gx 390 clone engine, no torque questions

harry44

hi guys, bought a golf cart for our farm in the uk, it had no engine so i have bought a clone gx 390, a reduction gearbox (2:1) put a reverse gearbox (from a quad bike) in also , as you can see from the picture i have added it is all on 428 chain.

i have added a mikuni carb, removed the governor and have an aftermarket exhaust and valve springs to put on

the problem is i seem to have no torque, i have started the engine pressed the throttle and the car won't move, so i have taken the sprocket off the reduction gearbox and the sprocket seems to be going too slow to power the car.

im a bit confused about it now, wondering whether i have put the wrong reduction gearbox on, or not geared it high enough? or have i assembled something wrong in the engine or gearbox?

any help would be greatly appreciated

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raydhd

You don't have the CVT a gas cart usually has.From the picture it looks like an electric cart converted to gas with a fixed ratio set up.The easiest way to solve this would be get a gas cart transaxle.

harry44

can you go into a bit more detail please?

raydhd

A factory powered gas golf cart has 2 variable pulleys than make a CVT type transmission.So you start in a "low" gear and as speed increases one pulley closes up and the other opens up to move to "high gear".Hopefully one of the more computer literate members here can post a video to show how this works.But by managing springs and or weights the rate of this "gear change" can be altered to suit the needs of the engine and the way the cart is being used.P.S. youtube under CVT in action shows a yamaha being put thru its paces

slonomo

I don't see any clutch there. How does this engine engage/disengage? There needs to be a clutch that allows the engine to spin without spinning the drive gears. Then, as rpm increases, the centrifugal clutch will engage and spin the drive gears. I don't see this in yours.

Also, in your setup it appears that you will have only one gear, correct? Or are you using a transmission from the quad?

Put the cart up on jack stands and see if the tires will move.

harry44

the actual clutch is in the reduction gearbox, and it does only have one gear. is the best way to go about this is getting a petrol rear end ?

harry44

this is the reduction gearbox http://www.engineman.co.uk/reduction...126a-280-p.asp

raydhd

Do they have golf cart wrecking yards there? Many times an engine can be beyond repair with the trans axle working fine.

ez-ha

Does the chain from the reduction box to the transmission tighten up and try to turn at all?
Possibly the engine is not getting up to enough RPM's to engage the clutch but it would still
turn the output on the reduction box by internal drag.

firemedic247

Yes a petrol transaxle would be the easiest way.