Comet Drive Problems - Alsport Tri-Sport

J

Jack_in_PA

New Member
#1
#1
I have a Tri-Sport with a Tecumseh engine and a variable belt drive. I believe this power unit is original to the machine. I don't know what model/HP the engine is, but if it matters, I can find out and post it. The center distance between the drive/driven pulleys is 6-1/2". Here are a few pics:



Problem in a nutshell - no 'neutral'. I haven't found a belt that will allow the engine to idle. The drive pulley is the original Comet brand (OD 4-13/16") and the 6" driven pulley is a new, unbranded recent replacement that is identical in all relevant respects to the original Comet. (I broke the original through stupidity many years ago when my sister got this unit; it's never been operational in the 12-13 years she's had it.)

Here are pictures of the drive pulley, both open and closed (The only reason you see the chain in the one pic is that it's not on its sprocket.):

<P>
<P>
<P>

Some observations/questions about this pulley: 1) It closes nicely when the engine speeds up (no belt on), but it doesn't open back up by itself - you have to push it back after the engine stops. Is it supposed to be like that, or is it supposed to be spring-loaded to open automatically when engine speed decreases?

2) That brass bushing you see in the bottom of the 'V' moves independently of the moving side plate, but never seems to get completely across to the fixed side. Is THAT supposed to be the case?

3) Does it appear to the experts that it's opening as far as it should? I can't get it to open any farther than it is in the pic.

A 1/2"-wide v-belt (Yes, I know that's not the proper belt configuration for these.) will not bottom out in this pulley. Am I correct in thinking that the belt bottoming (and the sides not touching) is necessary for this setup to 'freewheel' so that the engine will idle? If so, what width/length belt does it take and where do I find one? The only Comet belt I've been able to find locally, while it is the 'correct' length according to the chart on the packaging, is 5/8" wide and just won't work at all.

I've been able to ride it around with the 1/2" v-belt on it, by pulling the belt down into the driven pulley enough that the drive pulley can freewheel, then starting the engine and getting it rolling a little while opening the throttle. As soon as the drive pulley opens and contacts the belt, you're off! It goes about like I imagine it should, but when you stop, it stalls the engine. Not a realistic operating procedure!

I'm going to a Super Bowl party as soon as I post this and will not be back on until tomorrow. Thanks in advance for any help! If you have questions, ask away. I have more pics, and I can find out anything you might want to know to clarify things.
 
roccosbike

roccosbike

#2
#2
Looks like an H50 Tecumseh,Look on the shroud for numbers to confirm.Your driven unit on the engine needs to be removed and looked at.Should be a simple fix.Welcome to OldMiniBikes.
 
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james c

james c

Active Member
#4
#4
secondly, you need an assyemtric belt. its not a v belt clutch. its a comet 30 series.
its flat in the back and v" eed in the front. it should be 3/4" wide. ill check a belt chart for the correct size
 
roccosbike

roccosbike

#5
#5
james c said:
secondly, you need an assyemtric belt. its not a v belt clutch. its a comet 30 series.
its flat in the back and v" eed in the front. it should be 3/4" wide. ill check a belt chart for the correct size
Click to expand...
I got #203589A as the part number he needs.Is this correct James?
 
pop a wheelie

pop a wheelie

New Member
#7
#7
it does not look like your primary clutch is opening all the way you may have a bad spring or something preventing springs to close may even have belt string caught in from blown belt good luck i have two trikes
 
george3

george3

Active Member
#8
#8
pop a wheelie said:
it does not look like your primary clutch is opening all the way you may have a bad spring or something preventing springs to close may even have belt string caught in from blown belt good luck i have two trikes
Click to expand...
The driver is fine. might need lubed but that isnt the prob. the prob. is the wrong belt. you need the 30 series belt. like he said show pics of the driven clutch. I want to see if it has the angles like this |/ like your Driver clutch or the one like this V dont match. if they are both the same style then just get the correct belt comet 30. its 3/4 wide shaped like the pully. |/ That skinny belt will put burn groves in the drive clutch. here is a link.
http://www.bmikarts.com/item/30-Series-Comet-Torque-Converter-Drive-Belt-203589-203599-217248-3509
 
steven Durham

steven Durham

#10
#10
To be a proper Comet TAV it has to be a type 30 driver and driven so there is only ONE belt that is of course a asymmetrical belt with a fixed size and it is Comet part # 203589A
I just don't understand why this is so hard ?
As long as the backing plate is in use be it the old steel or the newer cast aluminum there is still only one belt.
Steve :scooter:
 
james c

james c

Active Member
#12
#12
i dont know what driven that bike came with so i couldnt recomend anything without seeing the driven. steven, you are familiar with these bikes and you know what they came with.
so its sounds good to me. if the clutch is sticking closed then lube it. thats what george did to mine and it fixed mine.
 
J

Jack_in_PA

New Member
#14
#14
Well, looks like you all have been having fun while I was gone!:smile: Ok, here's a picture of the new 6" OD driven pulley, along with another one of the 4-13/16" OD driver, just for easy comparison. Is, or isn't, the drive pulley open as far as it should be? (That's all the more it will open.)
[/IMG]

As I stated in the opening post, I'm well aware that a v-belt is not the right belt configuration for this, but it is the only thing I HAD that I could get to work AT ALL (even if not correctly.) I have an unused Comet #203589 (came with the trike all those years ago). It can't even be installed, with the driven pulley off (shaft pushed back, I'm not trying to get the pulley onto the shaft with it sticking out where it is when everything's together).

