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Old 04-08-2013, 08:46 PM
lewismug lewismug is offline
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Default Havoc M5 belt to chain drive conversion

Hey guys. First post and I know absolutely nothing at all about gear ratios, sprocket sizing, etc... I have been trolling around and reading up as much as I can to try and find the answer before posting, but I want to be absolutely sure before buying any other parts. I know a lot of you guys are really knowledgeable and I hope you guys can take the time to help me get this thing going. I picked up a used Havoc M5 go kart for my daughter and bought two new belts. Both belts lasted about 30 minutes each before they were shredded. So, I decided to change it over to chain drive. Went to Tractor Supply and picked up a 10t centrifugal clutch, a chain, and threw it all together. Daughter gets in, presses the gas, clutch smokes. Pick the rear off the ground, press the gas, and the thing wants to go fast. Clutch locks up fine with no smoking. The axle sprocket is a 60t and the clutch is a 10t. I believe the rear wheels are 13" or 14". The engine is a 5HP 126cc Subaru. I believe I need to go up to a 72t sprocket on the axle. Would that be correct? The belt setup went from a belt centrifugal clutch to a jackshaft then chain from the jackshaft to the axle sprocket. Also, when we give it gas, the engine sounds as if it's revving up and down and never steadies out. Is that the governor kicking in or is that abnormal? Daughter is 8, but I'm sure my wife and 14 year old son would love to hop in it every now and then as well. Here are couple of pics of the cart. These aren't pics of the actual cart, but some I found online that are identical to hers. Thanks in advance for any and all help!
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3282499_2PR0TGBJS.jpg   3282499_2PR0TGE79.jpg   3282499_2PR0TGH9Y.jpg  


Last edited by lewismug; 04-08-2013 at 08:49 PM. Reason: Add jackshaft info.
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Old 04-08-2013, 09:42 PM
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Your rear wheels are 18-20" so this won't work well.

You need to clean your torque converter and try again with a new correct belt.

If properly maintained the belts should last 8-12 months.
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Old 04-08-2013, 10:36 PM
lewismug lewismug is offline
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Thanks for the reply Blazkowiez! After the first belt bit the dust, I took everything apart and cleaned it really well. The second did the same as the first. The belts were both the correct belts. If I were to use the jackshaft with my setup, could I make it work then or am I stuck with a belt? I know all of my go karts I had when I was younger used chain drive and I really prefer it to the belts.
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Old 04-09-2013, 01:10 AM
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The problem with your setup now is that you have bypassed the jackshast and are running a 6:1 gear ratio with tyres that are waaaaay to big. You need to gear a lot lower for any centrifugal clutch to last. I would suggest going even lower that the 72T (7.2:1) ratio you suggeted. This means a large sprocket, which is sometimes not practical, hence the original jackshaft.

You could keep your setup now and change your tyres to 12 or 13" tyres. That might work for you, but I am not sure.

I agree with Blazkowiez that you would be better off servicing your TC properly, making sure you have the correct belt.

Post some pics of your TC and jackshaft so that we can see what it looks like.
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Old 04-09-2013, 09:00 AM
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Well, I guess what I need to do is replicate the belt setup with the chains maybe. I'll post pics later today when I get home. I'll put the belt setup back on it, post that pic and then the chain setup and post a pic. Thanks!
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Old 04-09-2013, 09:25 AM
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I had the same problem with my havoc. I would try climbing out of a ditch and it wouldn't go anywhere, just smoke the belt. I think they are junk in my opinion.i built a new mounting plate and bolted an 8 hp Briggs on the havoc and put a chain drive on it. Bought the slip clutch from northern tool supply which is rated at 13 hp . I put a 16 tooth sprocket on it and a #40 chain. Haven't tested it yet exept for jack stands.i still have the old setup if someone can convince me the belt works better but I really didn't like it.when I started it,it tried taking off on me and like I said wouldn't even move if you got stuck just smock the belt.
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Old 04-09-2013, 09:54 AM
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I have thought about going with a higher HP motor. I have a 14 in the garage that would work well for it, but I know the cart will have plenty of power for my daughter, wife, or son with the 5 HP, so I'll leave it alone for now. I want to at least get it in a drive-able condition before throwing a larger engine on it.
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Old 04-09-2013, 09:45 PM
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Here are the pics of my current setup. I have the chain going around the 10t clutch, a 10t sprocket on the inside end of the jackshaft, and the main axle sprocket. I believe I need to go from clutch to larger sprocket on the outside end of the jackshaft with one chain, and then from the 10t sprocket on the inside of the jackshaft to the axle sprocket with a different chain. Sound right? Anyway, part of the old belt clutch can be seen helping to hold the new clutch in place as a spacer. I know it looks rusty, but I can assure you that after sitting outside all winter, it was clean when we parked it last summer. Any ideas on what size sprockets I should go with on the jackshaft to make this thing go? I know the new clutch is on backwards, but it was the only way to get it to line up with the main axle sprocket. And the old torque converter (I think that's what it is) is still on the outside end of the jackshaft. Thanks for your help guys!
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CAM00036.jpg   CAM00037.jpg   CAM00038.jpg  

