Big Engine Bicycle 79cc 4-stroke

Not a spoke breaker

There's a reason spokes break. They're not tight enough. At least with multi-speed freewheels the left side spokes aren't tight enough. They're that way on purpose.

Grab two left side spokes. Feel the tension. Now grab two right side and feel the tension. The right side spokes are really tight to pull the hub to the left/pull the rim to the right in order to center the rim and allow room for the cogs on the freewheel.

The more sprockets (cogs) on the freewheel (or freehub in the case of 7, 8, 9 speed and above) the more the wheel is dished. I would never go over 6 cogs. 5 is much better for our purpose. I tighten up the spokes on the left side as much as I can without altering the dish too much.

Also, check the spacers/locknuts on the axle. Sometimes you can put thinner spacers and/or locknuts to give you some room to lessen the dish. You might have to add spacing to one side or the other. You might have to run the rim a smidgen closer to the left side stays.

I run at least 36 spoke wheels, the bigger the spokes the better. At least cross 3, with cross 4 being better.

Learn to true your own wheels. It's not hard and can be done on the bike if you're lazy and don't want to put the wheels on a stand. It's much easier to keep one true than to true it up after it becomes wobbly. But even that isn't hard.

Just do whatever you can to lessen dish and tighten left side spokes.

If you haven't yet signed up for Harbor Freight's email list/Preferred Customer List. Print the coupons and save. Also all you have to do is ask "Can I get this for the online price?" (which you already checked, right?) and they happily sell it to you for that.

If I had to get a job () I'd try to get hired at HF. Just think - an employee discount, too.(y)

Ted
 
One more thing to stop breaking spokes. The last thing I did.

I ordered a shift kit from Pablo.:shifty2:

Ted
 
"Also, I found Staton has a 24" plastic rear wheel with both left and right hand threaded hubs. http://www.staton-inc.com/Details.asp?ProductID=3191
I'd love to get one of those, but I'm not sure how to get a larger sprocket (44T or so) on that wheel, since they only sell a 16 tooth LEFT HAND thread freewheel that fits it."


Staton has a 24-tooth A-type sprocket with left-hand threads to fit their left-side hub. It threads on, but with no freewheel. With a centrifugal clutch, the engine won't mind, but all chain and sprockets will be spinning while coasting.

If Staton can thread a 24-tooth A-type sprocket with left-hand threads, then ANY sprocket with enough meat can be machined with left-hand threads. Ya just have to find the machinist to do it, or ask Staton if he could do it for you.
 
BTW - just got a HFT flyer today and the 2.5 OHV engine is "on sale" for $89 - reg price $109 until 12/23/08. So I paid the sale price with no discount for buying the display unit.
 
Plastic wheels are fairly durable, the only negetive thing I have to say about them is they don't like hot sunny days, if they sit for any period of time in direct sun on a day that is even slightly warm, you come back to a bike with warped wheels and your brakes rub, the only way to fix them is to find a freezer big enough and put them in overnight, then hope they remember where they were prior to the exposure, the lighter colors like white or yellow don't warp as quick, but they still warp ! black is terrible. I think Andy Inchville has the answer to the Hub/Thread problem, you might PM him and see what he say's ?
 
I'll PM andy again. He said there was no sprockets he had to fit the wheel, but maybe he knows if the 44T or 48T freewheel from bicycle engines will fit. I figured it's a freewheel made for their special two-side hubs for spoke wheels, so it hopefully fits the staton hub as well. I'm pretty sure being only a 3600RPM engine, that the 80CC is more likely to break stuff than a smaller Honda50, so I want to be sure I have overkill for my rim.

Also, I'm really looking forward to a freewheel if possible because I plan on pedaling a LOT, but want the option of having the motor as well.
 
Hello , I just went by my local HF and they have one 2.5 hp engine in stock, I almost bought it But I wanted to ask you guy's first about the size of the engine, Is it small enough to put into the frame of a bike, Whizzer style ?

Thanks Jim
 
The 2.5 is too large to fit in the V of the frame.

IMO, it is almost too large for a rack mount. It has the same size frame as a Honda GX120 series 118cc engine, and it weighs over 20 lbs. Also consider the weight of a clutch, jackshaft, and rack - which isn't trivial.

The little Honda GXH-50 and "clones" are the perfect size (and have legal cylinder displacement) for MB projects, but you can't by them for $89 at Harbor Freight. It's the low cost for a horizontal shaft 4 stroke that makes this a good find.
 
No problem!

Even if you strip off the stock muffler and fuel tank - the cylinder will still be canted the wrong direction unless you find a gear reduction box to reverse the CCW rotation of the shaft.

Rack mounting or a pusher trailer would be best for this little engine.
 
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