Modding Predator?

[Cyberninja]

What are the best ways to mod a Predator 212? I've heard that if you remove the governor you have to replace the flywheel and connecting rod and those are very expensive. So what are some cheaper ways to get more hp and speed? I have a header on but that's it for upgrades. Also, is it worth it to replace the carb with a mikuni clone?

 

[Cyberninja]

If I did decide to get a mikuni, would this be that right one?
VM 22 Mikuni Carbuetor Performance Kit (gopowersports.com)

 

[panchothedog]

replace the air cleaner with a low restriction piece, install a #37 jet in the carburetor because the engine will breath better, and put in some 18 lb.
valve springs to prevent valve float. If then you remove the govoner you will
pick up about 2 1/2 hp. A significant amount. You will also be playing with fire as far as keeping the engine together. If you keep it geared so it can't wind up too much ( 5200 to 5400 ) RPM it will probably survive. If it is geared real low
or a light load where it can really wind up you are going to blow it up. If it
throws the rod you will just ruin the engine, if the flywheel comes apart,
( explodes ) it could get ugly and dangerous. The parts I listed above are probably less then $50 for everything. The ARC rod and flywheel are expensive,
they are also VERY important of you want to build a hot - rod engine that you can have some confidence in.

 

[Cyberninja]

replace the air cleaner with a low restriction piece, install a #37 jet in the carburetor because the engine will breath better, and put in some 18 lb.
valve springs to prevent valve float. If then you remove the govoner you will
pick up about 2 1/2 hp. A significant amount. You will also be playing with fire as far as keeping the engine together. If you keep it geared so it can't wind up too much ( 5200 to 5400 ) RPM it will probably survive. If it is geared real low
or a light load where it can really wind up you are going to blow it up. If it
throws the rod you will just ruin the engine, if the flywheel comes apart,
( explodes ) it could get ugly and dangerous. The parts I listed above are probably less then $50 for everything. The ARC rod and flywheel are expensive,
they are also VERY important of you want to build a hot - rod engine that you can have some confidence in.

So if I gear it right I could safely run it without a governor? Not be dumb but how do I gear it

 

[Cyberninja]

Still not sure- is it worth it to remove the governor?

 

[jmaack]

I'd do a stage 1 and a torque converter. Leave gov intact. Very fun combo.

 

[panchothedog]

I see from another thread of yours you have a yerf dog kart and it looks like from the photo it has a torque converter transmission. That will keep the engine loaded and more than likely prevent it from over reving. If you want to go faster then you need to spin the engine faster. I have 4 karts, all of them are two seater with torque converter drives similar to yours. Two of them are yerf-dog
and on one of them I have a 196 cc clone engine with the stage one modifications ( pipe, intake, bigger jet and stiffer valve springs ) with the govoner removed and still running stock rod and flywheel. The kart runs real good and my grandkids drive the living crap out of it and it has held together.
your engine being 16cc bigger will have a little more power than mine but I
wouldn't think so much that it could over rev itself. Once the torque converter shifts into high gear it keeps the engine loaded pretty hard and they don't have the horse power to really wind up too hard.

 

[Dingocat]

I've got a predator with filter and exhaust and the throttle limiter screw backed out. That paired with a smaller 2 seat manco and a cvt is enough to spin the small tires.

I also have a gx160 that hasn't had a governer and has the filter and exhaust since I got it. It's been ran for 3 or 4 years and hasnt had any problems.

Really depends on what you want to do. I wouldn't advise heavier valve springs as they limit the rpm to a point where you don't have to worry about a conrod.

 

[Cyberninja]

I see from another thread of yours you have a yerf dog kart and it looks like from the photo it has a torque converter transmission. That will keep the engine loaded and more than likely prevent it from over reving. If you want to go faster then you need to spin the engine faster. I have 4 karts, all of them are two seater with torque converter drives similar to yours. Two of them are yerf-dog
and on one of them I have a 196 cc clone engine with the stage one modifications ( pipe, intake, bigger jet and stiffer valve springs ) with the govoner removed and still running stock rod and flywheel. The kart runs real good and my grandkids drive the living crap out of it and it has held together.
your engine being 16cc bigger will have a little more power than mine but I
wouldn't think so much that it could over rev itself. Once the torque converter shifts into high gear it keeps the engine loaded pretty hard and they don't have the horse power to really wind up too hard.

