Hello Everyone

[Peteypooldude]

I am from Myrtle Beach and an ex go-kart racer.
I recently bought my son a Scorpion Kart with a 6.5 hp Robins engine, the spring had come out of the T/C so bright me took it off. I figured I would use one of my old racing clutches and two piece gears. After realizing the chain and sprocket were not the same size I bought a 35 chain that works with my clutch and gears. The kart is extremely fast but has no power taking off and vibrates like crazy until its up to speed. This remains an ongoing project so I'll need help. Thanks for your information thus far and if I left anything out I should have posted let me know
Thanks again
Edit to add.. I'm an Autobody technician and Painter, if anyone needs paint help I can help

 

[OzFab]

Sounds like it may be geared a bit steep; what are the clutch & axle sprocket tooth counts?

Welcome to the forum

 

[landuse]

Sounds like it may be geared a bit steep; what are the clutch & axle sprocket tooth counts?

Welcome to the forum

Welcome to the forum!!

I also think it might be your gearing that is off. Changing from a TC to centrifugal could have affected the gearing negatively. TC's seem to be able to habdle steeper ratios better than centrifugal clutches

 

[Doc Sprocket]

Definitely gearing. We'll get you sorted. Welcome!

 

[Peteypooldude]

I used a 13 tooth clutch with a 72 gear. I never thought about the height of the rear tires. I'm using Hortsman gears but I think the sizes stop at 74 so I'm about maxed out. The clutch is a Norman . It would probably be a little better about taking off but the clutch is set up for racing and requires a pretty high rpm to engage. Pulling up any kind of hill is not an option but its fast once I get it going.
Thanks again for your help

 

[OzFab]

I never thought about the height of the rear tires.

No idea where that came from but, I'm glad you mentioned it. The height of your tyres will drastically affect gearing...

I used a 13 tooth clutch with a 72 gear.

That's 5.5:1 &, I'm guessing, the rear tyre(s) are around 16"-18". If so, that's not a good ratio, you should be closer to 7:1

the clutch is set up for racing and requires a pretty high rpm to engage. Pulling up any kind of hill is not an option but its fast once I get it going.

IIWM, I'd be looking for a 12t clutch (which will give you 6:1) &, maybe, a bigger axle sprocket, somewhere in the 80's

 

[Peteypooldude]

I haven't raced or set up any karts since 98. The refresher course was brutal. After thinking about it , the clutch is actually doing what it's suppose to. Im going to try to get some different springs for my clutch"I think it's set up to engage at about 4500". I found a 12 tooth clutch on a yard kart but its for a larger chain and I've changed everything over to a 35 chain. Id like to try a yard kart clutch to try, if not I'm afraid I'm going to have to put it all back stock. If that happens I will definitely need advice on it
I appreciate your time and patience. I learned a new trick that may or may not help someone. When working on my linkage I found that a sparkler has the perfect size wire to make the linkage rods .
Thanks again

 

[landuse]

I haven't raced or set up any karts since 98. The refresher course was brutal. After thinking about it , the clutch is actually doing what it's suppose to. Im going to try to get some different springs for my clutch"I think it's set up to engage at about 4500". I found a 12 tooth clutch on a yard kart but its for a larger chain and I've changed everything over to a 35 chain. Id like to try a yard kart clutch to try, if not I'm afraid I'm going to have to put it all back stock. If that happens I will definitely need advice on it
I appreciate your time and patience. I learned a new trick that may or may not help someone. When working on my linkage I found that a sparkler has the perfect size wire to make the linkage rods .
Thanks again

Can your engine rev more than 4500RPM's. That is quite high for any clutch to start engaging.

You still haven't told us what the tyre height is?

 

[itsid]

4500, that sounds like a 2stroke clutch you got there..
If it's a Horstman you may find springs to lower that value.
maybe you can use springs for a 4stroke Horstman clutch.

'sid

 

[Peteypooldude]

4500, that sounds like a 2stroke clutch you got there..
If it's a Horstman you may find springs to lower that value.
maybe you can use springs for a 4stroke Horstman clutch.

'sid

The clutch came off a 5hp Briggs I use to race. I turned it 7400 and as hard as 9600.
Im going to find some softer springs"it's a Normon clutch" i also think a regular fun kart clutch would help.I have a Hortsman clutch also but my smallest sprocket is like a 15 tooth. The stock Robins can't turn quick or hard enough to fully engage the clutch with the current springs. It's hard to get parts around my area , they are probably around but I'm a little out the loop. I still haven't measured the tires but I'll get it
Thanks everyone