Need info on heathkit boonie bikes

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Boarderboy217

New Member
#1
#1
I am wondering if you could help me out with some info I need to help me fix my boonie I just picked up. I like the look of it the way it is so I don't really plan on cleaning it up much and want to keep the 'patina' look.

What engines were offered with the boonie bikes? this one is a 4 hp from what ive been told, missing a few key parts, thinking about just putting a 5 hp Tecumseh or briggs.

my jackshaft is missing and they are offered through OldMiniBikes, just need to know how many teeth are on all of the gears so I can get close to the high gear. I will be running a single sprocket centrifugal clutch and would like to put the jackshaft back on. I will most likely use a band brake around the clutch for brakes. there is a nos brake on ebay right now for $100 but from what I hear, the original one did not work very well.

pictures of the bike are in my profile

thanks
boarderboy217
 
Sixpac440

Sixpac440

#2
#2
If your not concerned with stock then the sky is the limit ..

They came with a 5hp Briggs.
Dollar for dollar a Predator motor from Harbor Freight is better ... tho I am no fan of them, it's just a fact ...
The motor on the bike in your pic is a Tecumseh.
The Drum Brake is not as good as a clutch brake ...

This will help with gear ratios ...
Gear Ratio Calculator for Jackshaft Setup

Your Bike ...


Looked new ..
 
B

Boarderboy217

New Member
#3
#3
I am not too concerned with it being stock, I don't have a million dollars to restore it lol, I don't want the engine to stand out, I have a gx200 but it will ruin the look of the bike, I want the engine to fit in with the rest of the bike, ive never owned a predator and I don't really plan on it, id rather have a Tecumseh, Honda or briggs engine anyday.

it looks like ill be going with a clutch brake just for better performance.

do you know what the high speed gears on the clutch and jackshaft were stock? that gear ratio calculator will help a lot, thanks sixpac440.
the engine on mine currently is a 4 hp Tecumseh, that's all I know about it, the engine plate is missing.

thanks
boarderboy217
 
capguncowboy

capguncowboy

Well-Known Member
#4
#4
every single two speed I've ever seen had 2 12 tooth sprockets on the clutch. One went to a 1st speed 24 tooth sprocket, and the other went to the 2nd speed 12 tooth sprocket.
 
FOMOGO

FOMOGO

#5
#5
Boarderboy217 said:
I am not too concerned with it being stock, I don't have a million dollars to restore it lol, I don't want the engine to stand out, I have a gx200 but it will ruin the look of the bike, I want the engine to fit in with the rest of the bike, ive never owned a predator and I don't really plan on it, id rather have a Tecumseh, Honda or briggs engine anyday.

it looks like ill be going with a clutch brake just for better performance.

do you know what the high speed gears on the clutch and jackshaft were stock? that gear ratio calculator will help a lot, thanks sixpac440.
the engine on mine currently is a 4 hp Tecumseh, that's all I know about it, the engine plate is missing.

thanks
boarderboy217
Click to expand...
Do your self a favor and put that GX200 in it if it is a good motor and then ride the bike and enjoy it while you collect parts and work on the motor you want in the bike. Everything clutch and clutch brake with retrofit to anything that you change it too. A Tec or a Briggs. That will give you time to use the bike and find all the pieces. Then take it apart and do the paint work and install the fresh engine and new seat and you will already have plenty of fun under your belt.

That's just what I would do if I were in your shoes and wanted to ride and collect pieces instead of sitting in the corner and collecting pieces.

Doug

Believe me. I have plenty of projects sitting collecting parts and cant enjoy any of them.... Just ask Andy, [MENTION=47279]capguncowboy[/MENTION]. Hes seen it.....
 
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Boarderboy217

New Member
#6
#6
I have plenty of experience working on mini bikes and have my yerf dog mini bike which I ride about once every other week. I don't really want to take this boonie completely apart and paint it, I like the way it looks as it sits. I think ill just try to find an older looking briggs or tec 5 hp and rebuild it while keeping it looking old but reliable. either way the band brake will go on the clutch no matter what engine I put on it.
[MENTION=47279]capguncowboy[/MENTION], do you know how many teeth are on the output sprocket on the jackshaft to the back tire is?

thanks
boarderboy217
 
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Boarderboy217

New Member
#7
#7
[MENTION=44698]Sixpac440[/MENTION] , I used the gear ratio calculation using the gears offered for a jackshaft through OldMiniBikes,

Engine
Number of teeth on clutch sprocket - 12

Jackshaft In
Number of teeth on input sprocket - 13

Jackshaft Out
Number of teeth on output sprocket - 18

Axle
Number of teeth on rear axle sprocket - 72

Final Ratio - 4.33

given approximate 3600 rpm engine, what speed does that put me at with a stock tire? or what final ratio is average?

if I don't use a jackshaft and just run clutch straight to the back tire, my final gear ratio will be 6. another option I was looking at doing just to make it easier.

also, I took my lunch break and tore some of it down, its down to just a rolling chassis, the guy who owned it before must have used a roll of duct tape and a roll of electrical tape to hold the gas tank down.

I did find the serial number on the bottom of the seat mount along with a sticker on the bottom of the seat. can anyone decode them and tell me what they mean?

image1.JPG

image3.JPG

there was a switch on the forks which the previous owner taped up with the duct and electrical tape mentioned above, would this be a horn/turn signal switch?

image4.JPG

image5.JPG

image6.JPG

thanks
boarderboy217
 
Nalu808

Nalu808

Member
#8
#8
FOMOGO said:
Do your self a favor and put that GX200 in it if it is a good motor and then ride the bike and enjoy it while you collect parts and work on the motor you want in the bike. Everything clutch and clutch brake with retrofit to anything that you change it too. A Tec or a Briggs. That will give you time to use the bike and find all the pieces. Then take it apart and do the paint work and install the fresh engine and new seat and you will already have plenty of fun under your belt.

That's just what I would do if I were in your shoes and wanted to ride and collect pieces instead of sitting in the corner and collecting pieces.

Doug

Believe me. I have plenty of projects sitting collecting parts and cant enjoy any of them.... Just ask Andy, [MENTION=47279]capguncowboy[/MENTION]. Hes seen it.....
Click to expand...
Doug's offering some pretty solid advice. If you don't have other bikes to ride, take it.




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Boarderboy217

New Member
#9
#9
So I ended up deciding to paint it, blew it all apart yesterday, straightened the frame and forks and cleaned up all the welds and rust as best as I can, hopefully I'll have some paint on it by next week











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Boarderboy217

New Member
#11
#11
Started assembly today, decided I need to run a jackshaft because the weight makes the bike lean pretty hard, all new bearing and all new hardware






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