PMR Jackshaft kit for the Warrior

[noseoil]

I need to get working on the motor I built for the bike, but the TAV2 wasn't up to the job. I couldn't really do a proper job of tuning, since the TAV was limiting rpms too much & was not happy pushing it that hard. Above 4000 rpms, where it made the real power, wasn't too good for the TAV.

Was thinking about going back to the "factory" jackshaft setup, but after reading about them, I realized I would have too much trouble with bearings, the plate & other stuff. They just don't stand up to too much horsepower for very long. Spoke with Shaun at HotrodMinibike yesterday & decided to send for their upgraded kit for a warrior. Figured it was better in the long run to just get a good one. Shaun was a really good guy to deal with & his parts look very good, so I'm waiting to see what's in the box when it arrives.

PMR Jackshaft Kit Warrior/MB165/200

I've been looking at options for the bike & it came down to two basic choices, 1) weld on a stout jackshaft to the frame or 2) mount a better one on the motor. I wanted to keep the TAV2 for my mod 1 motor, since it runs so well & has been a very reliable setup for regular riding, so welding would limit the choices too much. The built motor is a beast, but it's a different animal & will need different gearing, tuning & setup.

Figured I can use the bike as a test-bed & for regular riding this way, so I'll post to the thread as work progresses. Just wanted to put something up as I recover from the flu (got the shot, didn't work too well this year, or maybe it did?). Will do pictures as I change things around on the bike & post some speeds as well.

Thinking I will build a "fast" warrior as I have a couple more now in the stable, which will need work to get running again. Found a pair of old ones to work with, so I should end up with my daily ride, a fast bike & another to sell. I think these things must attract others if they sit for a while....

 

[Raskin]

I'm thinking you just need lower gearing to use the tav..i went from 38t to 50t on my mb200-2 and my engine loves it on the top end ..I'm going to get a 52t to get a wee more scat on the flat trails i ride and put the 50t back on the ct200u w its 18" tires because I'm finally going to put a tav on it this winter .i just think a bit of lower gearing will help

 

[olddog]

I need to get working on the motor I built for the bike, but the TAV2 wasn't up to the job. I couldn't really do a proper job of tuning, since the TAV was limiting rpms too much & was not happy pushing it that hard. Above 4000 rpms, where it made the real power, wasn't too good for the TAV.

Was thinking about going back to the "factory" jackshaft setup, but after reading about them, I realized I would have too much trouble with bearings, the plate & other stuff. They just don't stand up to too much horsepower for very long. Spoke with Shaun at HotrodMinibike yesterday & decided to send for their upgraded kit for a warrior. Figured it was better in the long run to just get a good one. Shaun was a really good guy to deal with & his parts look very good, so I'm waiting to see what's in the box when it arrives.

PMR Jackshaft Kit Warrior/MB165/200

I've been looking at options for the bike & it came down to two basic choices, 1) weld on a stout jackshaft to the frame or 2) mount a better one on the motor. I wanted to keep the TAV2 for my mod 1 motor, since it runs so well & has been a very reliable setup for regular riding, so welding would limit the choices too much. The built motor is a beast, but it's a different animal & will need different gearing, tuning & setup.

Figured I can use the bike as a test-bed & for regular riding this way, so I'll post to the thread as work progresses. Just wanted to put something up as I recover from the flu (got the shot, didn't work too well this year, or maybe it did?). Will do pictures as I change things around on the bike & post some speeds as well.

Thinking I will build a "fast" warrior as I have a couple more now in the stable, which will need work to get running again. Found a pair of old ones to work with, so I should end up with my daily ride, a fast bike & another to sell. I think these things must attract others if they sit for a while....

I bought one of these a few years back for the Coleman after the original broke, it's a work of art and it fit like a glove. I think you'll be happy.

 

[noseoil]

Raskin, the problem I had with a TAV was the clutch couldn't hold up to the amount of torque the new motor produced. Best guess is that it's between 15 & 20 hp now, so I figured the TAV would be a problem sooner or later anyway, since it's designed to about 8 hp. That's why I decided to change the drive system completely.

