Chain/Sprocket/Clutch Allignment

[makisupa96]

Hi all,
I'm in need of some guidance again. Currently working on rebuilding a Manco Interceptor with a Predator 212.

I attempted to mount the engine yesterday which went fine.

When I added the clutch (from GoPowerSports 12T GPS Centrifugal Clutch 3/4" Bore, #35), I noticed that the gear doesn't line up with my sprocket.

I tried inboard and outboard with the clutch. No luck. (See photos attached).

Any insight would be greatly appreciated! Do I have the wrong clutch? Was the axle previously modified?

Thank you!
brian

 

[Edwin Spangler]

That came with a Subaru engine, correct? The shaft just doesnt line up the same way. Youre going to have to slot the mount to allow some horizontal movement.

-Unless the shaft is long enough to add spacers, which it doesnt look to be.

I wonder if a CVT/backplate setup would have the sprockets line up...

EDIT: Nevermind, AI says the CVT would not have them align.

 

[makisupa96]

It did have a Robin Subaru engine on it. I noticed that original had another gear/chain.

Seemed like the crankshaft drove the 'extra' component, and THAT then drove the axle with a separate chain.

I can add a picture of the old motor set up later today.

Thanks!
brian

 

[Edwin Spangler]

Jackshaft...

Pics will help but it will probably take some customization to get the 212 to fit/align.

 

[makisupa96]

These aren't pics from my exact kart, but it my original set up was identical. (minus the pink paint )

 

[JimD]

Let's start with the basics: how many teeth on the axle sprocket and how big in diameter is the wheel? Want from the ground to the top of the tire. Trying to figure out if it will work even if you get it aligned with the clutch and present gearing.

 

[Hellion]

As Edwin says, the kart came with a jackshaft (I forgot) so it was configured to work with one, with all the chain spacing and offset that a jackshaft “provides”. In your intro thread I posted the parts manuals, very helpful to see the way it was.

Newbie to the World

Hey Everyone, My daughter (10 years old) and I recently found an old Manco Interceptor on the side of the road for 10 bucks! It's in rough shape, we plan to rip it down, clean it up, and see if we can get it running. What started as a mouse infested, rusted pile of junk, is coming along! We...

www.diygokarts.com

 

[Hellion]

…how many teeth

Hey Jim, per 4 out of 5 of those manuals, what is the tooth count on Reference 66, part number 4335? Says it’s a .75 bore “Max T” clutch.

 

[JimD]

Manco was the only large volume kart builder still using #35 chain on the karts. Most of the competition went to #420 chain 10 tooth sprockets. Manco stayed with 12 tooth #35 chain to cut down on the number of parts they carried in inventory. Bill Hatlen the former owner of Manco used the KISS philosophy. He felt when someone called up and wanted a clutch you didn't have to ask the question which chain is it because on the clutch karts it was all #35 chain. 12/72 ratio

 

[makisupa96]

Thanks for all the help! I was able to get the jackshaft off the old engine and it seems like it will line up perfectly!

As soon as I get another chain, I should be in good shape! Fingers crossed!

Anyone see glaring issues here?

 

[panchothedog]

Looks like you've got it figured out. Good job digging up the original jack shaft assembly.

 

[Hellion]

Fine work, Makisupa. The jackshaft provides, I think, the low end grunt that a normal two sprocket setup can’t provide, so it’s more fun and you get a better takeoff when you gas it instead of a more gradual takeoff with clutch slippage(?)
Somebody explain this to me.

Hey JimD, his clutch says “Gopowersports”. Is that a China clutch or one of yours?

 

[JimD]

The easy way for me to tell looking at a clutch from the front is the snap ring holding the drum on the sleeve. The snap ring we use doesn't have the small ears it is completely round so it cannot snag clothing. Also when you look in the six holes you will see the holes in the drum line up with the six holes that cover the garter spring, From the back of the clutch the hub is press fitted into the harden drive plate and ours is a very distinctive look. The Max-Torque name is on the drive plate but one of the China copies also put the name on their copy.

Most of the china copies have set screw holes in the hub. We quit putting set screw holes in the hub because no one read the 'donut" on the clutch that says "DON'T USE THE SET SCREWS IF THE CRANKSHAFT IS DRILL AND TAPPED" . You want to always hold a clutch on with the bolt and washer. The clutch is shorter than the crankshaft for a reason, it is meant to float to self align with the rear sprocket which NEVER runs true. So don't put washer on the crank to prevent the float, you want it. Rear sprockets always have quite a bit of wobble to them and you want the clutch to be able to move on the crankshaft to self align as needed.

The is more critical in racing than back yard fun karts but it applies to both. Racers float the clutch as well as the rear brake disk because they know if they get hit on the rear axle on the left or right side the axle can move so to keep the chain on, the clutch floats and the brake disk floats so you don't have the brake drag against the pucks.

 

[Hellion]

I just noticed the extra large set screws, egad. ‘Can’t see the forest for the trees’, man. Anyway, that’s a 10/10 lesson there on clutches.

In the beaucoup parts manuals I listed, some of them have an “impeller“ on the clutch. A concept I have always liked. Thoughts? Some CVTs have had it too.

 

[makisupa96]

Those set screws ended up being removed. Someone posted here that the clutch should be free floating in order to self align.

Is that accurate? The clutch does slide a bit on the shaft, but I added the bolt/washer into the crankshaft to prevent the clutch from moving too much.

 

[JimD]

I know better than comment on something I know nothing about. I am not familiar with impeller on a clutch or torque converter. Anything to get air moving over them to cool them down quicker is to your advantage.

The early clutches were solid drums, no holes in them, then a company in CA, Tab Lock, put 4 louvers on the face of the drum to catch air to help cool it. Worked nicely as long as you outboard mounted the clutch. They quickly learned on the McCulloch engine you best inboard the clutch or you could snap off the end of the crank. It doesn't happen on acceleration it happens when you apply the brake HARD. The brake is much stronger than the clutch and it is stopping the axle quickly while the clutch is locked up which in turns gets all the transfers all that inertia to the crankshaft which is the weak point and off goes the end of the crank when it was an outboard mount. It happens because the crankshaft is tapered from 9/16 down to the threads which are 3/8". The sprocket is hanging past the threads and the leverage of the chain pulling on the crank --off it goes. I see even more of that today with these cranks now over 60 years old. Some of the very early karts, Bug, Rupp, and Fox you had to mount outboard there wasn't room to move the axle sprocket inward because of the placement of the axle bearing on the frame. So now you just have to drive smart and hope nothing happens in front of you where you have to slam on the brake.

Gear heads and racers are the innovators that come up with the changes the clutch companies have gotten over the years to make improvements to their products. I would like to take the credit for the changes but it would be pure bull sh-t. It has always been the end user that comes up with suggestion how to make something better. They are the ones trying to get another 1/10 of a second on the track. They share their secrets when they are getting out of the sport and then willing to talk about what gave them the edge.