I have a predator 212 on my mini bike whose governor has been removed. I know it is more of a "use at your own risk" kind of thing but I was wondering how much throttle I can give it before it blows or something goes haywire inside. I don't have a tachometer on it but I know that on 99% of my rides I am not going much over the 3600 rpm that the governor tries to maintain the engine at. So if I give it full throttle for say 10 seconds or so, how good is the chance that it'll get ruined? I have never used it to its full speed potential.
removed governor question
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karl
Well-known member
I use this guide
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J.S.@SMS
Road Hazard
If it has the stock 10.8 lb valve springs it shouldn't blow up. This is because the valve springs are weak enough to allow the valves to float (causing a loss in compression) effectively limiting the engine to 5200-5400 rpm, whereas the rod will usually reach its breaking point resulting in positive crankcase ventilation (a hole in the block) around 6000 rpm. So you should be fine.
I have personally held my un-governed 196 clone engine at valve float at full throttle for about 5 seconds, and it hasn't blown up yet.
I have personally held my un-governed 196 clone engine at valve float at full throttle for about 5 seconds, and it hasn't blown up yet.
tgus3
a member
I wouldn't keep it at full throttle for more than 5 secs with gov removed. I ran mine for minutes on end at full throttle and the results weren't that good
KartFab
Active member
there are no guarantees in life. through my little bit of research i have come to the following conclusions:
1) once you remove the governor all bets are off
2) there is no time or rpm limit on when or if a failure will occur
3) some "stock" go kart classes run their karts with "stage 1 mods" with no issues, chainging the rod out every 2-3 races.
4) if you do not check clearances, and hone the rod, you may cause the rod to seize and break due to oil starvation from the lack of lubrication at high rpm.
5) if you rev too high, the magnet (which is held on by a screw and some glue) can fly off and cause the magneto to break off and/or flywheel failure
6) anybody who says it is "safe" to run without a billet flywheel and rod after governor removal because of "insert anecdotal personal experience here" is a person that is ok with exposing themselves to a liability. The liability is your health and safety. Not many people are going to come out and say its safe or not safe at a given rpm because there is no clear consensus on what is or is not safe because sometimes thigns break and sometimes they dont. Asking for a finite answer is not going to get you anywhere. Nobody wants to say you should go ahead and send it, only for you to actually send it and the next thing you know you have a piece of aluminum or steel shrapnel hitting you in the shoulder, or leg, or worse. Is the risk of permanent serious injury really worth the cost of a safe flywheel or safe connecting rod? Im sounding old, but the more and more I see and learn about this, the more inclined i am to put a billet rod on there at a minimum, and a billet flywheel on there with any serious modifications. It only takes once to screw your whole life up and hindsight is always 20/20, shoulda woulda coulda.... they come pouring in after the fact.
Onto the gray area
If you didnt remove the governor, but backed out the throttle stop, you could actually rev to 4300ish rpm on a non hemi and 5200 ish rpm on the hemi. I have found this out experimentally.
Now I personally have ran engines without billet but only under load. If you "free rev" the engine, it floats the valves much faster. When you are floating the valves hard, the valves actually can bounce off of the seat and this causes, at best, premature wear on the valvetrain and can mushroom/distort the valve and seat, which causes loss in compression and power.
If you put in heavier valve springs, oil clearance becomes even more important. Any reputable engine builder will check oil clearance on the crank journal and hone the rod. The hone and measuring tools used to do this cost more than a $60 billet rod and some plastigauge....
If you advance the timing, by putting in one of those advance keys, you will have to torque the flywheel back to spec. If you undertorque it, the flywheel will spin on the crank, if you overtorque it (e.g. impact it on there), the flywheel may in fact shatter prematurely due to internal stresses and possible cracks. You must use a torque wrench and torque to spec.
If you put in a nice cam, you will get into the danger zone very quickly, and the more rotating inertia an engine has, the bigger the failure will become.
How much would a hospital bill cost? I can gurantee that it will cost more than the $160 it will take to prevent your engine from grenading at high rpm. What kind of loss are you prepared to take on because you wanted to save a buck? This isn't some fairy tale or myth. Once you are in the grey area, you really are gambling with your health and life at that point.
1) once you remove the governor all bets are off
2) there is no time or rpm limit on when or if a failure will occur
3) some "stock" go kart classes run their karts with "stage 1 mods" with no issues, chainging the rod out every 2-3 races.
4) if you do not check clearances, and hone the rod, you may cause the rod to seize and break due to oil starvation from the lack of lubrication at high rpm.
