new guy with new toy for the kid

[webrx]

Hi,
I'm a noob at go karts, I picked up a Dingo cart for my 10 year old, no motor, but I got a couple comet TCs, a jack shaft and a spare sprocket for $60. the kart has a 54 tooth sprocket on it and 9 inch wheels (9 inch to center of hub).

I did the calculator thing and it looks like this is a good ratio and should generate some speed for him.

I was able to find 2 engines for $20 bucks, a 3hp Briggs and Stratton and a 6 hp Tecumsah. The B&S runs, after a good carb cleaning, but has a 5/8 in shaft, the tecumsah has no compression, but has spark, I figure at a minimum it is gonna need a head gasket and maybe rings. I am an old (over 50) auto mechanic, so I figure I can rebuild the tecumsah eventually.

Here is the rub, I bolted the 3 hp to the cart, and now need to figure out how to get a direct drive centrifigul to work on it, I can buy one, no big deal, but, am not sure what teeth to get, I am thinking 12 giving me a 4.3 ratio, but I don't know what clutch to get. I am thinking of setting it up something like this http://www.diygokarts.com/vb/attachment.php?attachmentid=11324&d=1299810635 but it has to be able to engage with the gear internal to the clutch not external like in the picture in order to line up to the gear on the axle, so I am thinking one of the H5835 - Hilliard Extreme Duty Centrifugal Clutch. 5/8" bore, 12 tooth, 35 chain.

Will this work and will he be able to get around on the Kart with a 3 hp motor until I can rebuild the 6 hp? Mostly on flat dirt, not really looking to go hill climbing.

Second question, I need to get pics I know, but I can't figure out how to get the comet clutches I got with the Kart and the jack shaft to work, if I post pics of the parts I have, would someone be willing to help me figure it out, it appears to be a belt driven torque converter setup, similar to the one here http://www.diygokarts.com/vb/attachment.php?attachmentid=6236&d=1263262845 but I don't understand how the centrifigul makes this all work. Can someone explain in laymans terms how this parts actually work together to transmit power to the axle gears?

Thanks for reading,

Dave

 

[Bluethunder3320]

welcome to the forum!

"a couple torque converters, jackshaft and sprockets for $60," wow! $60 is a steal for just a piece of one of the torque converters. and you also got a great deal on the engines!

a torque converter works, (im no expert, someone can tell you better) by working as both a clutch and a variable speed transmission. when you apply throttle to increase RPM, the torque converter engages, with the ratio in torque position, that means more power less top speed. as you gain speed, the driver piece (that is on the engine shaft) actually gets smaller, and the driven (on the jackshaft) gets bigger, changing that torque you used for acceleration into speed.

with a 3hp engine, 10 year old, you should look for your ratio putting out about 20-25 in the calculator.

search "mini bike clutch 5/8" in ebay there are alot. also search "go kart clutch 3/4"

amazon has clutches as well. you will still need a nut to retain the clutch on the shaft if the clutch you are buying does not have a set screw (most dont)

$30 is about how much a centrifigul clutch will cost new.


and also you shouldnt put in 9" as the diameter in the calculator. measure from the ground to the very top of the wheel, that means your diameter will be 18".

check this, it might change your speed dramatically.

 

[B man]

Ok. so you put the jackshaft on then the motor.(keep in mind that u need to know wich comet have to make sure the driven and the driver are the correct distance apart) ok then the driver.(the smaller of the two units) goes on the engine.then u put the chain going from the jackshaft to the sprocket on the axel(does the jackshaft already have a sprocket on it?) the put the driven unit(the bigger one) on over the sprocket on the jackshaft.(make sure aline the driven and the driver. then put on the belt. NOTE this info is basic DO NOT try this with out proper instruction.

 

[webrx]

BlueThunder, yes, I used 18 inch for the tire measurement, I understand centrifugal force makes a torque converter work, and I have a basic understanding of how - i think. I was more concerned about whether a 3 hp motor would work, if I can find a direct drive Clutch with a gear on it that will work.

I have two units that hook on the motor both say comet industries, richmond VA, but no other markings that I can see tonight, I will take pics tomorrow, and post.

