212cc Questions and info needed!

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runnermike

runnermike

Member
Nov 18, 2012
936
0
16
Sanford, FL
I figured I would post here since the 212 Predator IS a high performance engine.

I have built 2 custom 4 strokes and am ready to build myself a 212. I have a great frame to build off of, a dyno thanks to DMB! I am now welding a lot more at work and spending more time on the mill and lathe so fabricating parts is not an issue. I am not wanting to build a powerhouse monster, but would like to do some upgrades to the engine. So, my questions are as follows:

Definitely upgrade the flywheel, right?

For the intake manifold, will I need to fabricate one? Does AGK sell the flanges?

What size carb?

I am wanting to go with a jackshaft setup. What gear ratio do I run, what size rear sprocket with this engine?? I have only built 79cc's.

Are there any other upgrades you guys can think of without me really tearing the whole engine apart? Yes, I am removing the governor.

Thanks for reading my thread and for any input you guys have!

Mike
 
scotto-

scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
6,505
24
38
Ridin' inSane Diego, CA.
Yes Mike, a billet flywheel is in order.

A 22mm Mikuni is a nice carb for the 212 and relatively inexpensive. I've gotten the adapters from AGK in the past and they work great.

One other important upgrade is heavier valve springs.......18lb. are fine.

A good final ratio of 10:1 to 13:1 will suit the engine well with a jack shaft. I run a 48T on the rear wheel.

Have fun!

scotto-
 
ocho ninja

ocho ninja

Member
Jan 14, 2012
564
2
16
San Jose, CA
I'm in the process of building a 212 as well. I was reading up that changing the valves for oem Honda valves and milling the head or using a thinner head gasket helps bump up compression, better bottom end torque.
 
scotto-

scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
6,505
24
38
Ridin' inSane Diego, CA.
This is the head that I run on my race bike and it is a Honda 160cc milled down .050". The stainless steel valves are oversized but use the stock size valve seats ground to fit the larger valves. It is fully ported and has 1:1.3 billet steel rockers pushing 37lb. valve springs with lash caps on both valves.

I'm using a stock type head gasket that is .040" thick as the flat top Wiseco piston sticks out of the cylinder by .020". I use several shims to index the NGK iridium spark plug and keep the piston from making contact to the electrode.

Hope this helps....











when your head is milled down enough to where your compression is high enough to run VP 110 octane race fuel, there is no need to run thin copper head gaskets that are nearly impossible to get a good non leaking seal. The new thin steel gaskets (multi-layered and such) form a much better seal than the copper gaskets, just so ya know.

Billet lifters and hollow chromoly pushrods are also a good idea if you are gonna build your engine past 10hp.
 
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