Old Manco three wheeler.

[ntjones]

Got this thing running today. Motor cranked on the first pull. I was surprised. Seemed to run good but took a minute to warm up. My problem now is that when it revs up it vibrates like crazy. Does anyone have any suggestions on how to solve that. I was thinking rubber washers but I will need longer bolts then which is ok I guess.


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[ps2fixer]

Rubber mounting the engine would probably work, not sure how good that works with the slides though.

Seems like the engine shouldn't vibrate too much though, are you sure something isn't off balanced? Maybe pull the clutch off it and see if the vibration goes away.


That chain drive system would bug me, shaft sticking out quite far with no support, has to be hell on the bearings inside the housing. If that housing is rigid mounted with no adjustments, I'd think adding a plate on the frame and mounting an external bearing would help the load a lot, but maybe the bearings are really huge inside the housing and have no problem with the extra forces from being so far from the pivot point. If that's how it was stock, then I guess it shouldn't be a problem.

[ntjones]

I’ll try taking the torque converter off and see if it still vibrates. The shaft from the gear box use to hold the old driven pulley. I think it had a 40 series torque converter originally.


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[ps2fixer]

Weird, never seen anyone call the "CVT"/clutch system called a torque converter before, only the torque converter for automotive car transmissions. I'm personally not a fan of belt drive like that though, so I avoid that design for cars/atv's etc. I'd only own a snowmobile with that style of drive, but I'm not north enough to have a long riding season.

Looks like Yamha called it the primary sheave, never heard that term either xD. Same term on their 2020 models too.

https://www.partzilla.com/catalog/ya...primary-sheave

[ntjones]

I think it’s called a torque converter. That’s what Amazon calls it. That’s were I bought it from. But yeah that’a similar to how it was stock only I put a smaller engine and smaller cvt on it. But it vibrates like crazy. I just took off the front pulley and ran it with nothing hooked to the engine and it did the same thing.


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[ps2fixer]

Vibration clearly coming from the engine then. It shouldn't vibrate too much, just normal vibrations like a 4 cyl car engine but only single cylinder. I don't know much about those engines, I'd assume the crank is internally balanced and not balanced by the flywheel, but if the flywheel is how the engine is balanced, maybe it wasn't done right at the factory (assuming new engine), or it's clocked wrong. The old like 70's era V8 engines where a mixed bag, some internally balanced, some used the flywheel to balance it. Swapping the fly wheel from one type to the other was big vibration and troubles.

Maybe it's normal for the engine to vibrate when new and once it breaks in it runs smoother. Might want to get a hold of the place you bought the engine from and get their input on the situation before trying to dig too far into it. I'm sure someone with more experience with that type of engine will chime in.

[ntjones]

I’ll do some research on these engines. It is brand new. Today is the first time it ran. Thanks for talking with me. I’ll update when I find something out on it.


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[ps2fixer]

No prob, it's an interesting machine, so following along with the progress.

[MrConcdid]

Yes, its a torque convertor or a variable speed trans or a CVT.
It the choke off? It should not vibrate that bad. those engines are bullet proof. I have used many in my go-cart days.
Take it back, I do not know what gear is in the transmission box but i bet its going to fly.

MrC.

[ATC King]

Looking good!

[ntjones]

I looked around online at some go kart forums. Some people say that it should have a little vibration to it. Others say return it for a new one. I just hate to return if that’s not the problem. I will just have to hope that’s it and return it. I am able to run it Down the road a little. It’s actually not that fast. It gets up to speed really fast but then it planes off like a golf cart. Top speed is slow. I would be fine with that if it didn’t shake my hands so badly. I’m going to finish painting it and making it nice either way though.


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[MrConcdid]

Easy fix change the sprocket on the CVT if its a 10t jump up to a 12t or 14t, you could also make the second gear smaller. if there different sizes now reverse them, as an experiment. it wont cost you anything and may point you to the correct gear size. they make gear into the 60t so you have tons of options
just like a bicycle, larger front/smaller rear is top speed. The CVT give you the best take off, so focus your jackshaft to compensate for mid to high speed.
cut up a rubber floor mat, put a piece under the engine and bolt through it, that will cut down on the vibrating.
with basically 2 transmissions it will be trial and error to get the right gearing.

MrC.

[ntjones]

Thanks. Those are brood ideas. I hadn’t thought about a rubber floor mat. I bet that will work wonders. I’ll also play with the sprocket set up also.


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[MrConcdid]

ok, try this first,
Mark the input shaft of the original trans and the out put shaft.
now spin the input and count the rotations and at the same time count the rotations of the axle or output shaft (same thing)
you may have a 4 to 1 reduction or something easy like that in the factory trans.
Disregard the CVT for now it gives you low and high gearing. Ideally what ever gear you use the CVT will take off quickly and both sheaves will compress/expand, getting you the full range of the unit.

Example with a 12 inch tire a 6.6 predator engine with a 60 series comet CVT a 10t on the CVT and a 48 on the axle works very well. top speed on a cart around 30mph with a lot of grunt down low for hills and take off. You have an additional trans to factor which is giving you even more low gear but also taller tires. reverse the two gears you have making the larger the one on the CVT the smaller one on the trans input. and try it, if you see an improvement than continue increasing the first gear, order two gear in a few tooth jumps until you get it right.

the gocart guys liked 6 to 1 as a good final ratio, I liked more torque so I used 8 to 1 for my carts.

You can play with this calculator if you want but the second trans may make it harder to use.

https://gokartguru.com/images/Go_Kart_Drive_Line.htm

MrC.

[ntjones]

Thanks. I’ll try to see what gear reduction it is and also Oder a new sprocket to try. Also I primed my plastics so now I have to decide on a color.


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