50cc two stroke boxer motor

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Greybeard

Greybeard

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Feb 8, 2011
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http://www.ebay.com/itm/50cc-Twin-C...15019&pid=100015&prg=1006&rk=1&#ht_1708wt_924

I often wondered if one could split the seat stay to allow for something like a Mantis tiller trans to be machined to fit onto one of the many boxer motors. I think the Mantis tiller gearbox is 5-1 and you could configure the drive to either side. Would take a good machine shop to help make it happen though.

The car in my sig has a few specially machined parts to get that engine/tranny to work so I'm sure there is someone with the imagination to do this.
 
wayne z

wayne z

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Dec 5, 2010
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motorhedfred said:
Wouldn't the output shaft be too small and spindly to handle the weight of a bicycle and rider ?
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That's an airplane engine. They are designed to take extreme side loads from gyroscopic forces as they change directions in the sky. That's why the shaft housing is so long, all bearing area.

If this engine was used with a 90 deg gearbox there would be hardly any weight on the engine shaft at all, just torque.
 
motorhedfred

motorhedfred

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Jul 31, 2009
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Opposed twin, shaft drive....somehow sourcing the engine from an airplane seems oppropriate. That's where BMW got thier start and what thier blue and white emblem simulates...a spinning propeller.

MHF
 
Ibedayank

Ibedayank

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Oct 29, 2011
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The_Aleman said:
Years ago I looked at using an R/C plane motor and contacted a site selling them about putting one on a bicycle.

I was told most of them take special fuel (not pump gas), don't make enough torque, and have short rebuild intervals.

I'd still like to see it done, tho. There's some really nice little R/C engines out there.
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looks like a 50cc pumpgas radio controlled airplane engine to me
http://www.nitroplanes.com/cr50gaen.html

even a twin
 
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The_Aleman

The_Aleman

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Jul 31, 2008
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Ibedayank said:
looks like a 50cc pumpgas radio controlled airplane engine to me
even a twin
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Like I said:

I was told most of them take special fuel (not pump gas), don't make enough torque, and have short rebuild intervals.
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4.9HP @ 7500 RPM out of a 3.63lb engine ought to be a clue. It doesn't have the rotating mass to make decent low-end torque, without a prop it would exacerbate the issue. Almost all aircraft engines regardless of size have relatively short rebuild intervals, partly because of FAA regulations and partly because of design. They aren't subject to the wide range of RPMs that we experience with bicycle engines. Model engines are much worse when it comes to longevity, they aren't designed for the stress and putting one on a bike would definitely make it work hard. Regardless, yes I'd like to see it done for prosperity's sake :D
 
Harold_B

Harold_B

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May 23, 2012
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I'm kind of operating in an "ignorance is bliss" sort of space on this so please hang with me on this. Would it be possible to install a flywheel on the flange where the prop would normally be in order to increase rational weight for low end torque?
 
wayne z

wayne z

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Harold_B said:
I'm kind of operating in an "ignorance is bliss" sort of space on this so please hang with me on this. Would it be possible to install a flywheel on the flange where the prop would normally be in order to increase rational weight for low end torque?
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Yes, a flywheel could be used in place of a propeller to give the engine rotational mass.
Look at the old school RC boat engines, they were standard model aircraft type engine design that used a sorta heavy flywheel. It helps smooth our the torsional viberation from the power pulses.
One could take one of these boxer engines and de-tune it some for motorbike use and proly get a lot more time between overhauls than normal.
 
Greybeard

Greybeard

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I know the old "hobby" motors were not built like these large RC aircraft motors. The ran no bearings, aluminum on steel, some had no rings, and they ran on Nitro.
Here we have a different animal. Take a look at the castings and fasteners on these large gas engines. Do you believe, that under the skin, they have poorer rings, bearings, crank material, construction detail, than an HT?
Not on your life. They have full stuffed crankcases, and I've watched the guys fly these things. Responsive to the throttle, idle well. The things they lack is a built in ignition source that would need to be worked out as they use constant loss battery, and how to start one.
To light? If the extra HP covers, gears, ignition coils, and shafts are removed, what do they
weigh?
 
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pocdragon

pocdragon

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Apr 30, 2011
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slap a drive peg on there and just make a WASP bike outta it

friction would be so easy and you can show off the motor via rack mount

cvlt1
 
I

ivan H

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Oct 8, 2011
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CroMagnum said:
That motor would work great if someone made a shaft drive bicycle.
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Hi again CroMagnum, Rock Solid Engines do shaft drives, all CNC Billet machined, & on bikes if u want, all hi quality stuff, I've got a few of their products, not 1 of these tho but they're on their site 2 check out. There here in Oz so u got 2 weeks & freight, which isnt bad. Cheers
 
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