Fuel economy

[al69]

Ok bit of a weird post this one.My fue leconomy has just rocketed up since ive had my 2500 mile service.Just had 129 mpg on the last fill up ! The only thing ive done different is ride a little bit slower on a route i have done loads of times before.What could they have done on the service to make a fuel efficiency improvement ?
The only thing i can think of is that they put some more fuel in the tank.I will be watching this tank of fuel with interest to see if its a consitent gain.

[gn2]

They might have reset the fuel injection..?
But riding slower and using smaller throttle openings is most likely to be the cause.
I never take too much notice of individual tank fill returns, the average over say ten fill ups gives a more accurate picture imo.

[Teamtd11]

As the fuel tank is so small and the potential MPG is so high. It only takes a small amount of fuel to fill the tank a bit more than last time and return a high MPG figure.
You are best working to a overall average. But that means to test out a change in riding style you will need to do that over several fill ups.

[maddiedog]

Teamtd11 has a good point, was that just your last fillup, or the average of the last few? They might have filled up your tank past the metal bar, giving you more mileage.

I get better mileage than average... I account it to slowly accelerating, and coasting as much as possible.

[al69]

Well im just coming to the end of the next tank and its already done more miles than normal for a tank.I always fill it up the same so its incredible really.Would love to know what they have done as im still riding it the same but getting better fuel economy which i cant complain at.

Just to add when i first broke the scooter in i really went for it doing it this way http://www.mototuneusa.com/break_in_secrets.htm perhaps its paying off now ?

[Chucklbowen]

My pcx ran badly after the 600 mile service, I bought a service manual and did the valve adjust myself at the 2500 interval. Now it runs just as bad as it did after the dealer service. At 3200 miles, I am only going 55 miles an hour and 75 mpg. I have noticed that I have oil in the crankcase breather tube. Anyone have any suggestions? Yes, the valves are " within spec".Thanks.

[Woolley]

Well im just coming to the end of the next tank and its already done more miles than normal for a tank.I always fill it up the same so its incredible really.Would love to know what they have done as im still riding it the same but getting better fuel economy which i cant complain at.

Just to add when i first broke the scooter in i really went for it doing it this way http://www.mototuneusa.com/break_in_secrets.htm perhaps its paying off now ?

I broke mine in like that too. Hope this happens to me after the 2500 mile service aswell...

[edscoot]

My pcx ran badly after the 600 mile service, I bought a service manual and did the valve adjust myself at the 2500 interval. Now it runs just as bad as it did after the dealer service. At 3200 miles, I am only going 55 miles an hour and 75 mpg. I have noticed that I have oil in the crankcase breather tube. Anyone have any suggestions? Yes, the valves are " within spec".Thanks.

Have you checked your air filter? You say you have oil in the crankcase breather, just to be sure - you're not talking about the clear plastic tube sticking out of the back of the air filter box are you? These just need to be taken off and cleaned every now and then, and it won't be the cause of your issue.

Have you checked the state of your oil and oil screen? Is your spark plug clean? Smokey exhaust? Plenty of coolant? When you did your valves did you make sure the timing was done (arrow inline with indicator on the fan etc. see: http://www.hondapcx.org/viewtopic.php?f=3&t=24). If all of these things are ok, you may ask your dealer if they can reset the ecu just to exclude it before going any further with your diagnostics. Good luck, and let us know what happens.

[gn2]

Could be an oil overfill.

[Chucklbowen]

I put in a K&N filter at the 2500 mile service, plug is clean and gapped. I may have overfilled oil. After reading other posts, I have not checked correctly. I also have not checked the screen (doohh!)

[Chucklbowen]

No smokey exhaust, have nor checked coolant since the service and I was right on tdc with the valves, I know this because I adjusted to exhaust tdc and thought it was way out and then double checked myself and corrected. I will definitely check the screen and coolant. Because of this nightmare poor performance I am almost ready to give up on this bike and or Honda. The overwhelming cost of maintenance and subpar performance does not give me the warm and fuzzy I thought 4 thousand dollars should give me.

[Esdain]

No smokey exhaust, have nor checked coolant since the service and I was right on tdc with the valves, I know this because I adjusted to exhaust tdc and thought it was way out and then double checked myself and corrected. I will definitely check the screen and coolant. Because of this nightmare poor performance I am almost ready to give up on this bike and or Honda. The overwhelming cost of maintenance and subpar performance does not give me the warm and fuzzy I thought 4 thousand dollars should give me.

subpar performance? what were you expecting from it? it is a 125 not a 600. it is one of the best scooters i have owned and ok it needs servicing on a regular basis but my last bike didn't and i spent more money on repairs than actually riding it, Honda's build quality is top notch, with a couple of hiccups but, with zoo many units sold there were bound to be the odd one.
sorry to sound harsh, but your bikes poor performance is more likely to be mechanic error as apposed to mechanical fault.

back on topic, i have individual fuel ups of 129 uk mpg but my average through the summer was about 117. i am with the rest, go with the average, but riding slower does help hugely

[gn2]

subpar performance? what were you expecting from it? it is a 125 not a 600.

If you look again you'll see that his PCX is 7.5mph down on what it should be and the fuel economy is only 75mpg.
Even allowing for that being US mpg it's sub-par for a PCX.

Now here's the facts about the PCX.
1: the fuel economy is good, but no better than many other 125 machines.
2: the top speed is deliberately limited to 100kph/62.5mph.

There are faster 125 scooters, e.g. Yamaha X-Max 125, Peugeot Citystar 125 but they are significantly more expensive than a PCX, have worse fuel economy and the service intervals are similar.

[Woolley]

back on topic, i have individual fuel ups of 129 uk mpg but my average through the summer was about 117. i am with the rest, go with the average, but riding slower does help hugely

I'm only getting about 100 uk mpg. But I'm still only on about 2300 miles. If it doesn't get better after the service maybe I'll slow down a bit lol. A 3 mile chunk of my 10 mile commute is on a 60mph dual carriage way though. And it's near the start so the bike hasn't really warmed up when I'm on it either.

[gn2]

Recently Ive consistently been getting 95-97mpg and mine is rarely below 55mph indicated.
That's good enough for me.

[edscoot]

I've stopped making a note of my mpg - it's good, I know that much. If I start needing to fill up earlier than normal then I'll know there's something wrong. I think/guess that if you keep your riding smooth and never at full throttle then you get the 125-130mpg (i got 132 once - UK), but if you ride a bit harder then your mpg will not surprisingly, drop.

Hey, