74' Super Bronc TAV Help - Engine Swap Help

P

Pink Pather

New Member
#1
#1
Good Morning OldMiniBikes,


I am in the final stages of restoring a Heald Super Bronc that was my Grandpa's Uncle's ice fishing machine. I received this unit in non-functioning condition. The screw that attached the choke butterfly to the shaft let loose, and both the screw and butterfly was taken into the cylinder and did some damage. I did not know the condition of the bottom end, so I opted to install a new HMSK-80. It has electric start and runs great. It was also sitting on my shelf, win-win. I tore it down, cleaned, painted, and re-assembled the mini bike. However, I was going to install the TAV system on the new engine and realized the crank on the old engine was 1.00”, whereas the new engine has a .75”” shaft. The original driver has the keyway cast into the bore, so I don’t think a reducer will work for this application. I think my only option is to buy a new driver. However, i cannot find one that is the same size. I will get the dimensions at lunch today. Any help is appreciated.









I have a couple of the big old skis for the front, and would love to get this together asap so I can play in the snow!
Also, has anyone ever added a set of carbides to the bottom of a ski? Pros? Cons?
 
P

Pink Pather

New Member
#4
#4
Roccosbike,

Thanks for the reply. I have the old engine sitting in a box with all the parts. Right now, I am just looking for a bolt on replacement. I am in the middle of a frame off restoration on an old Jeep, and would rather keep the time spent working on the Super Bronc to a minimum.

I considered getting a whole new setup, but the unit I have incorporates a drum brake on the driven shaft. I would like to keep this feature.
 
Docdc

Docdc

#5
#5
Call Ron Kimble at Powertec in Benton Harbor. I believe you can replace the driver and driven with a Comet 30 series driver/driven without too much fuss. Just the cost of the system.

Doc
 
Mark G

Mark G

#6
#6
That looks nice. I have a couple questions:

Is the seat original or repo?

What size are those tires, and where'd you get 'em?

Where in Wisconsin are you?

As far as your your Torque Converter goes: If you want just a bolt on replacement, you can just replace the driver clutch and leave the engine, and the driven alone. The drivers came in both 1" and 3/4".
 
Last edited:
P

Pink Pather

New Member
#7
#7
Hey Mark,

Thanks. I think it turned out well. The tires are 22x11x8. I was in the process of trying to get the rear bead seated, so it was over inflated. The tires are the same size. And I got them at the local fleet farm. Also, the seat is original.

I live near Menomonie. You?
 
P

Pink Pather

New Member
#8
#8
Just ordered

Genuine Comet 30 Series Drive Unit - 3/4"
Part Number 219552A

Comet TAV2 Torque Converter Driven Unit - 5/8"
Part Number 219456A

Replacement Belt Comet 203591
Part Number R_10052

#40/41 Chain 9 Tooth
Part Number AZ_2180

#420 Chain 10'
Part Number AZ_4035-10

#420 Chain Master Link
Part Number AZ_4036

#40/41 Chain 8 Tooth with Keystock
Part Number AZ_2182k
Chain Pitch: #41

I just ordered the above parts for the SB. I think that should take care of everything, and it might be driving mid next week!
 
chrisr

chrisr

Well-Known Member
#9
#9
I may be missing something here but I am not sure why you are ordering 40/41 gears and 420 chain. The Broncs that I have came with 40 gears and 40 chains and the 420 is close to the 40/41 they are not the same. You may want to give Ron Kimball a call and he can get you the gears and chain you may need for a Bronc.




Pink Pather said:
Genuine Comet 30 Series Drive Unit - 3/4"
Part Number 219552A

Comet TAV2 Torque Converter Driven Unit - 5/8"
Part Number 219456A

Replacement Belt Comet 203591
Part Number R_10052

#40/41 Chain 9 Tooth
Part Number AZ_2180

#420 Chain 10'
Part Number AZ_4035-10

#420 Chain Master Link
Part Number AZ_4036

#40/41 Chain 8 Tooth with Keystock
Part Number AZ_2182k
Chain Pitch: #41

I just ordered the above parts for the SB. I think that should take care of everything, and it might be driving mid next week!
Click to expand...
 

Attachments

P

Pink Pather

New Member
#10
#10
I am probably wrong, but won't the 420 chain work on 40/41 gears? I thought it was a slightly stronger chain option? The order has already been shipped.
 
toomanytoys

toomanytoys

Well-Known Member
#11
#11
I am running 420 chain on my super broncs for years.

I am running a TAV 30 on my identical bike. It works perfect!

You will be pleased with what you ordered.

I am not sure what belt you ordered..or even what belt I am using...make sure you have the measurement between the center of the engine shaft and the center of the jack shaft and look at the chart to make sure you have the correct belt.
 
P

Pink Pather

New Member
#12
#12
I took the measurements prior to ordering. I THINK I ordered the right belt. The distance was 7.625" center to center.

And if the chain will not function as intended, I can run to the local farm and fleet and pick up a section.

Thanks for all the input. I can't wait to get the parts needed to get her moving! There is snow on the ground and I can't wait to play.

Josh
 
toomanytoys

toomanytoys

Well-Known Member
#13
#13
Pink Pather said:
I took the measurements prior to ordering. I THINK I ordered the right belt. The distance was 7.625" center to center.

And if the chain will not function as intended, I can run to the local farm and fleet and pick up a section.

Thanks for all the input. I can't wait to get the parts needed to get her moving! There is snow on the ground and I can't wait to play.

Josh
Click to expand...
You should be good to go. I haven't ordered a belt forever. If you measured and followed the chart you should be golden. That's what I do.

Super broncs are so much fun. I have 3 and a roller. If setup right they will climb a mountain and go anywhere.
 
toomanytoys

toomanytoys

Well-Known Member
#15
#15
Remember alignment between the driver and driven is spot on. And make sure you put the belt on the right way. Flat towards the engine.

Just some advice in case you haven't messed with one before.

Good luck!
 
P

Pink Pather

New Member
#16
#16
Got almost everything installed last night. The only issue I am having is the throttle. I cannot seem to get the throttle to wide open. I am hoping maybe tonight will be the night!
 
P

Pink Pather

New Member
#18
#18
I think the problem is the governor. Engine off: Twist throttle and it will open the throttle to 100%. Engine off, the spring isn't strong enough to open past 15%. I can hit the throttle linkage by hand and it roars to life. I was messing with it last night, and after burning my hand on the exhaust one toomanytimes, I decided to call it a night.

I will post pictures of what I am dealing with after lunch.

Is it possible there needs to be a spacer between the driven and the crankshaft to line them up? I added two washers, and it is close as it is going to get.
 
P

Pink Pather

New Member
#19
#19
Throttle Situation

Here is the throttle set-up from the original HM80 that was factory:


Here is the factory throttle set-up from the new engine:


Here is what I came up with:


Note: There was a cable stop on the throttle cable. I removed it for clarity.

If anyone has any ideas on the most efficient way to make one of these mechanisms work, lets hear em'!

Thanks for your time,
Josh
 
You must log in or register to reply here.
Top