Need more torque, keep burning up clutches.

A

Aerindel

Member
#1
#1
Hi guys.

I keep burning up clutches on my BT200. They get too hot, the spring stretches and the clutch stops disengaging.

I put a 60 tooth rear sprocket in, which helped, but I just took out another clutch driving in the snow. (I studded my tires)

What I'm wondering, is what is the best solution for this? I haven't been able to find a larger sprocket than 60 teeth.

Would a torque converter help or hurt? Is this just the limit for this bike?

I don't care bout speed. 10 MPH is fine....I but I can use as much torque as I can possibly get and not fall over.
 
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SAS289

SAS289

Well-Known Member
#3
#3
First thing to do is make sure you are not running against a dragging brake.

Next thing is how you ride. If you are on the slip area of the clutch too long and too often it's going to heat up. Gas it to engage and go.

I know that there are 72 tooth sprockets that fit the Coleman hub but I don't recall who sells them.

A torque converter would help because of the gearing difference at slow speeds and works well with a 60 tooth. Both low end and top speed are better than the jackshaft.
 
A

Aerindel

Member
#4
#4
SAS289 said:
First thing to do is make sure you are not running against a dragging brake.

Next thing is how you ride. If you are on the slip area of the clutch too long and too often it's going to heat up. Gas it to engage and go.

I know that there are 72 tooth sprockets that fit the Coleman hub but I don't recall who sells them.

A torque converter would help because of the gearing difference at slow speeds and works well with a 60 tooth. Both low end and top speed are better than the jackshaft.
Click to expand...
Interesting you mention that, I've had some trouble with my brakes lately, after replacing the tensioning bolts and readjusting the chain. I seem to have very poor braking...but if I tighten the brakes to where they work again....they drag......any ideas how they could both work poorly and drag at the same time?

They used to work perfectly....but this fall I threw a chain because I had run out of room to tighten the chain. So I removed a link and slid the axle back in to the beginning of its range so I could tighten the chain again, which of course meant re-adjusting the brake cable...but for some reason I don't understand, they haven't worked right since.


I understand the WHY of what is happening with the clutch.....the issue is that I seem to often end up in situations where the engine does not have enough torque, to spin up fast enough for the clutch to stop slipping. Its not a matter of gas, I give it full throttle, its just a matter of not having enough power at that gearing to get up to an RPM where the clutch is fully engaged.

Is there a reccomended brand of torque converter? I see many options online with a wide range of prices.

I have also read that with some bikes/converters you have to remove and replace the stock muffler, intake and carb for clearance when raising the engine? Is that true for a BT200 or just some models?

Durability is more important than performance for me. I've had a hard time finding good information on torque converters as it seems everyone is trying to go faster....which I don't want....I just want it to stop burning up when dealing with hills and snow.
 
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J

JimN

#5
#5
SAS289 said:
First thing to do is make sure you are not running against a dragging brake.

Next thing is how you ride. If you are on the slip area of the clutch too long and too often it's going to heat up. Gas it to engage and go.

I know that there are 72 tooth sprockets that fit the Coleman hub but I don't recall who sells them.

A torque converter would help because of the gearing difference at slow speeds and works well with a 60 tooth. Both low end and top speed are better than the jackshaft.
Click to expand...
I believe this one works. This is where I bought my 72t from. Don't know if they have any in stock.
https://www.studzracing.com/product-p/bajasprocket420.htm
 
SAS289

SAS289

Well-Known Member
#8
#8
You may want to take the wheel off and have a good look at the brakes. And make sure the brake cable works properly. When you go back together with it be careful with the axle alignment. The brake bolts to the frame. If your axle is too far out of alignment, you may cause enough of a bind when you tighten the brake to the frame.

You shouldn't need full throttle to engage the clutch. Daddyjohn's question is a good one. You can't do slow speed riding with a straight chain from the clutch to the rear sprocket.

Not sure if you would need clearance after raising the engine for a torque converter. But with the up and forward engine riser you should be ok.
 
M

MJL

Active Member
#9
#9
Have you changed from the stock tires? 72 tooth sprockets are mighty close to the ground. I ran one for quite a while and whacked plenty of roots and had chain jumps due to small sticks and other debris. 60 is about right. Not all are in agreement, but I really like Juggernaut drivers on a TAV setup, gobs of torque.
 
Bird Brain

Bird Brain

Active Member
#10
#10
I would have to agree with going with a torque converter set up for anything with the larger tires such as what the BT200 come with. Could a clutches inner bell friction surface and shoes be modified with spray welded carbide and gain some grab and heat reduction along with added durability? Sure, but thats kind of going a long way also. The converter would be my choice personally.
 
A

Aerindel

Member
#11
#11
Thanks for the replies everyone.

I still am using a jackshaft, a brand new one infact as when I was working on it recently I found that the key had partially broken and torn up the keyway on the old shaft so I replaced it.

Tires are stock size, SunF brand,


JimN said:
While I agree with you in general, if the gearing is not right for the power to weight your just going to burn up belts instead of clutches.
Click to expand...

This is exactly my concern and why I'm asking questions here. Does a torque converter actually give you either more delivered torque or more durability than the clutch? I don't want to waste time and money just to find out that the bike just can't handle the slopes I'd like it too.

