Speeds of kart. New to this.

[hmdballa219]

Hello all, I'm extremely new to the go kart world. Bout one for cheap. It is a yerf dog 3203. Had a predator 212 motor in it, that was locked up. Put a new one in there. Got a new belt because it was broken, and some other miscellaneous things.
My question is what's a normal speed for this? I have no included, after market air filter, rejetted the carb with #37 jet, a d the 140 emulsion tube, and a aftermarket pipe with small muffler. So I can only get it up to 16 mph. I know the governor kicks in, you can deff hear the rpm just stop going higher, but is this normal speed?
These have the real big back wheels and a pretty big teethed sprocket where the chain goes on.


Help please

 

[Tpdingo]

Probably around 30 miles per hour. Most yard karts with TAV's go that fast. You will have to tell us the size of the rear tires and the teeth on the TAV and axle. Likely there is two probable causes for the loss in speed: Slipping belt or the TAV is stuck and wont open any more. I would check the TAV first. Try and turn the weights by the two pegs with your hands. It should move, but some friction is normal from the spring force.

 

[hmdballa219]

Tav is torque converter? Ya the belt goes freely. But I used the same torque converter that was on it and just ordered a belt that was close enough to the size after measuring. They said it should be a little lose so I can move the kart, then when gas given it should tigthen up and take off, it Almost like studders, u give it gas and it has a delay before it'll kick it, then like throw u. Also keep in mind I'm about 270 lbs. But I still think more then 16 mph on a long road. Full throttle.
I actually dropped the torque converter and it fell open, still moves tho lol and comes out to engage. Wonder if belt is to big.

---------- Post added at 07:43 PM ---------- Previous post was at 07:41 PM ----------

Tires are 20x10x8. In the back. Sprocket I can't tell how many teeth but it's alot. Around 50+ teeth, and on the axle looks to be about 8 or 10.

 

[Tpdingo]

Yeah, TAV or Torqu-A-Verter. Its the "brand name". It is used to prevent confusion with the torque converter used in automatic transmission cars which are totally different.

Those TAV's can haul 400-500 lbs around with no problem, it should work with you no problem. Pics would be helpful. The stuttering then going it pretty normal. Just the flywheel weights taking a bit of time to fly outwards and catching the belt. Mine does that too, although the belt is slipping and dying but when it catches, it moves.

Again, we need pics. the belt is likely too big and not getting the tension. I've dropped my TAV driver a few times without an issue. To make sure it is working right, on the driver(the pulley on the motor), hold the TAV by the bell housing or stick your finger in the hole and pull it up, if the sheave on the inside moves freely, it is fine. Otherwise, oil/clean/find the problem. For the driven(the one connected to the chain), pull it outwards with your hands. If it is pretty stiff but movable, it is good. Probably takes a good 10-15lbs to move outwards. Also make sure that you can rotate it by grabbing the sheave connected to the spring that you pulled out and rotate it. If it moves, it should be ok.

 

[hmdballa219]

Yeah, TAV or Torqu-A-Verter. Its the "brand name". It is used to prevent confusion with the torque converter used in automatic transmission cars which are totally different.

Those TAV's can haul 400-500 lbs around with no problem, it should work with you no problem. Pics would be helpful. The stuttering then going it pretty normal. Just the flywheel weights taking a bit of time to fly outwards and catching the belt. Mine does that too, although the belt is slipping and dying but when it catches, it moves.

Again, we need pics. the belt is likely too big and not getting the tension. I've dropped my TAV driver a few times without an issue. To make sure it is working right, on the driver(the pulley on the motor), hold the TAV by the bell housing or stick your finger in the hole and pull it up, if the sheave on the inside moves freely, it is fine. Otherwise, oil/clean/find the problem. For the driven(the one connected to the chain), pull it outwards with your hands. If it is pretty stiff but movable, it is good. Probably takes a good 10-15lbs to move outwards. Also make sure that you can rotate it by grabbing the sheave connected to the spring that you pulled out and rotate it. If it moves, it should be ok.

Oh wow ok, ya I was actually comparing it to a torque converter and calling it that, even tho like u said, completely different lol and Yes, I honesty think it is probably the belt too, it is very loose, but that is the best fit I could find when ordering. Had no previous belt on other set up to go off, so I took a shot in the dark on it. I will take the pictures of it tomorrow and go through the procedure u described to test it., just locked my garage up for the night.

I appreciate all your help too btw.

 

[hmdballa219]

There is pictures showing the slack off the belt. Thinking that's why I'm assuming? The back gear moved a little that is on the axle, enough to show it's working.

 

[hmdballa219]

Also picture of belt number for reference if needed.

