MM212 motor mount fail

[madprofessor]

The flex pipe for vibration isolation (Vibrasorber in my past refrigeration industry) is the perfect part for the job, locked down solid at the exit end, leaving entrance end free to move and/or vibrate. Wanted it for myself, but cost was too high for refrigeration grade 1.5", and found nothing decent in automotive parts. That's why the silencer in my pic is mounted solid, but the weight sits loosely supported in the oversized U-clamp with the (2) S.S. wool pads threaded onto it for cushioning.

 

[karl]

Yeah most the smaller ones are not braided. I would think
finding a replacement part for a utv or sled, ect would be more
cost effective than an off the shelf universal solution.

Now you can change the air filter without removing the motor!
Got it dirty, had lots of fun riding today! Headlights and tail goin,
found par36 LED replacement sealed beams for landscape use
that run 12v AC, and only use 6w each. Stuck them in rubber holders, Very bright!
More of a classic look, I did not want bright white led cubes on this bike.

 

[karl]

Well, riding at night, the side cover bolts backed off, and cracked the block around the locating pins.
Had no light , dark, and just rode it home thinking the belt started flying apart. Nope.

Replaced it with another brand new predator non-hemi, turns out the flywheel taper is slightly different
than honda/ true clone, and trashed the crank and charging flywheel I had after several hours of runtime.

So I gave up on the china junk, and hopefully this steel bore, bushing crank tecumseh flathead should treat me
right, 96w charge coil and added 12v starter. Had to put a 3/4 crank in so a tav2 will bolt on. Cleared the snow from my driveway for 2 years.

358cc , 11hp. Same bolt pattern as the 212's. Ported, eyebrows shaved, governor delete, improved rod oiling,
17.1 ft-lbs torque stock compared to the 8.1 ft-lbs of the predator 212. Should fit the coleman just right with
the motor mount spacer pulled from a 70's MTD snowblower with a h70 tecumseh.

Honda big block carb?

 

[madprofessor]

side cover bolts backed off, and cracked the block around the locating pins

I don't have enough bad experiences to tell me different, so just took my performance guy's recommendation that using a stud kit for the sidecovers instead of OEM bolts prevents them from backing off and having your bad experience. Took it a step further and double-nutted on the ones (that I didn't need to cut short) where a 2nd nut would bite on the stud.
Hopefully everyone understands that 2 nuts torqued opposite-rotation-together is an absolute guarantee that they'll never loosen up, but yet can still be easily removed later (ridged flange nuts don't do that as well either). No rating or type of Loc-Tite can both lock it that tight and be as easily broken free for removal later that way.

 

[karl]

Adding studs would be trying to solve the symptom, not the problem. When bolts start backing out,
the unit is trying to tell you something. I just did not get it right the first time.
Studs are not needed on a bone stock factory motor, and would have only prolonged the inevitable.

But now I do stud the head and side covers of motors I put billet rods and cams it, that are stressing
the block more than intended, meaning where studs are a good idea. Nr racing has a nice kit that
includes solid steel locating dowels. My local hardware store also stocks universal automotive studs ,
the right size for the side cover are like 79 cents each.

Professor, when are ya going to let your kart's engine breathe and upgrade the carb? The dinky factory carb
chokes the engine bad when you go above governed speeds.

Making the exhaust manifold is a challenge on these engines , same bolt spacing as a 5hp briggs, but 5/16 bolts.
I made it happens, fabed a manifold and got a big block honda clone carb mounted up. Should be a ripper, lots of power in a compact package.

 

[madprofessor]

Professor, when are ya going to let your kart's engine breathe and upgrade the carb?

Everything's been in a holding pattern for months, getting back on it as weather warms up, and when spine injections get finished.
Thing is, at last effort I was still trying to get a different gear ratio that was acceptable. Made it 9:1 before throwing a rocker shaft circlip (FYI, 7mm). All set to go again, but vascillating on the future of the 212. Seriously considering how to afford a 420 for SchizoBallz, and move that 212 heap of smoking demon jizz onto the next build, BareBallz. Pretty sure it's going to require wheelie bars. Guess I'll see how that carb acts then.

 

[karl]

I hear ya, trying to heat my uninsulated garage in 20 degree cold with a torpedo
heater that sucks down $5 a gallon diesel is not very sustainable.

Id fix ya up with a bit more displacement if ye were closer.

