Kid’s 4 Wheeler Motor Swap

My son has had this Chinese 4 wheeler for 6 years now but still enjoys it, even being 12. The only gripe I’ve had has been that it’s electric start only, centrifugal clutch and to make matters worse it has always killed batteries. Electrical not being my strong point, I ended up adding a toggle switch to disconnect the battery when it was sitting for more than a couple days. That worked for a while until the wiring for the switch randomly burned up one day. That was enough for me. As luck would have it, I had acquired a Chinese pit bike with the same 110cc engine that had a kick start and manual transmission. The frame was cracked and the spokes were all busted out, but it ran decent. Yesterday I took the motor off the bike and swapped it into the 4 wheeler:

Handlebars and plastics back on, controls set up:

What’s left of the donor bike:

All that’s left to do is extend the shifter, modify the kick starter to put it outboard a few inches, and modify the exhaust to the proper angles so that it clears the frame. Also I’ll have to make a 90 degree intake elbow to mount the air filter, as the frame comes close to the carburetor. I decided not to put the metal rack back on the back of the machine.

The original electric start engine:

 

Glad you found a motor for the wheeler I am sure your son will be riding until the wheels fall off it.
Unless he can get dad to buy him a bigger wheeler

 

We’ll see how much he’s into it once it’s going again. I’d love to buy him something bigger at some point, preferably made in Japan. I grew up mostly on dirt bikes but I had a couple trikes and a 1986 LT250 4 wheeler. Only problem in CT is there are very few places to ride (legally). But if he really likes it and it keeps him out of trouble, I wouldn’t mind getting something for myself, and registering a couple machines to ride the trails up in Massachusetts with him.

 

Nice work so far! Can you show the intake and exhaust interference points? Any way to use the intake and exhaust from the original ATV engine? Or is the issue the angle mount slightly different between the bike and ATV engine?

 

Thanks I'll see if I can take pictures tomorrow. The exhaust issue stems from the angle of the exhaust port on the cylinder itself. Although they're both 110cc Chinese engines, the ports are at different angles (same size I.D. and exhaust pipe though). The intake issue might be solved by swapping the "intake manifold" from one engine to the other. The carburetors don't mount directly to the engine. Rather, there's a manifold of sorts which is really just a tube with a couple flanges welded to the ends. The one on the original quad engine has more forward lean, which should give me the air filter clearance behind the carburetor, but it will also angle the carburetor down towards the front and lift it higher in the rear. I'm not sure if that'll be an issue or not, but I'll look into that before making an intake elbow for the filter. As it is now the carb sits level, which I think is the way it should be.

 

Yup, I have one just like that (50cc though) and the same issues...dang thing eats batteries, probably due to the "remote control/kill" and "anti theft" crap it has on it...I try to leave the battery maintainer on it.
Had to downsize the countershaft sprocket when I got it...didn't have the balls to take off from a dead stop without a push...but then it'd go 30 mph once rolling...ridiculous for a lil kid! I already have a 220 Kawi Bayou to replace it...but might hafta keep the lil 50 patched up a lil longer since lil sis is outgrowing the electric gator now...

 

A couple years ago I was gonna haul my dirtbike up to the NE. Started doing research and ultimately bailed due to seemingly no where to ride it. Have wanted to do some light touring of that region and the dirtbike was a good 'excuse'. Looked at Moab too. Read a lot of negatives. Something about having to have a license to ride offroad out there now? Lots of closures. Getting overrun with tourists. Sigh.

Still want to see the NE and the Red rocks if I can.

 

There are hundreds of miles of trails to ride up here, but depending on where you go, either you have to be registered in that particular state with an off-road plate (no motorcycle license required) or your bike has to be a dual sport registered for the road which means you need your MC license. It’s been probably 15 years since I did it but back then, New York State allowed off-road plates from out of state to operate on their trail systems. You’d have to look into it state by state, but we do have some phenomenal riding up here.

 

At first it seemed like it, but then I kept running into ATV and Snow machine only. It's like there was a big problem in the past and they decided that dirt bikes are the devil. Perhaps I wasn't looking in the right places. I was trying to put myself as close to the north woods as I could, thinking the remoteness would beget some trails to ride. I think a lumber company owns half of Maine? I do have my bike registered as a 'motorcycle' nowdays.

If you have any suggestions for areas to look at I would happily do so. My ideal setting is low population situated between/nearish 2-3 parks or trail systems. Can be a single trail system if large and no risk of closures. Would love to see parts of MA, VT, NH and ME. And yes...I know not to come during leafer season. lol

 

This is a place that I was homing in on before I abandoned the idea.

 

This is where I rode years ago, and it looks like it’s still open to bikes:
Lewis County ATV Trail System

I remember this one sand pit in particular was pretty large and had some nice rolling dunes. On my old CR125 I got into 6th gear and launched it pretty far LOL. It was like a mini version of the dune riding out west. A coworker friend had property in the area, and we would take off right from his camp and hit the trails. It was a mix of snowmobile trails, power lines, sand pits, mud bogs etc. A little something for everyone.
I have friends that ride here too:
Beartown State Forest
Massachusetts has a bunch of different state land areas you can ride if you get a registration sticker there before you head up.

 

Have a welder? Could cut flange on exhaust, rotate it, and weld it back up. I'm a little confused on what issue you're having with the carb...is it just that the filter won't fit? Could always make an intake tube out of hose and mount filter further back.

 

Get a couple quads, trailer em up and bring em to my house. It’s only slightly illegal and only if you stop
Be glad to give you the nickel tour. Havent been joy riding in awhile myself.

 

I do have a mig welder but the “manifold” is aluminum (maybe magnesium?) and I’d rather not mess with it. I didn’t get a chance to take pictures today but here’s my chicken scratch rendition of the carb issue:

 

Nice views, I really might take you up on that offer sometime Just gotta find something for me to ride now

 

Not trying to tell you what to do but.... an exposed air filter like a k&n can plug up/get covered in mud n water too easily. Our last trip riding it happened to an 80s xr250. Maybe made it 2 hours into the day before problems arose.

 

It's what came from the factory on both the bike and quad. Neither has an airbox with a foam filter element.

 

Better get two. The one your fixing won’t go far in these woods. If I could sell mud and boulders I’d be a rich man

I thin Orion is suggesting a rubber hose off the back of the carb to wherever you can slap that air filter.

 

Ah i c. Must work ok then on those little ones.

 

You're 100% right, those filters for off-road use suck. I don't think we're really going to be using this quad for intense riding, crossing rivers, mud bogs etc. so hopefully it'll be okay.