New here, first 212 build

HappyHeretic

New Member
Local time
3:48 AM
Joined
Jun 22, 2022
Messages
1
Hey guys, so i just posted my 'hi how are ya', which may have been long overdue... Im familiar enough with 2 stroke kits, but this is my first build from scratch, and my first 4 stroke...

This is a long post, so if youd prefer to skip the context, the TLDR is that im having trouble mounting a predator 212 to an aluminum gas tank frame in a way that is safe for the frame and rider. Vertical mount? Reasons not to? Solutions to how to nake horizontal mount work? Commercially available mounting kits specifically made for 212 bicycles? Improvised solutions that are tried and true?


Also, anyone who has an intimate familiarity with jackshafts, theres a question for you towards the end...


So heres where im at...

Predator 212
minus a governor and oil sensor.
on an aluminum gas tank frame,
vertical mount (im ALMOST sure)
bullet lines torque converter, looking at possible customized shaft for the output sprocket to mount behind the plate...
Magnesium wheels, road tread, canle disk brakes and 32 tooth sprocket

Pictures below...

So im stuck on the problem of mounting, and i might be overthinking it...

I went with vertical mount because horizontal had the engine floating all the way up, with a lot of empty space underneath, which i didnt want for center of gravity. Also, i physically couldn't fit it without the valve cover butting up against the tapped hole for the petcock and the spark plug wire pressing hard under the top... So vertical mount it fits great, although maybe too low for pedal crank. Thats a problem for later.

I have pretty much destroyed the original 4 stroke plate i bought by drilling different holes and cutting off the wings for space and whatnot, so if i need to buy a new one i will... What i have is an adjustable 212 plate, just the 3/8 aluminum top part with the slots. I have a few different kinds of mounts, kinda a brainstorming box... Rubber isolators, a bunch of the 2 stroke mounting blocks, modified to fit 5/16 bolts instead of 1/4, and one is filled in with JB WELD make it more stout, and plenty od the proper size c brackets for my seat tube...

And a cdhpower universal front mount, with the swivel head, although i am not sure exactly what i wound use to attach it to the engine... Maybe stabilizer links down to the fuel tank mounts on the engine, kinda like an aftermarket dynamic stabilizer kit for a harley,

And i have no solid idea as far as an upper mount, but im pretty sure i need one...

I need a voice of experience to let me know either if my mounting ideas are fine, or if there is a system i can buy somewhere just for this problem ... im REALLY stuck. I dont want to just mount it and then have the vibration wreck the frame.

Also as far as mounting goes, any thoughts on modifying the torque xonverter with a custom jackshaft to output behind the plate? I feel like if it can ve done, it makes mounting easier, as i wouldnt have to allign the engine with the rear sprocket, i could just make my jackshaft the appropriate length to allign. Also, bonus, if i can do it this way, i can equalize the engine for weight and clearance on both sides. Anyone experienced with having a jackshaft custom machined, or using a torque converter like this?

Ive read basically the whole Internet, and im at least vaguely familiar with most of the common issues that come to mind with rubber mounts and ungoverned engines and the aluminum frames, and all that... But i could REALLY use insight from people who have made the mistakes and found their way by touch, and so this is why im reaching out now... Please help, guys? Im eager to get this one back on trach and i feel like this issue has gad me at a standstill for so long and there are SO many other problems to ve solved further on...

Thanks for reading and sorry for the long post

P.S.
Ive considered buying a mig welder and tube bender, and will if i have to, but ive never welded and so its not ideal. Also considered brazing but i have no idea if it would produce a strong enough bond. Is it really the best way to go?
 

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DieselTech

Well-Known Member
Local time
4:48 AM
Joined
Sep 18, 2021
Messages
4,472
Hey guys, so i just posted my 'hi how are ya', which may have been long overdue... Im familiar enough with 2 stroke kits, but this is my first build from scratch, and my first 4 stroke...

This is a long post, so if youd prefer to skip the context, the TLDR is that im having trouble mounting a predator 212 to an aluminum gas tank frame in a way that is safe for the frame and rider. Vertical mount? Reasons not to? Solutions to how to nake horizontal mount work? Commercially available mounting kits specifically made for 212 bicycles? Improvised solutions that are tried and true?


Also, anyone who has an intimate familiarity with jackshafts, theres a question for you towards the end...


So heres where im at...

Predator 212
minus a governor and oil sensor.
on an aluminum gas tank frame,
vertical mount (im ALMOST sure)
bullet lines torque converter, looking at possible customized shaft for the output sprocket to mount behind the plate...
Magnesium wheels, road tread, canle disk brakes and 32 tooth sprocket

Pictures below...

So im stuck on the problem of mounting, and i might be overthinking it...

I went with vertical mount because horizontal had the engine floating all the way up, with a lot of empty space underneath, which i didnt want for center of gravity. Also, i physically couldn't fit it without the valve cover butting up against the tapped hole for the petcock and the spark plug wire pressing hard under the top... So vertical mount it fits great, although maybe too low for pedal crank. Thats a problem for later.

I have pretty much destroyed the original 4 stroke plate i bought by drilling different holes and cutting off the wings for space and whatnot, so if i need to buy a new one i will... What i have is an adjustable 212 plate, just the 3/8 aluminum top part with the slots. I have a few different kinds of mounts, kinda a brainstorming box... Rubber isolators, a bunch of the 2 stroke mounting blocks, modified to fit 5/16 bolts instead of 1/4, and one is filled in with JB WELD make it more stout, and plenty od the proper size c brackets for my seat tube...

And a cdhpower universal front mount, with the swivel head, although i am not sure exactly what i wound use to attach it to the engine... Maybe stabilizer links down to the fuel tank mounts on the engine, kinda like an aftermarket dynamic stabilizer kit for a harley,

And i have no solid idea as far as an upper mount, but im pretty sure i need one...

I need a voice of experience to let me know either if my mounting ideas are fine, or if there is a system i can buy somewhere just for this problem ... im REALLY stuck. I dont want to just mount it and then have the vibration wreck the frame.

Also as far as mounting goes, any thoughts on modifying the torque xonverter with a custom jackshaft to output behind the plate? I feel like if it can ve done, it makes mounting easier, as i wouldnt have to allign the engine with the rear sprocket, i could just make my jackshaft the appropriate length to allign. Also, bonus, if i can do it this way, i can equalize the engine for weight and clearance on both sides. Anyone experienced with having a jackshaft custom machined, or using a torque converter like this?

Ive read basically the whole Internet, and im at least vaguely familiar with most of the common issues that come to mind with rubber mounts and ungoverned engines and the aluminum frames, and all that... But i could REALLY use insight from people who have made the mistakes and found their way by touch, and so this is why im reaching out now... Please help, guys? Im eager to get this one back on trach and i feel like this issue has gad me at a standstill for so long and there are SO many other problems to ve solved further on...

Thanks for reading and sorry for the long post

P.S.
Ive considered buying a mig welder and tube bender, and will if i have to, but ive never welded and so its not ideal. Also considered brazing but i have no idea if it would produce a strong enough bond. Is it really the best way to go?
Check out my 50's rollfast build thread, but yes if you buy a longer driven pulley shaft, it gives you the possibility to mount your torque convertor sprocket on the outboard side of the torque convertor. A 10" long 5/8 keyed shaft should be long enough. I didnt even have to have anything machined it was a direct fit for my bravex torque convertor. I went belt drive to reduce vibrations & harmonics resonating thru the frame of the bike. & yes I've seen the 212 mounted upright but think you got to do some lubrication modifications to run the engine that way.
 
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