Twin Engines

The engine's in the mail!

I just contacted David Staton. This Mitsubishi engine kit will ship out today, and is engineered to bolt on in less than one hour.

Fortunately, the bike shop I do business with knows my bike. I bought it from them three years ago and buy all my bike parts there. Last month they scratch-built my new front and rear tires, wheels, axles and bearings specifically for severe-duty use. The matching pair have HD rims and spokes, kevlar protection, the same high-performance tires and high-speed grease.

I kinda miss the electric hub, but at times I could actually feel the bike's frame twist from the extra 100 lbs. of e-drive.
 
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good luck with it - the clutch thing I mentioned that worried me was if the clutch was stressed from the non drive side (while the engine is off or idling) through bad alignment it might hurt bearings and mechanicals and such...

I've had an interesting day - 2 busted spokes and a coaster brake that uncoastered itself at about 30 mph with a large and distincting pinging noise. I had to wheel the bike on the front wheel - not someone I want to attempt again - I was wheezing within 50 yards just because of the problem it caused with balancing and such.

we want to see pictures..

Jemma xx
 
Jemma, I'm banking on both clutches' complete disengagement on cue.

Hmmm, dual engines should produce twice as much drag at idle. Maybe if both clutches are engaged, there will be less rolling resistance at speed. If the drag is substantial, I'll try lifting the drive assemblies off the tires.
 
I've been thinking about this... Why bother with the two different gearings when you could run the same large roller on both and still have twice the power?
I know you already ordered but it would be really nasty to have those two engines howling together with a single throttle control :)
 
SirJakesus, that's a possibility I can experiment with, if and when I buy another 1.5" spindle. A large roller sacrifices low end, but two engines with large spindles MIGHT push harder at all speeds with 4.4 hp at top end. Granted, because of the layout all this hp would not be fully harnessed.

However, using different-size rollers would allow one engine to produce great low end torque AND be assisted by the second engine spinning slower and producing less power. The lower-geared engine is being helped throughout its range, so the bike should be quicker since more hp is being tapped. When the lower-geared engine reaches its peak, it is no longer usable and drops back to idle speed. The second engine is now in its optimum power range and pulls the bike to maximum speed. When you have an engine with 1.5" roller, it's like starting from a stop in second gear with a manual transmission car. Throttle response is sluggish and the engine stumbles weakly, trying to reach its sweet spot. Now if you start off in the correct low gear, the car engine will reach its optimum power quickly. Shifting to the next correct gear at a higher rpm will allow the engine to regain its optimum power range much faster. This would allow the car to accelerate quicker, hopefully reaching top speed before runing out of road.

Sounds logical?
 
Besides, the rear engine with larger roller has an ADA-1 tuned exhaust pipe, which is pretty conspicuous. The front engine will have the stock exhaust. Less power but more unassuming. I just hope the new engine doesn't **** out at high rpm. The rear engine pooped out with its stock exhaust. After I installed the tuned pipe, it screamed to redline with a 1.125" spindle.
 
I understand your point on gearing them differently however I think if you're able to manage with the single engine geared high right now having two engines geared high is still going to give you a substantial kick in the pants and it'll allow you to maintain high speeds even up hills. If you hit a hill that your current system farts out on you'll have to shut that motor down and go back to the low gear engine. With two geared the same you'll have lots of power through the full range of the engines powerband. It'll definitely be a cool experiment either way. Are you thinking about mounting one large gas tank that both engines feed from at the same time or are you going to run two separate tanks?
 
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Torques, it'll be like having two large red/black overgrowths instead of one.:cool:

Dave Staton reminded me that the bike might be off-balanced and heavy to steer. I've carried heavy batteries in my front basket for my e-motor before, so I can live with it. I hope I don't have to change my suspension fork, because it definitely softens the ride.

SirJakesus, my plan is to charge up the hills, maybe with both engines firing. The 1.25 low roller is a good compromise and should pull strongly. If it doesn't redline, then both engines pull the bike uphill. If the front engine overrevs, I release its throttle completely and rear engine is on its own. If high gear poops out, all I do is throttle both engines to accelerate the bike upward or pedal-assist. My hills are few, short and medium-sized, unless I take the long way home. There are two steeper hills worth challenging.

I'll use the stock tanks for now. The teardrop tank would be hard to mount, since "Girlie" doesn't have the center bar. It's an inconvenience to fill the tank every 20 miles, so now it'll be a double PITA.
 
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