Modified Clone clutch engagement speed

[bshinn]

Looking for a new clutch for a lightly modified clone, (stock valve springs) figure 5500 max RPM. What would be a good clutch engagement point? Seems to me like the HF clutch that I'm using is locking up too soon & bogging the motor.

Thanks

 

[ZnsaneRyder]

Get a Hilliard Extreme-Duty Clutch. http://www.bmikarts.com/item/Inferno-Fury-34-Bore-Racing-Clutch-from-Hilliard-404620-6512

It engages at 2300 RPM, and if you still need higher, you can put in springs that raise the engagement to 3000 RPM

 

[Swabbster]

Well if you run a comet torque converter you can buy new springs, but for those cheap clutches if it works good but just engages to quick drill the weights with a drill press with a depth set, you can weigh the weights but its just a go kart clutch, don't forget, it's easy to lighten, hard to add weight

 

[Doc Sprocket]

The cheap-and dirty is as follows-

Disassemble clutch and remove garter spring. Cut the last few coils off one end of the spring (say, 4-6) and re-bend the remaining last coild to form a hook again. Re-assemble clutch.

This forces the engagement RPM up. I did this on my older boy's Doodlebug.

Please note that this only works on clutches with a garter spring like a Comet or MaxTorque. The Hilliard has different (non-modifiable) springs.

 

[bshinn]

This clutch has 4 shoes that are connected with "C" shaped springs. Don't think they can be modified. I think Hillard has a design that is about the same, might try some of those springs. This one engages too low, & causes the motor to bog a bit.

 

[ZnsaneRyder]

This clutch has 4 shoes that are connected with "C" shaped springs. Don't think they can be modified. I think Hillard has a design that is about the same, might try some of those springs. This one engages too low, & causes the motor to bog a bit.

It sounds like YOU DO have a Hilliard, because nobody else has that design, because it's patented.

Is this your clutch???

If the clutch is too grabby, a very light amount of WD-40 on the friction surface will make a smoother engagement and allow some extra revs.

BTW, how BIG and HEAVY is your Kart? It's hard to believe a clone would have a hard time pushing your Kart with a stock Hilliard (2300RPM engagement) but if you DO need more power, then get the 3000RPM springs and put them in your clutch.

And if 3000RPM is too high, you can use two 2300 Springs and two 3000 Springs to have an engagement ~ 2700RPM

 

[bshinn]

Not a Hillard, but a knock off from NT. Kart's not that heavy..........it's me. 6'0 230# Gearing is 12/60 running 11" tires

 

[carter]

that's a 5:1 ratio, it's a bit steep if you're just running a clutch, your problem likely lies here instead of in the clutch.

 

[Doc Sprocket]

that's a 5:1 ratio, it's a bit steep if you're just running a clutch, your problem likely lies here instead of in the clutch.

Agreed. It's not the clutch bogging the engine, it's just the engine bogging. You can only compensate for that so much with a clutch. What needs to be addressed is power and gearing. Since it would seem you have a fair bit of power available, you need to work on the ratio.

 

[jandj]

I've got a HF 6.5 "new style" Blue clone, gov. out and 18lb springs (billet rod & wheel), K&N style air filter and a weenie pipe with thread on muffler. I use the Hilliard extreme duty clutch (got it at Northern) as it's made to handle repeated on-off throttle and brake/throttle at the same time without burning up. I run a 12/72 gear set up (wanted quicker acceleration, we run a small dirt oval) and it works great.