Ken's Esoteric Hobby Pages
My Welbike
Home | SDMHA | Fort Rosecrans | WWII Welbikes | Welbikes Today | Welbike Technical | My Welbike | Folding Bicycle | MINI's!!! | Re-enacting | Boat Building | Soling 50 | USCG 44' MLB | Contact Me | Favorite Links

My Welbike (aka Mowgli)

Below is the replica Welbike that I own. 

It was hand-made by a friend of mine: think of it as a tiny customized chopper like you see the guys on TV make.  The engine is a Chinese-built copy of a Honda Z50 which makes it go plenty fast.  The handlebars fold down and the seat compresses so it easily fits in the back of my Toyota Matrix  However, this engine is taller than the original Villiers, so this will never fit inside an original 13 inch drop canister.

My Wellbike

You'll also note that I've added crests on each of the "fuel tanks."  One is for the RAF and one for the Parachute Regiment.  I've seen photographic evidence for both, although the additions were probably post-war: they were probably added to the base run-abouts by the same sort of people who did nose art for the airplanes.  The RAF crest is a "RAF Effingham" sticker sent to me by Chris at Air Diggers (many thanks for that!) and the Bellarephone is custom artwork that I painted myself. 


Before you think I'm some sort of hot-shot artist, this was how I went about painting this:  I printed the design reversed from the original, then applied it face-down over the red background.  Carefully soaking the paper (and not allowing it to shift) transferred just enough of the ink to stain the paint, which gave me a pattern to paint to.  Then a few hours with light blue paint and a small brush got me some nifty artwork!

When the bike was first built, it was painted using a specially mixed paint that was color matched to the British Army green (the builder calls it British Racing Green, which is pretty accurate).  The closest color that I've found to it is called "Marine Corps Green" that's availible in spray cans in most surplus stores.  It's a bit darker than the British green: look carefully at the front forks in the pictures above; they're not in shadows, that's the darker shade of green.  There are also a few chip touch-up's on the top frame that show off the darker color. 

The original engine that the builder had used was a 32 year-old Honda 50cc engine from a Z50 motor scooter.  It's main strength was it was free, but it was also pretty worn out and barely made enough compression to run.  After some searching, I found Hooper Imports, a source for Lifan 50cc engines.  Turns out after years of building 50cc motorscooters, Honda has now abandoned the market, which is now filled by a Lifan Motors, a Chinese company who are taking advantage of the lapse in Honda's patents for these engines.  The engines are exact copies and the new engine bolted right into the bike.  The only modification was to drill out a bolt hole to fit a non-metric bolt.

"Old Mowgli" at a re-enactment at Fort Ord.

Then problem became how to make the replacement engine look "WWII-sh" enough.  As you can see in the picture below, the engine came to me with a bright silver crankcase and chromed cylinder head and carb.  Great for making your Z-50 trailbike look flashy, but not correct for the period.  To get the proper level of dullness, I painted the engine's crankcase and transmission Marine Corps Green (the closest color to British Army Green that's commonly availible), then used high temperature metallic grey paint to dull the chrome cylinder head and carburetor.  Good stuff, that cylinder head paint, and not very expensive, too.

February, 2006
Mowgli's first night in his new home, incomplete, inoperative, and unpainted.

A part that turned out to be surprisingly difficult to find was a proper air filter; seen below it's the green can-like object attached to the metal-colored carb above the engine.  Almost everything that's out there has chrome screens and brightly colored filter elements that would never look WWII.  However, after a lot of searching, I found one that came with a can-type cover that had some promise.  It was chromed (of course) so I sanded the surface with some wet-and-dry 400 grit sandpaper with the intent of just removing the high gloss finish to allow the paint to adhere.  However, a few minute's of sanding proved the chrome was very thin, so I ended up sanding it all off before painting.  A couple of minutes with a spray can and presto! one fairly convincing WWII air cleaner for not too much money.

Another bit of custom artwork, a broad arrow instead of a "LIFAN."

The other challenge was connecting the ignition system.  The modern electronic ignition was not quite as obvious to connect as the original points and coil system. After significant searching, I finally found several diagrams that worked, albeit after a lot of cross-referencing.  If anyone wants to use this engine and has problems connecting the Lifan ignition wiring, contact me for those diagrams.

And why "Mowgli" you may ask?  Well, that's the name given to it by my wife.  She felt it was appropriate to name this machine after the little boy who ran around the jungle in Kipling's JUNGLE BOOK. 



Since this is a reproduction machine it sometimes gets used pretty hard.  During the last re-enactment before I bought it, the bike was ridden into several walls during some "adventures" inside some condemned barracks.  This weakened the welds that attached the forks to the stem and they later partially failed during the first full event that I took the bike to.  That resulted in a trip back up to the bike's birthplace, the El Monte Tank Museum, for a repair day that included changing the handlebar coupling sleeve.


