Will this work for a Hemi 212?

Jerryburger

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Hi guys. So this is a, "This is what I'm going to try, any caution flags to watch out for?" thread.

I have a brand-new, still in the box Hemi 212. I plan on mounting it vertical for bicycle use, and to do so, I am:

1.) Grinding off the stock slinger and bolting on a Briggs Slinger that angles down into the "new" sump area and should be very close to the weight of the old slinger. This is to maintain the splash lubrication in it's new position.

2.) Removing governor innards- not because I'm seeking higher RPM, but because I'm...

3.) Mounting a PZ22 22mm knock off carb (because of the engine's new orientation. Is the PZ22 close-enough to the right size if I plan on keeping the RPM below 4500?

4,) Mounting a U-weld it header and exhaust (again, for orientation purposes.)

...as you can see, the engine isn't being modded for more performance, (a stock 212 is feisty enough for a bicycle!), but as a necessity of it's new mounting position. I know the mods will result in an almost "Stage 1 upgrade".

The only variable I'm worried about is the carb. Have I over-carbed it with the 22?
This is a (very rough) idea of what I'm doing to the poor thing. It'll have a DeathRow TAV2 with 10<60 final chain and 26" wheels. Thank you for your time.
HardRockMOD212.png
 

madprofessor

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Mikuni VM22 carbs are very common upgrades for the Predator 212cc. Just need to match your main and low jets to it for your application. A large hi-flow air filter is recommended for any carb upgrade, although there's lots of the little filters out there that folks stick on them. The adapter for the filter-to-carb connection should definitely be of the engineered venturi type as opposed to just the flat slab of metal with a hole through it.
 

karl

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The adapter for the filter-to-carb connection should definitely be of the engineered venturi type as opposed to just the flat slab of metal with a hole through it.
Im no rocket surgeon, but isnt the Venturi in the carburetor? Do you have an example of such manifold for a GX type engine?

Why would you want a Venturi in the intake manifold?

I thought the length of the runner had more of an impact, like the tuned ram air setups.


The only variable I'm worried about is the carb. Have I over-carbed it with the 22?

A tad bit large for the application. Id go for 18-20, but if you already have it might as well run it.

I assume your fabbing the intake manifold?
 

madprofessor

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The venturi I referred to is simply the hi-flow air filter's adapter to connect the wide filter throat to the carburetor. Same screws that go through the carb to hold it on also go through the adapter first to hold it onto the carb.
Go to ebay, type "Predator air filter" in the search bar, you'll see tons of them. Air filters both with and without the adapters.
The wrong adapters are solid, flat, billet pieces with a big hole drilled through them. The right ones are solid, flat on one side only, billet pieces that have a much wider, curved (venturi) opening on the inlet side of the hole that's been engineered eons ago to be the right shape for enhancing the draft of air funneling into the carb.
Note: Some adapters sold have a conical opening on the inlet side alright, but shaped like the inside of an ice cream waffle cone, an angled reducer only that ain't nuttin'. The ones that work have a graceful curved sweep shape as the reducer.
 
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karl

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The venturi I referred to is simply the hi-flow air filter's adapter to connect the wide filter throat to the carburetor.
Oh, thats why I got confused. He does not need an adapter. That is only if you are using the factory carb.

The clamp on filter just slips on, the Venturi is in the carb.

Yes those adapters are better but irrelevant for the OP.
 

OPmini

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I think it would be better if you get a cheap motorized bike conversion kit... not saying that your idea cant be done, just saying if the point isnt to go fast you might save yourself some engineering headache by getting a kit. Plenty of cool stuff you can do to those little 50cc engines, just look at the pocket bike community lol!
 

mindymogul

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I think it would be better if you get a cheap motorized bike conversion kit... not saying that your idea cant be done, just saying if the point isnt to go fast you might save yourself some engineering headache by getting a kit. Plenty of cool stuff you can do to those little 50cc engines, just look at the pocket bike community lol!
Sometimes speed isn't the issue. Where I use to.live when I was little (LOOOOOONG before the law was run by Karens) it was 15% grades both directions so I went fancy and went HUGE driven sprocket, tiny driver sprocket and I used a chainsaw engine. It was just to provide enough torque to assist gears 1-6. They also have old school motorized bicycles (Look at Mustie1 on the ol LubeTube) that used verticle shaft hit and miss engines with cowhide leather belts as the drive.
 
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