 

[Tpdingo]

That is the wrong belt. That is the problem. That is for the GY6 engines, not the comet TAV30. The belt has the wrong groove, is way too thin, and you aren't getting anywhere enough traction for it to work. I'm surprised it got up to 16mph as it is.

What you need is a TAV belt. Check the diameter of the driven(the pulley connected to the chain) and then measure the distance center to center between the driver and the driven pulleys. Go to this site to find which is the correct belt for this kart.

https://www.gokartsupply.com/tcbelts.htm

This seems to be pretty common that people find these karts and wonder why they don't move, to find that the previous owner jacked on some incorrect V-belt because it looked like it fit. These comet 30 series use a special belt that is asymmetrical and nearly flat on the side by the motor and tilted on the side facing away. Just confirm this for me but it is probably tilted on both sides.

 

[hmdballa219]

Man I appreciate it alot. So based on the comet 30 series I found it to be BELT 203591A.
It also says for yerf dog 3203. Although it doesn't have the same engine in it, I don't know if that changes anything really? Since the TAV and drive are still the same.

---------- Post added at 12:18 PM ---------- Previous post was at 12:11 PM ----------

No it's actually only tilted on the side away from motor which I seen that how how to do it from a YouTube video of course, but with the slack, and it being Improper that has to be it. .

 

[Tpdingo]

Maybe the GY6 has the same asymmetric design, just like how they copied everything else. Both MIGY125-3037A and 743 20 30 come up with the same belt for the 125cc and 150cc GY6 engine and transmission units.

The engine doesn't matter. The position of the mount holes and shaft is the same across all the motors of the same class for 30-40 years now. A 6.5HP predator 212 has the same mounts as the Tecumseh PowerSport 6.0HP that was on my Manco before it was replaced, and the Briggs FunPower 5.0HP that came before the tecumseh(not on my kart, just on earlier Dingos). Even if it did change, you could always get a bigger or smaller belt.

 

[hmdballa219]

Ok got it makes sense the mount holes would line up then. I'm about to order it. You have been a major help in pointing me in right direction. I just ordered it and when it gets here I'll post back here to tell my progress !!!

Thanks again!

 

[Tpdingo]

Ok got it makes sense the mount holes would line up then. I'm about to order it. You have been a major help in pointing me in right direction. I just ordered it and when it gets here I'll post back here to tell my progress !!!

Thanks again!

Well while it comes, ̶h̶e̶r̶e̶ ̶i̶s̶ ̶a̶ ̶l̶i̶t̶t̶l̶e̶ ̶t̶i̶p̶ a lot of tips. If you don't have an impact gun, which you likely don't, this will help you get the bolt off. Get a 1/2" wrench or whatever size is on the end. Use the box end of it(the closed end) and put it on, with the wrench tilted towards the engine, not towards you. That will make sure it stays on. Then you turn the motor until you can feel one of the compression strokes and the resistance from the crank will increase very significantly. Lastly , take a hammer, the bigger the better, and whack it loose.

To ensure the life of the belt, while you have the TAV apart, make sure to clean the inside of it and remove the rust. The rust will accelerate the wear. For the driver, I would take a wire brush and put the stationary sheave on the motor without the bolt and brush the dirt off. Put the TAV back together as if you were reassembling it but put the moving sheave on backwards. Now you can put the bolt in and clean, but do make sure you DO NOT rev the motor. That will likely result in damage to the TAV. For the Driven pulley, I took a 220 grit sanding sponge and shoved it hard into the pulley(the rust on mine was only around the outer edge) and pushed the kart back while maintaining pressure to prevent the sanding sponge from coming out. Having a helper would help out here a lot.

Also, while you have the machine apart, lubricate the TAV with dry lube. Don't use oil, it will need to be cleaned way too often. I do that with mine and the rubber particles turn the oil black in no time. Also clean everything with brake clean and lubricate the sliding driven in the back with oil if you want. Just make sure to not get any oil on the sheaves/clean the oil with brake clean or you will be going at 8mph because the belt will slip like it is right now. Pry the sheaves apart before dropping the oil in to prevent getting it on the sheaves.

If this doesn't cover everything you need to do when your new belt arrives and how to service your TAV, I don't know what does. When you are done, you gun it(giving yourself plenty of room to sort out problems and either slow down or turn off the motor, probably 500ft is suffice). If you are pushed back into your seat, accelerated like the wind, and going fast enough to reconsider your life insurance policy, well you did everything right !