Hopefully it will be the best of both worlds for both motors, an easy swap now between them. I can change drive ratios easily with the new jackshaft & not worry about shredding belts with too much hp on those small wear surfaces. Like I said, I'll report back once I get it & start work on things.

 

[Raskin]

Raskin, the problem I had with a TAV was the clutch couldn't hold up to the amount of torque the new motor produced. Best guess is that it's between 15 & 20 hp now, so I figured the TAV would be a problem sooner or later anyway, since it's designed to about 8 hp. That's why I decided to change the drive system completely.

Hopefully it will be the best of both worlds for both motors, an easy swap now between them. I can change drive ratios easily with the new jackshaft & not worry about shredding belts with too much hp on those small wear surfaces. Like I said, I'll report back once I get it & start work on things.

Ok..np i didn't know you were running that much hp..i do have a pmr js on another bike so yeah the pmr is a good unit

 

[cheezy1]

Had one on a Warrior for years now for racing circle track. Toss the TAV in the trash...once you go to PMR...you will never look back.

 

[noseoil]

Finally showed up (thanks USPS for the delivery, so much for fast shipping...) & getting it ready for the bike now. Hope to have it up & running later today. Still need to do a proper tune for the 24mm Mikuni, but I should have better rpms to work with, now that the Tav's not on the motor & holding things back.

 

[osu1978]

What clutch are you running with the PMR and 15-20 hp?

 

[delray]

noseoil, what kind of clutch is that your running. looks to be just a stock unit? if indeed you are running a 15 to 20 hp motor as you post earlier. you will need to install at least a 3000 stall spring. this will help the bike accelerate better off idle and for example slowing down and then accelerating out of a corner. the stock 2200 spring is like a brake on the engine and will not allow the engine to rev into the power band quickly. i am no expert on the stock clutch designs,but i wonder how well that will hold up?
i wish you all the luck when trying your new jackshaft out. i just don't want you and for anybody else that is putty a built engine on a minibike and then be disappointed in the performance.
did you get a tach for it?

 

[noseoil]

Thanks for the input guys. It's a stock (2200 rpm, max torque) clutch, so it's "soft" on the bottom end. It's just the kit clutch for now to see how I like it, but it's running well enough with it, at least once the r's come up a bit. It won't launch with this clutch, but for now I still need to break in the motor & get the tuning done. Not going to smoke this clutch, no reason to at this point. Seems to hold once r's are building, but don't really know.

Got it all in place this morning & have the tach to run with it installed & working. Warmed it up a bit & took it for a ride in the hood. Only ran up to 5200 rpm so far, but it's much nicer once it's hooked up & pulling. Ran out of street near the house so I had to shut it down, but it's a completely different feel with the jackshaft. Not a hard pull from the bottom, but it gets up to the top much better now & onto the cam.

Getting some vibration above 4500, but I guess it's normal with the reduced mass of the ARC flywheel & higher rpm range it's built for. Need to get more straight road to try it on, but it's getting to feel a bit spooky when it gets into the power band & just keeps pulling harder & harder. I need to dial in the 24mm Mikuni still (finally have the jet selection to work with), but so far I don't have enough road to go WOT for any length of time to find out where it is. I had drilled out the stock jet on a "best guess" so it wouldn't run too lean (#46, so about a 170 jet size, close to .080") since I was waiting for the jets to arrive when I first started it up. When I have more road, I can get it set up properly, but it's pulling well enough now with no flat spots yet.

Suggestions for a better clutch now? Is the Hilliard type a good choice & which one would be best for the bike (Blaze?), with 3000 rpm hookup or should it go higher? Don't want to start breaking things yet...

