Posted by: nwracing | June 24, 2015

Andromeda Tow Kart Part 6

A few weeks ago I had been talking with friends on the subject of photos taken with mobile phones and digital cameras and how few appeared to be printed. I was always worried that my pc would suffer a glitch and I would lose treasured memories. Sadly my comments now seem prophetic as I have lost a whole tranche of images including those for the tow kart. Worse still, my back up seems to lack these images as well! My intention for this blog was to detail how I fitted the engine. In view of this I have taken a different approach and have taken photos of the tow kart today and will use those to illustrate those areas where I don’t have any other images, so please bear with me. The engine chosen was a Chinese copy of a Honda motor that you see in almost everything from lawnmowers to generators. I chose this for two reasons, firstly I wanted to keep it simple and secondly crew member Julie who was going to use the kart had never ridden a motorcycle, so gears and clutch co-ordination was unnecessary complication. The engine came with a centrifugal clutch which made it a twist and go and very compact.

tow kart engine

Engine and clutch in tow kart

I made a plate welded it in and centered the engine on the plate. The clutch hub had a small sprocket built in so no messing machining hubs… …or so I thought! I worked out the gearing and realised that the rear sprocket would be bigger than the wheels and tyres! So after much messing about I machined and welded a hub to mount a different sprocket. So much for simple. I was so eager to try it out that I fitted the chain and started the motor. Steering was by feet against the front hubs!

Modified clutch hub

Hub modified to take bigger sprocket

DSC_2175With the throttle wide open it hardly moved and there was a horrible burning smell coming from the clutch! I went back to my gearing calculations. It was meant to provide a top speed of about 12mph and enough grunt to move the dragster. Err no, I had made an error and it was geared to do about 60mph! After much head scratching there was only one thing for it. I needed to make a jackshaft so that I could achieve the correct gearing without having ridiculously sized sprockets. I am lucky enough to have access to lathe and mill so this was knocked up in double quick time. One item that had to be scrapped was the clutch I had modified! So another one was purchased and fitted as supplied! It also meant that I had to cut the chassis and reinforce to clear the chain which took some time to achieve.

Go Kart jackshaft

Completed jack shaft

I have ended up doing far more engineering than anticipated but it is all good experience; and the cost is minimal. The disadvantage being time consuming reworking of the original design. Next time I tackle the steering system.


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