Buggy wont go..clutch or sprocket problem

[creakingcane]

HI

I have just put together an off road buggy which is powered by a honda GX200 motor, governor removed stronger valve springs fitted, I have fitted a maxtorque centrifugal kart clutch which has 16 teeth and a talon sprocket with 72 teeth and it has 22" balloon tyres. My problem is when at full throttle the kart just about gets going on the flat but as soon as there is any rough ground or very minor incline it just grinds to a halt...

I assume the ratio between the axle sprocket and the clutch sprocket is wrong? any suggestions as to what I can do..I am not looking for very high speed just more torque so I can keep going over fields etc....

also is there a right way round for the clutch or should it work when spinning in either direction?

I hope somebody out there can help?

thanks

Mike

 

[Kaptain Krunch]

centrifugal clutches are generally meant for flat and hard surfaces, the same thing happened with mine, my solution was putting a dirtbike engine in my kart, but an easier solution would be to buy a torque converter.

 

[r_chez_08]

your ratio looks quite tall for offroad, what chain are you using?
if your using #219 then you could get a bigger sprocket (90t ish)
on my kart for light oddroad i have 16:93 and 14" tyres. the speed calculator says you should go 52mph, which is very hard for a 6.5hp engine witout mods, especially offroad

 

[Kaptain Krunch]

your ratio looks quite tall for offroad, what chain are you using?
if your using #219 then you could get a bigger sprocket (90t ish)
on my kart for light oddroad i have 16:93 and 14" tyres. the speed calculator says you should go 52mph, which is very hard for a 6.5hp engine witout mods, especially offroad

Forget about the engine, the clutch is the problem. I had a 5.5hp tecumseh on a yard kart with 14 inch tires, and a 13/72 (5.5/1) ratio, and my hillard was slipping on the slightest incline.

 

[kart7094]

What you need is a jackshaft. Your 16/72 ratio is WAY too high for 22" tires. I had 12/80 combo with 15" tires and was unhappy with take off. By adding a 12/18 ratio jackshaft and a 66 rear gear, I had better take off and better ground to gear clearance. In fact, the reason torque convertors work so well is the gear reduction afforded by jackshaft system. My advice is to install a jackshaft with enough clearance to install a 7" pulley. This way you can keep your clutch and still get the gear reduction you need, but if you want to keep your top end, adding a torque converter later will be a lot easier.

Paul

 

[r_chez_08]

it could be the tall ratio or the clutch. i would try a bigger sprocket on the axle first, as it is the cheaper option, but it also does sound like the clutch could be slipping, like Kaptain Krunch said. if it is a new clutch, i would get a refund, if you can.

 

[Kaptain Krunch]

it could be the tall ratio or the clutch. i would try a bigger sprocket on the axle first, as it is the cheaper option, but it also does sound like the clutch could be slipping, like Kaptain Krunch said. if it is a new clutch, i would get a refund, if you can.

I still think he should just shell out for a torque converter, if he is going offroad the torque of any clutch is pathetic. After i ditched my clutch for a dirtbike engine i have no idea how i could have ever used one. Being able to punch it and do doughnuts off the line, and actually get stuck because my tires spun too far into the ground, not because the clutch is slipping, is a great feeling.

 

[kart7094]

it could be the tall ratio or the clutch. i would try a bigger sprocket on the axle first, as it is the cheaper option, but it also does sound like the clutch could be slipping, like Kaptain Krunch said. if it is a new clutch, i would get a refund, if you can.

There are two downsides to your suggestion. 1. New rear sprocket doesn't offer enough gear reduction for such a large tires. 2. A larger rear sprocket hurts ground to sprocket clearance which is a bad thing in off road karting.

I still think he should just shell out for a torque converter, if he is going offroad the torque of any clutch is pathetic. After i ditched my clutch for a dirtbike engine i have no idea how i could have ever used one. Being able to punch it and do doughnuts off the line, and actually get stuck because my tires spun too far into the ground, not because the clutch is slipping, is a great feeling.

I agree that a torque coverter would be the best way to go. The upside to torque converters is that it acts like a clutch and a transmission all in one. You get low end take off gear reduction you need without sacrificing top end speed. The downside is cost of the torque converter and the cost of parts already purchased that cannot be reused (clutch).

I suggested building the jackshaft system first is you can try to reuse the clutch and maybe save the expense of a torque converter. You need a jackshaft to run a torque converter anyways and if you use the same size chain from the clutch to jackshaft & jackshaft to axle sprocket, the only things thrown away if the clutch still doesn't work is the clutch and the jackshaft driven sprocket. The key here is to position the jackshaft so a t.c. driven pulley (6-7" diameter) can be added later on if you're not happy with the clutch.

Paul

 

[r_chez_08]

I still think he should just shell out for a torque converter, if he is going offroad the torque of any clutch is pathetic. After i ditched my clutch for a dirtbike engine i have no idea how i could have ever used one. Being able to punch it and do doughnuts off the line, and actually get stuck because my tires spun too far into the ground, not because the clutch is slipping, is a great feeling.

thanks, great to know, i am in the process of finishing my offroad kart with a clutch now!!! i would reccomend a torque convertor too, but depends on your budget.

 

[creakingcane]

Wow

thanks guys for all this information..I had come across torque converters before building the kart but winced at the price..re the jackshaft set up can you point me to a good description of how to set this up anywhere?

thanks

mike

 

[ed1380]

save the money and invest in a engine with a tranny

 

[Kenny_McCormic]

save the money and invest in a engine with a tranny

Yep buy a beat up/wrecked 250cc or higher motorcycle or quad, part it out to at the very least cut your losses(you might make more than you paid) save only the engine and wiring harness.