Rupp Torque Converter Advice

Ruppelstiltskin

Ruppelstiltskin

Member
#1
#1
So on my 72-75 Hustler, it's running the factory TC1 parts on a Honda GC160. Was having issues firstly with something hanging up and clunking on hard throttle at low speed. I lubed up the shaft on the driven and I think it freed it up some and seems to knock out 95% of the clunking.

So I was running around with the cover off to watch the operation and diagnose any issues. I think the driven still hangs a hair intermittently. The other thing is that if I go wide open from a stop, the belt slips on the drive which gives a kind of weak takeoff. If one tire is in a rut, it wont pull out of it. Once it gets moving it seems to move out pretty good.

I might be expecting too much but it seems to take a while for the belt to ride up to the top of the driver for maximum gear ratio which could possibly be slippage. I did pull 34 mph though at the top. Would sure like more out of it though. I see alot of people talking about running the comet 20 driver pulleys and claiming to have much stronger power delivery. I think this 160 Honda is soft on low end being a 160 cc but with rpms it should be decent. Wouldn't think it should be slipping the belt from a stop.




 
Last edited:
gumpit

gumpit

#2
#2

From a dead stop. Up a pretty decent dirt hill incline at Windber with a Predator. Mine with a 20 series carries me at 350 pounds no problem. I did try the stock set up but it was nothing compared to the 20 series. Could have been an old belt or not lubed 100% but I would never go back to it...
 
manchester1

manchester1

#3
#3
I think those Rupp clutches work great. Yes, those belts are pretty loose. Buy a new belt and take everything apart and give it a good cleaning. Doesn't look like any of those clutch parts have ever been apart.:detective: You should have plenty of low end, that's what makes them great. Could be your engine as those clutches kinda work on RPM's. My 2 Rupps try to throw me off when I hit the gas.:laugh:
 
Ruppelstiltskin

Ruppelstiltskin

Member
#4
#4
I'm only about 130 and there is nothing remotely close to throwing me off. I had one tire in a 3 inch rut and it just sat there and slipped the belt. Like I said though once I'm moving I get decent acceleration. I don't see any obvious signs that the belt is worn out and it seems to climb the driver pulley albeit after a long stretch. Black widow sells a belt I may have to try unless there is a certain one from a parts store anyone might know about (Found out the Gates 6061 is the overwhelming choice available through Oreilly and Rock Auto). I know the comet 20 is supposed to be a 3/4 wide vs 5/8 plus I think it grabs from both sides instead of just one? Its not like this 160 is a power house though that it should have belt slip.
 
Last edited:
Ruppelstiltskin

Ruppelstiltskin

Member
#5
#5
Repost got goofed

Did some reading and looks like the Gates 6061 is the most common belt suggested to work so I just ordered one from rock auto for about 12 bucks shipped. I'll try to make sure all is lubed well when I get it on. Not sure what there is to lube on the driver side without seeing it apart.

Also didn't think about the crank location being different with the honda :doah: what I should have asked is for what the distance from center to center is on an original bike.
 
Last edited:
Ruppelstiltskin

Ruppelstiltskin

Member
#7
#7
I measured 6 7/8" center to center roughly on the pulleys. Not sure what stock was. Hoping its close to the same.

I think Gumpit has convinced me that I need to see how quickly I can burn up the GC160 and replace it with a GX200 or better. My poor cars are getting neglected completely since I picked this thing up!
 
Last edited:
markus

markus

Well-Known Member
#8
#8
Either you currently have the wrong belt, your driven is not fully retracting, or you have some seriously wore out halves or ramp buttons, etc.. This is the only photo I have that shows the belt on one of my old bikes (its a 1970 so it may look slightly different than yours, but your belt at rest/idle should sit pretty high up in the driven, sometimes higher than whats shown on mine):




When you have it apart to service you can in fact fine tune them. The have 3 holes to position the spring-the center is usually factory setting, the setting that makes the spring tighter will delay the shift a little keeping it in low longer and not as much on the high end (heavy offroad) the setting that makes the spring the looser will let it get into high gear faster for onroad, flat applications. I honestly never messed around with them because I am too lazy to take it apart a few times to see how much of a difference it makes between the points though.....I just always put them in the center and go.
 
Cuda54

Cuda54

Active Member
#9
#9
I had one back in the mid 80s motor was trashed when I bought it. I had a 7hp Tecumseh we had to put a bottle jack in the frame we needed about a 1 1/2" to clear the plug and wire on top. The belt that was on it and the stock clutch held up to the 7hp. I was 180 back then and it would wheelie with me on it. Never check out how fast it went but one hell of a trail bike. The stock belt and clutch were surprising strong and durable. Your motor might be back to far or you might need to lube the secondary. I would lube the secondary and use the same belt and see how it works then.
 
Ruppelstiltskin

Ruppelstiltskin

Member
#10
#10
Thanks Marcus,

1. Your belt looks like it fits tighter without drooping, as well as sitting a bit higher in the driven. I don't know how exact these belts measure but I saw maybe 1/16 short of being 5/8 using a basic tape measure.

