1. Longer rod cranks can be found at
www.motorizedbicycle.ca . They sell the Grubee GT5 kits which have the 85mm rods, all the others, by comparison have 80mm rods. All have 38mm strokes.
1b. If you want a STROKED crank, you'll either have to make one yourself or ask around. Arrow made a few and they can be found in their super-super high performance 9hp race motors as far as I know, otherwise, to my knowledge, they are not for sale.
2. A good pipe is best made on your own. Getting some 3/4 or 1" I.D. Steel pipe for a header (you only need 2 feet maximum), Sheet metal for the belly (chamber, a 2' x 2' should be plenty, 18 ga. or about 1mm thick), and a 1/2" steel pipe for a stinger (you only need about 6-8" of this) However aftermarket, prebuilt pipes... its hard to say. Arrow uses the zig-zag race pipe JNM sells on their 9hp motors. Each pipe has its own characteristics for which your motor needs to be tuned for. Torque pipes will need torque tuning, race pipes will need race tuning. This is for full effect of course, you CAN just put a pipe on an untuned motor and get more power, but for your needs, you'll want a longer, slender expansion pipe (giving you a broader power band)
3. Reeds are great on many, many levels. They do not normally increase torque because the nature is they restrict air flow (and at higher RPMs mean they dont close completely), but allow better breathing through much longer intake strokes. If you have a 66cc, get Arrow reeds, RSE are the closest to a direct bolt on, but are so small and restricting, arrow can breathe well enough to get high RPM's out of your motor.
Reeds help through reed porting your piston (cutting a large window into the intake side to let air in even when the port is normally closed, this reduces piston weight, which therefore reduces vibrations = good for bearings. It also allows air flow by the wrist pin bearing, bringing oil with it and lubricating it.), boost porting your cylinder (a shallow groove dremeled into the side of the cylinder reaching up from the top of the intake port, as high as the transfers are. This needs to be about 6mm wide, and a very shallow angle so the side transfers air gets "scooped" up and out of the cylinder).
4. Getting "hauling power" (or towing power, aka torque) is difficult on 2-stroke engines due to the nature of the piston doing the port work. They work best at high RPMs. If you're having trouble getting up hills, you may want to invest in a larger sprocket (48 or 56 Teeth if it's really bad) which is the cheap way out. The disadvantage: you'll lose top end speed. I calculate that if you can do 40 kph (~25mph) with the 44T sprocket, with a 48T you'll do 37kph (~22.8mph) and with a 56T you'll do 31kph (19.5mph)
The alternative is getting a shift kit, which will get you low gears for hill climbing and high gears for top speed. The draw back? it's install difficulty is above the kit install, and it's complicated, you can't do rolling momentum starts without a fixed gear hub (so you'd have to get going first, let go of the clutch, and start pedalling again to start the engine)
However there are a *few* mods that will get the low end power you're looking for: Higher compression, torque pipe or expansion pipe with long header, intake extension (silicone tube works great for this), widening ports (do not make them taller!), a stroked crank (more displacement), a better carb, [controversial] transfer port angle corrections, and timing changes (advancing the magneto a few degrees).
And finally 5. No, all our china HT kits are 66cc and some are 70cc (40mm stroke), none are 80cc unless they're stroked or overbored in a custom job.
