Rpm limiter

[ginoz28]

Is there some sort of magic box to set the rpm at a certain point to not blow the engine with the governor off?

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[Gokartbill]

If u keep your stock valve spring in there and take your governor completely out, it will act like a rpm limiter due to valve float

 

[ginoz28]

But at what rpm range is that?

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[Doc Sprocket]

Too many variables to give a number. Usually between 5000-6000RPM, but not written in stone.

 

[ginoz28]

Too many variables to give a number. Usually between 5000-6000RPM, but not written in stone.

That seems like a high rpm, is that still safe in a stock gx160. So how high do they go with 18# springs?

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[Half-breeder]

That depends aswell... But if everything is done very correctly... 7-8k... Btw do NOT put a set of 18lbs springs in w/out putting a billit conrod in... Well u 'can' but u may have to rebuild/replace the entire motor, due to a metal rod ejecting through the case.

... and NO motor is safe when being pushed to its physical limits. Motors dont believe in the saying"... what doesnt kill you... can only make you stronger...".

 

[Doc Sprocket]

Motors dont believe in the saying"... what doesnt kill you... can only make you stronger...".

What doesn't kill you, can only cost you money...

 

[itsid]

well ther IS indeed such magix box...

called a programmable CDI;
unfortunately I don't know of any that's made for a GX ..
and although I haven't actually searched for one, I doubt somebody cared to make one that dropfits a GX

Anyways.. a (I think most) programmable CDI can be used to limit the rpms to any given upper limit.

'sid

 

[ginoz28]

well ther IS indeed such magix box...

called a programmable CDI;
unfortunately I don't know of any that's made for a GX ..
and although I haven't actually searched for one, I doubt somebody cared to make one that dropfits a GX

Anyways.. a (I think most) programmable CDI can be used to limit the rpms to any given upper limit.

'sid

Yes I know they make different CDIs for my gy6 motor. One that only lets you go 20mph and stock and one with out a limiter.

For it to work for the gx it would have to be built into the coil or in between the coil and mount using "ground".

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[itsid]

No you didn't understand..
the GX ignition coil is already a CDI (capacitor discharge ignition)
The magic word is "programmable"

And the gy6 cdi isn't programmable, even the "unlimited" cdi isn't,
at best it's trimmable.

'sid

 

[ginoz28]

No you didn't understand..
the GX ignition coil is already a CDI (capacitor discharge ignition)
The magic word is "programmable"m

And the gy6 cdi isn't programmable, even the "unlimited" cdi isn't,
at best it's trimmable.

'sid

To me and I think a lot of people that is just a coil , not a CDI.
I didn't say the gy6 was programmable, only 20mph, stock, and wide open.

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[itsid]

Well "just a coil" as in "only a ignition coil" is not igniting anything.

but you're right.. technically it's not a CDI but a TCI
(You got me, I lied.. on purpose... bad 'sid..BAD )

The point I was trying to make is..
a CDI has a fixed time of ignition.

Let's shortly explain the two:

A CDI
uses a pickup on the flywheel (magneto, hall effect sensor, or points)
to trigger a thyristor that discharges a small capacitor (tiny ~0.2 µF)
into the ignition coil that then sparks the plug.
the capacitor can be charged by the magneto (or a battery or lighting coils)

A TCI
uses a pickup on the flywheel (magneto, hall effect sensor, or points)
to trigger a transistor that collapses the magnetic field
of the ignition coil onto itself which then sparks the plug.
the coils electric field is produced by the magneto (or a battery or lighting coils)

So different systems, both completely static!

As you can see the technical difference is very small.
And within the room given it could be both.

And before you ask, yes most CDIs use diodes and resistors to allow for AC and correct charging of the cap.. again that's not the point


A programmable CDI (or.. -because there IS such a thing- a programmable TCI)
can alter the time of ignition within a few degrees.
because the controller is between the pickup on the flywheel and the thrysistor (or transistor for that matter)
so it can just refuse to trigger the spark.
it doesn't matter if it's a capacitor or a selfinduced magnetic field..

'sid

 

[Poboy kartman]

That depends aswell... But if everything is done very correctly... 7-8k... Btw do NOT put a set of 18lbs springs in w/out putting a billit conrod in... Well u 'can' but u may have to rebuild/replace the entire motor, due to a metal rod ejecting through the case.

Yeah. .....scratch the rebuild. ....when the rod goes through the case.....it's replacement time....

And you never know what kind of shrapnel may hit you in the back of the head and make you as goofy as me......

 

[ginoz28]

So I gues they don't make one. This one I found still doesn't have a rev limiter.
Plus it's super expensive

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[kaptnsmooth]

Ok quick question on CDI's....If I buy a 6 pin (unlimited rev) I have to be cautious not to over rev and blow engine. Is this correct? I wanted to purchase a CDI with unlimited rev potential but worried I will damage engine. Any thoughts on this? Is it worth having a little more top end by purchasing a new CDI. Also I have noticed there are CDI's out there (unlimited rev) and the cost varies. Any ideas on which is the best for money. I appreciate any feedback on this. Oh by the way I have a trailmaster XRX150 with gy6 clone.

 

[fowler]

Just keep your stock setup
As far as ign


Surely u could co e uo with something sid

Adapt it to the original setup

Once u have rpm read
Then you just gotta make it ground the coil at a set rpm

 

[freakincage]

This is what I did. I used a bolt and collar to limit the travel of the gas pedal, in combination with a tiny-tach.

It will easily rev to around 3300 RPM and eventually get up and past the 3600 RPM that my motor is rated for. For me, the kart is quite fast at around 3400 RPM, being that I drive it on grass and gravel without suspension.

 

[Doc Sprocket]

The fault with a throttle-stop, is physics. Throttle input affects engine RPM, but so do other factors, most notably load. For example: Lets suppose you have it set so that your throttle plate only opens halfway. Now- Start from a standstill. Acceleration will be dismal. Up to speed on a level plane, you may find your RPM acceptable. As you start to go up that incline, your revs are going to drop, even though your engine has the potential to make enough power to climb it. Levelling off, your RPM begins to climb back to were it oughta be. Now you've looped around and are heading back down the hill, with your lead foot on the floor... And your engine is screaming because there's no load on it.

A throttle stop set too low will also prevent clutch lockup, burning it out prematurely.

MY opinion? Deep-six the governor, and drive with your ears. Valves flutter, back off. Been doing this a long time, no failures.