 

[Daniel Coop]

Noseoil, if your Max Torque clutch is in good shape, I would just buy the $8 "black" 3000 stall spring for it and run with it for a little. It'll take 15HP...IDK about 20. Shaun actually designed that jackshaft system to run with a Max Torque clutch. It's all he sells... I used an ARC Mongrel clutch when I ran one on "Po White Trash" which is basically a modified Max Torque with a Bully style driver and thicker drum. 4200 ARC's Mongrel Clutch - ARC Racing

 

[delray]

sounds like you are slowly going in the right direction...:thumbsup:
i think before you spend any big money on a clutch and you say the stock unit is working ok. maybe purchase the black spring for your max torque clutch. i see it is rated at 3100 rpm's(stall) and the price is not that expensive. also at the same time i would install a larger gear on your jackshaft. setup you have now will take some distance turns some good rpm's.
do both at the same time. i know the rule of thumb is to try one thing at a time,but these two things will work better together.
nice thing about the baja bike it's heavy in the nose. making it more easier to controll a hard acceleration at very low speeds and not lift the front end up to the point where it's uncontrollabe like most lighter bikes would be.
i think the hardest part for your setup would be trying to achieve the rpm the cam is made for? 8500
i know i sound like a boken record,but it's almost to much cam for that bike setup
if you get it to reach 7000+ i would be happen. you are probably talking about 45-50 mph on them little sealed bearings.
thats moving on a baja bike....:thumbsup:

 

[Havasu Dave]

i think the hardest part for your setup would be trying to achieve the rpm the cam is made for? 8500
i know i sound like a boken record,but it's almost to much cam for that bike setup if you get it to reach 7000+ i would be happen. you are probably taking about 45-50 mph on them little sealed bearings. thats moving on a baja bike....:thumbsup:

All good points, and not to single out this guy, but a common goal. I dig the sealed bearing comment. When you compare those to a set of Timken LM1910 tapered bearings, you can really see the difference. Dare I mention 340 set again?

This thread was the first time I have looked at those PMR units. They look really nice. In addition to the Max Torque clutch as supplied being inadequate for 15-20 HP, how much lateral load does the JS (driven end) hold up? I'm used to full length JS with bearings at each end which supports more load, being longer.

I'd use a much stouter clutch than what is offered, even if I was building a lower powered bike, just for the weight and wheel/tire OD alone.

Cool thread though, and hope the OP gets this thing running like he was aiming for.

 

[noseoil]

Thanks again Daniel, Delray & Dave for your input. I think I'll try the spring swap first, just to see how I like it; simple, cheap & quick fix to get a better launch & pull at a higher rpm from a standing stop. I have a 20t for the jackshaft as well, but I want to run with a higher top end for now. Too bad I can't get back up to the salt easily, that's still the best place for running fast I've found, just a bit messy cleaning up after the fun...


What I don't want to do is start breaking things with too much loading (I know, I know, what kind of attitude is that when trying to go fast?). The primary #35 chain is rated at about 2100#, but the 420 is half again that much (3100#), so the 35 will be the first one to break under a hard load & pull. If that happens, I can always go up a size to 420, but there's a bit more friction loss that way, so hopefully the 35 is good. That, or I can always get a short piece of Gold for the primary side if I need to (2300#) to help out a little. Might do that anyway at some point.

Dave, I did think long & hard about adding a full length jackshaft to the frame, as I had the same concerns about twisting under a load on a smaller shaft length & the narrow set of bearings the PMR comes with. I chose the PMR due to the ease of swapping motors back & forth as the compromise. There are no problems with this setup yet & since it's simple to just move motors onto the same frame, but I looked at a 3/4" jackshaft setup welded to the frame as one option that was certainly better in strength. I don't want to run two different bikes, which would be a better solution in general, but not as "practical" in some ways for me with storage being tight at the house. The TAV is fine with a mod 1 motor, the PMR seems good with a fully modded motor.

