Predator 301 help with carb

Hey yall, been a while since i posted. Looking fir help with carb for a pred 301cc, looked thru forum didnt see anything right off, soooo im looking for some carb info, from what im seeing is a 28mm flat slide will work......but that $ is meh for now, will any 28mm carb work? I have a 28mm nibbi carb not in use at the moment, will thst work? Or any links to carb?


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I would imagine most any 28 mm. will work. What all modifications have you done to your engine? I have a 301 hemi on one of my karts. Milled and ported head, 50lb. valve springs, twister 250 cam, governor removed, header pipe and free flowing air filter. I use the stock carburetor with a .040 or .041 jet and the pilot jet drilled to .021". Very happy with the performance. If your engine hasn't been modified a bit, I think a 28 will be too much for it.
Stock carbs are great. They are already sized and fitted to the engine.
I don't understand the reasoning behind putting a motorcycle carb on a lawnmower engine.
I guess I'm just getting old and cheap. I like my engines to start, run reliably and require zero tuning.
Now, I will tweak some governed engines.
Right now it is a brand new engine, totally unmodified, will be adding a header pipe, and the carb, removing governor..only because i need to get rid of the bulkyness of the stock exhaust and air filter housing to fit properly on bike, i would like to keep the stock carb as ive got an adapter for the stock carb to use a cone filter, just not sure of jetting at this time, thats the easy part, my issue lies on how to hook throttle linkage after removing governor, as i usually just go with the aftermarket carb like on my 224, maybe should just zip tie for time being?


Well-Known Member
Did you figure out what kind of RPM you will be running? A big block should have a lot of torque so you shouldn't need to run high RPM.

What bike is this going on? Tire size and gearing?

I would run the slide carb first without governor removal. Then I could go back to the stock carb and run with a tweaked governor if the slide carb doesn't work well. The how much RPM question needs to be known prior to running this way.
Maybe try sitting the engine in the frame before you modify anything?
I had a totally stock 420 on a mini bike for about a week. That was one day to try riding it, three days for my buddies to try , two days to remove it and on the last day, we rested. You might decide a stock 301 is perfect.


Well-Known Member
If all you do is put on a header and a free flowing air filter, I would try a # 39 main jet and .020 for the pilot jet. After building mine, but with the stock size pilot jet, it was hard to start. Like 12 to 15 pulls. Eric Adams of the Grey Goat Garage suggested drilling the pilot out to .020". Bought a set of micro drill bits from Amazon, drilled it to .021". Starts 1st or 2nd pull every time. Night and day difference. Also in post #2 where I listed engine modifications I forgot to mention ARC billet rod and flywheel. Kinda pricey, especially for the big block,
but I won't remove the governor without replacing those two parts.