I can see from the pic in the link I posted how to set it up, and if I am understanding correctly, it seems like the belt rides on the brass bushing, and the comet unit expands and forces the belt to ride up as RPM increases - is that right? On the jackshaft there appears to be another centrifugal type unit and a belt pulley, no gears on the jackshaft, I guess he did not give me that part, but I will look closely and see if there is a way to attach one in the morning. Again, the parts he gave me look like these http://www.diygokarts.com/vb/attachment.php?attachmentid=6236&d=1263262845 minus the chain sprocket, but I will have to find one and figure out how to attach it on the sprocket, none of this setup will work though until I get the 6 hp running as they will not fit on the motor shaft of the 3 hp.

For the 3 HP, I am hoping to just go direct drive from a centrifugal clutch with a gear to the aluminum 54 tooth Axle sprocket. I am ok if this thing only goes 15mph or so with the the 3 hp, the boy is just 10, and that would be a good place to start. Do you think the centrifigual clutch I posted - the Hillard - will work for this? Do I need a special chain - roller chain? Do I need to worry about the chain size or some other variable I am not thinking about?

I know you guys answer a lot of questions and I am sorry to be such a noob, I am looking through posts and searching the forums, but have not found answers I can understand yet.

Thanks again.

d

 

[r97]

the 3hp might work, but you would need a sprocket with atleast 135 teeth (#35 chain, and 12t on clutch), you would probably want to stick to flat ground, theoretically, i would say yes. but in reality, i'm really not sure, the 18" tires are likely just too big for the little engine, maybe someone else can give you a better idea.

where did you post the hillard clutch? you mean the clutch in that picture?
here is what you want(note this one is 11t #35 chain), http://cgi.ebay.com/ebaymotors/NIP-...m19c3c80e74QQitemZ110658850420QQptZGoQ5fKarts

the chain, you will need some roller chain for your go kart. heres some info on determinig different types of chain, http://www.gizmology.net/sprockets.htm

your 54t sprocket is likely #40/41 (1/2" between teeth), but most 5/8" clutches have #35 chain (3/8" between teeth).

it's probably worth getting the 6hp running and using the torque converter (tc for short) instead of spending the money on the clutch and sprocket for the 3hp.

there is a chance you coulds make an adapter so the tc will fit the 3hp, but doing so wouldput more force on the key and keyway because the key would be lifted 1/16" out of the keyway.

 

[anderkart]

Some of those Dingo kart models are fairly heavy. I think a 3hp is too small for heavy karts, your big tall 18" tires are making maters worse here. But If you really want to try the 3hp with a centrifugal clutch for now, I'd suggest you install your jackshaft, and select your 2 jackshaft gears to end up with a 10 mph top speed.

Here's a link to a jackshaft gearing calculator: http://www.compgoparts.com/TechnicalResources/JackshaftRatioCalculator.asp
(Its just a little tricky to understand at first, just realise they've got their clutch located on the jackshaft output and you probably wont be doing this, so just enter your clutch tooth count in the engine driver window, enter 3600 for governed engines, and notice they want your rear tire circumference instead of diameter)

So then with calculating your current axle sprocket, and whatever clutch tooth count you purchase, simply play around with different jackshaft gear combinations until you end up with around a 10mph top speed. You might get away with a higher top speed with a 3hp, but I feel this is a safe place to start for decent acceleration and your clutch having a good chance of surviving.

When your ready to use your torque converter, you'll find some really good servicing info here:
http://www.diygokarts.com/vb/showthread.php?t=7332

 

[webrx]

Thanks Guys, this helps a bunch. The kid is so excited about having a cart and I am busting my butt trying to get it working.

The 6 hp is a Tecumseh 0hh60 7113c OHC and it is giving me grief, no compression, so I replaced the head gasket, and noted the valves were tight, never having any slop in them. I found out that they need .004 clearance, but I need to figure out where TDC is on this engine, no timing marks like on a car. Is TDC when the magnet lines with the coil? I loosened the valves a bit, and put a compression tester on it and got around 45 lbs by finding where the valves are the loosest, and setting things at .004, but it still does not "feel" like I have the valves correct, and the engine will not pop even with carb cleaner in the cylinder. I have spark, though not sure it is strong enough, it shows orange on my spark tester light.

