6.5hp Clone Performance

Clayton · Apr 16, 2011

Okay, I have a Baja heat, with a clone (non-original to the bike, was put on afterward). I can ge the bike up to 25mph or so, but then the governor kicks in and slows me down until I am revving signficantly lower than 3600rpm, and then lets rev to the max and then slows me down. I want to bypass the governor but I don't have the cash for the billet flywheel. Any ideas? Has anybody bypassed the gov without all the aftermarket stuff? :mad2:

Doc Sprocket · Apr 16, 2011

What aftermarket stuff?

You can do it for free.

Clayton · Apr 16, 2011

I know, but would the engine last? I know that on oldminibikesforum that they basically push that you use aftermarket valve srpings, pushrods, flywheel, and sometimes even more stuff (connecting rod ect.). You know anybody who runs a clone without gov with no aftermarket parts? How long has it been like that?

Doc Sprocket · Apr 16, 2011

Fear not. It'll be fine. The stock valvetrain will limit the RPM.

Anytime you mod an engine for performance you are potentially shortening service life. Heck some racers rebuild after every competition. At any rate, since you are NOT expecting to get 20 years of rototilling out of it, don't worry about it.

Clayton · Apr 16, 2011

So the valvetrain limits the rpm, to what? I guess that would make sense.

slideways · Apr 16, 2011

About 5500rpm.

Keep in mind that the engine will not live long at that rpm without the "go fast" stuff inside. Short bursts up to 5000rpm or so will be fine as long as you keep fresh synthetic oil in it. The rod will be the first thing to give up typically. With the flywheel your next most dangerous thing.

Clayton · Apr 16, 2011

What if I just set up a hardwire linkage direct to the carb?

Clayton · Apr 16, 2011

Or is there a way just to delay when the govenor cuts in?

Doc Sprocket · Apr 16, 2011

You can back out the throttle stop screw. This will cause no problems. I beat the wee out of mine at that speed.

Doc Sprocket · Apr 16, 2011

Clayton said:
What if I just set up a hardwire linkage direct to the carb?

It's the same thing- it defeats the governor.

Clayton · Apr 16, 2011

toystory_4wd said:
You can back out the throttle stop screw. This will cause no problems. I beat the wee out of mine at that speed.

Already did that, mine is on a baja heat with the jackshaft, I am jsut wondering how I can maybe delay the governor to cut in later.

Doc Sprocket · Apr 16, 2011

The more I think about it, the more I think you should regear. If you're bouncing off the governor that hard, then the engine's not seeing any load at speed. You can gear higher and gain top speed. Give me all your tooth counts and tire size- also, what size was the original engine?

Clayton · Apr 16, 2011

the original engine was a clone, pretty much the same (same power anyways). I have 10teeth on the clutch, 20 teeth on the sprocket that the clutch drives, then on that same shaft there is a 10 tooth that goes to the 50 tooth rear sprocket. I tried re-gearing, but I couldn't find the right srpocket(s).

Doc Sprocket · Apr 16, 2011

Holy cow, no wonder you're bouncing off the pin- you're running a 10:1 reduction!!! Regear!
Under most conditions, 6:1 on a minibike is fine. The simplest way for you would probably be to change the 20T jackshaft sprocket for a 12T. That will net you 6:1.

Clayton · Apr 16, 2011

Okay, do you have a website I could go to to get the 12 tooth sprocket? My local area stores can't seem to find sprockets to fit a metric shaft. Thanks soooooooooooooooooooooooooooooooooo much toystory 4wd, I was really starting to lose my mind, my ****ing db30 with a 2.8hp passes me easy peasy!

Doc Sprocket · Apr 16, 2011

Glad to help. Measure the diameter of your jackshaft and find your chain pitch. Finding a sprocket should be pretty simple from there.

Out of curiosity, what is your rear tire diameter?

EDIT- I believe Tractor supply has weld-on sprockets and hubs. Do you have one in your area?

Doc Sprocket · Apr 16, 2011

Jeezus, I'm a retard. I forgot you're Canadian, too. Go to Princess Auto- they've got bloody everything for this.

Must be tired. Can't believe I did that.

Bluethunder3320 · Apr 17, 2011

my baja is geared 10:1? wow.

they have 19" tires FYI.

im gonna look for a 12-15t sprocket. isnt the jackshaft 5/8 keyed?

Clayton · Apr 17, 2011

Today I never got to go to Princess Auto, so I bypassed the governor by running a hardwire linkage direct to the carb. I guess I am not gonna bother re-gearing, it hauls *** now! Plus I have a new project to start on.