Building a 'Restomod' Manco Dingo with my boys

[gmotz]

Got the new belt on last night, same issue... actually worse than the china belt. It might be articulating more smoothly but definitely wont disengage at idle.

The moving cheek of the drive pulley is fully retracted at idel and isn't moving, the belt is just way way to wide. The old belt that worked properly was .53 across the top and sat down in the groove nicely, this one is tight into the bottom of the groove at .75 wide.

I could get a longer belt, but it still wouldn't ride all the way down in the groove like it should.

The only thing i can think is that somehow a spacer was removed, ground down, or otherwise damaged. Honestly at this point the front sheave is so badly chewed up that it might be better to just order a new one. I just hate throwing parts at stuff. Its frustrating that it was working just fine with the belt that was on it, maybe a combination of failures that offset each other- Jenga theory i call it.

Oh well, now i have a literal lifetime supply of belts.

 

[Denny]

Having a front sheive that is chewed up or any other bad parts is no good but you knew that already. Sometimes it is just cheaper to replace than to rebuild. A slight amount of creep is normal. If it takes off on you your belt is probably too short or a clutch is not fully releasing.

 

[madprofessor]

The old belt that worked properly was .53 across the top and sat down in the groove nicely, this one is tight into the bottom of the groove at .75 wide.

Must be something really wrong with the mechanical components, because that ASYMMETRIC belt for a 30 series TC should definitely be .75" wide across the top, see the cross-section drawing at the top of the GKS chart linked previously...............Comet Torque Converter Belts | Go Kart Drive Belts (gokartsupply.com)
Sounds like that .53" wide old belt was actually a completely worn down .75" belt. Of course, that's assuming the old belt was an ASYMMETRIC belt. If true, it's likely the 18-degree beveled side that wore away, leaving a belt that would be almost flat on BOTH sides, not just the 2.5-degree side that's toward the engine.

 

[gmotz]

The old belt was marked with the murray equivalent part number for the manco 5959, so it definitely was the right size at one point in time, the question is just what is worn, missing, broken, damaged in the front sheave for the cheeks to be sitting .2 inches closer together than they should be? Obviously over the internet with no pics, you guys can't answer that, i was more asking if there is another adjustment point or something that i wasn't aware of.. which there apparently isnt.

My son is really, how should i say... risk adverse... so feeling like 'he cant stop' is pretty much taking all the fun out of riding it for him, he's scared to death even though its really not bad for anyone who is used to driving weird janky/homemade/cobbled motor vehicles. I think i can machine a spacer or stack some washers to space the cheeks out, but i'm gonna order the 'right part' and get a new genuine comet front sheave.

 

[Denny]

Might just be cheaper to order a whole new clutch from the jungle store. But I can’t help but wonder if the brass spacer is worn out or missing.

 

[gmotz]

Denny, i've heard people mention the 'brass spacer' there isn't one, its a bare rusty steel hub. We have 2" of snow on the ground so i probably won't be digging into the gokart again for a little bit. Plan is to order a new front pulley complete for 70$ from Comet, haven't got around to doing it. The weights are chewed up and everything is in bad shape so might as well just replace it.

 

[Dingocat]

Just read through this whole thread, brings up good memories doing similar with my dad. As for the torque converter. Simple fix for the belt issue

Theres actually a difference between the "new" drivers and the old commets, had this issue with some of mine, aka the origonal torque converter on my Dingo. They had a small (1/8in) spacer between the 2 halves of the driver vs new drivers where the back half (engine side) is longer.

I'll grab a pic of the difference tomorrow. Pretty sure it was because they used 5/8 or 3/4 belts. So different width pullies.

Most current pic of my Dingo on my phone. Ungoverned gx200 with "stage 1"

 

[gmotz]

Dingocat, that would certainly explain it... although i would feel a lot less crazy if i hadn't read the murray part number off the belt that was a direct x-ref to the 5959.

Its just very odd to me that the old belt worked PERFECTLY, fit perfectly and was very evenly .53" all the way around... I have seen cvt belts wear down quite a bit in some applications but they usually chunk out or show exposed cords or have other signs of damage... aside from being dry rotted from being outside for god knows how long, this thing was pretty consistent and intact.

Like i said above, i have no problem replacing worn stuff and buying the right parts to fix it i just HATE HATE 'throwing parts at the problem'... i already bought the belt which didn't help and worked worse than the china belt so I just want to make sure that the front sheave gets this fixed for good.

Do you know if the rear/driven sheave is different between the older/later models you talk about? I think the tecumseh OHV was only sold for a few years on these karts, they were a 'Fun power' briggs, then got the roll cage, then had Tecumseh, then went to a Subaru/Robin later i believe?

 

[Denny]

Mine and my brothers were Briggs powered. I’m sure Comet made running changes through the years. MANCO owned Comet when the economy tanked in 2009 and took out MANCO in 2010.

 

[gmotz]

interesting, yeah i still am thinking that there is some kind of spacer or bushing missing, but this is the kind of thing where a $70 part is a lot cheaper than the time i would spend messing with the old one, which is all wallerd out anyway.

it would be good to know if the driven sheave is somehow different or incompatable with the front sheave i would be buying, if i need to go out and take some more pics to help you guys ID it, i can do that this weekend.

 

[Denny]

If you would feel better I’d be happy to look at those pictures and make sure all is ok.

 

[Dingocat]

Here's differences. Both driven pullies are comet pullies. Pretty sure the newer driver pully is a knockoff. But yeah.

 

[gmotz]

oh wow, interesing, yeah thats exactly what i was saying about 'a spacer missing' with the .6 vs /.7+ shoulder. I was thinking that shank (being measured) needed to be about .15" longer give or take, and perhaps a spacer was missing or there were shims used for tuning.

The brass bushing there is nowhere to be found, doesn't look like it was ever there.

I guess i could always try ordering the knockoff from the jungle site and returning it if it doesn't work.

As far as the driven sheave, I don't remember it having a gap in it. Would the 3/4" belt one model (current production/clone) have that gap? It would also serve to take some tension off the belt

I think i know enough now to be dangerous, thanks for the help. I think i'll order the Amazon one for now since i can easily return it.

 

[Dingocat]

View attachment 135156View attachment 135157View attachment 135158View attachment 135159
Here's differences. Both driven pullies are comet pullies. Pretty sure the newer driver pully is a knockoff. But yeah.

I have the orig. Briggs (I think) off of mine. Currently on another kart but will be getting pulled soon.

 

[Dingocat]

oh wow, interesing, yeah thats exactly what i was saying about 'a spacer missing' with the .6 vs /.7+ shoulder. I was thinking that shank (being measured) needed to be about .15" longer give or take, and perhaps a spacer was missing or there were shims used for tuning.

The brass bushing there is nowhere to be found, doesn't look like it was ever there.

I guess i could always try ordering the knockoff from the jungle site and returning it if it doesn't work.

As far as the driven sheave, I don't remember it having a gap in it. Would the 3/4" belt one model (current production/clone) have that gap? It would also serve to take some tension off the belt

I think i know enough now to be dangerous, thanks for the help. I think i'll order the Amazon one for now since i can easily return it.

You could always just order a knockoff 30 series kit off the jungle and move both over. Wider is 3/4 pulley vs narrower 5/8

 

[Denny]

We haven’t found any difference performance wise between the jungle store and Comet when used with a Genuine Comet belt. If your going to go that route may as well order a jungle store driven also.