[Kartbuilding] [Kartbuilding Blog] Comment: "Plans for a Lawnmower Powered Go-Kart - Finished"

[Stephen Burke]

Hi Jonny,

Yes, there are some subtle things to watch out for on the belt drive 
setup. In particular the position of the idler pulley. Also the 
level/height of the pulley on the engine should be low enough to be 
parallel/flush with the bottom of the pulley on the rear axle.

Of course this twisted V-Belt transmissions is quite crude. It did work 
for me however on my earlier karts.

I wrote a webpage which is quite old now. Its at: 
http://www.kartbuilding.net/drive/drive.htm
Under Heading 2. Lawnmower Engines with Vertical Shafts I outlined some of 
the methods you mentioned regarding gearboxes and using a differential 
(rotated upwards).

The issue I found with gearboxes and differentials are they can be very 
heavy. On a small quick, rough and ready wooden go-kart I found the 
twisted drive belt to work reasonably easily and quickly.

Thanks for your feedback. If you do get making any karts or come across 
anything interested feel free to drop me a mail/comment.

-steve


On Thu, 18 Feb 2010, jonathan.lloyd2000 wrote:

> I just had a look at your slack belt clutch system. It's worth noting that the idler pully must be on the upper section of the pulley, as shown in your drawing, to avoid the idler pulling the belt off the drive pulley. I would also suggest that the type of belt used would be fairly critical. If the belt is too stiff it just won't want to twist with the obvious result of belts flying off all the time. I have considered using the small worm gearboxes that are often fitted to self propelled mowers. They are surprisingly tough and provide a ready made reduction ratio and horizontal drive all in one! Of course the best solution, if you can get one, is the small gearbox of a riding mower, either a transaxle with a built in differential or the smaller gear only boxes, with or without the differential, which incidentaly are usually fitted to the axle of these ride ons anyway. I often see old worn out ride on mowers on ebay with all these useful bits, wheels and steering etc. Someti
 mes they sell for very little.
>
> Jonny
> ---- Stephen Burke wrote:
>> Hi Jonathan,
>>
>> Thanks for your excellent feedback and comment on the kartbuilding blog (
>> http://blog.kartbuilding.net/2009/11/14/plans-for-a-lawnmower-powered-go-kart-finished/#comments
>> )
>>
>> I have replied to your comments and I will add some notes to the kart
>> plans reflecting some of the details you mentioned.
>>
>> Best of luck,
>> -steve
>>
>>
>>
>> On Wed, 10 Feb 2010, Jonny wrote:
>>
>>> New comment on your post #61 "Plans for a Lawnmower Powered Go-Kart - Finished"
>>> E-mail : jonathan.lloyd2000
>>> URL    :
>>> Hi,
>>>
>>> Just looked at your plans for a wooden gokart with a lawnmower engine. It looks great but I think you should mention that most lawnmower engines, of the push along variety, need the weight of a mower blade connected directly to the drive shaft acting as a flywheel. They are built with lighter flywheels, which are obviously cheaper! Without the blade, or at least some form of weight greater than an average pulley, the engine will be almost impossible to start and snatch the pull cord out of your hand.
>>> Also, your setup does not have a slack belt clutch system, which would never work with a twist of 90deg in the drive. How do you engage/disengage drive?
>>> Lastly, the machine is shown with a fixed rear axle. Without a differential and using a centre pivot steering system, the machine will, at best, be difficult to steer, at worst, just plough straight ahead!
>>> Sorry if I sound negative, I just think people who are going to spend a lot of time building should be aware of these things before they get to that stage.
>>> Good to see people putting stuff like this on the net though. You have done more than me!
>>>
>
>