Ultimate Bearing Solution for 4-Stroke Belt Tranny

Mike St

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I should describe what I had to do to remove a press fit bearing
in one of my friction drive units. No amount of hammering
would budge it. I had to buy a puller from Harbor Freight
and it finally gave with a large pop under extreme pressure.
I still believe with precise honing of the clutch bell, a good
press fit would work, and bearings would be unlikely to
move. You can debate until Biden speaks like a president,
but only testing will give the answer, and I may try it.
 

Karl Snarl

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I should describe what I had to do to remove a press fit bearing
in one of my friction drive units. No amount of hammering
would budge it. I had to buy a puller from Harbor Freight
and it finally gave with a large pop under extreme pressure.
I still believe with precise honing of the clutch bell, a good
press fit would work, and bearings would be unlikely to
move. You can debate until Biden speaks like a president,
but only testing will give the answer, and I may try it.
Interference fit bearings have been tested, billions of times, if not trillions or more. The whole reason they are used, they work. I would rather the industries spend their money with all the tests and follow their lead, I mean they do sell a lot more than I do. Why waste my money, when they have known this for longer than I have been alive, with already done tests. Here, simple test for you, slap a smooth piece of steel in a drill, spin it in a hole, close to the same size, but not tight fitting, a hole it just slides into. Spin that sucker for an hour. What happened? Now take that same drill with a new steel shaft and cram it in a hole, just slightly smaller than it is. A hole so tight it can't spin. Now run that drill for an hour, what happened? Which hole is still the same shape, which one is worn. The steel is a substitute for what the races will be doing on your shafts and housing, with each fitment way. If you must, go a head and experiment, but all the work has been done before you were born. Why not just take already had information and use it? You didn't need to stick ya hand in a blender to see if it will destroy your fingers, just to be sure, why waste time testing stuff that has been the norm for hundreds of years?


Edit: Even the wagon trains on their way to west coast knew this. If they didn't have a tight fitting bearing ( really a bushing), the axles go boom or the wheel falls off. Been the norm way longer than any of us here have been alive. Why you ask, because it works.
 

Mike St

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Here's the reason I am a little hesitant: At one time
BoyGoFast carried clutches and belt drives for this
tranny and engine but now they don't. The belt
drive and the clutch to fit the 15mm shaft motor
are off the market and no where to be seen. So
if I messed up the job, the entire motor and
tranny would have to be dumped. It's really a
cheap ebay Chinese kit I bought for about $180.
I would recommend to anyone to buy the best
which is the Grubee 4 stroke engine kit with
his belt drives which use bearings NOT
bushings.
 

Karl Snarl

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Here's the reason I am a little hesitant: At one time
BoyGoFast carried clutches and belt drives for this
tranny and engine but now they don't. The belt
drive and the clutch to fit the 15mm shaft motor
are off the market and no where to be seen. So
if I messed up the job, the entire motor and
tranny would have to be dumped. It's really a
cheap ebay Chinese kit I bought for about $180.
I would recommend to anyone to buy the best
which is the Grubee 4 stroke engine kit with
his belt drives which use bearings NOT
bushings.
You just said you are not sure if you have the skills. It was recommend early in this thread, if you don't have the skills, take it to a machinist. I am a machinists. I do make mistakes, but simply reaming/widening a hole for a bearing is easy with the proper tools. To create an interference fit, you need a caliper to measure as you go. You take off tiny amounts at a time until you reach the fit you want. Read into it. We can't teach you how to machine here, to much to learn on a pc without actually doing it. Making parts is pretty straight forward for something like this. You want the races to fit tightly, not slide in like on the video. Notice how his wobbles in the end. It is going to destroy the bearings, the shaft and the housing. A slide fit on something transferring power is not going to last very long at all. The races will spin, defeating the purpose of even having them in the first place. If you out of round the hole, you've essentially destroyed it. A shop isn't going to charge much for machinng out the hole or shaft for you. Probably take the guy 20 mins to set up and machine. While you smoke a cig and drink a pop in the parking lot.
 

2speedboi

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Edit: Even the wagon trains on their way to west coast knew this. If they didn't have a tight fitting bearing ( really a bushing), the axles go boom or the wheel falls off. Been the norm way longer than any of us here have been alive. Why you ask, because it works.

You ever seen a freight train rolling in with a burning bearing unit. Pretty interesting.

I would think the bearing slot would expand (under any kind of heat) and shrink, due to expansion and the bearing race would follow suit and expand.

