Install Problem. Need Help!

I have run into a serious problem with my engine install and I need advice. I mentioned in my original post (see here: http://motorbicycling.com/showthread.php?p=596759#post596759) that I was concerned about the wide tires on my Huffy Deluxe beach cruiser not leaving enough room for the chain to run past. It appears my fears have been realized (see photos at end of thread). After I took these photos, I removed the rear fender but there is still not enough room for the chain to run. The lower run off the sprocket, past the fork, is barely squeaking past, thanks to the pulley, but giving that enough space causes problems farther up. Where the chain needs to pass by the tire to the engine, the chain is rubbing against the tire, on both top and bottom runs. I'm confused because other people claim to have used a Huffy Deluxe but I have seen no mention of this problem.

Can I somehow move the drive sprocket on the engine out 1/2" or make some other modification? Someone suggested shifting the rear wheel over on the axle but that does not appear possible since the hub+nuts already takes up the entire space between the forks. Even if that were possible, the tire would then be rubbing up against the original chain guard on the other side.

Do I just need to buy a new wheel with a narrower tire?

Everyone,

Here is an update with new photos and answers to many questions. First, no, I have not yet shortened the chain. I looped it around the sprocket to see how it would run. The tensioner is loosely installed but it's easy enough to adjust it, of course. The rear sprocket bolt heads do not touch the frame; there is enough clearance there.

Regarding the dished sprocket proposal: I can't purchase that part right now because I'm in Panama! Shipping anything here is slow and expensive, assuming the package arrives at all. Regardless, I don't think a dished sprocket would help because the issue is that the tire comes out too far into the path of the chain as it leaves the drive sprocket on the engine. And I don't have enough clearance on the fork end to use a dish.

The wheel was properly aligned in those earlier photos, maybe the camera angle made it appear that it wasn't. However, I found that if I intentionally misalign the wheel a TINY bit (1/8''), the chain is no longer rubbing on the side of the tire and has a clear path between the fork part of the frame and the tire. My concern is that this path is extremely narrow (no more than 1/8'' for the tire up front or the frame in the back), so any sway in the chain at all would cause it to brush up against the frame or tire. This of course would be bad/potentially catastrophic.

Please examine the new photos and see if you have any ideas. My conclusion at this point is that a custom mount or rear wheel (or at tire) replacement are the only solutions. The former isn't possible given my current location and level of expertise, so I'm planning on the latter, assuming I can find the right tire/wheel at a bike shop in the big city.

Thanks,
Steve

Victory! I have almost everything installed on the bike now and figured out a solution. After half a day wandering around Panama City, I finally found a decent (and affordable) bike shop. Here's what I did:
1. Replaced the rear tire and tube with a narrower set. I was able to use the original rim, which saved me a lot more hassle.
2. Used a 2x4 to bend the fork wider.
3. Inserted 3 washers on the axle next to the nut inside the dropout. This also gave me the chance to learn the Spanish word for washer, "arandela."

This gave me enough space to run the chain past both the fork and the wheel while keeping it straight. The bike shop also had caliper brakes, so I have those installed front and back.

I have a couple more questions for which I am going to start a new thread, but I'm almost there. Thanks for all your advice!

Boxcar,

Good idea asking for the bike shop location. Should I post the info here or is there somewhere else it would be most accessible? Regardless, here's the scoop:

Panama City has nearly everything available but finding anything is an undertaking. I found multiple bike shops but most seem to be very small and specialized, with very few parts available. The one I found that has many parts at affordable prices (probably due to somewhat questionable quality...) is actually in a large "everything store" called El Machetazo. Anyone looking for it should know that there are several locations in the city but, as far as I know, the only location that has a large bike department is the one near the La Loteria metro stop in the Calidonia neighborhood.

For those looking for higher quality parts and very specialized items, there is also the Rali store on Avenida Balboa near the Multicentro, on the avenida just before it turns to the north, away from the Pacific. That store has a lot of gear and parts but buying what I needed there (brakes and a new tire) would have cost more than my entire bike! If you want the finest components and price is no object, then Rali is the place to go.

A final note about motorized bikes in Panama: A gentleman at one of the stores I visited warned me that the police might confiscate my bike if I did not have a motorcycle license, since they could consider it a motorcycle due to the gas engine. This presumably would not be an issue for electric motors. I'm not concerned for my bike because I'm using it in a very rural area which has basically no police presence. Even if they were here, they wouldn't care. But this is a consideration for anyone actually planning to use their rig in the big city.