Springs?

[SpeedBoy]

It wouldnt realy do to much to a stock engine as far as i know, I know you put in stronger valve springs for when you have more RPM so the valves make it closed in time for the compreshion stroke.

Would upgrading the springs be a good thing to do for a stock engine? Or does it only matter in more modified ones?

 

[exenos]

Tan is better as long as its not too light.

 

[Doc Sprocket]

and hit 6.5K with the governor right out of the box without me even touching it. I think someone was playing with it at the factory

And you verified this? If that's true, it's well out of the range of adjustment, and can officially be considered broken.

 

[exenos]

Ya, it came straight out of the box like that. It would never idle at less than 3-4k while the governor was intact adn would go around 6.5-7k when it was bouncing off the governor.

 

[cOw]

Do I need something like this:
http://www.affordablegokarts.com/mm...de=A&Product_Code=ARC6931&Category_Code=212cc

If I am goin to put a GX200 HP air filter on my Predator 212?

 

[tundrabeagle3]

(quote) Do I need something like this:
http://www.affordablegokarts.com/mm5...ory_Code=212cc

If I am goin to put a GX200 HP air filter on my Predator 212?
Today 07:09 PM (end quote)

yea thats what you need you need to mount an aftermarket air filter. I have the k&n type air filter and the $25 omb header and muffler. but any clone header will fit but you may have to drill out the holes on the header to fit the predator studs. the unifilters are the best but cost a little more. you can also buy a 90 jet.


(quote)(Ya, it came straight out of the box like that. It would never idle at less than 3-4k while the governor was intact adn would go around 6.5-7k when it was bouncing off the governor. (end quote)

3000-4000 is not idling your clutch engages at around 1800 rpm. unless your doing it with the clutch off or have a disc clutch the engine would just take off at 4000 rpm. 6500 to 7000 rpm? it sounds like your clone came de governed and with 18 lb spring just be careful not to keep it fully pinned unless it came with a billet aluminum flywheel and coneecting rod too

 

[landuse]

This is correct except you don't need a billet cam to run high rpms you need a billet rod since it is the first part to break at high rpms made with stronger springs.

I think you mean billet connecting rod, billet cams and cranks are not really required unless you are making around triple the HP of a stock GX.

Thanks you gentlemen. I did indeed mean billet rod. Thanks for the correction. I have edited my post to say rod

 

[r_chez_08]

Ya, it came straight out of the box like that. It would never idle at less than 3-4k while the governor was intact adn would go around 6.5-7k when it was bouncing off the governor.

How are you measuring this?
Your figures are about double what they should be.
Idle should be around 1500rpm, and governed rpm around 3600rpm.
Don't forget these engines have wasted spark, i.e. They spark on the exhaust stroke. This could be confusing your tach.

With the factory carb, muffler and airbox, you wont get much over 5500rpm, even with 18lbers.

 

[Doc Sprocket]

If any of that was actually remotely true, it should have been returned as defective.

Rob, you're right about the waste spark system. Let's not forget that the magnet rotates with the flywheel, and therefore blows past the magneto on every revolution. Since the compression stroke occurs on every other revolution, we end up with an otherwise unnecessary spark just before TDC on the exhaust stroke. You could argue that it helps with emissions as a last ditch effort to burn everything off before it exits the cylinder, but it really is just a side effect of the somplest design possible.

 

[r_chez_08]

Yeh. Forgot to add- A conventional 4 stroke such as a car sparks once every 2 rotations, whereas our engines usually spark every rotation. If a conventional tach is on the wrong setting or not modified, it will read double. Should be on the same setting as a 2 stroke IIRC.

 

[tundrabeagle3]

don't 18 lb springs allow you to rev up to 6500 rpms? i thought the trick springs allow you to rev up to 5500 rpms.

 

[r_chez_08]

Depends on many factors.
Edit: what I meant was the stock air box, carb and exhaust, and cam will restrict the rpm. Remove the governor and put 50lb springs in- you still will struggle to get over 6k.

 

[tundrabeagle3]

what about with a stock predator cam and stock rockers?

 

[r_chez_08]

I would say if you get a billet rod and flywheel, and a new header and air filter and springs you could probably get 6.5k, but you would have to gear right, the power will be trailing off.
Upgrade the cam, carb and head and you can make many more.
I am no expert tho. If you want better figures gead over to 4cycle.com. They really know their stuff.

 

[exenos]

Ya, like I said I don't know why its revving so high. I'm measuring the rpm with a laser tac so I am getting the true rpm, and when I feed it into a reverse speed calc it always spits out something in the 6-6.5K range. The internals are stock except for the governor removal because it was messed up. I have a straight pipe and the stock airbox with the stock jet. I have no reason to bs about this, I'm just wondering why.

Sorry for somewhat jacking your thread Cow.

 

[r_chez_08]

Wow. I have no clue. Just please get some billet components if you plan to keep those rpm

 

[exenos]

You don't have to tell me that twice, I don't relish the thought of being "One nut luke".
The minibike its on is geared so that the engine will only hit 4800 rpm after the longest stretch I have.

 

[tundrabeagle3]

I would say if you get a billet rod and flywheel, and a new header and air filter and springs you could probably get 6.5k, but you would have to gear right, the power will be trailing off.
Upgrade the cam, carb and head and you can make many more.
I am no expert tho. If you want better figures gead over to 4cycle.com. They really know their stuff.

i may just try the trick springs with the stock internals

 

[cOw]

I feel this thread may need a title change...I am glad it has been re purposed though, as my question has been thoroughly answered.

 

[Doc Sprocket]

I feel this thread may need a title change...I am glad it has been re purposed though, as my question has been thoroughly answered.

Get used to it... Happens a lot around here!