overpowering a 6 inch driven comet torque a verter? fixes? other clutch options?

SAS289

Well-Known Member
#21
I've been pushing around 17hp through a 6" Comet driven with no issues at almost 7,000rpm.
With what gearing?

I watched a video the other day that made no sense. A guy did a top speed run with a Juggernaut on his Coleman 200. He got 59 mph at nearly 8000 RPM. Then did another top speed run with the jackshaft and got just over 60 at a little over 8K RPM.

How would he get that kind of RPM with the Juggernaut and a 45 tooth sprocket? Just by the sound of the engine it sounded like the belt never shifted as he screamed up to 59 mph. It was like he was running a 9 or 10/1 ratio the whole run. Even if the final ratio of the Juggernaut is 1/1 in high that kind of RPM should have him over 100 mph with his gearing.

Are these designed for no belt shift if big power is being applied? Why even have one when his jackshaft had nearly the same results?
 
#22
Because its a jackshaft . I personally run Max Torque clutches on my Doodlebugs. Jim Donovan told me this little tidbit "Torque converters are great if you want to be in a parade. If you want to go fast for a long time, use a clutch!" If I had to run something with an offset, I'd run a torque converter though. My theory is if it's big enough to need one then I want as much control possible over the entire range of the motor. Jackshafts are meant to bring the ratio closer for better overall use of the motor where as torque converters are more variable. That said, if the sprocket on the torque converter is equal to that of the jackshaft they will have the same top speed the bigger question is which one gets there faster and which one has the best response after dropping the load after throttle release. I know that's not the complete answer but its my thought process when choosing between the two.
 

Li'l Popeye

Well-Known Member
#24
With what gearing?

I watched a video the other day that made no sense. A guy did a top speed run with a Juggernaut on his Coleman 200. He got 59 mph at nearly 8000 RPM. Then did another top speed run with the jackshaft and got just over 60 at a little over 8K RPM.

How would he get that kind of RPM with the Juggernaut and a 45 tooth sprocket? Just by the sound of the engine it sounded like the belt never shifted as he screamed up to 59 mph. It was like he was running a 9 or 10/1 ratio the whole run. Even if the final ratio of the Juggernaut is 1/1 in high that kind of RPM should have him over 100 mph with his gearing.

Are these designed for no belt shift if big power is being applied? Why even have one when his jackshaft had nearly the same results?
I have 2 identical minibikes; 1 with Juggernaut and 1 with stock driver.
With the Juggernaut the engine makes more rpm's (in my case up to 6700rpm) , but has the same topspeed (70km/h) as the other minibike.
The other minibike has aluminium weights in the driver, now with blue springs. Stock driven spring in 1st hole (the tighter one). Top speed reached at 5500-5700 rpm's. I have run this one with a overdrive lock out bushing, too; more rpm's, same top speed.
The Juggernaut seems to be a bit faster on take offs. It doesn't go into overdrive and I think it doesn't even reach 1:1 ratio.
 
#25
SAS289 Yup! It's all up to those gears at that point. Thats how I ended up back to centrifugal clutches on my Doodlebugs! If I get a good deal on another one, I'm going to do a torque converter to change it up though.
 
#26
Lil Popeye knows his stuff. That dude builds some really classy bikes from scratch with his daughter. I'm convinced they will probably CNC their own torque converter at some point!
 

Li'l Popeye

Well-Known Member
#31
I have an ohh55 powered trike that I've been slowly modifying for more and more power. as of my last mod switching from the stock carb to a tecumseh 10 hp carb I gained a ton of power but now my driven keeps un winding itself. It keeps pulling the clutch cam past the rubber stops and looses all tension. I tried another unit and the same problem. would A 7 inch driven fix this? and if not what other clutch could I use.?
I don't understand how it is possible for the driven to unwind itself.
 
#33
Maybe they didn't load it correctly or didn't install the retaining clip properly. It sounds like they are torque popping the spring some how causing it to unwind the preload.
 

joshua. c.

Well-Known Member
#35
I haven't fixed the issue yet the clutch ran fine for years then suddenly started twisting the outside sheaves buttons past the clutch cam ramps releasing all the pre load. I tried another clutch and same thing. this only started recently and as a note I added allot more power to the engine recently with a bigger carb and it started soon after that. I'm going to try replacing the clutches buttons and the retaining ring and the spring as well as removing 1 of the two jackshafts that my trike is running. I'll be re gearing the trike at the same time. hopefully one of these changes should solve my issue.
 
#36
I'm having issues with my Trailmaster MB200-2 and can see how this is possible. Just the stock 196 punched out to 15hp is working the bag out of the stock pulleys. I'm going to swap to a juggernaut before I get into gears but I'm learning about how the rear sprocket can lower the impact if geared down a bit. It's a shame because the motor can power through the ratio but the torque converter can't keep up.
 

SAS289

Well-Known Member
#37
I'm having issues with my Trailmaster MB200-2 and can see how this is possible. Just the stock 196 punched out to 15hp is working the bag out of the stock pulleys. I'm going to swap to a juggernaut before I get into gears but I'm learning about how the rear sprocket can lower the impact if geared down a bit. It's a shame because the motor can power through the ratio but the torque converter can't keep up.
If your issue is happening when the belt shifts the Juggernaut will help because as said earlier in this thread the Juggernaut may not even get to OD like the stock driven.

IMO you have the same gearing issue that so many others have had over the years. If your rear sprocket is 50 or under it's no wonder that you wouldn't like the performance once the belt shifts. When I put my 200U together last June I wanted the 60 tooth to start with but it was out of stock. I ended up riding it with the 9/50 tooth and didn't like it as expected. While waiting for the 60 tooth I tried an 8 tooth. Much better but not there yet. When the 60 tooth came in that was the sweet spot for me with the 9 tooth. I added the yellow spring onto the driven to delay the shift for more RPM during the shift. I would get the Juggernaut if I wanted higher RPM at higher road speeds but do not need that. Besides, I didn't build the engine for anything higher than 5800 RPM or so. Don't need it.
 
#38
If your issue is happening when the belt shifts the Juggernaut will help because as said earlier in this thread the Juggernaut may not even get to OD like the stock driven.

IMO you have the same gearing issue that so many others have had over the years. If your rear sprocket is 50 or under it's no wonder that you wouldn't like the performance once the belt shifts. When I put my 200U together last June I wanted the 60 tooth to start with but it was out of stock. I ended up riding it with the 9/50 tooth and didn't like it as expected. While waiting for the 60 tooth I tried an 8 tooth. Much better but not there yet. When the 60 tooth came in that was the sweet spot for me with the 9 tooth. I added the yellow spring onto the driven to delay the shift for more RPM during the shift. I would get the Juggernaut if I wanted higher RPM at higher road speeds but do not need that. Besides, I didn't build the engine for anything higher than 5800 RPM or so. Don't need it.
I think I'm getting close to that sweet spot you mentioned! Soooo much more fun!!
 

joshua. c.

Well-Known Member
#39
I did fix this issue. It appears it was a gearing issue, I remove the driven from the jackshaft on backing plate and re installed it on the second jackshaft eliminating the backing plate then re geared the trike and swapped the 6 inch driven for a 7 inch and now I'm running a 9 tooth on the jackshaft and a 54 on the axle. since the modification I've had no issues. thank you for all the advice.
 
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