So I bought a new predator engine recently, and have seen stuff all over the web about increasing their power and rpm and such, and was wondering what the safest max rpm these engines can handle? Over the this last winter, I had a snowblower that I was messing with (much smaller engine and 2 stroke), and it didn't seem to have enough rpm, so I messed (with what I now know was the governer) and after a few mins of high rpm, the backhalf of the connecting rod blew out the crankcase.. Obviously I don't want this to happen again.. So again, what can these engines SAFELY run at, and when they return to that rpm, will they stay there and not go dangerous high?
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Predator 212 CC
- Thread starter mgilker
- Start date
CoastalComputerPros
New member
it will be fine to take the governor out and run the stock flywheel. Just keep it under 5800 rpm and you will be fine!!! I did this to get seat time before I went to a clone. Ran 5-6 nights with no problem. Just be VERY carefully because when you take the governor out there is nothing to stop it from over revving.
CoastalComputerPros
New member
If you want cheap power put fuel pump and tank, air filter adapter and racing air filter, big pip, and jet the crab. 24 low speed jet and 56 main jet is a good place to start. may have to go up or down on jets. Run motor at about 400f degrees. ACR racing is a good place to get this stuff from.
If you want cheap power put fuel pump and tank, air filter adapter and racing air filter, big pip, and jet the crab. 24 low speed jet and 56 main jet is a good place to start. may have to go up or down on jets. Run motor at about 400f degrees. ACR racing is a good place to get this stuff from.
The jetting suggested here is for alky, your engine wont run using those jet sizes with gas for fuel
The jetting suggested here is for alky, your engine wont run using those jet sizes with gas for fuel
What kind of fuel is that? Iv seen that around here but don't know what it is... Also, another question.. Anyway to (relatively easily) hook up or build a charging system for this motor to charge a battery? Can it be charged using the coil already on it?
CoastalComputerPros
New member
The jetting suggested here is for alky, your engine wont run using those jet sizes with gas for fuel
my bad 36, not 56. haha do they even make them that big!!!
What kind of fuel is that? Iv seen that around here but don't know what it is... Also, another question.. Anyway to (relatively easily) hook up or build a charging system for this motor to charge a battery? Can it be charged using the coil already on it?
I dont think you can hook it up to where the coil will charge a battery or not, but you can get a charging coil to replace the stock one with and that would allow you to run lights or something like that, which is what some minibike guys i know have done in the past. I think charging coil is what those coils are called
Alky is Methanol, racing fuel. You can order it from VP Fuels online, some parts sellers at the track also carry methanol. Id stick with gas if your engine is mostly stock besides exhaust and air filter
backyardhack
New member
The stock valve springs will limit maximum RPM to low to mid 5,000. There are many people using these in mostly stock form, no governor, with stock flywheel with no problems. Adding racing valve springs will allow the engine to turn more RPM and things will start to fail. Top plate and fuel pump do not make hp. The gas tanks on the predator 212 motors are much better that the old Harbor freight motors that would crack and break loose. I would add an aftermarket air filter (must re-jet carb)and advance the timing 8 degrees
Bone Stock
Member
Ok, thanks for all the input. But how do I keep it under 5600? Rpm gauge? As far as people around me, don't have to worry about that as I'm not racing or anything, building an off-road go cart actually.
I also built my engine for offroad use and not racing. I learned a lot and continue to learn a lot from this experience. It is important to understand that there is difference between an engine built for offroad use and an engine built for race track use. Just like a car built for racing or street use. Your engine needs to be "streetable" in order for you to get the power you are looking for. Three things that I have learned about that have made the biggest difference between racing engines and offroad engines like ours.
1. Camshaft
2. Timing
3. Jetting
In racing the engine is running at wide open throttle around a track most of the time. The racing engine needs high lift camshafts with more duration in order to make max power and turn high RPMs (over 6000). The timing needs to be advanced 8 plus degrees in order for the engine to operate more efficiently at high RPM and the jetting needs to be big enough both low and high in order to richen the air fuel ratio enough that the engine will be able to start and flow enough fuel at higher RPMs. This is why racers will recommend buying an 8 degree timing key and jetting your carberator .024 plus (pilot) and .036 plus (main) I have done this and it is not the best set up for an off road kart.
