The original R10 bearings were good enough to re use but I stuck in new R10s that are about 1/3rd times as loose. The bolts are 3/8-24 UNF and drilled for safety wire although none was used. Both of my MK1s have all 4 axle bolts drilled for safety wire. The chain tension spacers are identical to all models up to present. There is no spacer to keep the drum from rubbing the frame on the non brake drum side. No doubt this is part of the reason why the bike squeaks so much. I will have to take a good look at this as it goes back together. I am thinking a 1/32″ thick spacer is a good idea.

Rear brake drum

I pulled the rear drum wheel to allow removal of the rear miter box, override and driveshaft. Turns out the rear drumwheel has an iron or steel insert for a drum brake. The brake drum measures 6.000″ inside diameter by 1.4375″ wide so I suspect this is for a USA made brake not a metric European brake like the Ducatis on our MK1 bikes. There is no provision for an anti rotation bracket like there is on the front fork.

Here is the front and back of the Aluminum dust cover that is probably the source of the squeaking that I heard since it was rubbing the brake drum insert at one spot. I can easily remove the offending dent. The dust cover is stationary and is retained between an inner axle spacer and the fork.

Swamp Fox II

The Swamp Fox II FOIA report showed up this morning. All 308 pages of it. I have skimmed through it and found 2 more Nethercutt pictures and a few more test results. I have yet to find a connection between Swamp Fox and RAVE testing. Looks like there were 3 Nethercutts submitted for testing. They did poorly. Fortunately the report is just a little bit under my website’s max file size so the whole thing is linked above. Best part is they did not charge me for the report.

I can clearly see the fuel valve on the left side. I will have to switch that. The tool box shows up quite well also. The front engine mount, fork and rear frame braces are not there.

Is the smoke from the Mutt or the Nethercutt?

Yeah….this looks so familiar…….


I am working on the rear fender now. It is the same width as a MK1 fender. The top had 4 layers of paint, some Bondo, a few dents and a small amount of surface rust. The first layer was red oxide primer, then Hunter Green, Bondo in a few places, another layer of red oxide primer and the yellow. The yellow came off easy. I used paint stripper, a wire wheel, a BFH, a Dynabrade belt sander, sandpaper, a wire brush, a sand blaster and my entire repertoire of cuss-words to remove the rest of the paint. There are a few cracks that need brazed. The bottom of the fender had Hunter Green directly on the bare metal and then the yellow. They used a 6″ by 3 3/4″ bolt pattern to mount what I suspect was a toolbox that I can just barely make out in the Swamp Fox II picture. The Bondo was covering the toolbox bolt holes. A 30 cal. ammo box is too big so the quest for a toolbox has begun. Old roadside flare boxes appear to be about the correct size. I see maybe the same toolbox in the 3a and 4a pictures.

The fender is attached with 2 1/4-20 UNC thread pan head bolts at the front that look like they came from a Power Bee. The 4 tool box holes are 3/16″ diameter for #10 bolts. There are 6 10-32 UNF thread bolts through the 3 rear rack tubes. 4 are flat head rusty steel and 2 are flat head stainless steel with Nylock nuts. MK1s use 4 bolts through the outer 2 rear rack tubes. There were no rubber pads between the fender and rack tubes like the MK1s have. I will replace the 4 rusted steel bolts with my stainless steel bolts and Nylock nuts.


This is Charlie’s patent and all of the patents that he referenced in his patent:

3,268,025 Filed Aug. 20, 1963, Patented Aug. 23, 1966, Charlie Fehn’s patent

1,107,990 Filed Sep. 24, 1913, Patented Aug, 18. 1914, Early 2WD motorcycle

1,139,622 Filed May 2, 1914, Patented May 18,1915, Early 2WD motorcycle

1,351,084 Filed Oct. 22, 1919, Patented Aug. 31, 1920, Early 4WD truck

2,357,338 Filed Aug. 7, 1943, Patented Sep. 5, 1944, Fluid drive details

2,435,021 Filed Mar. 11, 1944, Patented Jan. 27, 1948, 3WD trike

2,445,058 Filed Dec. 13, 1943, Patented Jul. 13, 1948, Fluid drive minibike

2,959,237 Filed Jul. 19, 1957, Patented Nov. 8, 1960, 4WD automobile

3,045,772 Filed Feb. 17, 1959, Patented Jul. 24, 1962, 2WD motorcycle

Fluid Drive

The fluid drive was an important part of Charlie Fehn’s invention. It is featured in his 3,268,025 patent. He referenced 2 fluid drive patents in his patent. 2,357,338 is very technical (boring) and details the internal fins inside the fluid drive. 2,445,058 shows the fluid drive engine mounted on a Doodle Bug minibike. I suspect this is where Charlie got the idea to mount the fluid drive on the MK0 engine. The drive on the minibike works without a hand clutch. The fluid drive on the MK0 needs the clutch since it does not slip enough to work like the Albion mounted fluid drives on my MK1 bikes. My first MK1 works best filled to 10:30. My Rust Bucket MK1 is filled to 11:00 and needs about a minute of hard riding before it grabs enough to take a steep hill. I have the MK0 filled to 9:00 (half full) and it still does not slip enough to ride without the hand clutch. Steep hills are no problem with the MK0.

My previous experience with fluid drives was in manufacturing plants where fluid drives were used between an electric motor and a variety of heavy equipment. I see they were also used on Simpson washing machines in the late 1950s. The MK0 fluid drive has a 17 tooth #35 chain sprocket on the engine side.

There is a one way bearing inside the fluid drive that allows kick starting through the Albion gearbox. I don’t want to wear the one way bearing out so I have been using my recently rebuilt Fairbanks Morse recoil starter which is already showing signs of failing. The engine is still difficult to start with the recoil so I may swap out the fluid drive for a 17 tooth sprocket until I can go through the engine and swap out the two .032″ head shims for a pair of .062″s. I have a couple years experience riding Rokons with handclutches. Once I have the engine starting easier with the recoil I will put the fluid drive back on. The 82001 engine is also wearing out the Albion kickstarter.