Under normal conditions with a correct diameter bearing slot it shouldn't walk out?

I think Stanton has proven this in his design, but also uses lock collars if I'm not mistaken.
 

DieselTech

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You just said you are not sure if you have the skills. It was recommend early in this thread, if you don't have the skills, take it to a machinist. I am a machinists. I do make mistakes, but simply reaming/widening a hole for a bearing is easy with the proper tools. To create an interference fit, you need a caliper to measure as you go. You take off tiny amounts at a time until you reach the fit you want. Read into it. We can't teach you how to machine here, to much to learn on a pc without actually doing it. Making parts is pretty straight forward for something like this. You want the races to fit tightly, not slide in like on the video. Notice how his wobbles in the end. It is going to destroy the bearings, the shaft and the housing. A slide fit on something transferring power is not going to last very long at all. The races will spin, defeating the purpose of even having them in the first place. If you out of round the hole, you've essentially destroyed it. A shop isn't going to charge much for machinng out the hole or shaft for you. Probably take the guy 20 mins to set up and machine. While you smoke a cig and drink a pop in the parking lot.
Lmao I had a machinist once tell me, the only way your going to learn the lathe is just get on it & use it. Lol i made a few mistakes, broke a few cutters, but know i can turn about anything i need on lathe now. I need to learn how to cut threads & taper a shaft yet, then I'll be pretty happy with what I can do on a lathe.
 

Mike St

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No, I do have skills, and have been in the hobby for a while, building
many bikes gas and electric, and original designs, but this is a no
going back procedure. Right now, I have the Oilite solution which
works and was relatively easy to mod. I have no interest in using a
machine shop. A goal here is to be able to mod with ordinary
tools so anyone can mod a change. I own a
great caliper and used it for the Oilite mod while honing the
clutch bell, a little at a time, and testing the fit. I have all the
tools necessary except a lathe, maybe too many tools and parts which
are stacking up in my garage.
 

Karl Snarl

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You ever seen a freight train rolling in with a burning bearing unit. Pretty interesting.

I would think the bearing slot would expand (under any kind of heat) and shrink, due to expansion and the bearing race would follow suit and expand.

Under normal conditions with a correct diameter bearing slot it shouldn't walk out?

I think Stanton has proven this in his design, but also uses lock collars if I'm not mistaken.
reread, what I wrote. If it is under extreme heat, sure, but normal operation no. If that was the case, why are my roller bearings on my motorcycle working as intended? If they expanded out of bore, or the bore expanded out of spec during use, the engine would die. Hence, why there is an " interference " fit. A slide fit will bore itself out under normal operation. An interference fit will not. The reason it has been used for many hundreds of years. If it's worked for hundreds of years, I think they were on to something. If the bearing fails, 99% of the time, the race is still there and you can swap them out. Like on an axle bearing on a tuck. If the bearing walks, it was either under extreme stress and heat, way out of spec's range, or the machining was not done correctly. Usually when out of spec with extreme heat, it was the operator not inspecting their machine before use. Not a design flaw, an operator error. The failed to see the bad bearing and replace before complete failure.

edit: an on these bikes, always an operator error for allowing it to go so far bad, when bearing swap should have been done. Most of you guys don't inspect your rides before riding. You jump on and go like it is a factory built motorcycle( I even inspect my factory built motorcycle before riding, I'm liable, not the maker), again, operator error. I have had one wheel bearing failure during my years of these bikes, why you ask, I failed to inspect the bearings. All my fault. I know everyone loves to blame the maker, over their own mistake. Hard for people to admit when they are an idiot. The wheel bearing failure, I was an idiot. I never have done it again either. I check my rides before riding. The failure is on me, not the engine company. If it fails completely, it was because I failed to check itm not because the manufacture of the kit. Now when it first rides, still check, there can be flaws, but if caught before complete failure, repairs can be made before injury or machine destruction.
 

Karl Snarl

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No, I do have skills, and have been in the hobby for a while, building
many bikes gas and electric, and original designs, but this is a no
going back procedure. Right now, I have the Oilite solution which
works and was relatively easy to mod. I have no interest in using a
machine shop. A goal here is to be able to mod with ordinary
tools so anyone can mod a change. I own a
great caliper and used it for the Oilite mod while honing the
clutch bell, a little at a time, and testing the fit. I have all the
tools necessary except a lathe, maybe too many tools and parts which
are stacking up in my garage.
You can use a drill press in place of a lathe, with the proper bits and vice.
 

DieselTech

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Grubee has these back in stock. Better act quick!

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