1948 JC Higgins Board Track

[Royale]

I have been planning a BTR build for a while now.

I originally had an old Schwinn cruiser frame but just traded it to an old hippy for a 1948 JC Higgins frame. I bought a JC Higgins beehive springer too which I love. It definitely looks a lot more board track now than it ever could have with the Schwinn frame.

Anywho, I figured I might as well start a build thread now that I'm starting to make some forward progress.

I am still waiting on my new jug to arrive. The one on it in the picture is one of my attempts to buy one from ebay that won't work on my engine.

I have a ton of stuff still to finish before this beast will run anyway though. Here's my motor specs so far:

Skyhawk GT5 motor
Puch hi hi head
Dellorto 15.15 carb
SBP expansion chamber
All new hardware

Planned once jug arrives:

Blueprint everything
Trim piston
Balance crank
Port match jug to base
Lap every mating surface

I want to build a new CDI too but I'm going to break in the engine and dial things in with the original first before I venture into that territory.

My goal is to have reliable power. I don't plan on riding it like a mad man. At least not all the time lol.

On the bike side of things I am going to be turning the fake tank sides into a real tank. I have the next two days off, so that is my next task. I will also be ordering a front drum brake wheel but I need to save for that as I have been spending way too much on this thing.

The pics are the new frame, frame with fork, and frame mocked up with engine:

 

[chainmaker]

That bike is killer, the paint looks perfect like it is. I really like those type of springers, great job.

 

[Whamo]

Love the lines on that bike, and I've never seen a springer fork like that. Very sweet.

All the engine mods that you are talking about, are they more for reliability or performance?

 

[Royale]

Thanks!

Certain engine mods such as balancing the crank, making properly fitting gaskets, lapping the mating surfaces, and replacing all the stock hardware with better stuff will increase the reliability of the engine slightly. Balancing the crank is really key for reducing vibration and increasing bearing life.

The other mods won't technically add power but instead will fix all the flaws that these cheap motors come with, and free up the power that any of these engines are capable of.

That includes making sure all of the ports are free of burs and slag so that the gas/air can flow smoothly, matching shape of the transfer ports, intake, and exhaust ports to the engine base and manifolds (blueprinting) so there isn't any obstruction of flow, adding a head with a real squish band for better combustion, replacing the carb with a better one, etc.

I'm planning on tuning it for lower end torque and not high RPM speed which will hopefully increase the reliability a bit as well. The speed limits in the city are usually around 30 so I don't need a screamer but I would like to get off the line with good power.

I'll post pictures of the mods I make to the engine as I build it, which will hopefully be this weekend if my new cylinder shows up today.

Then it's on to figuring out how to turn the fake tank into a real one...

 

[wheelbender6]

Where did you find the beehive fork?

 

[Royale]

I got it on ebay.

I was lucky in that the guy selling it lived close to me so we worked out local pickup to save money.

They can get a bit pricey depending on the condition of it.

 

[Velodrome]

Whatever you do dont paint that bike! Its perfect as is. And yes; nice beehive! I will let others caution you on the chain tensioner.

 

[truckd]

Velo is right about the chain tensioner here is a link that carries an in-expensive and really cool tensioner that mounts to upper and lower frame stays

www.custommotoredbicycles.com
here are the pic's of the chain tensioner $42.00 your life and well being is important, Don't! mess with that junk,you can even swap out the nylon wheel with a tensioner cog sold at Pirate Cycle.

 

[hsvmick]

have you bars for your ride as yet or know what you be using,it sure looks cool and like how you mounted the sbp chamber but should weld together only cause the joints will split unless you waiting to see where and what length works best ,i have used this pipe and thought it was amazing where it was but then changed it again and believe me its true what states you will know when it comes on song happy bicycling nice bike oh if you use a bigger dia out the port to chamber you will find alot off the mark better for what you after

 

[LabRat]

Velo is right about the chain tensioner here is a link that carries an in-expensive and really cool tensioner that mounts to upper and lower frame stays

www.custommotoredbicycles.com
here are the pic's of the chain tensioner $42.00 your life and well being is important, Don't! mess with that junk,you can even swap out the nylon wheel with a tensioner cog sold at Pirate Cycle.

