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Old 11-08-2019, 09:16 AM
Jamie P Jamie P is offline
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Default Centrifugal clutch sliding on Predator 212 shaft

I'm having trouble keeping the centrifugal clutch in its place on the crankshaft of my Predator 212. I'm running it on an old Thundercart. In the photo you can see what keeps happening. The clutch slides until the chain gets misaligned and pops off. It has two set screws that I added threadlocker to and tightened as tight as they can possibly go. My first thought was that maybe there is play in the hub causing the sprocket to pull sideways on the chain and clutch, but everything about the wheel feels perfectly tight with no play.

I know these clutches work better when the gear is on the inboard side, but without some frame modifications I'm not sure how feasible that is.

The shaft on the Predator 212 is threaded for a bolt, but the clutch is not all the way on the crankshaft, so I could add a bolt to stop the clutch from sliding outward, but I would have to be careful about how tight I install it, and I'm not sure if the clutch would have a tendency to slide inward, which if it did at all the bolt would have nothing to push against.

I have the ability to drill and tap the shaft to install longer set screws, but I'm not a big fan of this idea.

What do you guys recommend trying next?
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Old 11-08-2019, 10:42 AM
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get washers that are 3/4th inch for on the shaft, tighten the set screws, and put a long bolt in the shaft it will never move again if you tighten it well. the bolt will be 5/16"-24 and get one as long as you need with a 5/16 washer that is 1 inch around. thats what i do to all of my stuff and it works fine
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Old 11-08-2019, 03:20 PM
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Ok, I've got the same style clutch(a Max-Torque SS) with the set screw collar.
At least one of the set screws should be in the keyway of the crankshaft, and both should be tightened down(not enough to dig a hole in the crankshaft).
I do not have to run a bolt in the end of my crankshaft, and it stays just fine, even without a key.
Are you ABSOLUTELY certain your chain alignment is spot on? Get a straightedge and check.
Also, what is your chain tension like when you put it back together? About 3/8" of slack is needed.
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Old 11-09-2019, 11:31 PM
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If you want it secure you need to the use the proper shims behind the clutch. Use machine shims from tractor supply or some place like that. Use the right stack up for the proper alignment then put a bolt in the end of your crankshaft and properly bolt your clutch down with the right hardware and washer stack and you won't have this issue any more. Set screws alone won't hold without doing other things in addition. Most of the problem I see is improper engine to axle sprocket alignment. One of two ways two fix...move the engine ore move the axle sprocket. Or add a pile of shims as stated above for the Jerry rig solution.
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Old 11-12-2019, 07:59 AM
Jamie P Jamie P is offline
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Thanks for the advice. I didn't explain it well before, but the photo was meant to show the position of the clutch after it slid. It started in perfect alignment with the sprocket with just the right tension, but it worked its way out.

I bought the hardware I'll need to bolt the clutch in place. It's dark in the morning and dark at night, so I'll have to wait until the weekend to give it a test run.
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Old 11-18-2019, 08:00 AM
Jamie P Jamie P is offline
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I used Budget GoKart's suggested fix with the washers on the shaft and the bolt in the end, and it's working great. No movement of the clutch now and things are staying in nice alignment. I had a great time zooming around the yard this weekend. It brought back memories of being 10 years old again. I can't wait to get my daughter's cart going so she can join me.

Now that I've put a little time on it I've noticed the chain has more slack than it started with. I understand that a chain will stretch as it wears, but how much stretch is normal at the start? I'm running a 6.5 hp engine with a 35 chain (because the kart came with a 35 sprocket). Is this chain too small for that engine? If I take up the slack in the chain do you expect it to stretch some more, or is that just something that happens at the beginning?
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Old 11-18-2019, 09:39 AM
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Just start up slack. Set tension again you should be good. 35 chain is big enough for that engine.
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Old 11-18-2019, 11:23 AM
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your welcome i love to help out!
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Old 11-18-2019, 06:47 PM
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Just to clarify..Are you using the washers to align the clutch to the rear sprocket, with the engine in place.. OR The Washers are put on the shaft as to abut the clutch when tightening with the shaft bolt and the engine as a whole is aligned to the rear sprocket????
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Old 11-18-2019, 10:02 PM
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Your engine might have moved slightly too. I'd check just to make sure. Otherwise just tighten the chain. A 35 is just fine
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Old 11-19-2019, 07:45 AM
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I'm not following mckutzy's question 100%. I'll explain what I did. I can snap a photo tonight if it's at all helpful.

There is no side-to-side adjustment of the engine to align with the sprocket, so I mounted the clutch so that it was aligned. I put 4 washers behind the clutch and a bolt into the end of the shaft in order to keep the clutch right where I wanted it. Without the bolt it was sliding around. The two set screws were unable to hold it in place.

