Heathkit Boonie Bike 2 speed - how it work?
- Thread starter cfh
- Start date
The engine clutch has 2 sprockets on it. The jackshaft has 2 input sprockets. One jackshaft sprocket will free spin while the other is engaged. The shifter will switch which gear is engaged. You can only change gears while sitting still. That's pretty much it. I don't know how well they work or if people keep them or not. I don't recall seeing any with TAV systems on them. I know that I've seen some with a standard single speed clutch on them though.
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I have seen a few Boonie Bikes with the shift cable end bent or broken from trying to shift on the fly . You have to start out in high or low . The comet auto shift 2 speeds are nice but it always seems like the cruising speed is where it wants to shift at . Shifting in and out is what kills them . When you are riding them you don't feel them shift into 2nd gear and it sure gives you more high end speed . I currently own 3 Bird Roper 2 speeds and 2 Bird Super 2s . 1 of each are currently riders . Comet and Max Torque make the driven clutch . Pictured is Super 2 and 2speed set up .
My driven clutch seems to just spin. I’m not sure if the weld is broken or if the clutch is just some has malfunctioning. Because of this when you hit gas nothing happens besides the motor spinning.
So do people try and repair these clutches? That is are parts available? I couldn’t seem to find anything online.
Is there a suitable and more practical replacement?
Here’s my clutch what looks like it’s has a broken weld between the sprocket shaft and the bell housing
As a replacement I decided to give this one a try
http://rover.ebay.com/rover/1/711-5...0001&campid=5335845805&icep_item=331918771916
So do people try and repair these clutches? That is are parts available? I couldn’t seem to find anything online.
Is there a suitable and more practical replacement?
Here’s my clutch what looks like it’s has a broken weld between the sprocket shaft and the bell housing
As a replacement I decided to give this one a try
http://rover.ebay.com/rover/1/711-5...0001&campid=5335845805&icep_item=331918771916
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Oh yeah, that clutch is toast. I don't think that can be salvaged. you might be able to salvage the inner portion, but without that special 2-sprocket bell, it's just a standard inner portion.
Not sure on the Briggs stuff beyond telling the year. The first two digits of the Code indicate the year. I think the rest indicate displacement, engine designation (intended use) etc.
Not sure on the Briggs stuff beyond telling the year. The first two digits of the Code indicate the year. I think the rest indicate displacement, engine designation (intended use) etc.
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So i welded up the clutch bell to the spocket. installed back in the bike, and it worked great! It's stuck in low gear, so it's really powerful and only about 15mph to speed.
i sand blasted the clutch bell too, and there it was... Comet Industries.
All i need now is the gear shift lever mech... any body have that for sale??
i sand blasted the clutch bell too, and there it was... Comet Industries.
All i need now is the gear shift lever mech... any body have that for sale??
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So i pulled out the Boonie Bike jackshaft, and took it apart. Now i see why it seems like *no one* has a stock and working boonie bike 2 speed transmission!
Before disassembly:
More of the 2 gear side as it's being taken apart...
Removal of the 2 geared side of the shaft reveals the problem... that spring probably shouldn't be broken in half!
Also looking at the shaft itself, i'm pretty sure that's all wear you see here. I find it hard to believe it would be this conical shape from the factory!
I'm not even sure how this gear is supposed to work....
Bottom line... i'm pretty sure i'm never going to find these parts. What have others done? Do i just put a Torque Converter on the jack shaft and forget the original 2 manual gear transmission? or does anyone have these parts? thanks!
Before disassembly:
More of the 2 gear side as it's being taken apart...
Removal of the 2 geared side of the shaft reveals the problem... that spring probably shouldn't be broken in half!
Also looking at the shaft itself, i'm pretty sure that's all wear you see here. I find it hard to believe it would be this conical shape from the factory!
I'm not even sure how this gear is supposed to work....
Bottom line... i'm pretty sure i'm never going to find these parts. What have others done? Do i just put a Torque Converter on the jack shaft and forget the original 2 manual gear transmission? or does anyone have these parts? thanks!
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Here's a *good* copy of the Bonnie Bike assembly manual (the one that's going around was awful, a bad scan.) It does not identify parts or really any assembly info for the jackshaft. Well not enough to show the information and picture i posted above...
http://www.pinrepair.com/minibikes/heathkit1968_bonnibike_assembly.pdf
http://www.pinrepair.com/minibikes/heathkit1968_bonnibike_assembly.pdf
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Back in the 60's when I had my first Boonie I broke the spring on the jackshaft regularly. I kept a supply I bought from Heathkit around, never knowing just when one would break If I remember right it would stay in low gear when it broke? Can't really remember for sure or not now. The Boonie I am building now will just be a single speed only since I'm not doing a full restoration job. Unless you want an all original that 2-Speed setup just wasn't reliable enough IMHO.
Steve
Steve
Yes correct. My spring was broken and it was stuck in low speed. So how easy was it to break that spring? How often did you break them? Do you know if anybody sells them today? I like the idea of the original 2 speed. Mostly because I have all the parts to make it work except for the spring. Well I don’t know, that jack shaft looks pretty worn out....
So better off installing a torque converter on this thing and forgetting the whole manual 2 speed idea? I mean is that what most people do in this situation? Or is there some magic outlet that has these parts?
So better off installing a torque converter on this thing and forgetting the whole manual 2 speed idea? I mean is that what most people do in this situation? Or is there some magic outlet that has these parts?
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I rode it quite a bit and broke at least one a month. The problem was that the spring would tighten up on the shaft and constant twisting back and forth would cause it to break. I don't recall doing anything out of the ordinary to cause it to break. I don't know if anyone sells those springs today unless you found someone with an old supply of the. I used to order them direct from Heath-Kit usually getting 4 or 5 at a time to stock up. I think a torque converter would be more reliable. Only reason to keep the original would be to have a correct restoration. It wasn't really practical in operation because you couldn't shift it from low to high while moving anyway. I think trying to shift it on the fly would stress that spring out anyway. Would be cool if someone out there makes this setup still. I'd like to try it again just for the nostalgia of it.
Steve
Steve