Offroad engines need to make power at low and mid range range RPMs (2000 - 5000). The stock cam was designed for this. The stock timing was also designed for this. I have just recently took the 8 degree timing key out of my engine and put a 4 degree key in and it made a huge difference in torque and power! I am considering testing the stock timing key to see if I will get even more low end and mid range power. Jetting is also different for offroad set ups. After a lot of research followed by trial and error I found that with a performance air filter, header exhaust, stock cam and stock timing (also timing 4 degree advanced and 8 degrees advanced) that .020 (pilot) and .035 (main) is just right. The plugs will not foul, it will start and idle fine, be responsive and make plenty of power. There are a lot of performance parts that are designed for racing that are not worth purchasing for an offroad kart set up because they will not provide any performance gains in the offroad engine's operating range. They may even take power away from where you need it and shift it to a higher RPM range. I would recommend sticking with you stock cam, stock timing and purchase 18 lb valve springs, a high flow air filter, a header exhaust, GX140 E-tube, .020 pilot jet and a .035 main jet. This set up will give you about 10 HP and will make power in the low to mid range (where you need it).
Another thing to consider with an offroad kart is the gearing and your clutch/torque converter set up.
I also built my engine for offroad use and not racing. I learned a lot and continue to learn a lot from this experience. It is important to understand that there is difference between an engine built for offroad use and an engine built for race track use. Just like a car built for racing or street use. Your engine needs to be "streetable" in order for you to get the power you are looking for. Three things that I have learned about that have made the biggest difference between racing engines and offroad engines like ours.
1. Camshaft
2. Timing
3. Jetting
In racing the engine is running at wide open throttle around a track most of the time. The racing engine needs high lift camshafts with more duration in order to make max power and turn high RPMs (over 6000). The timing needs to be advanced 8 plus degrees in order for the engine to operate more efficiently at high RPM and the jetting needs to be big enough both low and high in order to richen the air fuel ratio enough that the engine will be able to start and flow enough fuel at higher RPMs. This is why racers will recommend buying an 8 degree timing key and jetting your carberator .024 plus (pilot) and .036 plus (main) I have done this and it is not the best set up for an off road kart.
Offroad engines need to make power at low and mid range range RPMs (2000 - 5000). The stock cam was designed for this. The stock timing was also designed for this. I have just recently took the 8 degree timing key out of my engine and put a 4 degree key in and it made a huge difference in torque and power! I am considering testing the stock timing key to see if I will get even more low end and mid range power. Jetting is also different for offroad set ups. After a lot of research followed by trial and error I found that with a performance air filter, header exhaust, stock cam and stock timing (also timing 4 degree advanced and 8 degrees advanced) that .020 (pilot) and .035 (main) is just right. The plugs will not foul, it will start and idle fine, be responsive and make plenty of power. There are a lot of performance parts that are designed for racing that are not worth purchasing for an offroad kart set up because they will not provide any performance gains in the offroad engine's operating range. They may even take power away from where you need it and shift it to a higher RPM range. I would recommend sticking with you stock cam, stock timing and purchase 18 lb valve springs, a high flow air filter, a header exhaust, GX140 E-tube, .020 pilot jet and a .035 main jet. This set up will give you about 10 HP and will make power in the low to mid range (where you need it).
Another thing to consider with an offroad kart is the gearing and your clutch/torque converter set up.
Very helpful, yeah I'll keep that in mind. Getting 10 hp (about a 4 hp gain over stock) would be nice. Eventually though, I'm planning on going to a performance cam, lifter, springs, piston, all that to make about 20-22 hp, seen a kit online that can do that. I'm making a fairly large 2-seater, and not only do I want the extra power, I think I'll need it!