Jack shaft vs torque converter

GoldenMotor.com

oldtimer54

Member
May 15, 2010
540
6
18
On a bike
Oldtimer said,
"By the way Iam using a jackshaft with my CVT so I can get a careful chain alignment to the rear sprocket and a power take off for a generator. Chain alignment is very important and kind of tricky."

I was thinking about running a generator or alternator off of the jackshaft and was wondering if you have pictures and commentary about what you did and how you did it. Thanks,
SB
I show how I did it in one of my build threads. Check it out and let me know what you need to know. Ill be glad to help if I can. Right now Iam rebuilding the bike from the hubs up. Just installed a disk break on the rear and now I have to build some way to reattach my rear rack as the break is in the way. Ill reinstall the electronics / battery in a trunk Ill attach to the rack.
 

oldtimer54

Member
May 15, 2010
540
6
18
On a bike
The chain alignment is going to be my main concern since that was the biggest problem on my last engine.
http://gokartsusa.com/Gokart_Torque_Converter_Compatible_.aspx
thats the cvt I'm thinking about getting
Is it possible to extend the shaft the second pulley sits on closer to the engine to accomplish that perfect chain alignment?
I don't think so? I had to mod the CVT back plate to fit the jackshaft I use for alignment closer to the engine. I cut out a part of the CVT back plate to let the alignment jackshaft's sprocket be driven by the CVT sprocket in the space I have in my bike frame. Take a look at my CVT build to see how I did it.
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
Fang,
That's a great price on the torque converter. Will that one work on the 212 Predator or does it need modification? I see with the TC2 that they have one especially for the 212... something being different about the engine casing.

Oldtimer,
Do you have a link to your build?
SB
 

Fang

New Member
May 4, 2013
90
0
0
35
San Diego
Fang,
That's a great price on the torque converter. Will that one work on the 212 Predator or does it need modification? I see with the TC2 that they have one especially for the 212... something being different about the engine casing.

SB
From what I've seen on youtube I think you have to just cut one or two fins off the inner side of the cvt plate to clear the engine.
There was one video where someone had to turn a few of the mounting holes on the cvt plate into slots to get them to line up with the holes on the engine

I've actually been looking up torque converter 3/4" on ebay and I've been finding em for as low as $120!
Only thing is although it's the same plate design from what I can tell some have engagement at 2350 and max out at 3100 rpm's...
Is that too low?
I'm not too sure what the usual range for idle rpm's on these engines are but 2350-3100 seems pretty limited especially since I made the rash decision to tear out my governor as soon as I got it laff
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
From what I've seen on youtube I think you have to just cut one or two fins off the inner side of the cvt plate to clear the engine.
There was one video where someone had to turn a few of the mounting holes on the cvt plate into slots to get them to line up with the holes on the engine

I've actually been looking up torque converter 3/4" on ebay and I've been finding em for as low as $120!
Only thing is although it's the same plate design from what I can tell some have engagement at 2350 and max out at 3100 rpm's...
Is that too low?
I'm not too sure what the usual range for idle rpm's on these engines are but 2350-3100 seems pretty limited especially since I made the rash decision to tear out my governor as soon as I got it laff
Been known to make rash decisions myself... went ahead and bought that torque converter. I guess we'll find out about the RPM's and idle, although you'll find out before me since my build is still a long ways off. I still have a few engine modifications to make... different carbureter, 18 lb springs and debating about the billet flywheel. I've been told that the torque converter will only wind the engine out to around 6,000RPMs where some of these hopped up 212s will go to 8,000. 6,000 seems like a lot to me.
SB
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
You mean something to worry about. Great. I have some thick aluminum plate. I wonder if I could make the plate. I don't weld aluminum, but I can drill holes. This is another one of those times that the less expensive is also cheaper.
SB
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
oldtimer,
That's a comfort to hear. I will I think keep an eye on mine half expecting trouble. That way if it does self destruct I may be able to catch it in time. And maybe there will be no trouble at all. Thanks!
SB
 

scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
6,505
24
38
Ridin' inSane Diego, CA.
You mean something to worry about. Great. I have some thick aluminum plate. I wonder if I could make the plate. I don't weld aluminum, but I can drill holes. This is another one of those times that the less expensive is also cheaper.
SB
Another note of interest....I snapped the GTC billet plate with a 212cc Pred running about 14hp at the time. Any aluminum plate of these thicknesses (1/4"-3/8") will snap eventually, cast or billet w/CVT on a 200cc.