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Old 04-09-2013, 11:39 PM
slipknot23 slipknot23 is offline
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I can see why you shredded your belts all that rust
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Old 04-10-2013, 12:26 AM
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I don't even know what to say....That setup is horrible, and doesn't make any sense at all. You have 2/3 of a torque converted (rusted to heck) and a centrifugal clutch. For what reason would the chain go round a sprocket that is the same size as the clutch?

Here are my suggestions:
- Get the replacement parts for your Comet driver and clean the rest of it up (wire wheel rust off). It will never work in the condition it is in. Get rid of the centrifugal clutch.
- Get rid of the TC and invest in a preper jackshaft and gear appropriately. You are correct in the working of a jackshaft
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Old 04-10-2013, 07:34 AM
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I believe I mentioned it sat outside all of last winter and was perfectly clean when I put on the belts last summer! I know it's a horrible setup. I've already established the fact that I do not know what I am doing in my very first post which is why I need your help to make it work.

I appreciate the suggestions Landuse, but I really do not plan on going back to a belt setup. My reasoning: chains last longer. I've never owned a go-kart that had a belt drive system. I had a go-kart when I was a kid and used the same chain for the entire time I had it (5 or 6 years). Why buy a new belt once or twice a year when the chain will last well after my daughter is too old to worry about riding it anymore? I'll just go buy random parts until I make it work if no-one is willing to help me get the sprocket sizes worked out.
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Old 04-10-2013, 07:59 AM
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Quote:
Originally Posted by lewismug View Post
I believe I mentioned it sat outside all of last winter and was perfectly clean when I put on the belts last summer! I know it's a horrible setup. I've already established the fact that I do not know what I am doing in my very first post which is why I need your help to make it work.

I appreciate the suggestions Landuse, but I really do not plan on going back to a belt setup. My reasoning: chains last longer. I've never owned a go-kart that had a belt drive system. I had a go-kart when I was a kid and used the same chain for the entire time I had it (5 or 6 years). Why buy a new belt once or twice a year when the chain will last well after my daughter is too old to worry about riding it anymore? I'll just go buy random parts until I make it work if no-one is willing to help me get the sprocket sizes worked out.
Whoa there! Who says noone is willing to help you? That is why I am spending my time helping you out.

Your kart came with a TC. Fact. If you want a chain setup and want to have even close to the experience that a TC will give you, you need a jackshaft. Fact. If you are going to be doing any sort of offroading or hill climbing, you should consider keeping the TC. Fact.

If you would like to get rid of the TC and go chain, then you are going to have to get rid of the whole TC (people on this forum will take it off your hands for you for free). You are going to want to want to either buy a jackshaft, or make one yourself with some axle and pillow block bearings.

You will need to gear to about 8:1. You have a 10T cltch. Keep it. You have a 60T axle sprocket. Keep it. You now need 2 more sprockets to fit on your jackshaft to give you a final ratio of 8:1. You could use a 20 tooth JS in sprocket and a 14T JS out to the axle. This will give you (20/10)*(60/14) = 8.57:1.

You get the idea, so play around with the sprockets that are available to you in the pitch that you need.

You might have to do some fabrication work to get the jackshaft mounted up and working properly for you

Have a look at this thread for jackshaft ideas

http://www.diygokarts.com/vb/showthread.php?t=5461
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Old 04-10-2013, 08:32 AM
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That's the kind of info I've been looking for! I appreciate the time you are spending to help me! I really do. I know time is one of our most valuable commodities and it's something that will never be regained. Thank You for spending yours to help me.

Several people have said to stay with the belt, but no-one has given a reason why it is preferred over a chain drive. All I know are chain driven carts, so that's why I'm being stubborn on that point.