 

[madprofessor]

Displacement (torque) is indeed the problem for poor ole SchizoBallz. Long explanation for it, but it accidentally turned out to weigh about 520#, with 8' wheelbase, 9' overall, nearly 4' wide. Doesn't matter that my demon of a motor would make 15+hp. when rapped up to max rpm, with that weight it can never get the rpm up to where all that power is hiding.
More rpm = more hp. = more rpm = more hp. = more rpm = on and on and you can picture it.
Torpedo heater? I'm so jealous. This is sunny N.E. Florida, but we natives are freezing when folks North would be sweating here. We use the torpedoes here for when a shop's garage door is rolled open in the winter. I love those things (except the refueling part), but have never used a (#2) diesel type. Down here they're all run with (#1) kerosene. Which BTW costs more here than #2 diesel. All of the fuel oil furnaces here run on #2 diesel from big tanks around back or in the ground, while space heaters run the #1 kerosene from gravity feed tanks. (Retired HVACR expert who probably still reeks of fuel oil.)

 

[Budget GoKart]

talking about displacement i found out my local scrap yard sells "mower" engines go karts etc by the pound now ive got two kholer vtwins to play with

 

[karl]

This is sunny N.E. Florida, but we natives are freezing when folks North would be sweating here.

I see, we got a guy in at work new from Florida, he's wearing a winter coat at 50 degrees, as im in a tee shirt enjoying the weather,
around 75 I start melting.

My heater is dual fuel, it has an air pressure gauge and can adjust it for kerosene or diesel / fuel oil.

talking about displacement i found out my local scrap yard sells "mower" engines go karts etc by the pound now ive got two kholer vtwins to play with

Sweet, that opens up alot of opportunities on a budget. Keep us updated!

Made up a throttle cable bracket, The tecumseh fits perfect, just needs some new holes drilled in the motor mount.
Should be a torque monster.

 

[madprofessor]

Just want to point out for others' benefit the placement of the footpegs on that Coleman. The 2 major factors are there correctly: (1): The pegs are hinged to swing up out of the way when leaning too far into a turn or powerslide. (2): The pegs' hinges are at a 45-degree angle, so the forward motion of the minibike will just sweep the pegs back, instead of jamming them as though they weren't hinged at all.
I've seen countless numbers of minibikes that just have a welded bar for footpegs, or that have hinged ones that are mounted to swing straight upward but will act like a straight bar if they hit the ground. Anybody who's ever dug something into the ground by leaning hard into a turn can speak to the rear tire jumping up off the ground, which of course drops the rider and the bike to the ground at speed.

 

[karl]

Well, it absolutely rips. The 30 series seems to be taking the punishment just fine.
I think id put up a fight against my stage four 212, with dumb torque.

It's a pain to pull start tho, should have the battery, solenoid, ect fixed up soon to solve that.

One problem I had was crankcase blowby, id drip the valvoline VR1 sae30 all over the rear tire when hot,
so I made a catch can from what I had, an echo backpack blower fuel tank. It is thick enough plastic to drill
and tap for pipe thread, and happened to to fit perfect. Will almost fit the motor's whole oil capacity,
decccent.

Who needs oil changes , just open the valve on the blowby tank, drain that, top off the motor, carry on

 

[madprofessor]

Good eye on seeing that setup would fit and work, looks like it should have been built to go there.
Just curious: You ever been in the HVACR field? Those heavy panduit straps all over the new catch can and on the remoted fuel tank are kind of hard to find outside of supply houses of the industry, where they get used almost solely for securing flex duct to rigid collars. Either way, do you have a panduit gun to cinch them up and cut them off with, or did you have to do it the hard way? .............and without one of those guns, beware of the sharp vein-opening corners of the cut end. I recommend a hot soldering iron to vanish that possibility.

 

[karl]

Thanks, and nope never been. I had no idea that's what they were used for.

And I never know there was a tool! Totally picking one up! Much thanks!

Yes the hard way I have been doing it, trimmed with the pair of flush cuts so no
sharp edges. The iron is a fantastic idea as well!

I got a lifetime supply of them straps from lawnmower crates, they wrap em around
the axles to the crate for shipping. Each tractor has 4 that can be trimmed and reused,
that are expected to be thrown away.

Ill clip a handful from the new arrivals fresh off the semi, before they have been exposed to sunlight/ elements.