Doodlebug Predator swap....low top speed?

Hey all! Forgive me for being spotty in my postings, i have rather poor internet here in camp.

So after getting my Doodlebug running well, i enjoyed it for a bit with the stock 97cc engine. Was quite reliable, and easy to handle. Struggled with inclines, but it had a respectable 27mph top speed with the cent. 11x70 gearing.
My coworker here is actually into motorsports and gokarts etc, and when he offered to have a friend send up a spare predator 212 i couldn't resist! It needed a new carb and clutch, which i got (max torque 12t). Bolted it up, and boy howdy...almost did a backflip! Tons of low end torque compared to the old motor, and hauls my 150# a$$ up 20 degree inclines like theyre not even there..and wants to wheelie unless i lean over the handlebars.
However, i can only get 26mph on flats with the new setup, which seems strange. The old motor with lower gearing did 27! Why would this be? Does the predator 212 naturally spin slower? Or am i missing out? I dont want to fully bypass any governors, as i know its frowned upon...and id like to keep my berries intact. If there is way to modify the governor setup whilst keeping rpms in a relative safe zone, id be all ears. Torque convertors are out of my budget for the time being, but on the horizon (possibly new headers, but how much do those help?)

Thanks in advance!


Not sure how your throttle is hooked up but there is a throttle stop screw you might be able to get a little out of it .the governor arm under the gas tank there are three little holes move the linkage to the inside hole two maybe three mph can be had there oh and rear sprocket the smaller you go the faster it is and bottom end torque is no issue rob some from there
If the new engine is turning the same rpms at speed as the last will be going about the same speed. You just get there quicker now. You need to step down the rear sprocket diameter to start gaining higher top end speed with the same rpms.

Daniel Coop

Well-Known Member
My dude's already hitting 38-40mph, thanks to some simple/costless suggestions from an anonymous ​mini biker.:thumbsup: He's well on his way to having a fun little DB:scooter:
What have you done? Mine is a direct swap, just removed the throttle stop screw and I've hit 35mph. The stock 2.8hp motor only got me to 18mph lol. I'm likely doing to do a stage 1 intake/exhaust/jet combo, mainly to get rid of the exhaust "box" I keep bumping my leg on.