Last, from the kill switch, there is a green and a black. The black goes to ground, the green is just hanging there in the back, and I figured it was for a remote kill, like I said, I have spark, am I right on the assumption that the other end of the kill switch green wire is for a remote kill or does this go to something that it needs to be hooked to in order for the motor to run?

 

[anderkart]

Green is your kill switch wire. Engine will run fine with it disconnected, you'd just ground it through a switch if you wanted to kill spark.

An easy way to confirm TDC is to stick a pencil in the spark plug hole against the piston and watch it coming up on the compression stroke.

Sounds like your getting close to firing that 6hp up

I think your engine has a compression release future, so that'd lower your test readings quite a bit...

If you cant get it going, you might take a quick peak and make sure your flywheel key hasn't sheared. You can usually tell just from removing the nut/washer and seeing if the outer end of the key is damaged or the keyways dont line up.

 

[bighead]

I love the Dingos. It is the best riding/turning Kart I have had. Here is the one I restored last year.

 

[webrx]

Thanks, I actually put a dowell in the cylinder hole (kinda like a pencil) and found TDC, set the valves, and sprayed a little carb cleaner in the hole. got it to fire and run for a few seconds, but no fuel getting to it. so, carb disassembled, cleaned (all gunked up), but gotta run get a new fuel line as the old one cracked and is barely long enuf to reach now. I feel we are getting close.

Nice Kart BigHead - I like this one we have but the previous owner cut the front bars and the roll cage off, not sure why you would do that, but, there you go. I will get some pics when I get back from O'reillys.

Thanks again.

Dave

 

[bighead]

Notice the bars going from the frame to the spindle brackets? Lots of people addd this bar when moding Dingos.

 

[webrx]

OK, valves set, new fuel line, carb cleaned, still did not start, found the idle mixture screw fully locked down, backed it out 1.5 turns and the engine fired and ran, of course, the screw kept backing off, so had to put some threadlock on it, not sure where these should run the best, but 1.5 as a starting point is something I learned back in the old days. Seems like it performs ok at around 1 turn open right now, but I want to run some good gas through this thing for a bit before committing to that.

no pics yet, wife made me come in and shower before for dinner, and now it is dark again, and I think she might get ticked if I go back out and tinker some more. Maybe tomorrow for pics on the TC parts.

Here is on of the boy on the Kart

here is one with the 3hp on the Kart - it is not there anymore now that the 6 hp runs.

Hoping to get the Clutch and chain tomorrow and make this thing work, gotta figure out the throttle linkage first, but, I have a few ideas on that one. figured I would get it running, let the boy run it around a little, then do the sand, pant, polish, new front tires, etc. He is gonna die if I don't get him on the dirt soon.

Dave

 

[webrx]

Notice the bars going from the frame to the spindle brackets? Lots of people addd this bar when moding Dingos.

I have a broken bar on the left side I need to get welded, but, I think I will have my buddy add the bars while I am at it - he is the welder - I can weld, but don't have one yet. I will see if I can pick up a couple pieces of pipe tomorrow too.

d

 

[redsox985]

How about run it and have a screw driver in there to play with the mixture screw so that you can fine tune it and it won't back out?

 

[bighead]

Did you know the Dingo pedals are reversable? The Dingo will be a great kart for your son. They turn great even on pavement. Manco got the steering right on the Dingo.

I cannot tell if the seat belts are still on. But with no roll bar I would NOT have belt of any kind. If you add a roll bar then you need belts.

If I was you I would make a dirt track sprint car cage around it. It looks like the main hoop is missing. Along with both front and back down bars.

Here a shot of a frame to see what you are missing. I did add the back cross bars and the gas tank mount.

 

[webrx]

Redsox - I agree, I will let it run some good gas through, I cleaned the carb, but want to make sure everything else is clean as well. Valves look ok, as does the piston and cylinders (I had the head off). So, change the oil out, run it a bit, adjust the carb mixture, and then a little more loctite to hold things in place and we should be good.