Sounds good I think I'll do that. Would 18 pound valve springs be the way to go? And as panchothedog said before, should I use #37 jet?

 

[Cyberninja]

Ok I see you said 18 pound valve springs. So if I bought this kit is that the right jet?

Stage 1 Performance Kit for 196cc/212cc Engines (STAGE1PK212-BLACK)

Introducing the Stage 1 Performance Kit, specially designed for 196cc and 212cc engines. This kit includes all the essential components to optimize the performance of your engine and take your ride to the next level. The kit contains an air filter, air filter adapter and air filter cover that...

www.gopowersports.com

 

[Denny]

Do not change valve springs unless you go billit rod and flywheel. You will aircondition the block. Others here have proven it many times.
The cheapest way to get a little more juice out of a Predator is to just remove the governor and a good Quality air filter. Then tinker with the jetting until the plug is nice and tan. After that it starts to cost real money.

 

[Denny]

It’s better to start off slow and change one thing at a time and sort it out. Than to change a bunch of stuff and have a bunch of stuff to try to figure out.

 

[madprofessor]

Start with the bigger performance air filter with the needed intake adapter to mount it. You've already got the header to more freely flow all that extra air intake. It's all a waste though without a bigger main jet, but also get the appropriately matched bigger low jet at the same time.
Removing the governor only helps where the engine is spinning up above 3600 rpm, no help below that. That's where the governor stops the engine from spinning up any faster for that extra speed, not much help with power. If governor's removed, the factory (10.8 lbs.?) valve springs will start to float around 5200 rpm, so it can't spin itself up any faster. 18 lb. springs will allow it to spin fast enough beyond that to explode the factory cast iron flywheel, the main reason for getting a billet flywheel that won't explode.
Ever seen from the old dragsters days where a flywheel had come through a car's firewall and maimed or killed the driver? Gokarts only use your seat coupled with your backside as a firewall.

 

[Cyberninja]

Start with the bigger performance air filter with the needed intake adapter to mount it. You've already got the header to more freely flow all that extra air intake. It's all a waste though without a bigger main jet, but also get the appropriately matched bigger low jet at the same time.
Removing the governor only helps where the engine is spinning up above 3600 rpm, no help below that. That's where the governor stops the engine from spinning up any faster for that extra speed, not much help with power. If governor's removed, the factory (10.8 lbs.?) valve springs will start to float around 5200 rpm, so it can't spin itself up any faster. 18 lb. springs will allow it to spin fast enough beyond that to explode the factory cast iron flywheel, the main reason for getting a billet flywheel that won't explode.
Ever seen from the old dragsters days where a flywheel had come through a car's firewall and maimed or killed the driver? Gokarts only use your seat coupled with your backside as a firewall.

Yeah, sounds good(or not). So that's a really bad idea to put heavier valve springs in and remove the governor. Sheesh! Thanks all for your help

 

[Denny]

Horse power goes up with rpm provided it has the intake air and fuel flow along with exhaust flow to support it.
Think of it this way. Torque=how much weight the crankshaft can turn. Horsepower=is how fast it can turn in a given amount of time. As told to me by a retired GM engineer I once knew.

 

[txluke]

Watch this video. I have done this exact thing to 6 or 7 engines and they all run fine.

 

[panchothedog]

txluke. Interesting video. That is a pretty hot set up for all stock internals.
but the proof is kinda in the pudding. I suppose the stock cam is the saving
Grace that keeps it from over reving. The karts looked fast and sounded great.

 

[ezcome-ezgo]

This forum has countless posts from folks who have changed everything at once, and then can't get the engine to start.

 

[madprofessor]

I've driven past that little racetrack no less than 200 times in my life, never knew they raced gokarts there. Mapquest says it's 31 miles from my shop. If my big monstrosity ever gets on a trailer, I know now where I can run it. If they let folks just run around doing testing, that is.

 

[panchothedog]

People who change everything at once and then can't g et the engine to run is because they screwed something up along the way. Of the 6 engines I have built over the past two years 4 of them came right out of the box and disassemble without ever being ran. I have never had one that wouldn't start.
pay attention to what you are doing, how things are orientated and even take notes of necessary. There is not one single thing that is not covered by some of the videos on Red Beards garage or the Grey Goat Garage and several others.
if you can't figure it out maybe you should consider oil painting or golf as a hobby. It just ain't that difficult. There are not that many parts to these things.