Frame advice for a newbie

[DWest]

Hello folks, I am a new old guy or an old new guy, anyway I am old and new to this. I have a bad case of "I wanna build a board track bike" and my niece, who is my partner in crime and projects like this, and I have come up with a few ideas for a frame and I thought it would be best to have you guys look it over and see what is good about it and what is not so good. This bike will use motorcycle wheels, tires and brakes and we plan to use a Briggs v-twin or a HF v-twin for power. This is a very basic drawing done full size with a CAD program. We have a couple more drawings of bicycle based builds that would be powered by 5hp Briggs or a 4 stroke 50cc motor ( mostly because I have a couple of them). If you'd like to look over those drawings too I can post them later. Since this is my second post and the first with a picture who knows what will happen. I have learned much from this forum already and I am very impressed with the quality of work shown by all of you, a lot of great builds.
Thanks,
Dan

 

[\./]

what size wheels are you using? Welcome to the forum!

 

[DWest]

We are planning to use 21" honda wheels and street tires that come out close to 28 " in diameter, and thanks!

 

[PeteMcP]

Hi Dan, and welcome aboard to you and your sidekick.
Wow! A V-twin powered first build, huh? Sign me up for the build thread. I'm all fired up just looking at your CAD drawing. Go for it.

 

[indian22]

Hello folks, I am a new old guy or an old new guy, anyway I am old and new to this. I have a bad case of "I wanna build a board track bike" and my niece, who is my partner in crime and projects like this, and I have come up with a few ideas for a frame and I thought it would be best to have you guys look it over and see what is good about it and what is not so good. This bike will use motorcycle wheels, tires and brakes and we plan to use a Briggs v-twin or a HF v-twin for power. This is a very basic drawing done full size with a CAD program. We have a couple more drawings of bicycle based builds that would be powered by 5hp Briggs or a 4 stroke 50cc motor ( mostly because I have a couple of them). If you'd like to look over those drawings too I can post them later. Since this is my second post and the first with a picture who knows what will happen. I have learned much from this forum already and I am very impressed with the quality of work shown by all of you, a lot of great builds.
Thanks,
Dan View attachment 97542

Welcome Dan, I'd suggest going to Lurker's V-twin thread, just scroll down the first page of this board track forum & read. Keep it handy and read it before you go ahead and as you go. That was his second build & he made some rookie errors that he quickly corrected along the way & his build turned out awesome! Your drawing is spot on, gussets well located And you indicate a knowledge of positive trail in your drawing of the fork & wheel relationship. Nice classic drop loop lines with girder fork and horizontal drops, The drawing shows great proportions but the numbers need to be filled in. Engine weight alone is right at 100 lbs. so D.O.M. tubing 1" or more diameter for the front frame .120 wall thickness would be a good staring point. My experience with larger engines in bicycle style frames is that it's crucial to frame the engine correctly, with plenty of room for electrical's etc. but not so much empty "air" that the bike looks silly. The 21" wheels should look right at home as well. 28" tire height was common in the early board bikes. I'd think 56" to 58" wheel base would be a stable length for highway speeds and also allow room for the large power and drive train. CVT seems the common "go to" drive on scooters, V-twin powered, bicycles and pit bikes.

I'm looking forward to following your build. Rick C.

 

[wret]

Welcome Dan! I can't wait to see how your project progresses. Your drawing looks good. Are you going to include a pedal crank/bottom bracket?

 

[DWest]

Thanks wret! That decision is still up in the air but I would like to if we can, I think that it would help make the vintage look a little better. There are probably a lot of changes that will be made on paper before we start the build. I hope that all of this drawing will help us bypass a few "major malfunctions" along the way but I can still manage to screw things up once in a while, it just sort of comes naturally with me.

 

[allen standley]

Welcome D, That's gonna be way cool. I'll follow along if you don't mind. Good Luck!

 

[wret]

Thanks wret! That decision is still up in the air but I would like to if we can, I think that it would help make the vintage look a little better. There are probably a lot of changes that will be made on paper before we start the build. I hope that all of this drawing will help us bypass a few "major malfunctions" along the way but I can still manage to screw things up once in a while, it just sort of comes naturally with me.

Well, my suggestion is to put a lot of thought into how much and where the bike will be ridden (and by whom). In my case, when I discovered board track racers, I thought they were the coolest looking things ever. My plan was to build one that would be completely road legal, safe and practical to ride around town and possibly even 25 miles to work. After riding around the block a few times (and being told by neighbors that it was the coolest thing ever) I decided that riding position would not work for more than a few minutes at a time and I adapted the hand and foot positions to a more laid-back configuration. My working pedal crank is gone with floor boards in place. This makes foot activated shifts and brakes far more feasible. I started down the conversion path planning that I could convert back to a racer config at any time but realistically that's not going to happen.

 

[DWest]

Wret, that is very good advice. The bike will probably only be ridden by me and then just on short trips to town, which is three miles from my home, and on the back roads as I am too old to make long trips on any bike - been there and done that years ago. When we first started thinking about building one of these bikes we came up with two designs that were bicycle based and powered by a 5hp Briggs flathead or a clone HF engine. Since my partner in crime has very little experience on motorcycles we did a street version that would be easier for her to handle and may build it before we tackle the v-twin for the learning experience. I will try to post some drawings of those bikes, they were also done full size with a CAD program except for the engine and I was too lazy to go out to the shop and measure one so it is purely imagination. It seems to me that as we age the comfort factor becomes much more important than the cool part of it....lol. Thanks,

Dan

 

[Ludwig II]

Comfort IS cool

 

[curtisfox]

Welcome D, That's gonna be way cool. I'll follow along if you don't mind. Good Luck!

Sign me on also, depends on where you live, if you do away with pedals you have to register it as a motorcycle, so you may want to check the laws and red tape...........Curt

PS i am using a 2 hp Lauson, it has the exhaust out the front, and carb on back.

 

[DWest]

Hi Curt, it seems that in Missouri just about anything with two wheels and an engine bigger than 49cc is a motorcycle but they have dropped many of the requirements to get a state inspection sticker so it shouldn't be too hard to get a tag on the thing. We also have some donner motorcycles one of which has a clear title!! Thanks, ....Dan

 

[fasteddy]

Welcome to the forum.You might want to look at Sportsman Flyer. I'll include a link below. Pat has all the parts to make a vintage style board track racer or road bike. They use a Harbour Freight 212cc engine and he and his brother hold world speed records using these parts.

You can buy everything from him or mix and match parts from other suppliers. This is a good way to get into motorbikes and would allow you to get into a bike to start. Hope this helps.

Steve.

https://www.google.ca/url?sa=t&rct=...anflyer.com/&usg=AOvVaw0WeqeGUJUxfh9BPD54PmFs

 

[DWest]

Hi Steve and thanks, I did check them out and they have some great stuff. I wanted to order a couple of their motorcycles but my wife said no, women are sure funny that way. Thanks for the link and I'll keep them in mind.

 

[fasteddy]

I've run into the same problem myself a few times over the years. The odd time I said I made an executive decision and bought something unapproved I was informed that I should have run it by the CEO first.

Steve.

 

[DWest]

Nothing much new here. We have decided to build a couple of bicycle based rigs before we tackle the v-twin that way we can screw up on a smaller scale. We've pretty well settled on one Indian style and one Merkel style frame probably with Briggs 5 hp flathead and one with a HF 212cc. We have been looking into frame jigs and, since we do not plan to build more than three or four of these things, have decided to make an attempt to build one out of square tube. What sort of jig do you guys use? Dan