Re-engine Buggy with a (modified) Predator 670

[darwinpayne2000]

So, maybe I didn't get any video of my ride, but I did snap this picture.
bigfoot_image2.jpg

[darwinpayne2000]

So maybe I didn't get any video of my ride, but I did snap this picture.

bigfoot_image2.jpg

[jimmyg]

Piss funny!

Pro tip.

Thin smear of grease on the lens gives that...Is it a bird, is it a plane, or is it......? What is that!? Vibe. Just for next time.

[LIDUNO]

So, maybe I didn't get any video of my ride, but I did snap this picture.
bigfoot_image2.jpg

I try to sneak off for a poop in the woods and you're taking pictures? Jeez!

[K-fab]

Ahahahahahaha!!!!

[darwinpayne2000]

I'm taking a break from the Predator engine project while I wait for the piggy bank to fill up a bit. Christmas is taking all of the "fun" money right now, so I'm pivoting over to a "no-cost" minibike rebuild that's been waiting patiently for me to come back to it.

The minibike is a Hawg-Ty bike that O'reilly Auto sold for about a year back in the early 2000's. It's one of the bigger minibikes out there, but it only has a 5.5 horsepower engine and a simple clutch for the drivetrain. Yawn.

About 6 years ago, I dragged an old Tecumseh 8 hp engine out of the parts pile and swapped it into the minibike. The Tecumseh had the governor removed and used a Honda clone carburetor that offered more horsepower over the stock carb. I also replaced the clutch with a Comet CVT.

That was a big improvement. Nice throttle response and it would easily go up the hills. Fun to ride. The only problem was . . . the Tecumseh engine. Back in the day, these flathead engines were ubiquitous on rototillers, etc. A workhorse, but it was also work to get them started. I now understand why companies emphasize that their engines will start on the first or second pull. It's no fun trying to start these old Tecumseh flathead engines and people probably have long memories of trying to get that *@#$# rototiller started every year.

To fix the problem, I picked up a Harbor Freight 8 hp engine. If you remove the governor and upgrade the carburetor, these engines will easily make 10+ horsepower without any other mods. The downside is that this engine is significantly larger than both the stock engine and the Tecumseh. It wouldn't fit in the minibuggy without a fight and I was already busy with other projects so the minibike rebuild was put on the back burner. Way back on the back burner.

I was cleaning up the back yard this fall and I saw the minibike sitting forlornly in the corner. I decided to put it back on the project list and get it running again.

I pulled it in to the garage last week and removed the Tecumseh engine. On the Predator engine, I stripped off the gas tank, the exhaust and the air intake because these will all be modified/replaced by other components. The engine would fit better in the frame, but it didn't really leave any room for the CVT jackshaft, etc. Raising the engine up and sliding if forward gave me the room I needed, but the 8 1/2 inch center-to-center distance between the clutches put the driven clutch right up next to the engine, where it was rubbing on the oil fill plug. I decided to bite the bullet (no-cost project, remember) and order a new clutch belt to move the jackshaft 9 1/2 inches back from the engine. That solved the rubbing on the motor, but now I needed another inch for mounting the jackshaft so, again, the engine had to go up and forward to give me more clearance.

When I was done, I had the room I needed and the position of the engine looked good, but the mounting plate, with the various spacers, etc looked like Rube Goldberg designed it. Knowing what I know now, I sketched out a cleaner design for the mounting plate, then I turned off the lights in the garage and called it a day.

Here are some pictures of the project so far. After I get the engine and jackshaft mounted, the rest of the work is mostly around the gas tank and a new seat. The upper frame bar had to go up to make room for the engine and it will be reattached as part of building the new seat. I had big plans to mount the rear tire on a swing arm, but that will be included in version 3.0, whenever that happens. Right now, I mostly want to focus on what it will take to get it back on the road.

Here are some pictures.

[darwinpayne2000]

A quick note. If you're thinking of picking up a Predator 670 engine (and who isn't), they're on sale right now through December 17th. Only $699, plus another $600 in performance parts to make it run like a gazelle. The perfect gift to put under the Christmas tree.

[darwinpayne2000]

I think I'm done fiddling with the mounting plate. The motor is sitting at the right height to fit in the frame and the jackshaft is also mounted to the engine plate.

After mounting up the engine/jackshaft, I started work on the exhaust. I drilled out and shaped a mounting plate to replace the stock muffler, then cut up some 1 1/4" tubing to form the exhaust. It turned out better than I expected on the first try. The exhaust is tucked up close to the engine near the exhaust port to keep from burning my leg, then it angles out slightly to clear the rear fender. For the moment, I just have a long, straight pipe until I figure out a slip-on muffler.

Here are some pics.
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[darwinpayne2000]

More progress. I have the carburetor mounted up. I played with different setups, including the stock airbox, etc, but this configuration puts the carburetor and air filter up next to the frame, instead of having it stick way up above the engine or having the air filter poking out against my leg. I need to finish welding up the air filter adapter, then paint it.

The carburetor I'm using is a Honda GX460 clone carb. I was using it on the Tecumseh engine and it ran way better than the stock Tillotson carb. It should also give me a boost in horsepower. Below is a picture showing the difference between the stock and the GX460 carb.

I didn't find a nifty muffler to use on the minibike, so I may just fabricate up my own.


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[jimmyg]

Good progress.