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Gas mileage only 81 to 85 MPG

Posted: Sat Dec 19, 2015 10:54 pm
by ahsteven
Hello, I just bought a PCX back in October and I am not getting the gas mileage I expected. I see people on the forum stating their getting over 100 MPG. I am only getting in the low 80s. My top speed is around 59 M/Hr and the bike shutters some on take off. What's wrong with it

Re: Gas mileage only 81 to 85 MPG

Posted: Sun Dec 20, 2015 12:32 am
by you you
ahsteven wrote:Hello, I just bought a PCX back in October and I am not getting the gas mileage I expected. I see people on the forum stating their getting over 100 MPG. I am only getting in the low 80s. My top speed is around 59 M/Hr and the bike shutters some on take off. What's wrong with it

How many tankfulls have you measured the mpg over?

Re: Gas mileage only 81 to 85 MPG

Posted: Sun Dec 20, 2015 12:36 am
by dkazzed
Used? Is that miles per US or Imperial gallons?

Might need a CVT servicing.

Re: Gas mileage only 81 to 85 MPG

Posted: Tue Dec 22, 2015 8:24 am
by stevecbr
are you UK based, just wondered if you have a 125 or 150?
I have a 2011 PCX125, 5500 miles,averages 98 mpg, and no shudder on accelerating. speedo reads 62/63mph most of time, i commute along A11 so WOT most of time
I believe if the valve clearances are incorrect, it could cause poor performance and mpg

Re: Gas mileage only 81 to 85 MPG

Posted: Wed Dec 23, 2015 8:10 am
by honkerman
ahsteven wrote:Hello, I just bought a PCX back in October and I am not getting the gas mileage I expected. I see people on the forum stating their getting over 100 MPG. I am only getting in the low 80s. My top speed is around 59 M/Hr and the bike shutters some on take off. What's wrong with it
Could be a number of things. Need to know more though.

How many miles are on the machine?
How fast are you normally riding?
Are your tires at the right pressure?
When was the oil last changed (oil condition/level)?
Have you checked the CVT for buildup on the cone surfaces?

Low speed could be due to an excessively worn belt. Shuddering could be due to a fault in the CVT cone surfaces (as simple perhaps as belt rubber adhered to the surface).

Poor performance can also result from failure to perform routine maintenance.

Hard to say without more info.

Re: Gas mileage only 81 to 85 MPG

Posted: Wed Dec 23, 2015 9:12 am
by honkerman
In addition, the faster you go, the worse your fuel economy will be. I find on mine that I achieve over 90 mpg when my speed averages under 50. Once I get over 50mph, the fuel economy drops.

Re: Gas mileage only 81 to 85 MPG

Posted: Wed Dec 23, 2015 3:58 pm
by gn2
ahsteven wrote:What's wrong with it
Not very much if it can do 59mph.
The clutch shoes might be glazed.

80-odd mpg at sustained 59mph is about right.
The people who get over 100mpg do not ride at such speeds.

Re: Gas mileage only 81 to 85 MPG

Posted: Wed Dec 23, 2015 5:18 pm
by Brent
I get around 106pmg when I stay in the city and don't go above 40mph. When I zip around the outskirts of town doing 60mph, the miles per gallon drops to between 91mpg to 96mpg.

Re: Gas mileage only 81 to 85 MPG

Posted: Wed Dec 23, 2015 6:33 pm
by gn2
Brent wrote:I get around 106pmg when I stay in the city and don't go above 40mph. When I zip around the outskirts of town doing 60mph, the miles per gallon drops to between 91mpg to 96mpg.
If you lived at sea level it would be less.
Plus your 2015 is more fuel efficient than a 2011 ;)

Re: Gas mileage only 81 to 85 MPG

Posted: Fri Dec 25, 2015 2:42 am
by you you
gn2 wrote:
Brent wrote:I get around 106pmg when I stay in the city and don't go above 40mph. When I zip around the outskirts of town doing 60mph, the miles per gallon drops to between 91mpg to 96mpg.
If you lived at sea level it would be less.

You'd be very wet though

Re: Gas mileage only 81 to 85 MPG

Posted: Fri Jan 01, 2016 5:30 pm
by ahsteven
Sorry for the delayed response. This is the first time I have used this forum and I thought I would get a notification if someone responded to my post.

Yes, I am referring to US miles per gallon. I don't ride it that fast usually around 45 MPH. I started accelerating faster because someone else mentioned that you can glaze the clutch by starting out slow. It seems to help a little with the shutter.

The bike has 2000 miles and the oil is in decent shape.

I checked the air filter today and realized there is oil in the air filter compartment. I am not sure what this means.

I will try to check the spark plugs and look into the transmission next to see if I notice any gunk or a warn out belt. Perhaps oil got in the transmission as well?

Thanks for your responses.

Re: Gas mileage only 81 to 85 MPG

Posted: Fri Jan 01, 2016 6:15 pm
by gn2
ahsteven wrote: there is oil in the air filter compartment. I am not sure what this means.
Perfectly normal, there's a little tube attached at the rear and you empty it out when it fills up.

Re: Gas mileage only 81 to 85 MPG

Posted: Fri Jan 01, 2016 9:40 pm
by honkerman
ahsteven wrote:Sorry for the delayed response. This is the first time I have used this forum and I thought I would get a notification if someone responded to my post.

Yes, I am referring to US miles per gallon. I don't ride it that fast usually around 45 MPH. I started accelerating faster because someone else mentioned that you can glaze the clutch by starting out slow. It seems to help a little with the shutter.

The bike has 2000 miles and the oil is in decent shape.

I checked the air filter today and realized there is oil in the air filter compartment. I am not sure what this means.

I will try to check the spark plugs and look into the transmission next to see if I notice any gunk or a warn out belt. Perhaps oil got in the transmission as well?

Thanks for your responses.
There should not be any oil in the tranny, but as GN2 observed, you will see it in the airbox because of the breather/air return from the engine. It should only be a bit.

Your fast starts will affect your fuel economy as well. I'll admit I'm a bit quick off the line myself and I've seen this affect fuel economy.

I've never known slow acceleration to glaze the cone surfaces in the cvt. I'd think quick sudden starts would be worse for it really. Think about it: Metal surface against rubber. A quick movement is more likely to slip, but a smooth, steady movement should not. I'm going to guess your jackrabbit starts may actually be the cause of the juddering and the low fuel economy and a cleaning of the CVT plates will help.

I could be wrong, but you'll get a better idea when you open up and inspect the cvt.

Re: Gas mileage only 81 to 85 MPG

Posted: Fri Jan 01, 2016 9:52 pm
by honkerman
Hmmm...Did a little poking around...Someone with a similar issue, and some folks suggesting one or two jackrabbit starts to clear it up. As both GN2 and I have noted, it's probably glazing on the CVT surfaces. I used to get the same issue with my Kymco.

Does seem counter-intuitive that gentle riding would cause more glazing than aggressive...but hey, what do I know...

Here's the thread:
http://modernvespa.com/forum/topic75035

Re: Gas mileage only 81 to 85 MPG

Posted: Sat Jan 02, 2016 1:49 am
by gn2
When you get glazing affecting starts making them juddery, its the clutch shoes.