Gearing / Torque Converter Question

[tony7281]

I'm currently running a 6.5 HP Honda GX200 (governed at 3600 rpm)with a torque converter and a jack shaft. There is a 10 tooth sprocket on the jack shaft and a 72 tooth sprocket on the axle, and 20" diameter rear tires. (see picture below) I'm assuming when the kart is at top speed the torque converter should give me a 1 to 1 ratio. The speed calculator says I should be getting about 30 mph, but I'm only getting about 20 mph according to the GPS on my phone.

I had the kart when I was a kid, and just got the thing going for the first time in about 10 years about a month ago. I've installed a tiny tach and it's reading very close to 3600 rpms. I'm a quite a bit fatter than I was when I was a kid (weigh about 200 lbs now) but I do remember it going closer to 30 then. Is there something wrong with my torque converter, do I need to gear it lower because I weight more, or what could be wrong?

Also, in the very near future I do plan on removing the governor, and installing a billet rod, flywheel, 16# valve springs, new intake and exhaust, and rejetting the carb. Will I need to gear it differently or am I ok? I'd like to be able to go closer to 45-50 mph and still have some low end power for climbing small inclines, etc.

 

[wall gator]

Is that a tav 30(assymmertical belt) set up????

 

[wall gator]

Need more pics of tav set up....PTO SIDE/TOP.....SPROCKET(AXEL) SET UO SIDE/TOP PICS......

 

[tony7281]

The go-kart is at my friends house that is about 40 miles away. I'll see if I can get some more information on the torque converter tonight. The go-kart is currently disassembled because I've been welding and painting the frame, so I won't be able to take any pictures of it assembled. Here are a couple more pictures I had saved to my computer. I don't have any pictures of the sprocket side, but it is just a #40 chain that connects the jack shaft to the live axle. Any other information you need while I'm up there?

 

[wall gator]

the go-kart is at my friends house that is about 40 miles away. I'll see if i can get some more information on the torque converter tonight. The go-kart is currently disassembled because i've been welding and painting the frame, so i won't be able to take any pictures of it assembled. Here are a couple more pictures i had saved to my computer. I don't have any pictures of the sprocket side, but it is just a #40 chain that connects the jack shaft to the live axle. Any other information you need while i'm up there?

no pics sent........need to see how tav is connected to motor..looks like driven connects directily to j/s? And a sprocket on other end? Belt no. Would help,,,walt

 

[tony7281]

Sorry, pictures are attached now. Driver unit is connected directly to the motor crank shaft. Driven unit is connected directly to the jack shaft. On the other end of the jacket shaft is the 12 tooth sprocket, with the 72 tooth sprocket on the live axle.

 

[tony7281]

I did some research. It looks like I am running a asymmetric Series 30 comet torque converter with a 7" driven pulley. Apparently this set-up does not have an overdrive. The lowest ratio is 1.12. I did some math and I should be able to get up to 27 mph. I looked up the number on the belt, and it should be 3/4" wide. Almost 1/8" is worn off. I'm assuming this is why I'm not getting the extra speed? The buttons look good. Also, it looks like it has a blue spring. Should it have a green spring? I remember replacing the spring when I was a kid, and maybe I got the wrong color.

 

[wall gator]

Look's like drive and driven out of aligment!(gonna eat up belt's/poor performance). Both inside flat pullys(closest to motor) need to be straight......make sure you jackshaft is square w/PTO. Once all is square/aligned,use old belt to test run, then get new belt......Unless it's the pic,look's like driven pully too far out. Let me know..WALT

 

[tony7281]

I've attached another picture. It's not the best picture, but it's a little better. Is it out of alignment? I replaced the original 5hp Briggs with the 6.5hp Honda a long time ago, and I think that is what might be causing my alignment issues.

The hubs closest to the engine look like they are close to being in line, but the belt definitely looks crooked. What is the proper way to align it?

What's the easiest way to get it back into alignment? Could I make the engine mounting holes in the block wider side to side somehow without a mill, and without hurting the structural integrity of the block?

 

[r_chez_08]

Looks a little out.
Either remove spacing from the driver or add to the driven.

 

[redsox985]

I think that's a 20 series based on the open driver in the very first picture posted.

 

[brandongeiger2]

I've attached another picture. It's not the best picture, but it's a little better. Is it out of alignment? I replaced the original 5hp Briggs with the 6.5hp Honda a long time ago, and I think that is what might be causing my alignment issues.

