Could an 18 hp engine pack a good enough punch?

[Raywelder]

British lawn mower racers use motorcycle clutch baskets mounted on the driven end of their mowers.

I have one from a broken engine if someone wants one to mess around with.

I think you would mount the basket to a sprocket or pulley, then you have to have something that will push the pin on the side to disengage it,

 

[andynerd]

ok so here was my idea: use the general principle that toroidal CVTs work by(http://auto.howstuffworks.com/cvt3.htm) but instead of having the electronic shifter finding the best ratio use a shifter. So ya pretty much use the idea of the cvt but to change ratios i would have a small bar connected to each ratio adjuster on the sides to change the angle they would be of equal length then at the end have them toothed and have a bar that's toothed with a shifter connected to it to rotate it and change the ratio. Or use the cord wire things that are on lawn mowers. Here is a drawing to give you an example.

 

[Kaptain Krunch]

Sounds more complicated than it should be... Belt tensioner would be a lot easier.

Ray, how much you want for that clutch basket?

 

[andynerd]

ya you may be right but in the mean time well i am waiting for the engine I may build a small model of it just to try

 

[andynerd]

So with a tension belt setup were you thinking a simple pully on engine to jackshaft then chain from jack shaft to rear axle?

 

[Kaptain Krunch]

So with a tension belt setup were you thinking a simple pully on engine to jackshaft then chain from jack shaft to rear axle?

Yup, would be very simple. just need some strong springs for the tensioner.

You should try to make a model of that CVT thing, then take a video of it working. You could just use a small motor from an erector set or something as the power source and give it a try.

 

[Raywelder]

I have a v-belt clutch, Well my friend does anyhow. It will fit on your crankshaft.
Not sure if it would tear up belts or not though on a 18hp. I wouldn't imagine it tearing it up anymore than a slip belt type you guys are thinking of.

 

[Kaptain Krunch]

It really shouldnt rip up the belt much at all, think racing mowers that use 18 twins, lots have the slip belt clutches and are geared pretty high.

 

[Raywelder]

It really shouldnt rip up the belt much at all, think racing mowers that use 18 twins, lots have the slip belt clutches and are geared pretty high.

Yea! they do.
Seen em on hey mow!
But mowers use longer belts, they run cooler and usually last longer.
A shorter belt may not last as long,

 

[andynerd]

Yup, would be very simple. just need some strong springs for the tensioner.

You should try to make a model of that CVT thing, then take a video of it working. You could just use a small motor from an erector set or something as the power source and give it a try.

Ok will look into the tensioner springs, also for the model I will use a simple model electric motor since i have lots around!

 

[Raywelder]

So with a tension belt setup were you thinking a simple pully on engine to jackshaft then chain from jack shaft to rear axle?

Just like this,

Except that setup usings a v-belt clutch, in your case you would just have a manual operated tensioner.

 

[Kaptain Krunch]

That looks like a nice clutch you got on that engine, what make is it?

 

[Raywelder]

That looks like a nice clutch you got on that engine, what make is it?

Couldn't tell you! It came with that engine. Has no markings that I could see.
Works pretty well though.

 

[andynerd]

ya that's what i was planning on doing, the same setup as my old diy riding lawnmower go kart thing except this time I use a jack shaft instead of a 3 speed f/r transmission. Would it also be a good idea to have a clutch pedal and a brake/clutch pedal so it automatically hits the clutch when braking?

note: by clutch i mean tensioner just saying because i am a newbie and might get the terms wrong.

 

[Kaptain Krunch]

the thing about a clutch/brake pedal is that most of the time the stroke of the brake is shorter than the stroke of the clutch pedal, if you can get around that it would be perfect.

 

[andynerd]

hmm have to think about how i am going to do that. :rolleyes3:

 

[Raywelder]

Did you grab the engine yeT?

 

[andynerd]

No still waiting or they sold it to someone else should hear from them in a few days maybe be Tuesday.

 

[Raywelder]

Aw, that would suck if they sold it.

 

[modelengineer]

If you want a clutch and brake pedal (not recomended) then you just have to make it so the first 1/2" of pedal travel is *just* the clutch, and the rest is the brake & clutch (or just the brake if you can figure that out!)

GL, but I'd go with 3 pedals.