This is the Welbike right after that work was completed, with the museum's work area behind.  You can just see the unpainted repair and new coupling at the front of the bike.


Below is the actual repair made to the backside of the forks, after painting was completed.


The hinge that folds the handlebars is a old universal joint for a 3/8ths socket.  While we were installing the new coupling, the original hinge pin broke (probably because we were using a 5 pound hammer to realign the coupling after it was welded in crooked).  Lucky enough, the second hinge pin was undamaged; here it is cleaned up and ready for replacement (but don't get me started with how tough it was to remove the broken remnant of the old pin).  The brass washer is a custom shim designed to take out some of the play in the hinge and correct the bike's notoriously sloppy steering.  It's a standard #8 washer, hand-filed down to .025 of an inch: a job that took about 3 hours (while watching A BRIDGE TOO FAR, of course).  The steel washer is the universal joint's original lock washer that was supposed to do the same thing, but is now too compressed to do the job. 06/10/2009: don't use a brass washer, it flattens out after a short period of time and breaks.



Since first getting this machine, I've talked to several people about the Lifan built Z50 engine.  One of the common problems I've encountered is a distinct difficulty with adjusting the engine's carburetor.  One thing I've found is it runs rather lean, and the idle mixture adjustment screw needs to be almost fully screwed in for the engine to run.  I'm still getting this adjustment set, so stay tuned for further developments.  If you know of any unique tricks regarding the Lifan-built carb (like what to clean, or unique adjusting tricks) I'd like to hear them.


After the better part of a year, I finally found out several important details:


First, I found out that the carburetor fuel valve (the handle above the sediment bowl) is in the off position as pictured above.  Since the engine gets 100 mpg, it runs a LONG time with the fuel turned off, which makes deducing this fact a bit difficult.  06/10/2009: I've finally tested how long the engine will run with the fuel turned off: 10 minutes at full throttle, 10 more minutes at idle.
Second, there's a dedicated carburetor float bowl drain with a needle valve and drain line; really nice for vehicles that don't run much.  Much easier to drain the fuel from the carb and prevent it from gumming up.
Third: this carb has a sediment bowl.  Be sure to clean it regularly!

In case you care (and I guess you do, since you've bothered to read down this far) the carburator problems continue.  Had the Welbike out at the Chino Air Show and the carb still doesn't work.  Had an air show attendee suggest I run a cleaner through the main jet, sometimes they clog and the engine only runs on the idle jet.  I've pulled the carb off, taken off the float bowl, and cleaned out the main jet.  Sorry, didn't get any pictures of the process, might do it again to get them.  Now I'm waiting for a good day to test it.  Wish me luck!

Yay!  Finally an operating Welbike!  Turned out to be a blocked main jet, a common problem for these engines, according to the Chino air show attendee who suggested I look at it (THANK YOU, WHOEVER YOU ARE!).  To fix it, I pulled off the carb's float chamber; remove 4 screws and the bowl, valve, and fuel line assembly comes off.  I ran a small welding tip cleaner through the center brass main jet.  Reassembled the machine and rode it throughout the Wings Over Gillespie air show.  Sorry, I forgot to take pictures of the cleaning process, but you can see the bowl in the picture of the carburetor above.
I hope to have some pictures of the SWOD (Screaming Welbike Of Death), in all its 35 mph glory, posted here before too long.  I call it SWOD because I found out the hard way that with the engine running well, the bike will accelerate faster than I can.


If you're wondering exactly what I do with this machine, here is a picture to show you.


Here I am goofing off behind the designer and builder of this machine, Danny.  We're at Old Fort MacArthur Artillery Days, a annual fundraiser for this museum and a huge re-enacting event in Los Angeles.

The good news about this event is I found out the Welbike runs great.  The bad news is we also found out that the last repair on the steering column wasn't very good, because it broke when I loaned the Welbike to a friend, and he drove it over a series of speed bumps at 25 mph.  We ground away too much of the weldment to get the adapter to fit onto the forks, so the whole thing was held together by only a few fractions of an inch of welding.


Here is a picture of the repaired connection, still in the vise after the welding was done.  Instead of a internal weld, we found some steel rod stock, and machined it down to fit inside the part that broke.  That gave 1/4 inch of space to make a nice, solid weld and now the extra material fits inside the fork stem.  It's a LOT stronger now.


And to prove it actually works, here's Danny riding the Welbike back into the El Monte tank museum's workshop area.

Well a new year and a new failure.  Again, this one was at the hinge for the folding handlebars, and AGAIN it happened after I loaned the Welbike to someone else.  This time, the connecter inside the 3/8 inch universal socket broke at the lower hinge pin.  As you can see below, here is the new installed 1/2 inch universal joint, with the old, broken 3/8 inch sitting on top of the folded steering column.  I'm still resolving an alignment issue caused by this new installation, but things are progressing well.

Repair, 2014.

On to my other folding vehicle!