The hubs closest to the engine look like they are close to being in line, but the belt definitely looks crooked. What is the proper way to align it?

What's the easiest way to get it back into alignment? Could I make the engine mounting holes in the block wider side to side somehow without a mill, and without hurting the structural integrity of the block?

Well first of all do you have a jackshaft mounted on a plate below the engine thats what i have and it keeps my torque converter perfectly aligned its with a box stock project clone or was it welded on or somthing
but either way belts need to be replaced everyonce and a while so dont be surprised if is worn down

 

[r97]

1. your belt could be worn, that would reduce top end.

2. your driver is 20 series comet, or a max torque, not 30 series.

3. can't be 100% sure but, it appears to me your belt says "this side to engine", if so your using an asymmetrical belt on a symmetrical driver.

4. does the driven have one almost flat side, and one angled side? if so you have a 30 series driven, not correct for the driver. if both sides of the pulley are angled significantly, you have the correct driven for your driver.

5. about the spring, i'm confused. a 30 series uses a green spring which is made for an outboard driven. a blue spring is used in the 20 series, but (IIRC) the 20 series driven only runs inboard, and if i'm thinking right an inboard spring wouldn't work right at all on an outboard driven.
max torque does offer an outboard driven, but that shouldn't use a blue spring either. so unless there is something i'm missing, you have the wrong spring.

i would suggest:

- take the belt off the tc and take lots of pictures, that way we can identify it.

- take pictures of the belt

- clean the tc

 

[redsox985]

The 20 series driven runs inboard or outboard, but needs the correct spring.

 

[r97]

ok, thanks for clearing that bit up, do you know if the outboard spring is a different color?

 

[brandongeiger2]

1. your belt could be worn, that would reduce top end.

2. your driver is 20 series comet, or a max torque, not 30 series.

3. can't be 100% sure but, it appears to me your belt says "this side to engine", if so your using an asymmetrical belt on a symmetrical driver.

4. does the driven have one almost flat side, and one angled side? if so you have a 30 series driven, not correct for the driver. if both sides of the pulley are angled significantly, you have the correct driven for your driver.

5. about the spring, i'm confused. a 30 series uses a green spring which is made for an outboard driven. a blue spring is used in the 20 series, but (IIRC) the 20 series driven only runs inboard, and if i'm thinking right an inboard spring wouldn't work right at all on an outboard driven.
max torque does offer an outboard driven, but that shouldn't use a blue spring either. so unless there is something i'm missing, you have the wrong spring.

i would suggest:

- take the belt off the tc and take lots of pictures, that way we can identify it.

- take pictures of the belt

- clean the tc

im pretty sure its a 30 series asymetrical
the 20 has a spring facing the engine the 30 series faces away
i know this because i own both

 

[redsox985]

im pretty sure its a 30 series asymetrical
the 20 has a spring facing the engine the 30 series faces away
i know this because i own both

The 20 series can run inboard OR outboard! Look at the driver closely in the first picture. It looks sloped on both sides.

 

[tony7281]

Alright, I finally figured out what was going on with help from Wall Gator. Red sox and R97, you were correct. I do have a 20 series with the two angled sides on both the driver and the driven, but I have the wrong asymmetrical belt. I am going to take everything apart and clean and lube it per Comet's instructions, and order the correct belt + a spare.

I did some more research and this set-up on the TC only goes down to a 1.4 gear ratio. I did the math and that equals 21 mph @ 3600 RPM. This makes more sense now.

I do have to run it with the spring out. How do I know if I have the correct spring??? I am running a blue spring currently.

Also, I ordered a bunch of replacement parts for 30 series when I thought I had a 30 series: New driver springs, and new plastic stops and snap ring for the driven. Will these work with the 20 series or are they different???

 

[r97]

not sure what color driven spring you should have for outboard operation of a 20 series, maybe redsox or blaz knows for sure.

the replacement parts you have should work. make sure the springs are the same color as the old ones, and the cam buttons look the same.

new belt,
http://www.gokartsupply.com/tcbelts.htm

 

[wall gator]

not sure what color driven spring you should have for outboard operation of a 20 series, maybe redsox or blaz knows for sure.

the replacement parts you have should work. make sure the springs are the same color as the old ones, and the cam buttons look the same.

new belt,
http://www.gokartsupply.com/tcbelts.htm

ORANGE SPRING #216095...Walt