68' Harley 208cc Princess Auto Engine Swap

[rider.prider.king]

Hi Everyone,

This may sound sacrilegious to some HD owners but here’s the story: I got an old 68' 3 wheeler from my great uncle, it seemed to be working fine and with a bit of tuning I had it running, somewhat ok but never great. Then the cart lost compression in 2017 so I got a bored out top end kit (0.040”) that contained new rings, piston and refurbed cylinder. I installed it and it ran decently in 2018. However, in 2019 it didn’t want to run, seemed like it wasn’t getting fuel so I sprayed some carb cleaner in there. Unfortunately, that dried out the cylinder and it caught the rings and broke them and the piston. The cylinder still seems fine, it has no scratches on it that I could see. I've put a lot of time, effort and research (here, THANKS) trying to get the old two stroke to run effectively but now I'm officially giving up on it. It's just been a money pit.

I've seen a few youtube videos where guys put 212 Predators into these old carts. I don't need it to golf but it would be an extremely useful vehicle around my 10 acre berry orchard. I like that it has the big truck box for carrying stuff. I won't be doing burnouts or anything, just need enough power to get me around, and to run back and forth to the shed. Princess Auto (Canadian Harbor Freight) sells a 7 HP honda clone engine with electric start that I'd like to use because it's short enough to fit under the body.

I'm going to put the old parts on ebay. Might post in the classifieds as well. Hoping to get enough $$$ to offset the cost of the new clutch, belt and engine.

Here are some challenges I foresee:

The old engine has a 6 splined hub and clutch. I wouldn't mind reusing the clutch just to save money. Not sure if this could be done even with machining. Realistically a comet 20 or comet 40 clutch would probably work better. I'd have to adapt the 40 series clutch to a 3/4" bore but that wouldn't be hard. The benefit of using a 40 series is that the belt size is closer to the secondary clutch's original belt size of 1 3/16" and it would also let me upgrade the engine someday. I could also likely find a standard belt that I can get in Canada that might be close enough, say the HP 3025 belt from Dayco. It's not exactly the same width (31/32" vs 7/ or angle but it might be close enough and it's easy for me to get. One challenge about living in Canada is that the comet belts and clutches are harder to get, they have to be ordered online, and are comparatively expensive with the exchange and shipping. Otherwise, I could just order a comet 20 clutch and a 3/4" belt and use that with the secondary clutch. Anyone have thoughts on the knockoff comet 40's?

Another challenge will be building a mount for the new engine. It has to be mounted on a downward angle to properly align with the secondary clutch. I've got decent welding abilities so I'll just need to design a mount that is fairly adjustable and weldable to the existing engine mounts. I'd like to use those mounts because they are already at the proper angle. The mount also has to be adjustable so that if I do use a different clutch and belt then I can adjust the slack in the belt so it works properly.

I'd like to get the electric start engine so that I can mount that up front and not have to lift the body off the cart each time I want to start it. I don't foresee this as being an issue but will take a bit of time.

Anybody have any thoughts or advice?

I'll try to post updates as I go. I'm trying to sell the old parts before I buy new parts so it might be a slow build.

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[raydhd]

You might want to look at my 440 suzuki in a HD in the sled section of big blocks. I use the original secondary. Even with the 40 hp + of the sled engine there have been no issues.

[raydhd]

The issue you REALLY want to think about is can a 4 stroke engine with its oiling system survive that 30 degree angle it is tipped at.

[rider.prider.king]

I too was concerned about the engine operating on an angle but the guy in this video https://www.youtube.com/watch?v=EtzUtqkWJHk said that’s the question he’s asked most and it sounds like his engines are fine with it.

A guy wants to buy my secondary and primary clutch together. So new question, the shaft on the secondary clutch is tapered. How hard would it be to adapt it and put a normal comet secondary clutch on? Anyone know what size that shaft is and what the taper is? I would be willing to get it machined down to a straight shaft but I’m not sure I could get it out of the rear diff either. Anyone ever try that?

Thanks for the help.

[raydhd]

The harley secondaries can be a problem to find for certain years. I would personally not sell it. The video does touch on the other issue of the cart being geared for a 2 strokes greater rpm range and with a governed 4 stroke it is going to be very slow. I put 20" tires on to gain gearing and MAYBE you could get a 22" tire in the well for more speed. P.S. If your primary is in good shape you will find plenty of buyers on E bay.

[Backroadbomber]

Which way does the rear axle input need to turn in order to drive forward? I remember having an ezgo that would’ve been a pain to predator swap because the secondary clutch would be turning the wrong way. Also, i would not sell your secondary clutch. Much easier to use it than to try to adapt another one to fit.

[raydhd]

The harley uses a CCW engine that faces backwards as the youtube video shows and the secondary also turns CCW with it facing forward.

[rider.prider.king]

It does seem to turn the proper direction to mount a 4 stroke in there. I got the secondary clutch off today. It actually has a hub with a shaft that looks like it’s about 1 3/8 in diameter. This would be perfect because then I could get a key way cut in or just bolt a sprocket with weld on hub to that shaft. I could then trim down a similar hub and sprocket to fit on a torque converter. Then I could adjust the gear ratios slightly to give me some better top speed. Only problem is that the guy buying the secondary clutch might want that hub with shaft but we’ll see.

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[rider.prider.king]

Update: Sold off almost all of the parts from my engine so now I have the freedom to buy new ones. Had to get a custom shaft built to mount to where the 4 bolts go through the brake to hook up to the rear diff. Fortunately I have a friend who works at a machining shop and can custom build the part for me. It'll have a 1" keyed shaft which will get a sprocket that will be chained up to a Torque A Verter 30 series torque converter. The beauty of this system is I can easily change my gear ratios however I want. The TAV will be mounted to a 7 hp engine with some minor mods for extra hp.

I'll need to do some modification of the frame to get the engine mounted and I also want to level out the axel so the diff and brake sit straight. Sounds like this is what people mean by reclocking the axel. Can I just unbolt it and toss in some washers under one side so it stays level or is there an easier way to get it so that the axel, rear diff, brake etc are all on a level plane rather than having it stick up like the stock version is?

[sho305]

Figure most stock GC engines are 8.5-11hp, the 212 will work but not be that powerful. Others have done it and on level ground they run ok. I don't know much about harleys but the torque converter setup is best way for you to go. You may not have reverse most 2 strokes run the engine backwards for reverse. Clocking the axle usually you either cut the mounts off and re weld them on, or fab up a shim/block to twist it and still securely mount it. You'll have to check other things like brake cables to make sure they still fit.