Series 40 eating belts

[Jsnscott]

I have a hammerhead 150 buggy I just modded for a predator 420 and a Polaris 250 trailboss gearbox so I could have reverse. I machined the gearbox shaft to a 3/4 dia and cut the 3/16 key so I could use the series 40 clutches. Which I thought was a good idea at the time. I'm beginning to wonder now if I should have just left it as it was and used the Polaris driven and got the tapper adapter and stayed with the Polaris clutches and belt.... anyway my issue is that it eats belts fast as in a couple of hours..my driver is brand new (clone I believe. Doesn't say comet on it ). My driven was used and did have some light rust inside where the belt rides. I'm my rush to try it out it ate belt no.1. lesson learned there. I took it apart and cleaned it back to looking new. So I was ready for belt no. 2.
In two evenings it wore so much it was causing it to get sucked into the driven clutch.
I read somewhere... maybe here that the clone clutches have poor quality springs. I just ordered all new springs for both clutches from BMI...and instead of going back to the series 40 belt 7/8 wide I'm thinking of trying the series 500 belt .920 wide.
... Oh i did try the original Polaris belt with the series 40 and it will pull like a mule until the belt pops off....this is what gave me the idea to try a 920 wide belt....am I on the right track or way off base.

 

[Kartorbust]

I'm wondering if the final drive ratio from the gearbox sprocket to the axle sprocket might be too low numerically. What's the tooth count on the gearbox and the count on the axle? Internally the ratio might be too high. Ideally youd want an overall final ratio of 6:1 or lower (7:1, 8:1).

 

[Jsnscott]

7 1/2 driven on the Polaris gearbox. The gearbox has a gear reduction of 2.5:1 to a 13t and a 58t axle sprocket. Tires measure 21" dia. This thing is geared like a tractor. My trails have a lot of hills. With a new belt it can't be stopped. Low end torque is great.

 

[anickode]

How's your alignment and spacing? A pic or two might be helpful.

 

[Jsnscott]

I not sure I can post pics from my phone. When I mounted everything up I machined my motor mounts to have slots to be adjustable. Going off the belt chart from go kart supply I made my center to center spacing 10 1/8 ... according to there chart ordered the correct belt size. My alignment isnt far off if any at all. I'm just not sure the series 40 can handle a predator 420 in this heavy of a machine with a 7/8 wide belt woods Riding. Unless you guys tell me otherwise. Stock it had a 20mm wide belt and a 150cc motor and it didn't cause me any grief. Didnt have the torque of the 420 either..lol

 

[anickode]

I not sure I can post pics from my phone. When I mounted everything up I machined my motor mounts to have slots to be adjustable. Going off the belt chart from go kart supply I made my center to center spacing 10 1/8 ... according to there chart ordered the correct belt size. My alignment isnt far off if any at all. I'm just not sure the series 40 can handle a predator 420 in this heavy of a machine with a 7/8 wide belt woods Riding. Unless you guys tell me otherwise. Stock it had a 20mm wide belt and a 150cc motor and it didn't cause me any grief. Didnt have the torque of the 420 either..lol

A 40 series is good for 18 hp, and can handle 22-25 or so at the expense of belt life (shorter but still not "eating" them), but if you're geared right, as it sounds like you are, a 420 should be no problem for it.

Do you have the driven mounted with the spring pack inboard, with the proper spring on it, and the cam indexed on the proper side of the lobes? I can never remember if it's red or yellow for inboard mounting.

 

[Jsnscott]

A 40 series is good for 18 hp, and can handle 22-25 or so at the expense of belt life (shorter but still not "eating" them), but if you're geared right, as it sounds like you are, a 420 should be no problem for it.

Do you have the driven mounted with the spring pack inboard, with the proper spring on it, and the cam indexed on the proper side of the lobes? I can never remember if it's red or yellow for inboard mounting.

I think you may be on to something.I think inboard is spring on driven towards engine and outboard is spring away from engine. If this is correct. I have my driven mounted outboard (spring away from the engine). It has the red spring in it.
I think I read on go kart supply I need the yellow spring for a outboard driven. Is this correct??

 

[anickode]

I think you may be on to something.I think inboard is spring on driven towards engine and outboard is spring away from engine. If this is correct. I have my driven mounted outboard (spring away from the engine). It has the red spring in it.
I think I read on go kart supply I need the yellow spring for a outboard driven. Is this correct??

You'd be far better off turning it around and modifying the engine mount accordingly. the 40 series torque converter is a symmetrical belt system, so if you have the driver and the driven mounted outboard, as it changes ratio, adult gets pulled further and further out of alignment. If you mount the driven pulley inboard, both halves will move the same direction, maintaining belt alignment through the full range, which will also drastically improve belt life.

 

[Jsnscott]

You'd be far better off turning it around and modifying the engine mount accordingly. the 40 series torque converter is a symmetrical belt system, so if you have the driver and the driven mounted outboard, as it changes ratio, adult gets pulled further and further out of alignment. If you mount the driven pulley inboard, both halves will move the same direction, maintaining belt alignment through the full range, which will also drastically improve belt life.

You know when I had it up on jack stands running it I noticed how the belts alignment gets further out. Thought that wasn't right and I seen instructions somewhere online that you set it up with a 3/8 offset. Which I done. Looks better when running it on the stands. But unfortunately I can't flip my driven without moving a lot around.
But I am happy that a yellow spring may fix it for the most part..
I just ordered one and will definitely report back when I get my order in and get it back to together.

 

[Jsnscott]

Update.. I got the reverse wound spring put in and it works perfectly. Does exactly the way it's supposed to. Thanks for all your help help. My grandson is one happy camper.

 

[Joe-405]

I was getting ready to comment about the spring but you got it figured out. I switched the spring on my 44c magnum driver and standard 40 series driven and it worked great.