 

[hmdballa219]

Ok belt finally came, and finally got a little time after work tonight to put it on. Drives much better.very torquey, I have a 2018 mustang GT 5.0 and it makes me feel like I'm driving that almost, how much it throws u back in the seat and take off. I used the gps speedometer on my phone and disappointingly it only read 18 mph top speed. By the seat of the pants speedometer. I don't believe it. If that's all it really was I can live with that. Much faster and oulls through the bottom rpms amazingly. My chain Has popped off twice tho. And I'm confused why. I was driving in my blank lot and tearing it up and it popped off. I'm wondering if it's cause it was so bumpy and hilly .

 

[Tpdingo]

Ok belt finally came, and finally got a little time after work tonight to put it on. Drives much better.very torquey, I have a 2018 mustang GT 5.0 and it makes me feel like I'm driving that almost, how much it throws u back in the seat and take off. I used the gps speedometer on my phone and disappointingly it only read 18 mph top speed. By the seat of the pants speedometer. I don't believe it. If that's all it really was I can live with that. Much faster and oulls through the bottom rpms amazingly. My chain Has popped off twice tho. And I'm confused why. I was driving in my blank lot and tearing it up and it popped off. I'm wondering if it's cause it was so bumpy and hilly .

That isn't right. You are on grass or pavement? The very high low end torque and it feeling like it is throwing you back in your seat means the TAV is doing its thing correctly. Is it getting up into the 3500RPM range or it is staying in the 2000RPM range? The chain falling off indicates either very loose tension or more likely an incorrect alignment. Also confirm that the chain and other various moving parts are lubricated correctly. If you can, and do this safely, get the kart up to speed and look at the pulleys to make sure they are moving into top gear. The belt should be on the very outer edge of the driver. Refer to the second picture. It could be getting stuck. Confirm that the TAV is assembled correctly. When you take off the driver, the weights should have the curved side facing you. If it is the flat side, it is wrong. Also make sure it has dry lube. Get some dry lube if it doesn't have any.

Also, what GPS app are you using? On my android phone, I found DigiHUD to be the best and dead on. I took an old phone and ziptied it to the steering wheel.

Here is an image of the assembly.

Here is an image of the TAV in top gear.

 

[hmdballa219]

Ya the chain is kind of loose, it happens on grass. On paveme t I am fine, when I go I to the grass and go balls to the wall and almost tip over is when it falls off lol. 2 times in the grass on hilly rough terrain. Never on the pavement have I had a problem. I was going to take a link out of the chain last time it fell off. But couldn't find the master link. I put hi temp grease on it, and didn't think about it, now of course it's filled with gunk. Ok I know it was a big pain for me to pull that TAV out whatsoever. So I can gurantee that's why it's not going I to tip top speed. Also it's not lined up 100%. Since it's a predator the shaft is shorter, I put in a much larger bolt just to bring out the pulleys a bit to get it as straight as I could! Still of a bit.

App is just called speedometer on Android market. Im gonna go with yours. Lol

Also with that picture u posted. Mine looks opposite for the bigger gear. (Driven?). U can see the spring on the outside

---------- Post added at 08:51 AM ---------- Previous post was at 08:50 AM ----------

See my previous pictures and u can see how mine came set up. I never touched that. Assuming it's how it should be.

 

[Kozi]

Ya the chain is kind of loose, it happens on grass. On paveme t I am fine, when I go I to the grass and go balls to the wall and almost tip over is when it falls off lol. 2 times in the grass on hilly rough terrain. Never on the pavement have I had a problem. I was going to take a link out of the chain last time it fell off. But couldn't find the master link. I put hi temp grease on it, and didn't think about it, now of course it's filled with gunk. Ok I know it was a big pain for me to pull that TAV out whatsoever. So I can gurantee that's why it's not going I to tip top speed. Also it's not lined up 100%. Since it's a predator the shaft is shorter, I put in a much larger bolt just to bring out the pulleys a bit to get it as straight as I could! Still of a bit.

App is just called speedometer on Android market. Im gonna go with yours. Lol

Also with that picture u posted. Mine looks opposite for the bigger gear. (Driven?). U can see the spring on the outside

---------- Post added at 08:51 AM ---------- Previous post was at 08:50 AM ----------

See my previous pictures and u can see how mine came set up. I never touched that. Assuming it's how it should be.

I am new to Karts also but feel like I have learned a lot from this forum.

For chain tension you can loosen your 4 engine mount bolts and adjust the engine back/forward to achieve desired tension.

You will be surprised how off alignment your TAV can be. Belt should be completely in line with with both pullies. Thanks to a few members here I quickly learned that I need to add spacers on my engine shaft to push the unit out to align it with the driven. No problems since.

 

[hmdballa219]

For the chain are you referring to the same set up as this kart? Moving the motor wouldn't help me with the chain I don't think. It doesn't connect to the motor.
And same motor the predator 212 you used a shaft extension on? Or the spacers. How and where do I buy.