2. I think my driven was fairly hung up on the shaft which is possibly why I clocked 5mph higher after lubing it and working it back and forth (And stopping the clunking). Its still kind of rough feeling to slide on the shaft so I may need to try polishing the shaft. That spring does not feel very strong, but then I don't really know how much its really working. I'm assuming that's the one you are talking about being able to index.

3. The buttons are there and look to be consistent in size. They are about 1/8" tall and grab about halfway up the ramps. The halves do seem to close all the way on the driven. The spring return force is unimpressive feeling to me though.

4. So I took a good look at the pulley halves. The driver right halve has a pretty deep groove worn into the middle third of the face and the left side just slightly less severe. The driven has a small wear depression in the middle nowhere near as bad as the driver.



So right now my guess is that the gouged driver combined with, worn/long belt is the main causes of slippage/softness. I'll probably mock up and try the new belt to see what improvement I get. If its a good length and still takes off weak, I think a comet 20 set would be the only answer. Yay more money! :drinkup:


Cuda: Yes I was wondering if the crank is possibly further rear than stock due to aftermarket motor. The belt on there has no visible markings though so I won't know very good till I get the correct belt on there and see what play it has. Lubing the secondary did seem to help clunking problem it had as well as adding some top end, however shouldn't have really affected the take off from a stop because the pulley should be fully together by my understanding until higher speeds.
 
Last edited:
danford1

danford1

#11
#11
Your comment on the return spring force in the driver being unimpressive is most likely your problem. When you put it together you are suppose to wind the spring a little. You wind it to the next tower so it has tension on it. That closes the sheeves tighter and gives you the low end you need.

Danford1
 
C

caver1510

Member
#12
#12
danford1 said:
Your comment on the return spring force in the driver being unimpressive is most likely your problem. When you put it together you are suppose to wind the spring a little. You wind it to the next tower so it has tension on it. That closes the sheeves tighter and gives you the low end you need.

Danford1
Click to expand...
I am confused....if you are talking about the spring on the driver...it slips on so it keeps the two pulley sheave apart at low RPM. I don't remember it having a way to "wind' it....Now the driven pulley does. Are you talking about winding the driven pulley?
 
Ruppelstiltskin

Ruppelstiltskin

Member
#14
#14
I was talking about the pigtail on the driven being unimpressive feeling. After looking at my driver sheave face being worn the way it is I decided it had to be the main culprit. I decided to remedy it with Comet 20 series driver and driven. Should arrive Monday. New Coker 3X10 Trials showed up today from OldMiniBikes :xmas-smiley-016:
 
C

caver1510

Member
#16
#16
Ruppelstiltskin said:
I was talking about the pigtail on the driven being unimpressive feeling. After looking at my driver sheave face being worn the way it is I decided it had to be the main culprit. I decided to remedy it with Comet 20 series driver and driven. Should arrive Monday. New Coker 3X10 Trials showed up today from OldMiniBikes :xmas-smiley-016:
Click to expand...
Yeah....the face of the outside pulley is supposed to have some ridges on it so the weights catch them...if they are worn, the centrifucal weights sill slip
 
danford1

danford1

#17
#17
caver1510 said:
I am confused....if you are talking about the spring on the driver...it slips on so it keeps the two pulley sheave apart at low RPM. I don't remember it having a way to "wind' it....Now the driven pulley does. Are you talking about winding the driven pulley?
Click to expand...
Yes. I was talking about the driven. I meant to type driven but typed driver instead. My bad. Sorry for any confusion.
Let us know how the series 20 works out.

Danford1
 
C

caver1510

Member
#18
#18
danford1 said:
Yes. I was talking about the driven. I meant to type driven but typed driver instead. My bad. Sorry for any confusion.
Let us know how the series 20 works out.

Danford1
Click to expand...
YOU were 100% RIGHT. I got to thinking about mine, so I checked it out. I noticed the belt on the driven was not riding near the outside of the edges of the pulley..I took it apart and wound it to the next "tower"....The two pulleys are closer now and the belt rides higher. It improved my torque from a standing stop. The one thing I did notice is that it lowered the high end top speed. For my fat ass, this is now better. I did see there were 3 holes to choose from for the other end of the spring...Wondering about the difference when the spring end is changed.
 
danford1

danford1

#20
#20
caver1510 said:
YOU were 100% RIGHT. I got to thinking about mine, so I checked it out. I noticed the belt on the driven was not riding near the outside of the edges of the pulley..I took it apart and wound it to the next "tower"....The two pulleys are closer now and the belt rides higher. It improved my torque from a standing stop. The one thing I did notice is that it lowered the high end top speed. For my fat ass, this is now better. I did see there were 3 holes to choose from for the other end of the spring...Wondering about the difference when the spring end is changed.
Click to expand...

Trial and error are your best bet here. The 3 holes allow for different settings of the wound spring tension. The lighter the tension the faster it will shift out into high gear. For a light weight rider on flat ground that would have the highest top speed. For a heavy rider, the light setting may now let it shift as high for top speed. It may try to hold it at a lower gear ratio.
Try each hole and determine which one works best for your riding style and conditions. If you climb a lot of hills then the tighter spring setting would probably work best. Flat paved surface riding ???
Experiment with it :)

Danford1
 
Last edited:
You must log in or register to reply here.
Top