Project 29er With Twin CY460 Engines!

[5-7HEAVEN]

My Project Scooterguy w/Tanaka 47R engine is done!

Project 29er started late last year, but a few changes will be made. The same goals of quick acceleration, brute midrange and 40 mph cruising speeds are in mind.

However, with what I have learned from my center frame engine build, there are issues I'd rather not deal with. Chain jumping and breaking is one. And no matter how well you seal a two-stroke engine, EVERYTHING behind the front of the engine gets covered with a fine mist of engine oil. Besides that, there are interferences with exhaust, Happy Time fuel tank and the rider's legs. Burns on both legs are possible.

This build will use TWO CY460 4.5 hp engines, rack-mounted w/Staton twin-engine gearbox. The NuVinci hub is already mounted on HD double-walled aluminum rims. "Big Apple" 29" tires should work very well for this street application.

The frame being used will either be a steel KONA or aluminum DIAMONDBACK 29" unit. I really like the Happy Time 4-liter fuel tank. It holds enough gas to feed a Tanaka 47R for nine days. Five days of feeding two engines will work for me.

Exhaust and noise might pose issues for the twins. I've run a SBP Happy Time expansion pipe on a center frame-mount 460 engine before. Despite the serious mismatch between exhaust port and SBP pipe, there was a huge power gain, especially at low and midrange. This pipe also made the 460 EXTREMELY quiet, which was surprising. The only downside was that engine oil spray from the muffler was very significant. This shouldn't pose a serious problem if exhaust tubing extends past the rear wheel.

Since both engines have separate centrifugal clutches, their throttles do not need to be synchronized. Methinks that two hand grip throttles and a set of hydraulic disc brakes will simplify matters on the handlebars.

Engine clutch springs are my favorite things to break, especially miles from home. Twin engines should eliminate a total breakdown on the road. If one engine craps out, the other will bring me home.

I can't wait to get this show on the road!

 

[MotorBicycleRacing]

Sounds like another wild machine so we need pictures!

 

[5-7HEAVEN]

This project is moving slowly. I'm a full time student AND a full time State worker and a family man, so time is precious. My commuter MB broke its new cassette; luckily, I had bought two, so repairs were done within 36 hours.

My friend Rick gave me his broken Staton twin-engine gearbox. I ordered every moving part in the gearbox from Staton today, and will reassemble it myself.

Looking for that second 460 engine now.

 

[darwin]

9 ponies and your hoping to go 40 mph? Your funny...........as far as throttle would one of those dual pull brake levers work?

 

[5-7HEAVEN]

LOL, I meant CRUISING at 40mph.Of course, the bike should have enough power to push past 50 mph. I need to be VERY careful not to break the speed limits here.That's a good reason to get pulled over.

Dual brake levers might work well if each engine controlled separate rear wheels, like on a trike. Separate throttles work better. I had two thumb throttles on my twin-engined cruiser. They worked perfectly.

 

[Deleted Member 4613]

But can you actually finish such a project?

 

[sparky]

If you're really shooting for top speed, I would theorize that one engine is plenty and will provide a better set of trade-offs than two engines.

Especially with a Nuvinci & Tanaka 47cc on a 29er frame.... you're definitely going to be able to take care of some hills and get your top-speed up there, as well.

Either way, I can't wait to see how this turns out.

EDIT: Nuvinci on a 700c rim w/ Big Apple 2.3" tires is my ultimate, long-term goal. I just want to use the lighweight 5:1 reverse gearbox that's only $25 or so on Dax's website and elsewhere. If you can figure out how to mount your 1 engine to this 1 gearbox to your 1 nuvinci 29er wheel... I think you'd be pleasantly surprised at the weight, speed, & acceleration. Only problem is that the gearbox doesn't freewheel and the nuvinci's sprocket is fixed... so a freewheel must be added one way or another. I think that solving that dilemma would be more worthwhile than a second engine that will just weigh you down and add more friction. Just my humble opinion, of course...

 

[sparky]

Hmm.... it appears that you already know of a "freewheel mechanism" that bolts to this gearbox...

I do.

