starting a board tracker/vintage inspired bike build

My wife and I are getting prepared to haul our RV cross country, and we couldn't thing of a better way to have a second (and third) haul along vehicle than to build a couple of motorized bikes. This will not be my first motor bike build, and i've even built a couple of custom choppers and a cafe racer along the way, so it should be fun! I've always been inspired by the old 1910's era board track racers (as we all are on here), so i thought I'd try and model my current build off of one of those. Not any bike in particular, but taking ideas from that era and making it look like its something home made from that era.

I got this Worksman bike and frame for really cheap. It's an industrial Tall Cruiser frame with a 3 speed shifter hub. I would have preferred the News Boy frame, but i do like that the top bars run the full length, which will be perfect for the tube tank i plan on putting in it. I also wish that it came with the drum front brake, as the coaster brake will not work with the SBP jackshaft im planning on running. First thing I did was strip it down and mock up the wheels, and bottom drop loop frame section. I made a 'template' out of some twisted up bailing wire and had a buddy of mine from a fabrication shop mandrel bend a section of 1" .065 tubing (same as the factory tubing). i made two of them, one for my current bike and one for my wife's bike (building that next).


Here's the frame all welded up. It went together nicely and has plenty of room for the engine I'm running (HuaSheng 4 stroke 49cc with SBP jackshaft)


Here's the 3"' tubing tank welded up with mounting hardware attached. We mocked it up with zip ties until i can make some nice brass over the tube bracket clamps. Still need to weld in the filler and petcock bungs.


Here's my brother mocking up where the engine will be placed


That's all we got done in day one...should be doing this in no time!

That style handlebar is exactly what i'll be running...I'm probably just gonna bend my own up, but just like that style. For the front end, im def not running stock. I have my eye on a couple of vintage Monark forks or if not that, I might try my hand at a 1/4 leaf spring front end. I love the look of the brass truss rod front ends, but i want a little more actual cushion lol. Whatever i use, there will be brass, copper, and brown leather bits all over this bike.

That leaf spring front end looks awesome! But it looks like its longer than stock, if Im seeing it right. I wonder if he can build one that will keep it low and tucked how I like it? @Velodrome, yeah that's my Brother's restored Unimog. he's about to buy a second one too. my RV is an old restored Silver Streak (coach built airstream style). That mog does have a radio box that is converted to a mini RV! You might have seen it around, my brother lives in Mesa, so not too far from you! The tank is actually just an 18" piece of 3" O.D. .065 wall tubing with some weld on caps from the local metal supply store.

Im sure that was his. He's always at the Pavilions with one of his projects or toys. He's either in that or his absolutely mint 90's era 535IM BMW.

I'm just going to run the Grubee 5t going to a SBP jackshaft. Then final drive will just be my 3 speed hub shifter that came with the worksman bike. if that fails, I'll swap it to a beefier hub shifter, but it should work fine for now and look clean and simple.

@Crazy Horse, you're 1910 Harley tribute is partly what inspired me to use the M2600, that and the parallel top bars allow for a loooooooong gas tank! i did the math and this tubular tank should hold about .65 gallons, or enough to drive about 70-80 miles! My hardtailed Harley Chopper has a range of about the same so I can deal with that!

That girder fork would be about perfect! Im still leaning toward a leaf spring fork though. I saw a build up on another forum. it looked okay, but it didn't look nearly as old or vintage as what i would want on mine.

I got around to pulling this out today. Had to cut the crank arm off to get it out, but after that it was pretty easy. Just put it in my giant vise and whacked it a couple of times from the inside and the bearings and races came right out.

Then put the New splined cartridge bottom bracket together that i got from SBP...went in really nice and easy. I had to pop it with a rubber mallet a couple of times to get the threaded inserts in most of the way, and the 4 long allen head screws pulled the sides the rest of the way into the housing. I need to get or borrow a splined bb wrench to get the bearings in all the way, but the hard part is done. This went way easier than i thought It would. My brother got a kit from SPB way back in their prototype days (his gary fisher is the one on SBP's website, and he said he had to hunt all over the place for all the parts to make the freewheel chainring work with his bottom bracket, but it seems like they've got it all dialed in as a kit. It came with everything i needed for this part anyway.
You can also see in this picture that i got a steel plug that clicks into the Bottom bracket lug, so i don't/won't have to grind the lug down. Its probably stronger in one piece like this anyway.

I started getting my SBP jackshaft kit and freewheel chain ring installed this weekend. The motor mount will not work because of my drop loop modified frame, so Im going to be welding up an angle iron motor mount, and also going to weld on the jackshaft plate to eliminate the twisting problem that people have had with them. I'll probably run a spring loaded tensioner on both the left and right side jackshaft chains since there won't be any real adjustability once it's welded. So far, everything fits okay and pedals nicely. There is a very slight wobble in my freewheel chainring, don't know if the pedal shaft is bent or if it isn't seated properly on the shaft. I will examine this more later, but it probably won't be a big deal.