From the responses it sounds like the chain I have is not undersized for the horsepower. That was my biggest worry. I'll take up the slack, putting the chain back to proper tension, and I'll mark the exact location of the engine on the frame, so if it happens again I can rule out any sliding of the engine.

I'll update you guys soon. Thanks for the input!
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Old 11-19-2019, 08:38 AM
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I see.. (yes pics will also help)
Your going to have to mount the engine closer to the sprocket...
Having the clutch out on the end of the shaft, is really going to torque the clutch and the main bearing....Both not good at all.

Your going to have to add some extension bars to mount the motor on or drill/ grind out the slots already on the motor plate, for more lateral movement towards the rear sprocket...
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Old 11-19-2019, 12:20 PM
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Quote:
Originally Posted by Jamie P View Post
....I know these clutches work better when the gear is on the inboard side, but without some frame modifications I'm not sure how feasible that is....

.....What do you guys recommend trying next?
I recommend starting over with a clearer explanation and a proofread before posting(?).

The clutch sprocket on the inboard side being the best is debatable, but it is paramount to have the clutch installed (in either orientation) so that it’s ‘snugged up’ on the crankshaft and as close as possible to the centerline of the engine. To have the clutch ‘loitering’ out on the far end of the crankshaft is going to stress that side of the engine and its bearing. You’re going to roast that bearing prematurely, at the minimum, if you persist.... but it might be fun to see the results.



Joking aside, being in your shoes I would examine the engine mount to see if there’s been any alterations made to it in the past that would have you resorting to a less-than-optimal fix such as this. Then I would alter the frame, not the engine or clutch.
...
Industrial 4 stroke engines are designed as bolt-in replacements, so the bolt pattern on the block’s base is the same across all manufacturers and the spatial relationship between the crankshaft and the engine base is supposed to remain constant so everything lines up—I’m not saying variations don’t exist however.



And while some may run their clutch without a retaining washer and bolt on the end of the crankshaft, it’s not advisable.

The set screws and/or keys serve only to prevent the clutch from rotating freely about the shaft and also enables the transmission of torque. The bolt on the crankshaft is what keeps the clutch from flying off.

Oh dear, sorry about the ‘book’. Almost went into full-Sid mode.
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Old 11-19-2019, 03:56 PM
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And this is exactly why I said in my post above it would be advisable to adjust either the engine or the axle to bring the sprockets into proper alignment so it could all be correctly installed...but does anyone listen? Nope...
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Old 11-19-2019, 04:33 PM
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Jamie So these people stop whining about it remove all but one washer behind the drive wheel if any or add washers to the front of the sprocket to move stuff inward so you can remove washers on the clutch
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Old 11-19-2019, 04:45 PM
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Run it like you want to, it's yours. I really don't care. I'm not whining now and I won't be whining when somebody else smokes clutches, shaft seals, and crank bearings...whoop-dee-doo---waaaaa----my hellion hurts!!!!
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Old 11-19-2019, 05:32 PM
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Run it like you want to, it's yours. I really don't care. I'm not whining now and I won't be whining when somebody else smokes clutches, shaft seals, and crank bearings...whoop-dee-doo---waaaaa----my hellion hurts!!!!
I have had that experience already big Wes. My yerfdogs chain was too tight and there goes horrible imbalance and wobbly engine hating life
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Old 11-19-2019, 06:03 PM
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Quote:
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And this is exactly why I said in my post above it would be advisable to adjust either the engine or the axle to bring the sprockets into proper alignment so it could all be correctly installed...but does anyone listen? Nope...
I dunno if you're talking to me, but if you were just know that I'm backing you up, just with
more verbosity.

I just want to see the final pics because the first one threw us all off until the OP explained that it showed the clutch in the process of coming off.

P.S. YEAH! Run it into the ground, don't change the oil or maintain it (that's too much trouble)!
A new one is only $99.99 plus tax.
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Old 11-19-2019, 06:22 PM
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Quote:
Originally Posted by Hellion View Post
I dunno if you're talking to me, but if you were just know that I'm backing you up, just with
more verbosity.

I just want to see the final pics because the first one threw us all off until the OP explained that it showed the clutch in the process of coming off.

P.S. YEAH! Run it into the ground, don't change the oil or maintain it (that's too much trouble)!
A new one is only $99.99 plus tax.

Nah we good! I know you are like me and enjoy some fun and games occasionally...but just like you said...

A new one is Only $99.99 plus tax!!!

And I got a bunch collecting dust out back in the shed cause other folks can't seem to make'em go!

Yep... I'll give ya ten bucks for it to get it out from under the back porch...it ain't good for nuthin' no how

I updated my engine thread with a pic...teaser pic...check it out bruh!
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Old 11-20-2019, 08:18 AM
Jamie P Jamie P is offline
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This discussion is very helpful. If I start wrecking engines or clutches that would quickly take the fun out of it.

I'll get some better photos, measurements, and explanations this weekend when I've got some daylight to work with.

Stay tuned...
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