Got the 33Saw running, 34 mile roundtrip test ride.

Thanks for the report!

Yeah, the Bell walmart stuff is O.K., but not great.

Good job, Charles!

Don't forget to grease the pivot hinge for less resistance and friction.

As a suggestion, try moving the springs' attachment point TEMPORARILY to the top of the hoist. You should have greater mechanical advantage and need less spring tension.

JMO, the cheapest way would be to find a larger, more powerful chainsaw engine. You might get 5mph faster.

The cheapest and most effective way to double your hp would be to install another engine in front.

Once you go twins, you'll never go back.

1. At walking speed, the dual-engined bike feels awkward, like having a front basket full of groceries. When parked, I use a rope to tie the right handlebar grip to the seatpost to keep the bike from twisting and falling over.

Once it rolls past 5mph, it feels stable. When both engines had friction rollers, with both engines off, my bike felt sluggish with resistance drag.

2. It doesn't matter if the engines are matched or not. You mightl favor one or both engines at top speed, one or both engines at low and midrange. There are a lot of combinations of using two engines, all of them pleasant, a few you will find are awesome.

3. The front friction roller is 1.25", which is equivalent to 24:1 gearing with sprockets.

The rear sprockets have 18.75:1 ratio, equivalent to a 1.6" roller.

If you throttle the 1.25" roller engine to midrange, release throttle and stab the rear engine, it sounds just like shifting gears.

I start by pushing off, with a little throttle on the chain drive. This saves the front tire of friction wear from its roller. One second later, I throttle both engines simultaneously and the bike launches harder than a moped.

Both engines like to cruise between 20-25mph and are very mellow running together or alone.(I think the engines like to run together ALL the time.)

On hills I like a running start with both engines pushing the bike uphill with 4.4hp. The front engine peaks and starts to strain. I release its throttle and the chain drive rear engine is on its own(but doesn't want to be alone). A few seconds later you hear the rear engine lose rpm. Before power is lost, I floor both engines. It's almost like a supercharger because power is increased 100%, from 2.2hp to 4.4hp. The rear engine REALLY appreciates the extra assistance and gains speed. Sometimes if it's 20-something mph going uphill I also pedal with the smallest sprocket.

4. I fabricated a lever which raises and lowers the front roller onto the tire. It works VERY well in applying pressure. However, I just lock the lever in place and leave it there. The rear engine is powerful enough to overcome the front engine's drag.

The rear engine has chain drive so freewheels and no drag.

Both engines have centrifugal clutches. They work VERY well together. The rear engine never strains because of its high ratio and never overrevs. When it begins to run low on its power range, its twin kicks in like a supercharger.

Twin engines are an awesome, almost unbeatable combination.

Charles, it is easier to fabricate a lever/gravity clutch on a front engine than the rear. Take a look at how comfortableshoes did her rear engine install for suggestions.

Or do a mirror-image install of your rear engine onto the front.

I'm running two Mitsubishi 43cc 2.2hp engines. One Mitsubishi is not enough for my needs.

Sometimes TWO Mitsubishis doesn't seem like enough.

They probably are. I am FLYIN' uphill and on the flats.

I just need to find the right gearing combination to maximize efficiency.

Right now my rear gear is 18.75:1, which is like 1.6" roller.

My front roller is 1.25", which is like 24:1 gears. It's like shifting gears when running only the front engine, then only the rear engine.

It's easy to swap to 15t rear sprocket which is 20:1. I can try that.

It's much harder to press out and change rollers, but I also might try 1.375".

Or I might try a front 1.5" roller and a 18.75:1 rear gear(like 1.6" roller).

Orrr 1.5" front and 15t back sprocket, which is 20:1.

The bike, engine combination and I (the whole package) likes to cruise between 20-25 mph.

Actually, the engines could probably cruise between 25-30 mph or even faster, but the bike's weak points, my own human responses, road conditions and traffic makes it too hazardous.

If the road is clear and the cars are a couple of city blocks behind me, I will full throttle it until the cars catch up. Then I jump on the sidewalk until they pass me by.

When full throttling the rear chain-driven engine I can hear it start to lose rpm on flat ground. Then I simply floor both engines(and maybe also pedal). The front engine is at its max rpm and hp range. You can feel the bike accelerate and the rear engine pick up speed, then you release throttle on the front engine. When you hear the rear engine's rpm lower, you full throttle the front engine to pick up speed and help the rear engine accelerate.

On a long stretch, this procedure is replayed over and over, like intermittent injections of nitrous oxide.