Comet torque converter problems

David wulf

David wulf

#1
#1
Well i have put a comet 30 on the super powell , and it doesn't work worth a damn .

The problems .
It launches great goes up to 4100 or so and then starts to decline , and settles in at 3180 and stays right there .
The motor will not pull past 3180 and this is a motor the screams past 8000 with a kart clutch and 9.0 -1 gearing .

The gearing after the TAV is 5.0 -1
I have heard that TAV's will hold down rpm's but this is unreal.
Its hard to believe that this TAV can hold this motor down the way it is , like having a governor kick in .
Does anyone have any suggestions as to why ?
 
Jamie1972

Jamie1972

Active Member
#2
#2
I dont know if this answers any of your questions?? But hear is what i did......

I did not like how "high" the Clutch would in gauge the belt on my Rupp Roadster 2 with factory secondary drive system (On the jackshaft) And I did not wanna get a wider belt cause that would change my ratio gearing on the jackshaft system. (I would loose low end) cause the belt would start 1/4" of the way into the seperated plates...Following me:wink:.......

ANYWAY!!!!.........I removed the outer cover part of the comet clutch (Where the mounting bolt go's through) and pushed the outer sheeve inward towards the factory belt.
Stopping it just before it would touch it. Took a sharpie and marked the sleeve the comet pully slides on drilled it and put a roll pin in! Now the sheeve stays close to the belt at idle and freewheels but comes in much quicker with out having to rev. the engine.
worked like a charm:thumbsup:
 
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Boostinjdm

Boostinjdm

New Member
#4
#4
David wulf said:
this is a motor the screams past 8000 with a kart clutch and 9.0 -1 gearing .

The gearing after the TAV is 5.0 -1
Click to expand...
That's your problem. You ran out of horsepower. The clutches are shifting out real fast and stuck with too much secondary gear. Add a tooth or two to your jackshaft sprocket and I bet things improve. Otherwise, you need a stiffer spring in the driven to keep it from shifting out so quick.
 
Boostinjdm

Boostinjdm

New Member
#7
#7
I'm assuming you are running a 6" driven.

The 30 series will go from 2.68 when first engaged to .90 when fully shifted.
So when it shifts out too early you are ending up with a total ratio of 4.5 to 1.
You need a stiffer spring in the driven to hold back the driver until you gain some ground speed. This will also apply more pressure to the belt.

That's my 2 cents. It's late and I may be off a bit...
 
David wulf

David wulf

#8
#8
george3 said:
:laugh::laugh::laugh: Told you so. What is your top speed now? What was your top speed before?
Click to expand...
Well you probably did tell the owner of said bike , i did also . Thats why we went with a chain drive .

Now we are here cause some in Cali have said you got to run a TAV .
Top speed you ask. with the first setup anything we wanted to gear it to it would pull .
With the TAV about 30 maybe .
 
bikesandcars

bikesandcars

New Member
#10
#10
David wulf said:
Yes they do , because if you have got any kind of power a TAV is useless .
Click to expand...
You are likely on the wrong side of your HP curve, but I have no idea of what your power curve looks like

think about it this way: If you are topped out with a max speed of 30 and you're running at 3000 RPM, but your engine has a max RPM of 9000, you have essentially established a gear ratio capable of 90 mph.

I would try a much smaller front sprocket or larger rear sprocket to try and get the power band of the engine matched with your intended speed.

TAV clutches with stock sprockets / gearing are made for GOVERNED vehicles turning 3600 rpm with top speeds around 30 mph.

If you have a worked engine that revs higher you need to alter the drive sprockets to use that rpm.

Note, changing the sprockets is essentially like changing the driven spring.

Changing the Drive clutch springs may help as well, but I don't have much experience fiddling with that.
 
125ccCrazy

125ccCrazy

Well-Known Member
#11
#11
like mentioned you need a lower gear ratio, once the clutch is in overdrive you have lost your pull.... a spacer on the driven between the sheeves to keep the sheeves from coming as close together hence keeping it out of overdrive will help... spacer thickness will have to be played with to get the desired set up..
 
paul_probus

paul_probus

Member
#12
#12
I would not use a spacer to keep the TAV out of overdrive. Allowing it to go into overdrive helps to spread out your gear ratio range, the fix is what everyone is saying, change the final drive ratio. That would allow you to get the full gear ratio range of the TAV and, when the optimum ratio is found for the top end, allow you to get the max speed out of the system that you can.

My $0.02.

Paul
 
125ccCrazy

125ccCrazy

Well-Known Member
#13
#13
paul_probus said:
I would not use a spacer to keep the TAV out of overdrive. Allowing it to go into overdrive helps to spread out your gear ratio range, the fix is what everyone is saying, change the final drive ratio. That would allow you to get the full gear ratio range of the TAV and, when the optimum ratio is found for the top end, allow you to get the max speed out of the system that you can.

My $0.02.

Paul
Click to expand...
depends if your dragging or riding
 
Newoldstock

Newoldstock

New Member
#16
#16
Works very well.
Its a yellow spring with a counter wound spring of my own making.
Also included is one white spring with one stock shortened spring in the driver.

Bikerscum used a green spring opened up to fit over the yellow with different weight and spring combo on the primary for a higher engage.
His engine turned faster, mine made a lot of torque.

Its all in the TAV mixed springs thread previously posted on page one of this thread tha no one appears to have read......
 
Newoldstock

Newoldstock

New Member
#17
#17
Much experimentation was done using OEM comet parts and weights



More than one clutch was modified....


And they were damn hard to assemble again with all the extra pressure too.
 
David wulf

David wulf

#18
#18
NOS thank you for the link and the info . You and bikerscum are a wealth of info on TAV's .
I want to try to mod the TAV but i'am thinking the owner doesn't want to and we may just go back to the original setup .NOS how do the belts hold up with your mods ?
 
Newoldstock

Newoldstock

New Member
#19
#19
Belts hold up well if you start with a quality belt.

I use good belts from Comet or .....
I can't think of the name but they are of the same manufacture.

PIX makes a belt that works but the kevlar belt they use causes driver wear and the compound is soft.
This means they wear funny.
Throw some power at it and they wear faster than they should.
How long a belt lasts is entirely up to you and how you drive.
You can make a belt last a good long time if you are careful to keep the slip to a minimum.
This means gentle careful application of power.
A 30 series belt will easily handle 12 hp without issue and more if you don't mind changing more often.

Conclusions about how these things work:
They are torque sensing not so much RPM opperated.
To increase the range and solve your troubles you need to tune it to handle extra torque and hold back the up shift.
Its not the RPM in this case, its the torque that you throw at it that causes the Secondary clutch to open.
The primary is trying to pull belt out of low range.
Its secondary presure that prevents it from shifting too early.
Primary weights and springs re more for adjusting engagement speed ( both do however have an effect on one another ).

first mod is always the comet yellow spring..

http://www.bmikarts.com/Comet-Yellow-Torsion-Spring-_p_1028.html
 
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