If you don’t feel like reading all of this crap, then Click Here to see the video of the transformation of this engine from factory fresh, into the realm of badassdome.
The first step in building my Longtail Mud Motor has got to be the motor, right? As mentioned in other articles, I started by purchasing a Predator 212cc 6.5 HP engine from Harbor Freight. Is that the best choice?…maybe not, but I had a gift card for $100.00, and the engine was on sale for $99.95 (regularly $119.99). That made it an easy choice for me. If any of you want to build a larger horsepower motor, you will spend at least double what I did, and the mud motor kits will be more heavy duty, thus slightly more expensive.
The Performance Modifications:
- Re-jetting the carburetor;
- Addition of high flow, inline air filter;
- Addition of a sick sounding header (or muffler during duck season).
All of this can be done with hand tools that you probably already have.
Lets Get This Party Started:
Remove the Air Box:
- Remove the two 10mm bolts.
- Disconnect the two vent hoses, then you can just slide the air box off, and set aside (you will not need this part again).
Removing the Governor: Nobody likes to be over governed! Fight the power! The first thing you’re going to want to do is remove the governor. Caution and restraint is due here because you can push the engine too hard, and float the valve springs, throw rods, etc. which is bad.
- Remove the Gas Tank to get to the Governor.
- Disconnect the fuel line from the tank.
- To the Governor! Unscrew the bolt on the Governor arm.
- Use a flat head screwdriver to pry apart the Governor arm.
- Remove the Governor Arm, and all of the springs, and throttle rod.
Re-jetting the Carburetor:
- Remove the Carburetor.
- Unscrew the bolt on the bottom of the carb.
- With a flathead screwdriver, unscrew the jet, and dump out the factory jet & emulsion tube.
- Insert the Go Power Sports Emulsion Tube (skinny end first) & Jet (with the recess for the screw driver facing you).
- Slide the carb and spacer/gasket back on the engine. Now you’re ready to bend a new throttle rod.
Making a Throttle Rod:
- Get a coat hanger, or similar gauge wire (you can use the throttle rod that you removed in the prior step if you want)
- Using a pair of pliers, bend the throttle rod to fit between the throttle on the carburetor, and the throttle arm.
- The fitting of the throttle rod will probably take a few tries. Just remove, bend a little, and re fit. Have patience and you’ll get it.
- When I get one that fits well, I go ahead and make an extra one to carry on the boat (just in case).
Installing the High Flow Air Filter:
- Slide on the Air Filter Adapter:
- Slide on the Air Filter, and put on the air filter cover.
Remove the Factory Exhaust & Install Go Power Sports Header:
- Remove the factory Exhaust by removing the two bolts:
- Replace the exhaust Gasket if needed (mine did, and my engine hadn’t been run).
- Screw on the Go Power Sports Header.
I gotta tell you, this thing sounds freaking amazing. It sounds like a motor cycle. Click Here for the Performance Kit used in this post. However, for hunting season, I plan on removing the strait pipe header that’s on this engine currently, and replacing it with Go Power Sports muffler. It will take the Sons of Anarchy sound away that I love so much, but the critters I’ll be chasing don’t particularly care for it.