SBP 4 Stoke Prototype

glacknoid said:
Houghmade: Where exactly did you drill a hole, at the end of the pipe on the bottom of the fat part? And does it help.
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Yes- right in the center...and- other than being a bit louder, don't know if it did anything. I was making a lot of changes when I did that and I cannot tell if that change did anything. All I can say is that it runs fine, a bit louder than stock, bit that's fine with me.
 

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Well I finally got to take her for a spin and I must say it is pretty fun. Completely different experience from the 2 stroke, of course it is on a Cruiser as apposed to a MTB. The torque is pretty awesome but it doesn't seem to pull top end like the 2 stroke but then again that is the difference between a 2 stroke and 4 stroke. So I am in the process of double checking all the hardware and adding lights and speedo, etc and the weather is supposed become decent again by this weekend so I should be able to get some performance figures.
 
Hi Ghosto,
My 4 stroke pulls very hard on the top end, and easily out paces a 138 CC Whizzer up to 37 MPH [top speed with current ratios]. When cruising at 20 MPH and grabbing a "handfull" of throttle it will lurch forward with serious gusto.
After testing it against the "Hoot" & "Grubee" gearboxes it soon becomes clear that the EZM drive system doesn't eat up most of the power in the gearbox [the EZM doesn't use gears or grease], and the loud "singing" noise is gone.
Of course the EZM flex exhaust system sure doesn't hurt the power any, and appears to allow the motor to vent the the spent gases more freely.
The most common asked question is "I know you are well known for pulling power from a motor, so what have you done to the EZM?" Other than changing the exhaust sytem the motor is 100% stock, and I only changed the exhaust for cosmetic reasons.
I am going to run the STOCK 49 CC 4 stroke on the "Roller Road" in Dawson Springs, KY next month, and I will share the results on this site.

Have fun,
Quenton
Get YOUR EZmotorbike TODAY!
 
My 67 cc modded China motor with SBP shifter kit easily pulls away from Whizzers, so that's not a huge thing IMHO.

We'll need to see your gearbox to see if we can adapt it to our jackshaft. The goal is to get away from the "bolt on spoke bender" and use the bike's gears.
 
muder 15
There is a freewheel in the chainring assembly allowing you to pedal the bike but once the engine speed becomes faster than your pedal speed the pedals can remain stationary.
 
Hi Pablo,

Consider the following........
When compairing a single speed 4 stroke EZM [49 CC]against a single speed 4 stroke Whizzer [138 CC], the larger displacement Whizzer has a hard time keeping up. If the Whizzer or the EZM were able to use your shifter system it would be an advantage over the single speed. For example if the Whizzer could change ratios it would most likely out run the EZM, or if the EZM were to use your shifter kit it would only increase the amount the EZM would be out front.
It is also important to relay a few more interesting facts, we started with ratios of 22 X 1 and soon found the motor maxing out the RPMs. We continued to change the ratios to cause the motor to "hit the wall", and because of the desire to cruise within the 4 stroke's torque curve we ended up with a production ratio of 16.3 X 1. Our kit will easily exceed the current top end speed by changing the ratios. When I displayed the proto-type at Lewes, DE last year it was geared at 17.56 X 1 and went faster, both in take off and top speed. Both the Honda & HS 49 CC 4 stroke motors will reach into the higher RPM levels when the "drag" is reduced, and both motors find RPMs above 8000.

With our current ratios the motor is only turning 6350 RPMs at 30 MPH [38 @ 8000 RPM].

Your shifter kit would most likely increase the top end of our motor above 45 MPH, and also take off faster. The ability to "shift" would be an advantage in hilly terrain, and an advantage with heavier riders.

Have fun,
Quenton
Get YOUR EZmotorbike TODAY!
 
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GHOST: Does it seem like it doesn't pull the same top end because the gearbox does'nt produce the same rpm's at the output or because it doesnt' have the torque it takes at high rpm to push the bike? Would a step up or down with the final sprocket on the jackshaft make for better top end?
 
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All good questions which I don't have an answer to yet. I haven't put a speedo on it yet so it is really hard to judge speed. It may be singing right along but I just don't know it. My initial feeling is that it is geared a bit tall and I may go down to a 9 tooth on the jackshaft but is still starts from a stop without assist very easily so only more testing will tell.
 
I'll gladly volunteer for high altitude testing. I was bummed that I didn't get chosen to test the new SBP tuned pipe.
 
In relation to the exhaust pipes. I have one bike with the kit exhaust on it and one still with the original honda muffler and I think the honda one sounds better. Both have the gearboxes bolted on and I swear the original sounds more appealing to me than the kit pipe. These four strokes need a pipe that sounds smoother. I'm tempted to try leaving the original one on to see if the exhaust pointing forward is a big deal or not.
 
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