Bighead, definately, it is on my list to stiffen the front spindle bracket frames and rebuild the roll cage, the seat belt brackets are still there, but no belts, so that is on the list also.

Took a pic of the parts I had on the bench:

Looks like I have a full TC (minus the jackshaft sprocket) an extra comet centrifigul clutches, not sure what series it is but I am guessing it is a 30. One of the clutches is symetrical, one asymetrical, and I have a belt for each. the Kart of course, and 3 motors (1.5HP, 3HP, and 6 hp) the 3 and 6 now run, have not looked at the cause for the lack of spark on the 1.5 yet, but, it isnt gonna push much anyway.

I ordered a centrifigul clutch with a 11 tooth gear today, should be here for the weekend. So far I have 60 in the kart, 30 for the clutch, 30 for the motors, and miscellaneous 30 or so in other stuff, so less then $150 in the kart and all i need is the clutch to show up and get a piece of chain and I should be able to run this thing.

Dave

One more question if you don't mind, I need to replace the axle sprocket on the kart with the one on the bench, is it as simple as removing the rear axle and right rear tire and unbolting the gear from the hub and swapping the two out?

d

 

[anderkart]

is it as simple as removing the rear axle and right rear tire and unbolting the gear from the hub and swapping the two out?

d

Yep, as long as its bolt pattern matches up.

Your sprocket on the bench looks quite a bit bigger. How many teeth?

 

[bighead]

I would try to run the TC and not the clutch you bought. Your kart will be much funner. Keep the stock gearing. Dingos rip.

 

[webrx]

Thanks Anderkart, and bighead,

The sprocket on the bench is 72 teeth and I am going to have to use it since the one on the kart has broken teeth - unless I buy a new one.

I would use the TC, but, I don't ahve the gear for the driven shaft, and I am soaking it in liquid wrench right now so I can get the centrifigul unit off so I could possibly put a gear back on it. It seems a bit beat up, or at least neglected, but I will see what I can do with it.

The biggest problem I have right now is the 6hp isnt running very well, and twice now it has dropped a push rod, the rod is not bent, and the rocker arms look ok, so I am beginning to think there is something wrong down below. It feels like there is a groove or socket inside the engine, but the push rods don't snap into it in any way, they just kind of sit in it. Maybe I didn't get the adjustment right, but too tight and no compression, too loose and I drop a push rod. In thinking about this I think I might be adjusting the valves wrong. don't I want to adjust the intake valve at TDC when its push rod is also at its lowest in the engine, and then cycle the engine until the exhaust push rod is at its lowest, then adjust it there. I have been adjusting them both with the engine at TDC on the same stroke. maybe this is why one is loose and keeps dropping out. Someone please correct me if I am wrong, this is my first foray into small engines.

Also, the carb adjustment screw does not want to stay put, though I can fix that, and getting the throttle linkage to not bind on the throttle cable is a bit of a pain. Looks like the ear in front of the gas pedal is broken off also so the pedal spring does not help in returning the carb to the idle screw. Oh, well.

If I have to go back to the 3 hp until I can afford a harbor freight special I am going to have to shim up the 5/8 shaft to fit the new 3/4 inch Clutch. That or the boy is gonna have to wait until payday for me to get the engine. I was thinking about cutting some 1/32 thick sheet metal and wrapping the shaft in this (minus a slot for the keyway) to see if that will fill the gap and still keep the clutch centered at least long enough for him to run the kart for an hour or so.

d

 

[webrx]

OK, got back out in the garage last night, made sure I was at TDC on the compression stroke, set the valves again, and now am getting 70+ lbs compression, and the kart fires ups and runs - again.

Switched the pedals so the boy can reach them easier, gonna need to weld a stop on for the gas pedal spring, looks like it is snapped off, also gonna need a new spring for it. I figured a way to put together a makeshift stop for now. Got the throttle linkage fixed and working, and now I need to swap out the sprocket on the axle.

Maybe I can get that tonight.

D