Clutch recommendations

[deano10972]

This question has probably been asked several times but I need a good clutch recommendation.
I recently built a 212 Predator and installed it on a doodlebug minibike, I coudnt decide what clutch I wanted to use so I took the one off my gokart, it's a Hilliard Extreme-Duty Centrifugal Clutch — 3/4in. Bore, 12 Tooth, 35 Chain Size. The clutch works pretty good but man this thing makes a lot of racket. I think it's set to engage at 2300 rpm, I would like to have one to engage @ 2500. Can someone recommend a better clutch, but not lookin to spend too much. I think I paid 50 bucks for the Hillard from Northern Tool, just looking for something a little better. This motor runs around 5500 rpms
Thanks

 

[itsid]

Both the Hilliard and the MaxTorque six-shoe are well made clutches..
and IIRC both are slightly tuneable only.
the Hilliard extreme for example (yours) should have the white springs installed .. the next option are the black springs but they engage at 3000 rpm.. so that won't help much.

Same as the black spring for the MaxTorque black spring (2900 - 3200rpm)

So you'd need advice by a professional:
see this thread and ask jim @ maxtorque for advice maybe

Or you step up in the price range and get a Hilliard flame, fury or blaze.. all of which have a much wider tuning range since different springs can be changed in pairs of two to get intermediate values.

Oh.. btw a higher engagement speed might be a bad idea,
keep in mind that this means a bigger load on the clutch (heat wise)
okay, 200 rpm might not sound like much at first.

but look at it this way:
2300 rpm on a 6:1 ratio and 15" wheels mean a speed of a bit over 17mph.
so from take off to 17+mph your clutch will be stressed and heat up due to friction of the shoes.
depending on the acceleration that might take some time to reach

with now 2500 rpm you need to reach 18.6mph before the wheel can keep up with your clutch, 1.5mph again, depending on acceleration that fraction of a second of additional heat can make a difference between buying a clutch every other year and buying a clutch every year

So, at least think twice before making the final decision!
(personally I think you should still be safe with a 2500 clutch as long as your gearing is good!)

'sid

 

[deano10972]

Both the Hilliard and the MaxTorque six-shoe are well made clutches..
and IIRC both are slightly tuneable only.
the Hilliard extreme for example (yours) should have the white springs installed .. the next option are the black springs but they engage at 3000 rpm.. so that won't help much.

Same as the black spring for the MaxTorque black spring (2900 - 3200rpm)

So you'd need advice by a professional:
see this thread and ask jim @ maxtorque for advice maybe

Or you step up in the price range and get a Hilliard flame, fury or blaze.. all of which have a much wider tuning range since different springs can be changed in pairs of two to get intermediate values.

Oh.. btw a higher engagement speed might be a bad idea,
keep in mind that this means a bigger load on the clutch (heat wise)
okay, 200 rpm might not sound like much at first.

but look at it this way:
2300 rpm on a 6:1 ratio and 15" wheels mean a speed of a bit over 17mph.
so from take off to 17+mph your clutch will be stressed and heat up due to friction of the shoes.
depending on the acceleration that might take some time to reach

with now 2500 rpm you need to reach 18.6mph before the wheel can keep up with your clutch, 1.5mph again, depending on acceleration that fraction of a second of additional heat can make a difference between buying a clutch every other year and buying a clutch every year

So, at least think twice before making the final decision!
(personally I think you should still be safe with a 2500 clutch as long as your gearing is good!)

'sid

Thank you Sid for the advice, I was looking at the Maxtorque.. The Hilliard has been a good clutch, I was just looking at options. My engine idles @ 2000 rpms and the minibike wants to start moving while its on the kick stand, that's the only reasons I was thinking about raising the engage rpm. My rear sprocket is still stock (70 tooth) and my tire is 13". Seems like I have a good set up, I haven't checked the mph yet the engine is still in break it period. With that 70 tooth it's not going to be that fast, but man will it get up and go..

 

[itsid]

drop the idle speed.. even a modified predator 212 shouldn't need more than 1600 to stay alive.

13" 70T axle.. that's 16.58mph @2500 rpm and 15.26mph @2300 rpm

your gearing (assuming 125kg just to have a number) is a tiny bit low with 5.83:1;
but let's just assume the engine mods are in your favour and cover for that..
with 5500 rpm you should hit 36.5 mph

'sid

 

[54inches]

sid, do you happen to know what a Kartco 455 had from the factory? I put a Predator 212 on it last year and the clutch gets too **** hot.

Should I replace the clutch, spring or sprockets? It has stock sized tires and wheels.....

 

[Russ2251]

I put a Predator 212 on it last year and the clutch gets too **** hot.

This ALWAYS indicates an overloaded condition.
What is tire diameter?
What type clutch and how many teeth?
Tooth count on driven sprocket?
What size chain?