Used three of these myself. Never had a problem and personally I think they look cool.

 

[Sledge]

That thing looks great, I have seen those tensioners break down though with a long chain. Good luck!.

shft.

 

[Royale]

Thanks for the compliments!

I will definitely pick up one of those tensioners. I think it will keep with the vintage look of it perfectly and replace that stock piece of crap. I got a Sturmey Archer front drum brake hub too for safety reasons.

This project has been on the back-burner for a couple weeks as I just changed jobs and I'm buying a house and I'm about to start taking a couple summer classes in a week. So my life is a bit nuts right now.

I did tear the engine down and am putting the last pieces back together on it today! There are some pics below of some of the port correction mods and stuff that I did to it.

Then it's on to figuring out what to do about the gas tank. I'm thinking of doing a fiberglass shell inside the fake tank so that I can leave it as close to factory looking as possible. I would only have to cut a hole for the filler to come out of and one for the valve at the bottom. It's still up in the air though...

 

[silverbear]

Nice looking project. Before WWII JCHiggins was Elgin. Just a name change by Sears for marketing. They still had the same designers as before and knew what they were doing. The Bluebird and Robin are among the most beautiful bikes ever designed, in my opinion.
SB

 

[Royale]

I agree. The shaft driven Elgin Robin, to me, is probably the most beautiful bike ever built. I love the torpedo tank.

I just ordered a vintage Elgin springer seat on ebay that still had the leather intact. I also got a "lucky 7" JC Higgins seatpost that I'm going to run low and backwards to keep with the boardtracker look.

I can't wait for them to come in!

 

[konig44]

Wow. That elgin has me drooling

 

[silverbear]

My pick would be the 1936-1938 Elgin Bluebird.
SB

 

[Gbrebes]

Dang! Those pictures of the Bluebird are so cool.

That frame looks like it was absolutely made to fit an engine in there. Are those frames pretty rare? I would guess so.

Gilbert

 

[silverbear]

Dang! Those pictures of the Bluebird are so cool.

That frame looks like it was absolutely made to fit an engine in there. Are those frames pretty rare? I would guess so.

Gilbert

Yeah, wouldn't that be something... plenty of room for a nice four stroker. I'm not sure how many years Elgin made the Bluebird and Robin models, but they were very high end, expensive bikes even in their day, so not many were purchased at a time when the great depression was still a lingering reality. The economic boom didn't come until after WWII when they were no longer produced. I'm sure that back in 1938 many a lad stared at the Sears catalog and made a Christmas wish that never came true.
They rarely come up for sale at auctions and are always crazy expensive. If a reproduction of either one was offered I'd start saving my pennies now, maybe get a paper route and start writing feverish notes to Santa Claus. I have been a very good boy this year, most of the time...

 

[SHEW SHOW]

Royale,

Everything looks bad ass so far! Can't wait to see this one complete.
I had similar plans for an engine that I just ordered. Which Puch h hi head did you go with? I have heard some say that the 50cc heads perform better than the 70cc head. Then of course I've read the exact opposite.
Are there any fitment issues with the head you ordered, or is it a direct fit?
Sorry for all the questions, this will be my first build so I'm not at all familiar with what jives and what doesn't.

Thanks,
SS

 

[Royale]

I went with the 70cc hihi head.

I've read about both and have heard the good and bad for both as well. With all the variance in tolerances between every motor and brand it's hard to really know what will work best for your motor without just trying it for yourself. Lucky for us that parts for these are so cheap so it makes that an easy thing to do.

Anything is going to be better than the stock head though.

As far as fitment goes though, you will have to drill out the mounting holes wider and bigger to get it to fit. I have 8mm studs so I'm not sure if it's different for the 6mm engines.

I just put the original head face to face with the Puch head until the holes lined up as evenly as possible and marked through the hole with a marker. When you drill it, the new holes are offset to the outside so it will be difficult to do without a drill-press. You could also probably use a dremel with a carbide bit to kind of "port" the hole bigger.

I also had to use the dremel to remove material from the fins around the head bolts so that I could get a socket on it to torque it down.

Overall it's more work, but that's the difference between the $30 Puch head and buying one for $60-70 that will bolt right on.