Are there any available jackshaft sprockets that I could use to lower the gearing on that end?
 
J

JimN

#14
#14
Aerindel said:
This is exactly my concern and why I'm asking questions here. Does a torque converter actually give you either more delivered torque or more durability than the clutch? I don't want to waste time and money just to find out that the bike just can't handle the slopes I'd like it too.
Click to expand...
Yes and I don't know. Welcome to the jungle. :D
The TC multiplies torque. It also allows you to change gear ratio pretty easy by changing the driven sprocket. But, it is all about weight, and weight bias. Post on about about what total weight your dealing with and riding terrain, and quite a few people on hear can give you a more informed opinion than I can.
Like @BrownStainRacing says, It's a little turd motor your dealing with.
Have you backed out your throttle screw yet?
 
SAS289

SAS289

Well-Known Member
#15
#15
Aerindel said:
Thanks for the replies everyone.

I still am using a jackshaft, a brand new one infact as when I was working on it recently I found that the key had partially broken and torn up the keyway on the old shaft so I replaced it.

Tires are stock size, SunF brand,





This is exactly my concern and why I'm asking questions here. Does a torque converter actually give you either more delivered torque or more durability than the clutch? I don't want to waste time and money just to find out that the bike just can't handle the slopes I'd like it too.

Are there any available jackshaft sprockets that I could use to lower the gearing on that end?
Click to expand...
There are 8 and 9 tooth sprockets you can get for the jackshaft if you want more low end than the 10 tooth the torque converters have.
 
A

Aerindel

Member
#16
#16
JimN said:
Have you backed out your throttle screw yet?
Click to expand...
Yes, its nice when I'm on the flat but doesn't really help for hills, which is most of what I deal with.

In theory, no matter how crappy the engine is, you should be able to develop infinite torque.....just at increasingly lower speeds. I mean it when I say that 10 MPH is okay....heck, 5 would probably be okay, as long as I can do that 5mph up a 40º slope.
 
SAS289

SAS289

Well-Known Member
#17
#17
Aerindel said:
Yes, its nice when I'm on the flat but doesn't really help for hills, which is most of what I deal with.

In theory, no matter how crappy the engine is, you should be able to develop infinite torque.....just at increasingly lower speeds. I mean it when I say that 10 MPH is okay....heck, 5 would probably be okay, as long as I can do that 5mph up a 40º slope.
Click to expand...
What you are saying there is one of the reasons why I won't run any less than 6:1 with a torque converter. Where I ride there's one hill that I wouldn't even try with a clutch and would even be difficult with the stock (5:1) gearing and the torque converter. And 6:1 or more works better after the belt shift than the stock gearing.
 
M

MJL

Active Member
#18
#18
Aerindel said:
This is exactly my concern and why I'm asking questions here. Does a torque converter actually give you either more delivered torque or more durability than the clutch? I don't want to waste time and money just to find out that the bike just can't handle the slopes I'd like it too.

Are there any available jackshaft sprockets that I could use to lower the gearing on that end?
Click to expand...
Here is a video my son made of our hill climbing bike. Stock 224 limited to approx 3600 rpm, but the 196 did almost as well. Torque converter with Juggernaut driver. 10/60 sprockets. It has never shredded or “burned up” a belt despite many hours of use. Performance is no different with my 230 lbs on it. The hill climbing is around the 2:15 mark. Might not look like it in the video, but the hill is probably in the 30-40% range.

IMG_0822.png
 
Mark G

Mark G

#19
#19
Aerindel said:
Yes, its nice when I'm on the flat but doesn't really help for hills, which is most of what I deal with.

In theory, no matter how crappy the engine is, you should be able to develop infinite torque.....just at increasingly lower speeds. I mean it when I say that 10 MPH is okay....heck, 5 would probably be okay, as long as I can do that 5mph up a 40º slope.
Click to expand...
That's asking a LOT of any stock minibike. Forty degree slope? Yikes.
Weight has nothing to do with it, my Hauler is over 600# and uses a torque converter. If you are burning up belts there's something else wrong, usually improper spacing, gearing as mentioned above or using low quality belts.
You may be over thinking this. If you want quality, just bite the bullet buy a Comet. If you want to save a few bucks, buy a knockoff, plenty of people have had good luck with them. My personal experience is they are a waste of money. YMMV
 
A

Aerindel

Member
#20
#20
Mark G said:
That's asking a LOT of any stock minibike. Forty degree slope? Yikes.
Weight has nothing to do with it, my Hauler is over 600# and uses a torque converter. If you are burning up belts there's something else wrong, usually improper spacing, gearing as mentioned above or using low quality belts.
You may be over thinking this. If you want quality, just bite the bullet buy a Comet. If you want to save a few bucks, buy a knockoff, plenty of people have had good luck with them. My personal experience is they are a waste of money. YMMV
Click to expand...

I don't mind spending the money, as long as it works. 40º is actual conservative. Most of my property is steeper, My house is definitely in a 'not buildable' zone by the graph posted above.

Maybe I just need to build a gearbox of some kind...

....or

anyone ever put one of those little diesels in one of these bikes?
 
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