A digression about old age & minibikes: fixed income & I'm back at the chiropractor again for my back. The trip over Thanksgiving was upper back/lower back on the right side (heavy BBQ, lifting wrong I guess, bad mattress at my son's house afterward = a very sore back on the right side). Came back with the flu & coughing wasn't helpful at all at that point. Spills this year, the mud in August after the rains (right knee) & soft sand more recently (left knee), but it's mostly healed now. Pulling the rope yesterday wasn't fun, at least not yet. The motor seems to lurk & wait for an opportunity to kick once in a while, really painful when it does on my right side with the 11:1 piston, so I go back for another "adjustment" at the Marquis de Sade school of chiropractic care. Man, I love getting old like this, but I'm still working on things, so it's all good. Mini bikes are fun!

Here's my buddy George on his DB from this year on the salt.

 

[noseoil]

It's running better now. I was jetting way too rich with the motor initially, but with the TAV it couldn't pull enough rpm's to do a good tune. It just wouldn't let the motor build enough speed. The jets I sent for came after I'd pulled the motor to swap out the jackshaft, so I had to start over from scratch.

For anyone running a Mikuni VM22-133 (the real one, not the smaller Chinese copy), you might try a 170 main jet for a starting point, as this one seems to be pretty close now. I didn't bring a 160 to try yesterday (started with the 190 & dropped down), so it still needs to drop a size to see if this one (170) is really right. I really like the ability to change jetting so easily with this carb. Just pull a bolt at the base of the bowl, swap the main jet & go back to riding to check it. It's finally getting up to 7500 rpm now, which was my target with this setup. Gearing is 13t at the clutch & 18t for the jackshaft input, with 10t jackshaft output to a final drive of 50t at the 19" Kenda K572 rear tire.

I've ordered a length of the #35 gold chain & a 3100 (black) engagement spring for the clutch, which seems to be holding up well. Going to change out the sprocket on the jackshaft to a 20t, to lower the final ratio from the current number 6.9 to a 7.5 & use the gold chain. It should launch better but still have a top speed of 55 mph. This drops a bit on the top end, but should get up there quicker. I'm finding 60 to be a number I don't want to ride past now.



https://www.youtube.com/watch?v=ZD5CNIfi7vM

 

[The.MiniTard]

Good afternoon fellas, I see you guys have a decent conversation about a product that I may be looking into getting for my bike. Would it be ok if I kinda jumped in and asked some questions?

 

[noseoil]

No need to ask, just go for it!

 

[The.MiniTard]

How does the pmr jackshaft setup work when compared to a traditional setup that runs acroos the frame. Ive never seen a setup that keep the driveline on the same side.

 

[noseoil]

It's very similar to the factory setup on a Warrior type of bike (, Heat, Blaze, Carbon, etc.) which mounts to the motor instead of the frame. My concern was that the factory one, just heavy sheet metal which can deform, wouldn't hold up to the load from a modified motor. Since I have two similar motors, I can swap them easily this way without changing anything on the bike but the rear axle spacing & the throttle grip.

I'm going to build another Warrior to set up differently for the modded motor, but for now one bike will take both motors with only about an hour of work for the swap. The PMR jackshaft kit is a quality assembly which is simple to install & seems fairly rugged with the way it's made. For a Mod1 motor the TAV is great, but the higher hp motor was needing something different (clutch didn't like the rpm range), so that's why I changed it over.

 

[The.MiniTard]

It's very similar to the factory setup on a Warrior type of bike (, Heat, Blaze, Carbon, etc.) which mounts to the motor instead of the frame. My concern was that the factory one, just heavy sheet metal which can deform, wouldn't hold up to the load from a modified motor. Since I have two similar motors, I can swap them easily this way without changing anything on the bike but the rear axle spacing & the throttle grip.

I'm going to build another Warrior to set up differently for the modded motor, but for now one bike will take both motors with only about an hour of work for the swap. The PMR jackshaft kit is a quality assembly which is simple to install & seems fairly rugged with the way it's made. For a Mod1 motor the TAV is great, but the higher hp motor was needing something different (clutch didn't like the rpm range), so that's why I changed it over.

How does this jackshaft setup work on a non warrior type of bike?