99cc PREDATOR FUEL ECONOMY ?

compared to what motor with what gearing
what rpm range will your be used in and what gearing
with what weight and how are you going to put the power to the ground



a motor that never sees above 3600rpm at 30mph will get better mpg then the same motor and bike that is run at 5500 rpm to do the 30mph

Andrew I also will be building a Predator onto my bike and am following this thread to find out what others experience has been if any. My set up will be Identical to yours as far as having a stock Qmatic and have a modified intake but I will be running a muffled exhaust. I have also decided that I will run a final gear ratio of 9.88 X 1 with keeping my 48t rear sprocket on my Pirate hub adapter on a 26" wheel. I may change the gear ratio by way of changing the primary pulley on the Qmatic to an adjustable from Grainger. Like you, if no one has provided any real world experience, I will post what my findings are after I build it in about 3 weeks. It will be interesting to see your results being in thinner air compared to mine at sea level also.

Andrew
Scotto gets around 80mpg with his 212cc pred motor so the 99cc should at least get that and better

I built a worksman folding trike for a friend with the 99cc predator, he gets 130 mpg + with his 270# butt on it

The manual for my Lifan 97cc states 445grms/hr @3600, thats around 15.7oz. Basically you get 8hrs/gal. run time. My bike averages about 20mph, 24 on the flats, 19 up the worst hills. That would compute to 160mpg not unreasonable, I have heard of higher. These are ideal conditions though. Hills really eat fuel as does high speed(wind resistance). In real terms I am getting 120-40 depending on conditions. The Preadator may do better as it is OHV vs. the Lifan being a L head. OHV being more efficient. I have based these figures over about 2K miles of riding and they are pretty accurate. This is on a touring bike in a cruise configuration. I am sure a lot of WOT on a more sporting ride would eat more fuel.

Cannonball

is that with a cvt or centrif clutch and jackshaft ?

the comet cvt has reduction of 2.73-1 and a overdrive of .90 using 35 chain and a 72 tooth sprocket out back at 3600rpm 26 inch tires gives 42mph WOT

No this is a big bore FD Running a 2.125 roller. Also the engine is still governed. It acts basically like cruise control, set it and forget it. The top rpm is around 3800. For long term cruising its great. Out in the sticks I can ride great distances and never deal with the throttle. Also makes it more fuel efficient I believe.

I have the AGK big bore carb and a 1" muffled exhaust on mine and I can say fuel economy is not it's strong point, top end with a ratio of 10.5 with 29" wheels, 45mph top speed, takes a bit more throttle for the hills due to gearing and my weight(235), cruise on level ground @ 25ish is like 3600rpm, hardly touching the throttle. all in all I feel it gets less MPG than the HS49, but I never have to pedal!!

Mac

High top speeds and a higher ratio would reduce ecomomy as the engine is under a constant heavier load of some sort. My criuse bike is ratioed so it runs at 3400 at 22mph. On the flats its is really unloaded and easies along on low power output. It does drink some fuel up hills as much as a 20mpg loss in hilly rides. I recently went on a 100+ mile round about and on the return I was bucking a 15-20mph head wind, that eats fuel also. If gas really goes to 5 bucks a gallon milking the most mpg might become an issue, right now Im not too concerned. I had been running a 2qt tank and carrying a full gallon can on really long rides. I have since replaced the 2qt with a one gallon ao I dont have to stop and top off the tank on all but the longest rides. I still can carry the gallon can also. I dont mind feeding a 97cc, I never have to pedal either. Got another bike for that.

I've run three tanks of fuel through my predator 99cc, a little over 200 miles on it now with an average speed of about 21 MPH according to the bike computer. This is stop-and-go city commuting.

Tank 1: 118.2 MPG
Tank 2: 119.1 MPG
Tank 3: 105.1 MPG

I think the drop in the last tank is because we've gotten a lot of rain the last week. This is on a friction drive so there is some inefficiency there as well. I get a lot of roller slipping in the rain.

I ride about 12 miles per day, and like to cruise around 3400-3900 RPMs which is about 24-28 MPH.

RicksRides said:

I built a worksman folding trike for a friend with the 99cc predator, he gets 130 mpg + with his 270# butt on it

Click to expand...

However he rarely takes it past 26-2700rpm. He has balance issues and cruises on the slower side

LOL both of mine will only start on the first pull when hot and choke applied. Nature of the beast, made that way to meet CARB regulations.

same here, usually takes 2 pulls when cold, one pull when warm/hot. and ALWAYS needs choke on for starting.

If you pull a time or 2 just to open her up and spread some oil, can accidently start her.

Other times, she just messes with me! snork.

Is real important to follow the starting instructions. It is a simple engine but you can rip up the pull start real easy.

What I do is (in warm weather, cold starting) 2 easy pulls to turn her over and find where she is ready. Then one sharp. Normally fires off on the meaningful pull.

From the manual;

1. To start a cold engine, move the Choke to the
CHOKE position.
To restart a warm engine, leave the Choke in the
RUN position.
2. Slide the Throttle or Speed Control Lever to 1/3 away from
the SLOW position (the “turtle”).
Note: Some tools have a Speed Control Lever located
elsewhere on the tool which functions the same as the
Throttle. Use the Speed Control Lever in place of the Throttle
when the tool is so equipped.
3. Turn the Engine Switch on.
4. Grip the Starter Handle of the Engine loosely and pull it
slowly several times to allow the gasoline to flow into the
Engine’s carburetor. Then pull the Starter Handle gently until
resistance is felt. Allow Cable to retract fully and then pull it
quickly. Repeat until the engine starts.
Note: Do not let the Starter Handle snap back against the
engine. Hold it as it recoils so it doesn't hit the engine.
5. Allow the engine to warm up for a minute then
slowly move the Choke to the RUN position
if it is not already in the RUN position.
Note: Moving the Choke Lever too fast can stall the engine.
IMPORTANT: Allow the engine to run at no load for five
minutes with no load after each start-up so that the engine
can stabilize.
6. Adjust the Throttle as needed.

Just what I do. Is embarrassing trying to "yank" start her when she just don't wanna go. Warm up pulls make it look like ya know she will fire off on the hard pull.

That's tha same procedure I use for hand propping my Continental aircraft engine or kickstarting my Harley.

I flip it thru 3 or 4 times with ignition off to charge the cylinders with fuel, then they start on the first brisk flip with ignition and slightly cracked throttle on the harley.

I finished my fuel milage test yesterday. I have been running thru this tankfull with moderate use by trying to maintain speed at 30 mph and 4200 rpm with stopping and take offs about 3 miles apart average.

I used almost exactly one ounce per mile,or 128 mpg. Never did that good with the Chinagirls. They are mostly run at nearly WOT to make 30mph.