Vanishing Hobby

As you know, Jerry, that's the power plant I used on my Higgins build. Slap her in a frame, swap out the carb for a bike-friendly one, and you'll be surprised at how well it performs. The 142f on my other bike is a jewel, but nothing runs like a Honda (to steal a phrase from John Deere)! I've been looking for another to duplicate a Whizzer type built with sheave and belt. Belt drives are so smooth compared to sprockets and chains. Thinking about using a step-thru frame (girls bike). They are more plentiful and sometimes are cheaper simply because they are less desirable marketwise.

Just what I need, another build. Wish one of you guys lived nearby to share the adventure!
Ride on.
 
wrenching4fun said:
As you know, Jerry, that's the power plant I used on my Higgins build. Slap her in a frame, swap out the carb for a bike-friendly one, and you'll be surprised at how well it performs. The 142f on my other bike is a jewel, but nothing runs like a Honda (to steal a phrase from John Deere)! I've been looking for another to duplicate a Whizzer type built with sheave and belt. Belt drives are so smooth compared to sprockets and chains. Thinking about using a step-thru frame (girls bike). They are more plentiful and sometimes are cheaper simply because they are less desirable marketwise.

Just what I need, another build. Wish one of you guys lived nearby to share the adventure!
Ride on.
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I have a new girlfriend now and want to build her a bike using that engine. Since she's a 100 lbs lighter than me I wouldn't need as wide of a gear ratio range on a shifter bike for her. Combined with the extra power it should be able to handle these Tennessee hills just fine. I'd probably do something similar to what you have with a 5 speed IGH.
 
wrenching4fun said:
We have a high bridge over the Neuse River and my Honda chugs up in 2nd gear with help from the Shimano hub. Don't know the ratio, but it does the job.
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I'm 245 lbs and my bike weighs 100 lbs. The ratio range I use is 66.79\1~16.25\1. I use a Robin Subaru EH035. That little joker just won't wear out lol. Up to 30% grade hills are common here. Neither she nor I care to go over 30 mph. Like I said I plan to do the same concept you used but do a rear rack mount instead of a mid-frame. I may go with 24" wheels since she's 5'3".
 
wrenching4fun said:
Jerry, why don't you swap your engine out for the Honda and put the Suburu on her bike? That would match weight with horsepower. Since she's 5'3" I'm guessing she isn't as hefty as you!
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You have to have a special adaptor that David made specifically for connecting the Honda to the 18.75\1 gearbox. Unfortunately, I never bought one when David was making them. He's just selling off his remaining inventory now and isn't making anything new.
 
My pulley-fitted centrifugal clutch is fitted directly to the output shaft. Since the engine came from a water pump it has the metric shaft, 17mm if I recall correctly. I ordered adapters that jump the outside diameter to 3/4" to fit my clutch. An endcap was welded onto the sleeve of the clutch so it threads onto the output shaft. A good number of early GX50s had a straight 5/8" shaft like the 142Fs, so a centrifugal clutch slid right on. If you have the tapered shaft version, you'll need the integral clutch and belt drive that Grubee use to sell. Things get complicated with all of the variants. My variant came with a governor which I had to remove. Yours probably didn't. Mine also came with a Japanese Keihin carb that I swapped out for one that's adjustable.
 
wrenching4fun said:
My pulley-fitted centrifugal clutch is fitted directly to the output shaft. Since the engine came from a water pump it has the metric shaft, 17mm if I recall correctly. I ordered adapters that jump the outside diameter to 3/4" to fit my clutch. An endcap was welded onto the sleeve of the clutch so it threads onto the output shaft. A good number of early GX50s had a straight 5/8" shaft like the 142Fs, so a centrifugal clutch slid right on. If you have the tapered shaft version, you'll need the integral clutch and belt drive that Grubee use to sell. Things get complicated with all of the variants. My variant came with a governor which I had to remove. Yours probably didn't. Mine also came with a Japanese Keihin carb that I swapped out for one that's adjustable.
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I have a straight shaft and the original Japanese carburetor along with the governor
 
I'd crack the case and yank the plastic governor drive. You can close the shaft hole with a self-threading screw. With a straight shaft you can throw a centrifugal clutch on and you're good to go (might need a jackshaft for 5 to one reduction). You are in good shape.
 
We're thinking alike there. A rear rack mount can also give you more versatility on bicycle choice and space for reduction pulleys.

To do 30 mph on 24" wheels at 7000 rpm would require a 16.66\1 reduction in 5th gear. This means in order for that to happen you need a 26.66\1 reduction being input into the 5 speed IGH.

The bike would then have a 42.65\1~16.66\1 reduction range. This would be more than enough to take a 145 lbs rider up 30% grade hills on 24"wheels and using a Honda GXH50 engine.

I like what you did putting a sprocket and a freewheel on the jackshaft eliminating the need for a shift kit. I however will be lacing the 5 speed IGH into the rear wheel.
Shimano cog.jpg.jpg
 
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