212cc predator need suggestions!

S

SouthernLand

New Member
#1
#1
How’s it going everyone! First post here although over many years I have looked to this forum for advise as I used to ride mini bikes,

Wasn’t sure on where to post but I think you group may help me the most. This motor is on a backwater mud motor kit instead of a Minibike frame, so turning a shaft with prop instead of a chain and sprocket.

This mud motor frame is on a very very light 10ft aluminum boat, I am wanting to upgrade the motor more but would like some mechanical minds assistance, I have the stock carb with a bigger jet, and header with a open styled muffler made onto it. The issue is I think I am hitting governor limit because I’m able to get to 9mph fast but doesn’t go a bit faster, so I plan to remove the governor and while I have the motor apart replace some internals... I know the billet flywheel is a must as well as the connecting rod, but which cam would best suit me as I have no class restriction lol, lookin at the 265 lift? Also I would get any springs needed for cam. Can I leave the rest of valve train beside springs stock? This is a motor that will run WOT for long periods traveling on the water. I want speed strength and reliability. Also I am going to upgrade to the 8mm msd coil.

Also! Are genuine mikunis a thing anymore??can not find a single new or used
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ole4

ole4

#2
#2
there are a lot of 265 grinds which one are you looking at? Rod and flywheel plus governor delete plus 18lb springs will help a lot Even with stock cam. Once you make it rev too high then your reliability goes away. Boats are tough on these engines. Search the forums for a gent BWL who tried modding one and it constantly blew up. I think he finally got a big block.
 
ole4

ole4

#4
#4
one of his.
That's exactly why I recommend leaving the governor in a mud motor. This was a contributing factor why both my motors blew, especially skipping across lily pads and dense weeds. People simply don't understand the harshness of the marine environment. As you've learned you can easily go from 3,000 to 7,000+ RPM in less than a second, several times a minute for as long as you're running, depending on the environment. Even choppy conditions on open water can make for the same situation.

The last thing mud motor builders should do is remove the governor. If you need more power than that, you need a bigger motor. Mud motor building is about building a more efficient engine, not more powerful.

Below 6,000 RPM you're best off with a governed engine with the throttle screw adjusted to keep your motor less than your desired RPM. I've learned that building mud motors is not like mini bikes and go karts. It isn't a toy. It is a wilderness machine designed to get you in, out and back alive. Yet the first thing people do is remove the most important safety feature on their engine: the governor. This is one item that isn't worth removing on mud motors used for serious work.

I realize this doesn't answer the basic question, but the larger issue is how to build a mud motor. The other issue, is you have and ungoverned engine, yet you'r basically asking how to regovern the engine, electronically instead of mechanically, but the solution is to govern the engine. Just buy a second governed engine, and put all your good parts on a governed engine. The adjust the governor

I don't have any experience with PVL ignition and such, so I can't answer that. I just don;t want anyone to ruin their motor because they applied go kart and mini bike knowledge that really isn't suitable for the mud motor environment.

I keep my motor set to 5,000 RPM or less. I run a billet ARC flywheel as well. Champ motor has the good valve train. I run a bone-stock cam as well for better low speed idling as I run catfish jugs. Trappers and the like are better off with stock cams for the same reasons.
 
delray

delray

Well-Known Member
#9
#9
stock engine with a good valve train(retainers and springs) billet rod and a arc tall fin flywheel(heavier) or you could call it there standard billet flywheel. because they do build a short fin flywheel now. stock carb re-jetted/good header with governor set high at 5000+ if can be done. should keep the motor from going to the moon.
if you really want to go with governor delete and a mikuni carb. then maybe run a briggs pvl ignition( 6100 RPM Rev Limiter) and a CL1 dyno cam. this way if your motor is pulling 4000+ rpm's in the water and gets bumped out for a second or too 6100 won't kill it at all and you know this will happen more then once.
now if you haven't purchase your 212 yet? go right a 225 tilly and take advantage of the stroker crank/bore and the stronger block design and a EC billet side cover. it should be a real torque monster in the water.
 
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