Need 212 advice

[Joe R]

Hi all,

I'm a newb. I recently restored a kart I was given and I've got some engine questions.

The kart is a torque monster. It has a 30 series comet clutch with a 7:1 gear ratio, 18" rear tires and I put a Predator 212 on it.

I'd like to get a little more top end without changing the gear ratio. I started reading about 212 mods and it seems everyone had a different opinion depending on their skill level, setup etc.... Eventually I'd like to swap out the flywheel for a billet, upgrade the rod, cam, head and carb but for now I'd like to take the cheap yet safe rout.

I was thinking of starting out by swapping out the jet, exhaust and new air cleaner and then messing with the governor. I don't want to remove the governor considering I'll still have the stock flywheel and I'd prefer not to grenade it. What's the best way to go about squeezing out a few more RPMs yet keeping it within the safe zone? And what is considered safe RPM for all stock internals?

Appreciate your input.

Joe.

 

[Poboy kartman]

Well..."messing" with the governor is a good way to grenade the motor....either remove the gear inside or leave it alone....

You don't need a billet flywheel if you keep your stock springs.....

Yes....better air filter, exhaust, rejetting, and govenor removal is the cheap first step....

 

[shyflyguy]

No advice to offer from this noob, but that's a sharp looking kart!

 

[OzFab]

The simple fact is there's only two ways to increase top speed:

1. Play around with the gearing or
2. increase engine RPM...

So, as you're not willing to do either of those, we can't really help you...

As poboy mentioned, you can't simply "play around" with the governor, either leave it alone or remove it completely...

You can use the biggest/best jet, air intake & exhaust possible, they will help low end acceleration but, they won't affect top speed; as I already mentiond, there's only two ways to increase top speed...

 

[rmm727]

You can adjust the governor by turning the throttle stop screw on the top of the engine. You can get the engine to turn about 5000 rpm that way. Still pretty safe for the flywheel and rod.

 

[OzFab]

...But that's not safe for the governor, which will self destruct at that RPM (believe me, I've done it)...

 

[Poboy kartman]

....That's the danger....the governor gear exploding...not the rod or flywheel....so remove or leave alone....

 

[rmm727]

Do you both realize that go kart racing classes that use an out of the box Predator engine adjust the governor for 5000 rpm operation? That's what this throttle bracket is for.

http://www.bmikarts.com/Throttle-Linkage-Kit-for-Predator-212cc-Engine-65HP_p_3069.html

The governor will still function. Just the engine will rev higher. Not as high as it would with the governor removed.

Read down thru these rules.

http://karting.4cycle.com/showthread.php?36285-HRK-Predator-Rules-and-Cheating&highlight=governor

 

[Poboy kartman]

Do you both realize that go kart racing classes that use an out of the box Predator engine adjust the governor for 5000 rpm operation? That's what this throttle bracket is for.

http://www.bmikarts.com/Throttle-Linkage-Kit-for-Predator-212cc-Engine-65HP_p_3069.html

The governor will still function. Just the engine will rev higher. Not as high as it would with the governor removed.

Read down thru these rules.

http://karting.4cycle.com/showthread.php?36285-HRK-Predator-Rules-and-Cheating&highlight=governor

Yeah....I did....and what YOU missed...is BOX STOCK!!!! People here are modding the engines as well....they aren't necessarily going to "fall off as quickly ".....and ....just because rules in some racing class dictate certain components remain in place....does not prove it's the most prudent thing to do....just a limiting factor to restrict "cheating" ....and not being "box stock "...

However, that information...should be very useful should he decide to race that class....meanwhile....we will err on the side of caution...and encourage people to adapt their engines for longevity....rather than some class racing rules.....

 

[rmm727]

He asked what he could do to squeeze a few extra rpm out of his engine. I told him. If karters in those classes can race around the track for 30 mins @ 5500 rpm and that gear doesn't fail, its probably not going to fail on him. Down the road when the OP decides to upgrade to a billet flywheel and connecting rod, he can do away with the governor all together. If "we" are so concerned about engine longevity, maybe "our" advice to everyone should be to leave the engine stock.

 

[Bosch]

For what it's worth, I did remove the gov from a new 212 and picked up about 8 mph top speed, phone gps measured.

I have intentionally run it wfo to see if I could get the valves to float, but not yet. I'm 200 lbs, so it may not happen. Rounghly 6-8 hrs on this motor now.

Not saying "Do what I do." Just sharing my experience so far.

 

[Joe R]

Bosch, just curious, what gear ratio are you running and what size rear tires?

 

[Bosch]

Not sure how you calculate gear ratios with a comet 30 series torque converter, but the jack shaft is a 10 tooth small, & a 60 tooth large. 16 inch rear wheels.

It goes 31mph on flat road, and 34mph down hill. Not record breaking, certainly capable of getting hurt real good in a crash..

 

[Peteypooldude]

The simple fact is there's only two ways to increase top speed:

1. Play around with the gearing or
2. increase engine RPM...

So, as you're not willing to do either of those, we can't really help you...

As poboy mentioned, you can't simply "play around" with the governor, either leave it alone or remove it completely...

You can use the biggest/best jet, air intake & exhaust possible, they will help low end acceleration but, they won't affect top speed; as I already mentiond, there's only two ways to increase top speed...

Could he jet it for methanol ? I know on a Briggs it's a pretty simple task but I'm not sure about the predator

 

[landuse]

Could he jet it for methanol ? I know on a Briggs it's a pretty simple task but I'm not sure about the predator

Methanol is too labour intensive. It eats anything rubber, so you have to flush the system out after each time you ride it. That is too much work for me

 

[shyflyguy]

30 series torque converters have a 2.68 ratio for low, and .9 for high. For your final ratio after the TC you'd individually multiply your current 6 ratio (10:60) to each one of these.
That gives you a gear range from 16.08 at the low end to 5.4 for high end.
Remember numerically high gears are actually low end for starting and hill climb. Numerically low gears deal with max speed. The higher your low, the faster you accelerate. The lower your high, the faster you can go. Remember that too low of a high gear will mean that your engine won't have the torque output (even with a torque converter) to reach that high speed. FWIW, I'm not counting mile long downhill stretches as reasonable attainment of top speed!

 

[Holybeen]

So its safe to pull the governor straight out of the box without any other modifications. I wasunder the impression you had to have the billet flywheel to safely remove it

 

[landuse]

So its safe to pull the governor straight out of the box without any other modifications. I wasunder the impression you had to have the billet flywheel to safely remove it

You only start needing billet parts when you install stiffer valve springs. The stock valve springs will limit the RPM when they start floating at high RPM's.

 

[JDMac]

This thread is confusing me. If I buy a Predator 212 and remove the governor, add a cheap exhaust, and intake, will my engine be safe? I know it won't be as safe as stock, but I mean being able to have plenty of hours on it without being a grenade? I dont want to spend $300 on billet parts for a $120 motor. If so about what RPM will it be running?

I am planning the driveline for my kart now and that is my plan so far.

 

[Scout]

No advice to offer from this noob, but that's a sharp looking kart!

If I'm not mistaken, that's a BKS Grasshopper, or Go-Fur. My friend knows more than I do, but I think the grasshoppers are clutched, and go-furs have a torque converter. And maybe it's "Go-pher".