My 5hp+ GP460 high-rpm engine is connected to the 5:1 pocketbike $25 gearbox that no one here mentioned. The box then bolts onto the Scooterguy frame-mounted engine plate.

JMO, this 5:1 is the most versatile, compact tranny available. Linked to the Scooterguy frame-mount, any engine with a 76mm clutch will bolt on. There are quite a few engine sprockets that are available. You can use SBP or pocketbike chainrings and freewheel mechanisms, which then transmit power back to the rear derailleur.

This is the cheapest gearbox available. Combined with a NuVinci hub or multi-speed cassette, there is no other combination that will better maximize any engine's performance.

Ahhh... but now that I'm looking at it, it appears you're referring to freewheeling crankshafts.... which wouldn't help out on most rack-mounted setups. But this is in the frame-mounted forum.... and by reading your complaints with frame-mounted setups in the OP... I am officially confused.

 

[5-7HEAVEN]

But can you actually finish such a project?

This project is more than just slapping on the Staton drivetrain and two engines. Whichever bike I choose will need total engineering and upgrades.

Weight might need to be added to front end.

 

[5-7HEAVEN]

If you're really shooting for top speed, I would theorize that one engine is plenty and will provide a better set of trade-offs than two engines.

Especially with a Nuvinci & Tanaka 47cc on a 29er frame.... you're definitely going to be able to take care of some hills and get your top-speed up there, as well.

Either way, I can't wait to see how this turns out.

EDIT: Nuvinci on a 700c rim w/ Big Apple 2.3" tires is my ultimate, long-term goal. I just want to use the lighweight 5:1 reverse gearbox that's only $25 or so on Dax's website and elsewhere. If you can figure out how to mount your 1 engine to this 1 gearbox to your 1 nuvinci 29er wheel... I think you'd be pleasantly surprised at the weight, speed, & acceleration. Only problem is that the gearbox doesn't freewheel and the nuvinci's sprocket is fixed... so a freewheel must be added one way or another. I think that solving that dilemma would be more worthwhile than a second engine that will just weigh you down and add more friction. Just my humble opinion, of course...

I have two 29" frames. One will be a 29er w/twin 460's; the other will be another Tanaka 47R engine w/center-frame mount, that 5:1 gearbox, shift kit w/8-speed cassette. Both will have wide rims w/Big Apple tires.

Actually, I'm shooting for acceleration, but speed will come..

Here's why I need this: I always claim the lane. I don't share the curb lane, so I don't have to worry about a car edging me into the gutter or curb. I also don't like to worry about last-minute drivers pulling in front of me or stopping in the middle of turning the right corner.

Here's what I do: In heavy traffic, I'll hop the curb, cross the street and wait for the red light. When the light changes, I hop back onto the main road and blaze down the road at the speed limit. This gives me an excellent headstart from the flow of heavy traffic. When this particular hill(short and steep) is gridlocked, I jump onto the footpath until I get to the hilltop. I'll wait on the roadside until there's a red light or a break in traffic. Then I'll blow down the road at the speed limit or 5mph over it.

What I need is power to accelerate and maintain 5mph above the 35mph speed limit, if necessary. There is also a half-mile strip of one-way traffic with a 45mph speed limit. A Morini engine or twin 460's would provide enough push to consider using this route to work. Any other engine setup that I have considered is too weak to try this fast route. I'm not considering Morini because of its troublesome clutch. The 460 also has an unreliable clutch. However, using TWO 460's would solve the problem of breaking down 20 miles from home. If one engine quits, I can get home on the other engine.

The Tanaka engine on my 26" Diamondback bike is very reliable, with a shift kit and 8-speed cassette. I've also had a 460 engine on this bike with friction drive, then with the shift kit. Between high horsepower and a steep learning curve, I've broken many 8-speed chains with the 460 and 47R engines. In fact, I bought a NuVinci hub, figuring that the cassette and 8-speed chain could never survive the abuse of a powerful engine. It has, so now I have a new NV hub to stick into my next MB project.

Actually, this 460 twin-engine idea was my friend Rick's idea. Sadly, he blew the Staton gearbox, gave it to me, and is now working in the Middle East. Now it's my turn to develop this crazy project.

Many members have used Morini engines; no one has ever tried twin 460's.