EZ Q-Matic for 79cc Predator

What drivetrain would you use?

  • Use the jack shaft

    Votes: 3 33.3%

  • Use the EZ Q-Matic

    Votes: 3 33.3%

  • Comet tav2

    Votes: 3 33.3%
  • Total voters
    9
waynesdata

waynesdata

Active Member
Is the EZ Q-Matic for 79cc Predator any better than the jack shaft setup you see in the 79cc Predator kits? I found a video of a EZ Q-Matic and 79cc Predator on youtube. The video is very short and tells you very little.



 
I went to the EZ site and it’s a little confusing. I too am interested in this transmission for my 79cc Predator project. What needs to be ordered to make it work?
 
TXepikat said:
Does anyone make a CVT granny for the 79cc predator? Would that be a better choice?
Click to expand...

You can get a shaft adapter to increase the diameter from 5/8 up to 3/4. This will allow you to use the tav2 (torque converter) there's a little bit of work involved. There's also a couple guys who utilized the qmatic output gear to run on the tav2 in order to run the drive gear on the back side of the backing plate. The tav2 output gear is directly behind the driven pulley which means a far right offset on motor mounting to accommodate the drive gear location.

I personally like the gear reduction setup for the 79s. Ive done some gear changes for better accel and kept my top end within 2mph of where it initially was. You just gotta play around...my setup might not be right for your setup...

Mine goes 11t clutch to 24t, that 24 is backed by a 14t out to my wheel which is 58t on 16" moped wheels.
 

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I don't want to sound like a paid for political advertisement. The Q-Matic is a strong reliable bicycle engine transmission. The clutch is on the reduction side of the transmission so I think there is less wear on the engine's crankshaft bearings and maybe it spins up faster. I would upgrade the transmission's 2 inch cast aluminum engine crankshaft drive pulley to a steel pulley (at Tractor Supply) or a balanced cast iron pulley maybe at Grainger. You could call Quenton Gunther he used to always answer his phone. The Q-Matic is also made with commonly available parts.
 
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Wow! Be a lot of money for both, Q-Matic is nothing but a jack shaft with a clutch on it.( although a nice unit, love belt drive ), and the mounting plate right to the engine.. you sure don’t need 2 clutches, just my 2 cents............Curt
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Curt, there is more to a Q-matic. The crankshaft sheave is adjustable for torque. I bought one from Lynn but in the end, did not use it. $300 just resting on the bench.
 
Wickedest1 said:
You can get a shaft adapter to increase the diameter from 5/8 up to 3/4. This will allow you to use the tav2 (torque converter) there's a little bit of work involved. There's also a couple guys who utilized the qmatic output gear to run on the tav2 in order to run the drive gear on the back side of the backing plate. The tav2 output gear is directly behind the driven pulley which means a far right offset on motor mounting to accommodate the drive gear location.
Click to expand...

After reading your post I started looking on google. Found Comet tav2 torque converter kits.


I searched this site and google. Could not find an example of a qmatic and tav2 torque converter. What would the advantage be? Seems like the qmatic and tav2 setup could be thinner but I could not find anything.
 
A CVT is a power vampire at the start of drive train, but none the less it works well.

2_79cc2-DoneL-1280.jpg

2_79cc2-DoneR-1280.jpg


I fashioned the mount with new parts I had in the shop.
I could only get like 40mph out of it, my 48-53cc 4-stokers get that.
 
waynesdata said:
After reading your post I started looking on google. Found Comet tav2 torque converter kits.


I searched this site and google. Could not find an example of a qmatic and tav2 torque converter. What would the advantage be? Seems like the qmatic and tav2 setup could be thinner but I could not find anything.
Click to expand...
Comet is good, the ones sold in kits has a diecast back plate that the variable pitch sheaves are mounted to. It cracks and breaks at a knit line in the casting frequently. Got a buddy that can tell you all about it.
 
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Tom from Rubicon said:
Curt, there is more to a Q-matic. The crankshaft sheave is adjustable for torque. I bought one from Lynn but in the end, did not use it. $300 just resting on the bench.
Click to expand...
if you have paypal and are willing to ship it, ill help you recover at least some of that 300... lol


For any questions, and to even order for the best price, your best bet is to just call the creator, Quenton, at the phone number listed on the ezmotorbike website. i ordered mine from him a year and a half ago, and he was very friendly, knowledgeable, and helpful. His advice for me and my build, turned out to be 100% spot on.

remember, you get what you pay for. If you buy one of these, you will never have to worry about a transmission problem again
 
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iHaveAdog said:
if you have paypal and are willing to ship it, ill help you recover at least some of that 300... lol


For any questions, and to even order for the best price, your best bet is to just call the creator, Quenton, at the phone number listed on the ezmotorbike website. i ordered mine from him a year and a half ago, and he was very friendly, knowledgeable, and helpful. His advice for me and my build, turned out to be 100% spot on.

remember, you get what you pay for. If you buy one of these, you will never have to worry about a transmission problem again
Click to expand...
iHaveAdog, Thanks for the offer, but it is paid for.. Heavy as a Q-matic is it should be quiet. Quenton was making adaptors for 49cc Huasheng engines that my Huffy-Davidson is powered with. I will have to browse his site again
 
Tom from Rubicon said:
Quenton was making adaptors for 49cc Huasheng engines that my Huffy-Davidson is powered with. I will have to browse his site again
Click to expand...
I am supersized an HS 49cc can make a Q-matic CVT even work they use so much extra power just to function.
Not that big of a deal with big engines, but if you are trying to stay as legal a possible with a ~50cc 4 stroke yet still be able to climb hills and haul ass, put your CVT on your back wheel like this ;-}

2_Copper10GDoneRightDrive-.jpg.FP


That has a NuVinci 360 CVT rear hub.
Note the Axle Tug on the rear wheel, that is an HS 144F-1G 53cc and 10G 5-1 reduction, the rear wheel wants to move forward where the power is and a tug stops that.
You will most likely need an axle tug for your build as well with your engine power.

Let me E with Don Grube about adding the bolt holes in this version of of the 4G.
http://grubeeinc.com/4G Model PARTS 2.html
That would be cool for any Predictor owner ;-}
 
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I have given the 4G some serious consideration and may in the end go there on my Huasheng. But the Q-matic is way more robust in every way. The V-belt may induce drag but hugely strong. Favoring the 79cc and 212cc Predators. KC is our leader in the use of the NuVinci variable speed drive they are spendy. That KC used them on his builds aces my concerns about reliability in tolerating the power pulses of an engine.
 
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