5) if you rev too high, the magnet (which is held on by a screw and some glue) can fly off and cause the magneto to break off and/or flywheel failure
6) anybody who says it is "safe" to run without a billet flywheel and rod after governor removal because of "insert anecdotal personal experience here" is a person that is ok with exposing themselves to a liability. The liability is your health and safety. Not many people are going to come out and say its safe or not safe at a given rpm because there is no clear consensus on what is or is not safe because sometimes thigns break and sometimes they dont. Asking for a finite answer is not going to get you anywhere. Nobody wants to say you should go ahead and send it, only for you to actually send it and the next thing you know you have a piece of aluminum or steel shrapnel hitting you in the shoulder, or leg, or worse. Is the risk of permanent serious injury really worth the cost of a safe flywheel or safe connecting rod? Im sounding old, but the more and more I see and learn about this, the more inclined i am to put a billet rod on there at a minimum, and a billet flywheel on there with any serious modifications. It only takes once to screw your whole life up and hindsight is always 20/20, shoulda woulda coulda.... they come pouring in after the fact.
Onto the gray area
If you didnt remove the governor, but backed out the throttle stop, you could actually rev to 4300ish rpm on a non hemi and 5200 ish rpm on the hemi. I have found this out experimentally.
Now I personally have ran engines without billet but only under load. If you "free rev" the engine, it floats the valves much faster. When you are floating the valves hard, the valves actually can bounce off of the seat and this causes, at best, premature wear on the valvetrain and can mushroom/distort the valve and seat, which causes loss in compression and power.
If you put in heavier valve springs, oil clearance becomes even more important. Any reputable engine builder will check oil clearance on the crank journal and hone the rod. The hone and measuring tools used to do this cost more than a $60 billet rod and some plastigauge....
If you advance the timing, by putting in one of those advance keys, you will have to torque the flywheel back to spec. If you undertorque it, the flywheel will spin on the crank, if you overtorque it (e.g. impact it on there), the flywheel may in fact shatter prematurely due to internal stresses and possible cracks. You must use a torque wrench and torque to spec.
If you put in a nice cam, you will get into the danger zone very quickly, and the more rotating inertia an engine has, the bigger the failure will become.
How much would a hospital bill cost? I can gurantee that it will cost more than the $160 it will take to prevent your engine from grenading at high rpm. What kind of loss are you prepared to take on because you wanted to save a buck? This isn't some fairy tale or myth. Once you are in the grey area, you really are gambling with your health and life at that point.
Tpdingo
Member
Thats basically the same thing as removing the governor. No guarantees. It was a motor rated at 3600 RPM and no faster. Ive been running my hemi w/ the throttle screw backed out for a while now. I've probably run full throttle for maybe 20-30 seconds but that is under full load...kart on the grass bobbing up and down hills. It has survived thus far....but I run Penzoil Platinum in it if that has anything to with it. (yeah you can call me an idiot for putting 1/10th of the value of the motor into its oil) YMMV.
J.S.@SMS
Road Hazard
I would say no. You could rev to 5200 if you want to, However holding it there would cause a failure. And KartFab made a very good point. Every engine is different, so each engine will blow up at a different rpm. So it is your choice as to weather or not you get a billet rod and flywheel. These will let the engine rev much higher before the rod breaks or the flywheel grenades.
If you don't want to buy these parts, you might be able to use a replacement governor assembly, or you could turn the throttle limiting screw in to limit the engine to the stock rpm or a little over that.
Now, the reason that I removed the governor on my engine is because I wanted a more direct throttle, less rotating mass inside the engine and the gearing setup that I have restricts the max rpm. I was riding the bike with a stock predator 212 through a field, and I wanted to see how fast I could get it to go. I was already at full throttle, so I reached under the tank with my left hand and pushed back on the governor arm which should have opened the throttle more by overriding the governor. However the throttle was already wide open at the carb so it didn't speed up any. At the time I had a TC with a 5.5:1 gear ratio and 19" tires.
If you don't want to buy these parts, you might be able to use a replacement governor assembly, or you could turn the throttle limiting screw in to limit the engine to the stock rpm or a little over that.
Now, the reason that I removed the governor on my engine is because I wanted a more direct throttle, less rotating mass inside the engine and the gearing setup that I have restricts the max rpm. I was riding the bike with a stock predator 212 through a field, and I wanted to see how fast I could get it to go. I was already at full throttle, so I reached under the tank with my left hand and pushed back on the governor arm which should have opened the throttle more by overriding the governor. However the throttle was already wide open at the carb so it didn't speed up any. At the time I had a TC with a 5.5:1 gear ratio and 19" tires.
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