New Guy First Build

[Soquel Flyer]

Hello out there! I introduced myself in the "new guy" section and promised pics of my pile of parts so here goes...

I've been thinking about a motorized bicycle for some time now, then when I saw Pat's Sportsman and the Bonneville Flyer on the salt I was hooked BIG time. I want to build a board track bike. I did my reading homework and then got lucky and found a very used old Boeing Worksman Newsboy on the local Craigslist.

It needs some help on the upper frame tube due to some really bad welding to install what I guess was an engine at some time in it's life.

Here's the current pile of parts. I've disassembled everything for inspection, repair, paint (black) and a Honda 4 stroke If I can stuff it in there.

How not to weld your motor mount - hole blown into the tube

The other motor mount spot. This one had caused a 3/4" crack and a hole in the tube -

Here's what the "Good old days" thick American chrome was like. Check out how well the chrome cleaned up compared to the untouched wheel -

The fenders are not going to clean up like the wheels, but that's just as well as they will get media blasted and painted black with old school red pin striping . They will be shortened as well -

First "new" part to go back on and I don't have to do any hard work to it - Yay! Monark forks -

SORRY ONLY 5 PICS ALLOWED... OH WELL.

OK, back to work for me. Time to set up the welder and fix the frame tube. More pics to follow...

 

[Velodrome]

Hey S.F. Welcome aboard! Looks like you off to a good start with some quality parts!

 

[curtisfox]

Welcome aboard
Thats a good start and if you need more room find a girls bike down tube and fit it in. The old Schwinn have really good curved down tubes...........Curt

 

[Tinsmith]

Good start! Like Curtis says, an early 50's girls Schwinn frame will match up well with the Worksman to give you extra room. Three or four years ago when I got my Worksman I was looking for a way to get more room to mount an EZM 4-stroke. Happened to be at an auction and saw the old girls bike and thought it might be worth a try. I bought it for $35, brought it home and layed the framd over the Worksman and it matched up perfectly. I'm sure some of the real experienced guys on this site already knew that, but for me it was like winning the lotto. Cut both frames up and put things back together and it has worked great ever since. I think there are some pics of my bike on a thread called EZM/Worksman Stretch. Take your time and ask questions. The fellla here have the answers. Good Luck, Dan

 

[pedalslow]

Use aluminum foil and water and those fenders will clean right up dude.

 

[truckd]

I have found that Oxalic Acid/Wood bleach works GREAT for removing rust you can get it at a hardware store couple of scoops in a large plastic storage container, little brushing with a tooth brush and terry cloth every thing should look new again.

 

[Soquel Flyer]

Wow, great tip about the girls bike tube, thanks! I would not have thought that one up myself.

One thing I'm trying to understand is the options for getting the power from the motor to the rear wheel and not have the pedals turn via the engine power. I want to use a centrifugal clutch. I have the Shimano rear coaster hub that comes stock on the Worksman. I'm thinking the coaster hub/sprocket would freewheel if I was driving a second sprocket on the right side of the rear hub via the engine with a chain?

If that's the case then I just need to get the engine sprocket inline with the rear hub sprocket and add some kind of intermediate idler/chain tension device between them?

Never done this before, can you tell? I appreciate your help.

 

[curtisfox]

Your thinking is right,but depends on what engine you run. The best is a jack shaft then you can center the engine and have room to line the sprocket to the rear.

Myself i like the Wizzer belt to the rear wheel, but that just my thoughts. Belts are quieter.

 

[KCvale]

One thing I'm trying to understand is the options for getting the power from the motor to the rear wheel and not have the pedals turn via the engine power. I want to use a centrifugal clutch. I have the Shimano rear coaster hub that comes stock on the Worksman.

With a 4-stroke you can either mount a big huge sprocket or pulley to the left side of the back wheel, or use some gear reduction in between the engine and a much smaller sprocket on the left.

I haven't built a big pulley belt drive so I have no pics of that.

Personally I like the $350 49cc HS 142F 4-stroke Honda 50 knockoff engine and 4G belt gear reducer kit from gasbike.net for most 4-stroke builds, it's easy and reliable.

There are other gear reducing transfer cases like Q-matics which work well especially with a bigger engine like this 79cc Prediator with Q-Matic but I don't thank an engine that size will fit in your frame, not easy anyway.

One other drive option I particularly like is 'jackshafting' the left side drive over to the right side pedal drive system.

As far as I am concerned this is a waste of time and money if you don't take advantage of rear wheel gearing so your engine has a shifting transmission which of course changes everything!

You can avoid a separate gear reducing transfer case by sizing the 3 sprockets in a homemade Jackshaft chain system but I find all the pioneers that came before me have it down pretty good providing a 'box of parts' that has everything that works well together like SickBikeParts.com offers for $200.

To answer your question about how to keep the pedals from spinning when the engine is powering the back through the pedal drive system, that is accomplished with a 'magic' bottom bracket pedal/sprocket combination that isolates the dual sprocket chain rings to spin free from the pedal axle like a socket set ratchet.

It is called a freewheel bearing but it's a special one designed to fit a standard size 3-piece pedal BB shaft and allow 2 sprockets to be attached to it and not cheap for a good one, ~$75 and when you add in a wider crank axle, sprockets, chain, wider pedals etc it all adds up to a lot of parts, a whole engine kit box size full.

I suggest you read the installation manual for the SBP 4-stroke shift kit regardless of what system you use as it does a great job of helping you understand how a JS system like this works like my latest HS 49cc 3-speed shifter.

It looks a lot like the direct drive above expect there is no left side drive chain to the wheel, just a hint of a gear there.

On the right side you can see how the SBP's custom motor mount plate, jackshaft sprockets, and the 'magic' dual sprocket ring work to put both pedal and engine power to the 3-speed internal gears on the back wheel.

That should set you on the right path for selecting a drive train for a small pull start centrifugal clutch 4-stroke drive train be it DIY or kits.

ONE NOTE ABOUT BUY 2 KITS:

The $200 SBP 4-stroke shift kit replaces everything in the $350 gasbike 4-stroke kit except:
Engine & 4G gear reducing transfer case.
Gas Tank and throttle.

Left over gasbike parts:
Engine mount plate and all of it's hardware.
410 chain, tensioner, back wheel sprocket and rag joint mount.
Entire BB assembly including wide pedal crank axle, bearings, pedal sprocket and wide cranks.

If you don't want nor need another leftover box of parts you will never use I would suggest going with the SBP shift kit and just getting the rest of parts you need piecemeal.

Depending mainly on if I was going to use a kit gas tank or custom I can go either way as the cost is close I have to manually do the math but for the most part I build bikes for a living so all the leftover parts go into inventory for me dirt cheap and why I do it that way.