I bought a Comet brand belt that was the same length but only 5/8" wide. I could install it, but it was too tight for the engine to be started - just tried to drive the trike forward when you pulled the starter rope. I took it back for a refund, so I can't tell you exactly what # it was.

Even the only-1/2"-wide V-belt (a 27-1/4" o.c. Rupp #17617 that also came with the trike) will not let the engine be started unless I pull it down into the driven pulley so it's WAY loose on the driver (not even touching it, period)

Let's say that the driver isn't opening all the way, and I need to take it apart to check it out. What's the best way to keep the engine from turning so the bolt can be loosened? And are the threads right or left-hand?

This Comet Clutch lube you're talking about - that's something that gets put (sprayed?) in the works of the driver (and driven?) to keep it operating smoothly? Or is it something that goes on the belt and/or the pulley surfaces? (Seems rather unlikely that you'd 'lube' something that depends on friction to work, but maybe it prevents too much friction??) Is there any "generic" substitute?

Maybe I'm missing something here, but I don't understand how the engine can 'freewheel' (start and idle) with the belt touching the sides of the drive pulley? That's why I asked in the OP if the belt was supposed to bottom in the driver, at which point it seems like there wouldn't be any significant force/friction between the belt and the pulley sides.

Is this whole Comet Clutch setup something like a bumblebee, where it shouldn't be able to fly(work), but it does anyway?:laugh:
 
J

Jack_in_PA

New Member
#16
#16
Oooh, I had missed Post # 11 - with all the red links and the big cart picture, I passed it over as an ad!:laugh: Thanks, Big Jim!

I had a couple of my questions answered on the Troubleshooting page of that 3rd link (lube). Namely, where the lube goes and the fact that I was correct in thinking the belt should bottom in the driver. Well, none of the belts I've had on this thing have even remotely bottomed, so I have to think the driver sheave isn't going back as far as it should.

So my main questions now are the ones I asked when the situation was hypothetical: How best to lock the engine to loosen the driver bolt, and is it regular or left-hand threads?

BYW, the engine is a Tecumseh H50.
 
roccosbike

roccosbike

#17
#17
The thread is regular not left handed.Take out the spark plug and bottom out the piston,then take about 1 foot of pull cord or similar rope and put it in the plug hole.You can then remove the bolt on the clutch.Leave a little rope hanging out so you can pull it out when your done.
 
george3

george3

Active Member
#18
#18
steven Durham said:
To be a proper Comet TAV it has to be a type 30 driver and driven so there is only ONE belt that is of course a asymmetrical belt with a fixed size and it is Comet part # 203589A
I just don't understand why this is so hard ?
As long as the backing plate is in use be it the old steel or the newer cast aluminum there is still only one belt.
Steve :scooter:
Click to expand...
Its not tuff at all. He said the driven was replaced.
 
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james c

james c

Active Member
#19
#19
Jack_in_PA said:
Well, looks like you all have been having fun while I was gone!:smile: Ok, here's a picture of the new 6" OD driven pulley, along with another one of the 4-13/16" OD driver, just for easy comparison. Is, or isn't, the drive pulley open as far as it should be? (That's all the more it will open.)
[/IMG]

As I stated in the opening post, I'm well aware that a v-belt is not the right belt configuration for this, but it is the only thing I HAD that I could get to work AT ALL (even if not correctly.) I have an unused Comet #203589 (came with the trike all those years ago). It can't even be installed, with the driven pulley off (shaft pushed back, I'm not trying to get the pulley onto the shaft with it sticking out where it is when everything's together).

I bought a Comet brand belt that was the same length but only 5/8" wide. I could install it, but it was too tight for the engine to be started - just tried to drive the trike forward when you pulled the starter rope. I took it back for a refund, so I can't tell you exactly what # it was.

Even the only-1/2"-wide V-belt (a 27-1/4" o.c. Rupp #17617 that also came with the trike) will not let the engine be started unless I pull it down into the driven pulley so it's WAY loose on the driver (not even touching it, period)

Let's say that the driver isn't opening all the way, and I need to take it apart to check it out. What's the best way to keep the engine from turning so the bolt can be loosened? And are the threads right or left-hand?

This Comet Clutch lube you're talking about - that's something that gets put (sprayed?) in the works of the driver (and driven?) to keep it operating smoothly? Or is it something that goes on the belt and/or the pulley surfaces? (Seems rather unlikely that you'd 'lube' something that depends on friction to work, but maybe it prevents too much friction??) Is there any "generic" substitute?

Maybe I'm missing something here, but I don't understand how the engine can 'freewheel' (start and idle) with the belt touching the sides of the drive pulley? That's why I asked in the OP if the belt was supposed to bottom in the driver, at which point it seems like there wouldn't be any significant force/friction between the belt and the pulley sides.

Is this whole Comet Clutch setup something like a bumblebee, where it shouldn't be able to fly(work), but it does anyway?:laugh:
Click to expand...
jammed up driver for sure. the driven is a 30 series so you have the right belt.
but isnt fitting because of the driver not opening. get that bolt out and solve your problem as its in the driver
 
george3

george3

Active Member
#20
#20
I think it has old lube on the driver hub. gumed up, or rusted. clean and relube, comet lube works the best.
 
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