Predator Components

Huffy Cranbrooks come with 12 gauge spokes ? That's good to know....that's a major re-do for most bikes. What kind of fork did you use on your 2-speed Wayne ?

MHF
 
Just some cheapo Mtn bike suspension forks and brakes I found for $10. Here's a pic before I added the second speed.
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We built a test bike with the 99cc Predator engine. We are using a 12.12:1 gear ratio. Hills are not a problem for this setup. We have a hill near by that is 1/2 a mile long and a 8% grade. The 99cc Predator climbs this hill with ease (just like our 79cc bikes do). We haven't checked top speed yet. Based on comparison with our 79cc bikes this bike should go a little over 30mph at 6000 rpm. Our speed calculator says it should go 38mph. Our Predator has a high flow exhaust and the govenor has been removed. The 99cc Predator is a great little engine!
 
frozenveinz said:
3/4 EMT.. Sounds good, was it easy to bend? I am assuming that is the SBP muffler? Does it fit on easily? Lol sorry for so many questions, just wanna get this all right.

http://www.homedepot.com/h_d1/N-5yc...splay?langId=-1&storeId=10051&catalogId=10053
This here should be enough for so many bikes.. And at 15 bucks too.
EDIT: Nvm the 3/4 steel conduit is better. 10ft $4 and is supposeedly flexible and resists kinking.
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I believe the muffler is just a 3/4" hot dog muffler (you can find it at any lowes/homedepot). I am using it as well, and it seems to work great. Very high flowing, and reduces the sound output quite well. BTW you can't use that flex conduit in your link because it is aluminum.

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I found a possible option for a nice exhaust system... I was shopping at lowes today and some stainless steel flex tubing caught my eye. I checked it out and it looked pretty beefy, and it did not have a liner on the inside that could melt if used as an exhaust.

Here is is:

Shop Watts 1 FIP x 1 FIP x 18-R Inch Corrugated Stainless Steel Water Heater Connector at Lowes.com

The picture makes it look small, but it is indeed 18" long. Let me know what you think of this option...
 
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ThatS right, I used a 3/4" hotdog. Started with a 1/2" but found it restrictive
If you improve the breathing of this engine, you will need to drill out the main jet some. I drilled mine out to .028
 
I used 7/8" I.D. exhaust flex pipe [tuned], drilled main jet to .031". Ratios in the high nines exceeded 50 MPH [way too fast]. During original tests [11.55 X 1 ratio] bike easily pulled long steep hills [high windy bridge]. Did several test runs from a complete stop at the base of the hill, and motor accelerated easily, gaining speed all the way to the top. The motor has a lot of torque for its size, and pulls hard.

Have fun,
 
That all sounds great. My funds for this build should come in tommorow morning. Then I will begin the wonderful process of buying toys and the ordeal of waiting for them to come. :) BTW, whats the max I should safely rev this engine?
 
frozenveinz said:
That all sounds great. My funds for this build should come in tommorow morning. Then I will begin the wonderful process of buying toys and the ordeal of waiting for them to come. :) BTW, whats the max I should safely rev this engine?
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Keep it around 5000 and the engine should last you. A properly tuned engine will be able to possibly hit 6000, but nobody knows how long they will last at those RPM's.

On a side note, nobody's predator has broke yet since people started putting them in bikes with the governor removed, so that's a good sign!
 
It is very possible to exceed 6000 RPMs with the right intake and exhaust system, however I would strongly suggest not doing so. I can assure you the plastic section of the flywheel won't stay intact at higher RPMs for a long time period. I know this to be a fact as the plastic on my test motor has already loosened and cracked. It was necessary to re-secure it to the flywheel and repair [hot glue] the cracked section.

I have been testing this motor using the Q-Matic drive, and I only mention this to explain the reason for faster and higher RPM levels. The Q-Matic locates the large Max Torque clutch to the rear of the drive, not on the motor crankshaft. By NOT installing the clutch on the crankshaft, there isn't as much flywheel weight, and the motor spins up much faster. In addition, locating the clutch at the rear of the drive also allows the reduction to be ahead of the clutch, meaning the clutch only spins at 1/2 [approx.] motor speed, using far less energy.

It is also important to do a proper "break-in" if you want the motor to last longer. According to the manual the "break-in" is a two stage event, and on page 10 it explains it.

7b. "The operational break in period will last about 3 hours of use".

7c. "The maintance break in period will last about 20 hours of use. After this period: change the oil".

Looks like it has a "operational" and a "maintance" break-in period, which totals 23 hours. If you travel at say 25 MPH average for 23 hours it would be approx. 575 miles before complete break-in.

I started off on the wrong foot as I changed the oil at 50 miles, and most of the milage was at speeds below 25 MPH. I have also changed the oil at 100 miles, 300 miles, and again at 500 miles [whoops, too many oil changes]. It currently has over 14 hours of running time, and just over 500 miles, which makes the average speed approx 35 MPH during break-in. I am running this motor hard, trying to locate any weak parts, and other than the flywheel issue it is doing very well.

I just returned from a 15 mile run at WOT and the motor pulled hard up to 50 MPH and stayed there with very little effort. Please don't try this on the average bike, as I am using a HD frame, Worksman wheels, front Whizzer brake, HD Whizzer front forks, flat road, no traffic, wearing a helmet, leather coat, and 15 years experience as a professional motor cycle racer [x-racer, not current]. I am also somewhat "speed crazy", and suggest you don't go this fast, as it can be very dangerous.

Have fun,
 
Quenton Guenther said:
I just returned from a 15 mile run at WOT and the motor pulled hard up to 50 MPH and stayed there with very little effort. Please don't try this on the average bike, as I am using a HD frame, Worksman wheels, front Whizzer brake, HD Whizzer front forks, flat road, no traffic, wearing a helmet, leather coat, and 15 years experience as a professional motor cycle racer [x-racer, not current]. I am also somewhat "speed crazy", and suggest you don't go this fast, as it can be very dangerous.

Have fun,
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Out of curiousity Quenton, do you use the CB-110 hub with your worksman rear wheel or do you beef up the hub also? Thanks.
 
Hi jowens,

The wheels were taken from a Worksman tandem. I relaced the front to include the Whizzer front brake [works great]. The rear hub is the HD CB-110, and is larger than the stock CB-110. I took it completely apart, cleaned, inspected, and re-greased with hi speed synt. wheel bearing grease. I then installed a hub adapter [from Pirate Cycles] with a 56 tooth sprocket.

The Worksman wheels have the .120" spokes [11 ga.], and I doubt I will have any issues with the wheels.

Have fun,
 
DOH, forgot about a wide crank. What would be the easiest to install and where could I get one? Or could I bend the stock ones wide enough?
 
If you use the right motor mount and mount the motor high you can use a shorter pedal crank and pedal extensions. This is far less costly and easy to find the necessary parts. The pedal crank used on most 24" bikes are 1" shorter, and normally will pass under the motor, just need to add pedal extensions.

I doubt you will be able to bend the original pedal crank enough to clear the wide motor.

Have fun,
 
I had no problem reshaping the stock preal cranks on my Schwinn to clear the Predator. Of course the engine is mounted 180 degrees from your mounting. That may or may not affect it.
 
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