another which clutch question

[Jimbobcwby]

ok, i'm starting with this chassis for a base. it's got 22 inch tires and I've got a predator 420 that'll get at least a stage 1 kit. I already have a new comet 780 drive clutch. with this set up would you get the 780 driven to go with it, or get a full comet 40 series set-up. it's around the same price either way. I'm just not familiar enough with these clutches to know if one offers something more over the other. thanks.

 

[itsid]

Get a series 40 for the simple reason that spares are more widely available and likely even cheaper...
(a series 40 belt costs ~40 a series 780 belt ~70 for example)

plus selling the 780 drive clutch you have, you will get the series 40 plus a handfull of belts basically for free

The 780 has a nicer ratio than the series 40
LOW - 3.71:1 HIGH - .69:1 (780)
vs
LOW - 2.43:1 HIGH - 1:1 (series 40)

But this comes at a price, not only it's more expensive but it's also much bigger
(the driven of the series 40 is about the same size as the 780 driver you have)
Powerwise both are rated up to 16 hp on four stroke engines .. so there's no benefit at all there.

So if you're sure your final ratio is good enough and you do not need to buy an excessive amount of belts and spare parts over the time..
the 780 is the "better" one.

'sid

 

[Jimbobcwby]

okay then series 40 sounds good to me, I am tight on space. I'm looking at the gopowersports series 40 with the backplate. If I understand there description correctly the secondary clutch acts as a jackshaft which they supply a 10 tooth sprocket. Can I come off that sprocket to another jackshaft then to the axle? I'm trying to use the 22" tires that came with this cart but i'm after low speed torque, not so much top end speed. I wanta gear this down to around 30-35 mph, I might find out I want more speed after I drive it abit. thanks again.

 

[itsid]

Well you already have a jackshaft on the kart, don't you?
(it's a yerfdog 3020, isn't it?)

So no need for the backplate, just use the jackshaft you have (one is enough)
the axle sprocket needs to be big of course if you want to slow it down
so that you'll hit about 7.6:1 ratio (76 teeth axle) that'd be ~31mph..
but with wheels that size that shouldn't be a problem at all.
if you want a bit more speed the sprocket will get smaller and smaller so less and less clearance issues
(with a 420 engine I think you can go as low as 5.4:1 that's about 44mph)

'sid

 

[Jimbobcwby]

I have no idea what brand/model this kart is. I currently have only an engine and an axle, and the chassis I guess, there is no jackshaft at the moment. previous owner had a 250cc 3wheeler engine in this which I've spent a lot of time removing all of the things that were birdcrapped in. the reason for the double jackshafts was I was thinking about a putting in a torque cam from vegas carts which they claim 5500rpm which would put me at 50 mph. maybe I don't need the cam? these karts are new to me, i'm more into this kinda machinery

 

[Joe-405]

I have the go powersports 40 series bolt on kit on my mini Dragbike if you need any dimensions. It is a nice setup tho.