[Kartbuilding] Connecting a General Purpose Engine to a Gearbox unit for a Kart
sburke at burkesys.com
Sun Jan 28 14:04:10 GMT 2007
2 versions of connecting up a general purpose engine to a gearbox.
The First Setup - I got a Honda 50 gearbox. It had 3 gears which I wanted to
utilise. I already had a centrifical clutch on the general purpose engine,
however I badly needed gears. The centrifical clutch on the Honda 50 was oil
based, and I only had the bones of the Honda50 gearbox with no casings.
Using the dry centrifical clutch I connected up the General Purpose engine
directly to the Input of the Gearbox as can be seen here:
So the engine and gearbox are facing one another (was pretty wide). It was good
tho - the engine speeded up - and drove the gearbox direct, and from the
gearbox to the rear axle - sprockets and chains.
Honda50 Gearbox Input shaft:
Honda50 Gearbox Output Shaft - showing gearlever also:
This setup worked fine for a while. However I had to manually apply and setup
an oil feed to the gearbox - as there was no resevoir of oil etc. It was a very
wide setup as the engine and gearbox had to be side by side. Easing off the
throttle to change the gear (via the dry centrifical clutch) wasn't the best
and the gearbox took a little abuse - but worked ok.
But.......I wanted a manual clutch, and a clutch pedal. So......
The second setup was to get a Honda90 gearbox which had a Manual Clutch (old
model). The engine had siezed etc. but the clutch and gearbox was fine. I
removed the Piston Connection Rod, leaving the crankwheel in place (with the
counterbalance). I sealed up using a plate and instant gasket - the cylinder
Where the alternator/magneto went - I attached a sprocket to the crankshaft. As
the magneto/alternator was dry (gearbox was sealedup and filled with the
correct amount of oil for the wet clutch and gearbox.) and I could easily
attach the sprocket. I initially mounted the engine, then the gearbox in a
straight line, giving the setup here:
I found that the first engine was pulling the gearbox a lot and it took up a
lot of room. I then adjusted the engine-gearbox setup, mounting the gearbox
ontop of the engine!! as can be seen here:
It wasn't pretty (or light!!) but it did work. It gave me a single powerpack
which i could mount onto the kart and drive the rear axle. The gearbox had too
good of ratios and I had to mount a large sprocket on the output shaft of the
gearbox to link up with the rear axle. It did hold fine. It was very heavy. It
worked fine. I had my manual clutch (woohoooo) and I had my 4 manual gears.
Clutch lever: http://www.kartbuilding.net/gallery/v/Kart_Clearance_and_Mem
GearLever (via a lever system):
This setup cost pennies to get working.
However, I started working for the summer, and I came across a crashed 100cc
motorbike (rxs100)...so thats what I started at and I ended up with a much much
simpler and easier setup resulting in:
Anyways thats it. It was a HUGE learning experience working with the gearboxes
etc. getting them to work. So....it all depends on what tools you have, and the
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