I just fabbed one up out of steel and bolted the aluminum jack shaft support to it and it worked better than ever. An easy fix really.
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
Scotto,
With what modifications I have in mind I doubt that the hsp of my engine would exceed 10 hsp. I wonder if making up the steel additional plate would be a good precautionary move from the get go. Think so?
SB
 

scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
6,505
24
38
Ridin' inSane Diego, CA.
Scotto,
With what modifications I have in mind I doubt that the hsp of my engine would exceed 10 hsp. I wonder if making up the steel additional plate would be a good precautionary move from the get go. Think so?
SB
It certainly couldn't hurt, and it's easy enough to do with a piece of 3/16" steel plate.

You could also just make an additional aluminum back-up plate for stiffness and longevity. Jeff (ccc) made some real nice plates out of 1/4" aluminum doubled up for stiffness if I'm not mistaken......check his builds.

Here what the steel one I made looks like before the aluminum carrier is bolted on....





You will like the CVT i'm thinkin' silverbear.
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
Thanks, Scotto!
I feel better about my purchase and yes, I think I'm going to like the CVT. I'll figure out what to do once I have the converter in hand. Backing it up with the 1/4" aluminum plate I have would probably do it. It would be lighter and another thing I like is that I already have it. Ha!
 

Fang

New Member
May 4, 2013
90
0
0
35
San Diego
I still have a few engine modifications to make... different carbureter, 18 lb springs and debating about the billet flywheel. I've been told that the torque converter will only wind the engine out to around 6,000RPMs where some of these hopped up 212s will go to 8,000. 6,000 seems like a lot to me.
SB
Yeah I think I'm going to go with the 18lb springs also I'm just nervous about setting the valve leash since it's very new to me!
I've also heard about the cooling fan being a piece of junk since its plastic, someone online suggested cutting off every other fin to reduce drag but weakening a potential plastic bomb waiting to explode and ruin my engine doesn't seem like the best idea to me...
I'm thinking of maybe getting one of the metal fans I've seen online as well as the billet flywheel too.
And those rpm's do seem like quite a bit although I might need a good amount of power with the moped wheel's and frame modifications I'm trying to work out... and also since my doctor considers me morbidly obese hahaha
laff
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
It is the billet flywheel that is most worrisome to me. The engine self destructing is kind of bad, but another engine isn't all that much. However, explosions that send metal bits through me family jewels and less dear body parts is the stuff bad dreams are made of.

My torque converter just came via Fedex. Merry Christmas! Time to open it up... thank you Santa! (I have been a fairly good boy this year, not so much by choice as by lack of opportunity.)

My doctor would never say such thing to a bear. More like, "all set for winter, eh?" Hah!
SB
 

Fang

New Member
May 4, 2013
90
0
0
35
San Diego
It is the billet flywheel that is most worrisome to me. The engine self destructing is kind of bad, but another engine isn't all that much. However, explosions that send metal bits through me family jewels and less dear body parts is the stuff bad dreams are made of.
Yeah I'm trying to figure out what would be better, spending all that money on a flywheel or maybe just some sort of skid plate/shield for the ol family jewels haha

So I ended up getting the tav2 from ebay for about $109 shipped
They sent me one wrong bolt but I ended up getting it for free from a local bolt supplier
Looks solid so far!
I thought about mating the cvt shaft into a jack shaft set up but it seems the existing shaft wouldn't work since its too long and I don't want to cut into this nice plate it came with
So it appears I will be using a jack shaft AND a torque converter to re route the chain a bit
I plan on using a barrel style motorcycle oil tank with some strategically placed slots and holes for the chains to cover the whole jack shaft assembly