The TC is still there just to fill a void. I knew it didn't need to stay on for any other reason. And, the thing looks scary to take apart. Looks as if it would not be fun putting it back together anyway. I thought I already had a jackshaft on there? The pics aren't the best in the world and maybe don't show it very well, but the tc is sitting on the end of what I believe is a jackshaft.
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Old 04-11-2013, 12:40 AM
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A TC gives you variable gear ratios. It starts of at whatever you have geared it to, and as you go faster it moves through higher gears until it reaches 1:1 when you are at speed. This helps if you are doing any offroading, hills etc. With a centrifugal clutch you are either engaged or not. The slipping inbetween does nothing for you except burn the clutch.

The TC is not hard to get off, and is not complicated at all. All you have to do is undo those nuts and they should theoretically slide off. With the rust you might have to use a little penetrating oil.

Have a look at these links regarding TC's

Comet identification, installation and belts. Sprocket and spring changes
http://www.gokartsupply.com/identify.htm
http://www.gokartsupply.com/tcbelts.htm
http://www.bmikarts.com/PDF/Comet_40series.pdf
http://www.key-ideas.com/TC-Sprocket-Change.htm

Take some better pics of what you call a jackshaft, but I am pretty sure that you don't have one there. A jackshaft is a piece of axle where you can have 2 sprockets, one on each end. I don't see that on your setup. You have the clutch and axle sprocket, but where are you going to put the extra 2 jackshaft sprockets? It looks like you just have the backplate that came with the TC.

The pics below is what a jackshaft can look like. The last two are from mckutzy's thread that I linked above. It gives some great info, pics and advice regarding making a jackshaft. The first few pics I linked is a premade setup that I bought.
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10102011639.jpg   23072011528.jpg   25062011485.jpg  

DSC09527.jpg   DSC09531.jpg  
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Old 04-11-2013, 08:27 AM
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why not buy a new torque converter for it or fix the old one? Are you sure they were the right belts? they should have about a 1/2in of play in them they aren't like a normal belt on a lawn mower where they need to be tight. Also a belt should last as long as a chain will and you would be having way more fun with the torque converter
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Old 04-11-2013, 08:35 AM
lewismug lewismug is offline
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Better pictures of the jackshaft can be found in my DropBox account click me. The sprocket and pulley are both on the same end since the axle sprocket is on that side of the kart. If the axle sprocket were on the other side, then it would look more like the pictures you posted.

Gran_Pann has been helping me to understand why the belt setup will work better for me than a chain setup. I still have my Comet TC and the driven TC as well. I'll be cleaning those up properly and making sure I have everything aligned.

I know I was pretty adamant on wanting to use a chain setup, and it was simply a result of my inexperience with belt drive systems. Hopefully the tips you all have given me will help me to get it running.
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Old 04-12-2013, 01:03 AM
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I am sure you would prefer the TC is you get it set up right
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Old 04-12-2013, 10:01 AM
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I spent a couple of hours last night cleaning the Comet clutch. First, I removed all of the rust with my wire brush which is attached to a table grinder. I then gave all of the parts a bath in a gallon of B12 Chemtool to remove any residue and to clean any oils or grease from them. I took out my 600 grit sandpaper and scrubbed all of the surfaces of the clamshell until they were as smooth as possible. Tonight I plan to give them another bath in B12 chemtool, dry them, and do a wet sanding with the 600 grit sandpaper on my random orbital sander and some WD-40 to give it an ultra smooth surface. Finally, I will give it all one last bath in the B12 chemtool and some Carburator cleaner to remove the WD-40 residue. Hopefully I will get it all put together tomorrow morning for a test drive. I will post pictures of the cleaned clutch tonight. I also plan on taking the driven unit off, cleaning it thoroughly and putting it all back together. It seems to be stuck in its current position and probably needs a good cleaning anyway.
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Old 04-13-2013, 01:26 AM
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Dont forget to only use dry lube like graphite
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Old 04-13-2013, 06:41 PM
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Well, I got everything finished up last night. Woke up this morning and threw it all together and my daughter has been riding non-stop all day. Well, she ran out of gas a few times and had to stop for a restroom break a few times as well. Everything is working like a charm! It'll even spin me around the yard at a pretty good clip! Thanks so much for all of your input guys! It means so much and makes me so happy to see her finally get to enjoy the kart!
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