Rupp torque converter question

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cfh

Well-Known Member
#1
#1
On a rupp torque converter, it doesn’t seem to change size much. That is, the drive and the driven pulley don’t seem to change size very much, as engine RPM changes. How do you rebuild these? Or do you just buy a new comet torque converter? What is the general thinking of Rupp torque converters rebuild vs. replace?
Thanks!
 
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older then dirt

older then dirt

Active Member
#2
#2
All the parts needed to rebuild the driven side are available from blackwidow motorsports. It's not a hard job at all. If the drive clutch is bad, swap it out for a comet 20 series also available from blackwidow, but I have found them cheaper on Ebay (comet part#219559A). The Rupp clutches were not that great to begin with. You will be much happier with the comet. Keep in mind the Rupp clutch on the 1970 models uses a shorter belt then the 71 and up models. The comet 20 has a smaller inner diamiter then the Rupp drive clutch. I found the shorter 70 belt works better with the comet 20 series drive on the 71 and up bikes using the stock driven.

Good luck!
 
C

cfh

Well-Known Member
#3
#3
Ok thanks that is helpful.

I sent an email to the guy at Blackwidow.com. He disagrees with you on the Rupp quality... he thinks the rupp torque converter is the best design and better than comet. I suggested he make a rebuild kit available. But he said it's never clear what wears, it's inconsistent. He suggested i just take it apart and clean it, and re-evaluate.

Fair enough, i did just that... pictures follow....
 
C

cfh

Well-Known Member
#4
#4
After removing the TC black cover, the first step is to remove the driven (motor) side of the torque converter. It is standard threads (not left handed). I used vice grips to hold the TC in place as the center bolt is removed.

tc01.jpg
 
C

cfh

Well-Known Member
#5
#5
After the mounting bolt is removed, the entire front section of the TC can be removed. Also the belt can be removed too.

tc02.jpg
 
C

cfh

Well-Known Member
#6
#6
There's a large center ring and washer which can slide off. I expected wear on these, but found none.

tc03.jpg
 
C

cfh

Well-Known Member
#12
#12
Here's a comparison of the Comet belt (new) and the Rupp belt. This is the Comet belt you get when you buy a complete Comet TC kit. Notice the Rupp belt is 5/8" wide, and the Comet belt is 3/4" wide. The length is about the same, but the width is different. they are not interchangeable.

View attachment 104271
 
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C

cfh

Well-Known Member
#13
#13
Last, after cleaning, the outside driven unit can be re-installed. The big spring goes on first, and the outside slice pushed into place. You need to hold the slice inward, against the spring, while tightening the bolt. It's not that difficult, but worth mentioning.

View attachment 104272
 
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C

cfh

Well-Known Member
#14
#14
So now the Driven (motor) side of the TC is cleaned. How does it operate? Here's a video:

https://youtu.be/b-yfwEvDfbk

So is there any change in the ride? I would say yes. But it's not as dramatic as i would have liked. Maybe a new belt is in order? Or maybe i should do a similar treatment to the Driven (non-motor) side of the TC...
 
delray

delray

Well-Known Member
#15
#15
have you found any info if rupp had any different options on the stall speed engagement for the driver unit. i'm assuming if so must of been just a different spring?
 
C

cfh

Well-Known Member
#18
#18
when i get some more time i will put on a new belt next. then i'll try a comet clone driver and see what that does.
 
capguncowboy

capguncowboy

Well-Known Member
#19
#19
cfh said:
So now the Driven (motor) side of the TC is cleaned. How does it operate? Here's a video:

https://youtu.be/b-yfwEvDfbk

So is there any change in the ride? I would say yes. But it's not as dramatic as i would have liked. Maybe a new belt is in order? Or maybe i should do a similar treatment to the Driven (non-motor) side of the TC...
Click to expand...
The belt you're talking about using is 3/4" wide? The pictures aren't loading, so I'm not sure. If so, that might be the issue. The 3/4" belt would ride pretty high in the saddle, and wouldn't have as much room to move as the clutches widened or narrowed.

If you want something closer to the original belt, get a TC88 belt replacement from Comet. I can't remember the exact part number I used on my 70 rupp but it fit exactly like the original belt. 200423 maybe?

https://beltpalace.com/comet200423.html

The 70 belts were a little shorter than the 71 and later bikes. Gates also makes a good replacement for pretty cheap for the 71' and up bikes. Part number Gates 6061.

https://www.ebay.com/itm/Gates-6061...385173&hash=item33e19292aa:g:BKoAAOSwkNpaeiU6

Both of those options are 5/8" wide and will work great depending on what year your bike is.
 
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