Clutch help needed!!!!

M

meowy84

Member
I've got the PowerKing/Zoomcycles 80 (66cc) engine and I've run into a snag with my clutch. Went to adjust the flower nut and noticed that the threads on the threaded shaft that the flower nut screws onto are so badly cut/machined that the threads in the flower nut don't properly engage them. It seems the threaded shaft is simply too small a diameter as compared to the diameter of the threaded hole in the flower nut. When I adjust the flower nut for proper clutch disc clearance and then let go of the clutch arm the flower nut simply pops off the threads. I can't believe I didn't notice this right away. I also can't believe the workmanship is so poor on this vital part. Any suggestions on a fix?

Anyhow, since I got the engine last July btut never got around to trying to mount it until now I figure the warranty thing is out of the question.

So my question is where can I find a replacement shaft and flower nut that will actually have proper threads cut? I don't think Zoom sells small odds and ends like that. Anyone on here have a replacement kicking about that I could buy from them that would fit my engine?

Also just to verify, but I wasn't planning on splitting the cases until I've had some running time on the engine but I guess now I'll have to since there's no way to remove the threaded shaft without the cases being split correct?

If I can't find a replacement I'll have to take the threaded shaft and use my handy dandy tap and die set to cut some new threads (I just hope I have a small enough die set) and use a small nut and fashion a concave shaped washer or cup to act as a flower nut.
 

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BTW, the picture I attached is just for illustration purposes and shows the clutch assembly and the threaded shaft. It's not my particular shaft, since the picture is actually Norm's. Hope he doesn't mind me posting it.
 
I'm inclined to give the same advice as Bikeguy Joe. I would try filling the hole closed and re-drilling and tap it. If you can't braze you could try using Alumiweld. That stuff is great and it works with only using a propane torch. I have also used this stuff...

Aluminum welding repair rods, weld any aluminum metal by using a Propane Torch - Alumaweld

Marine Tex, epoxy resin, adhesives, silicone grease, engine treatment, cleaner, repair, bond, fill, seal, fiberglass, aluminum, plastics, Starboard, wood

Never for my bike but on other stuff and it hardens like steel I have never tried tapping it but you could give it a shot.
 
Wonder if you could turn a piece of steel dowl into a shoulder shape and drill and tap the center of that ,then slip a fender washer on it and tac weld it,though the shoulder would hold it in place
 
corgi1 said:
Are the threads out of the flower nut and off the shaft?
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The threads on the flower nut are in place. It's just the threads on the shaft are so poor as though the shaft was too small a diameter when they cut threads onto it in the first place so that the flower nut does not thread onto the shaft properly. Either that or they cut the threads in the flower nut too big. There is so much play between the threads that when the flower nut is threaded on I can actually rock the flower nut side to side quite a bit and the when the clutch arm is released the flower nut simply pops off from the spring pressure.

I've atached a simple picture for illustration. Picture A is the way my threads are and picture E is the way they should mesh. Obviously I've exaggerated picture A slightly because the threads on my engine's shaft/flower nut do mesh but just ever so barely so that there's not enough force to hold the nut n when the clutch lever is released.
 

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Bikeguy Joe said:
How about brazing the hole shut, re-drilling, and then tap it?
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You mean instead of messing with the threads on the shaft itself just weld, drill and tap the threads inside the flower nut itself? That's actually a pretty damn good idea. Seems much simpler than my original plan of messing with the threads on the shaft and using a nut and then either fashioning a new flower nut or drilling an indent into the original flower nut to give room for the nut to sit.

My only concern with this of course is that hopefully they used a realistic tap/die set (either imperial or metric) at the factory and not a set with some weird Chinese system of measurement (LOL) so my new cut threads will match the threads on the shaft. Other than that I might just do both threads on the shaft and the flower nut to make sure they will mesh with no issues.
 
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corgi1 said:
"http://www.pistonbikes.com/SearchResults.asp "page 5 engine parts,mandrel
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Thanks for the link. :) I see they're only $3 and a new flower nut is $4. All this headache over $7 worth of parts. Sheesh.

Once I get some time in the new week I'll try cutting new threads first and see if that works. Once the clutch gear is off and the clutch lever depressed it looks like the threads on the mandrel protrude far enough so that new threads can be cut without cracking open the cases and disassembling the engine which should be a time-saving bonus. If that doesn't work then I'll have to go the long route and order the replacement parts and crack the engine open. Either way this whole situation 'sucks' since it puts me several days behind in having my bike on the road. But it's already been almost a year since I got the kit so what's a few extra days eh? LOL

I'll let you guys know how it works out.
 
what if you took a hammer and a punch and whacked the flower nut right next to the hole? like, putting a ding in it, maybe 3 or 4, so the metal protrudes outwards, into the threaded hole. then kinda force-thread it on.

obviously, do this with it off the motor.

not exactly something i'd attempt on a precision vehicle, but it's already messed up, and you have a new one on the way, might just get you riding for a few days...
 
bairdco said:
what if you took a hammer and a punch and whacked the flower nut right next to the hole? like, putting a ding in it, maybe 3 or 4, so the metal protrudes outwards, into the threaded hole. then kinda force-thread it on.

obviously, do this with it off the motor.

not exactly something i'd attempt on a precision vehicle, but it's already messed up, and you have a new one on the way, might just get you riding for a few days...
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You mean sorta (not quite but a similar principle) like they do on many economy front wheel drive cars with the front wheel axle nut to keep them from backing off instead of using a castle nut and a cotter pin. There's usually a little lip on the nut and an indent in the end of the axle shaft itself so you whack the lip so it bends into the indent. My Geo Metro uses this method. So do many others.

Anyways, what you mention would probably work but with the frequent cluth-in clutch-out and vibration I'm sure for only a short while. I've though of doing that out of frustration. .kick2 heh heh
 
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So here's a quick update. Over the weekend I reworked the threads on the mandrel shaft. My thread guages couldn't 'read' the pitch of the Chinese threads (LOL) so I used the closest die I could find which turned out to be the M6X1.0. Then a trip to the hardware store netted me a new nut for the mandrel shaft. Now I just gotta rework the flower nut itself and I'll be ready to go. I'll be posting pics of my solution soon.

CLUTCH GEAR: With the clutch arm depressed I had enough clearance to cut the threads without taking off the clutch gear which is a good thing too because I did try taking it off with the supplied puller and it didn't want to budge even though I was at the point of almost stripping the puller. I'll save this fun task for when I actually take the whole engine apart after some riding.

BTW, While at the hardware store I also picked up some regular grade 5 nuts (M8 if I recall) for the head to replace those pesky acorns. I noticed with the acrons when I tried to torque the head the case bolts were digging into the roof of the acorns. So instead of filing/cutting the studs a thread or two I just got the new nuts.
 
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CoastalCruiser said:
The secret to using gear pullers is to crank it down REAL tight and then whack it with a hammer. The gear will pop right off.
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You mean disassemble them the way they were assembled...with a hammer? LOL

I though about that but didn't want to do any whacking since I was playing with the engine at the kitchen table. I already put marks in the table before and the wife forbade me from working on my junk at the table. heh heh
 
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