Karttekk
Well-known member
Zade, you'll need to find out if your kart has external reverse or internal if you were going to replace the engine with another GY6. . Look on the shifter. Does it have FNR or FR? FNR means you have internal reverse. Keep in mind right now (if the engine was running), you would have electric start and reverse plus working disc brakes. That will all go away with the 420 engine. You'll need to figure out where to put the disc brake rotor and mount the caliper. You'll need to push a huge machine around without reverse if you can't get reverse working on the 420. There's a lot to think about, just trying to point out what you could run into. The Hammerhead Performance engines aren't cheap, check Facebook Marketplace just for the heck of it. Use the 420 engine on your next go kart build, it will work out much better in my view. These links show the difference between the two types.
hammerheadperformance.com
hammerheadperformance.com
Hammerhead Polaris 150cc Engine Assembly with Internal Reverse and Oil-Cooler Holes for 150cc, GY6 - 006-JL150-03 replaces 006-JL150-02, 15332, 006-H1200011
006-JL150-03, 15332, 150cc IR (F/N/R) 150cc Engine with Oil Cooler Holes
Hammerhead 150cc Engine with External Reverse (F/R Only - No Neutral) for GY6, 150cc - 2.000.009
2.000.009, ENGINE. 150cc (external reverse) (no neutral postion...forward/reverse ONLY)