Super Bronc Torque Converter Question

#1
This one is for all you Super Bronc owners out there....
I have a Super Bronc VT-8 with what appears to be an original Comet 30 Series Torque Converter. I was doing some maintenance on the bike today and had the cover off of the torque converter. My question is about the rear driven unit. I noticed that there are 3 holes in the sheave to insert the spring, numbered 1, 2, and 3. Mine is installed in the # 1 hole. Is that the factory setting? If not, what is the factory setting? What spring position/setting are you using on your bikes?

The bike rides nice and the torque converter seems to work OK. The bike is used for a combination of both on and off road. What can I expect in performance if moving the spring around to either hole # 2 or #3? Any particular "head's up" to taking the driven apart to set the spring?
Thanks in advance,
Michael
 
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toomanytoys

Well-Known Member
#4
It changes the spring preload on the driven. It'll make it stay closed longer before it shifts to high range.

Middle hole is where they are factory set on every 30 series driven I've ever messed with. I have a 10 gallon tote full of torque conveters parts.

1st hole early shift 3rd hole late shift.

If you move it to the middle or 3rd hole you should feel an increased mid range pull.

This is not specific to a super bronc.
 

kayde

Well-Known Member
#5
Heres my experience with my 74 vt812

I have had mine in the 3rd hole for a while now and it works ok for the way I use the bike.
Theres alot of variables in spring settings. Like worn springs,riding terrain, belt condition,weight.

I pull a loaded lawn wagon up and down hills, and ride 2up at times.
I feel the third hole let's the pulley shift at the proper time while under a load.
Like it keeps the driven pulley in the lower ratio longer.

A single rider on mostly hard level ground might prefer the first hole with a quicker shift.

Really best way is too way is know is too try each hole:cool: and ride it a few times before changing it again.

No big thing too pull the clip and swap holes, the original circle clip can be a pita though.
 

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#7
It changes the spring preload on the driven. It'll make it stay closed longer before it shifts to high range.

Middle hole is where they are factory set on every 30 series driven I've ever messed with. I have a 10 gallon tote full of torque conveters parts.

1st hole early shift 3rd hole late shift.

If you move it to the middle or 3rd hole you should feel an increased mid range pull.

This is not specific to a super bronc.
Heres my experience with my 74 vt812

I have had mine in the 3rd hole for a while now and it works ok for the way I use the bike.
Theres alot of variables in spring settings. Like worn springs,riding terrain, belt condition,weight.

I pull a loaded lawn wagon up and down hills, and ride 2up at times.
I feel the third hole let's the pulley shift at the proper time while under a load.
Like it keeps the driven pulley in the lower ratio longer.

A single rider on mostly hard level ground might prefer the first hole with a quicker shift.

Really best way is too way is know is too try each hole:cool: and ride it a few times before changing it again.

No big thing too pull the clip and swap holes, the original circle clip can be a pita though.
Thank you both very much for the replies- very much appreciated. OK, something is a little "funky" on the driven on my bike. There is no circle clip holding the driven on the jackshaft. There is a 5/16" bolt, lock washer , and large "cap" washer (similar to what holds the driver on) that secures it to the jackshaft, which tells me the jackshaft end must be internally threaded. I don't know if this was ever a factory setup or someone switched it over. Most of my riding is off road/hills so I think I would like to at least try the spring setting in the # 2 hole based on what I'm learning from you. I am assuming that I will need to "pre-load" (wind) the spring when I go to reinstall?
Michael
 
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chrisr

Active Member
#8
Not sure if this will help you...

"Adjusting the spring tension on the driven pulley changes the rpm range at which the unit shifts into high gear. The three numbered holes on the cam are used to change the spring tension. Hole #1 provides the least tension and allows the unit to shift gears at a lower rpm. This is good for flat ground. Hole #3 provides the most tension and allows the unit to shift gears at a higher rpm. This is good for hilly terrain. Hole #2 is the factory setting providing medium tension good for the most common riding conditions.

You must pre-load the spring when installing it into the driven pulley. After placing the end of the spring in the desired hole and aligning the flat spots in the center of the cam with the flats on the post, just before pushing the cam all the way on to the post, turn the movable sheave clockwise -- tightening the spring -- bringing the buttons past the points of the cam and into the next valley. While holding tension on the spring, push the cam all the way on to the post and secure it with the snap ring. When you release the movable sheave the spring should rotate it counter-clockwise until the plastic buttons press against the cam. The insert buttons must not "float" between the cams."

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

mustangfrank

Well-Known Member
#9
Thank you both very much for the replies- very much appreciated. OK, something is a little "funky" on the driven on my bike. There is no circle clip holding the driven on the jackshaft. There is a 5/16" bolt, lock washer , and large "cap" washer (similar to what holds the driver on) that secures it to the jackshaft, which tells me the jackshaft end must be internally threaded. I don't know if this was ever a factory setup or someone switched it over. Most of my riding is off road/hills so I think I would like to at least try the spring setting in the # 2 hole based on what I'm learning from you. I am assuming that I will need to "pre-load" (wind) the spring when I go to reinstall?
Michael
+1 on the second hole as found on a survivor and no marks in the other holes. That is the factory mount with that tiny/easy to over-torque bolt/washer. I learned my lesson and replaced with a grade 5 or 8 bolt.
 
#10
+1 on the second hole as found on a survivor and no marks in the other holes. That is the factory mount with that tiny/easy to over-torque bolt/washer. I learned my lesson and replaced with a grade 5 or 8 bolt.
Thank you mustangfrank,
Do I understand correctly that your driven was also held on with a bolt like mine is and not the circle clip? If so, then I guess at least SOME of them came from the factory this way.
Michael
Not sure if this will help you...

"Adjusting the spring tension on the driven pulley changes the rpm range at which the unit shifts into high gear. The three numbered holes on the cam are used to change the spring tension. Hole #1 provides the least tension and allows the unit to shift gears at a lower rpm. This is good for flat ground. Hole #3 provides the most tension and allows the unit to shift gears at a higher rpm. This is good for hilly terrain. Hole #2 is the factory setting providing medium tension good for the most common riding conditions.

You must pre-load the spring when installing it into the driven pulley. After placing the end of the spring in the desired hole and aligning the flat spots in the center of the cam with the flats on the post, just before pushing the cam all the way on to the post, turn the movable sheave clockwise -- tightening the spring -- bringing the buttons past the points of the cam and into the next valley. While holding tension on the spring, push the cam all the way on to the post and secure it with the snap ring. When you release the movable sheave the spring should rotate it counter-clockwise until the plastic buttons press against the cam. The insert buttons must not "float" between the cams."

https://www.gokartsupply.com/asymapp.htm
Thank you chrisr- That information is very helpful.
Michael
 

mustangfrank

Well-Known Member
#11
Thank you mustangfrank,
Do I understand correctly that your driven was also held on with a bolt like mine is and not the circle clip? If so, then I guess at least SOME of them came from the factory this way.
Michael

Thank you chrisr- That information is very helpful.
Michael
Yes, the 1/4- 20 or 5/16 bolt is factory...at least on the version with the TAV and chain on the left side.
 
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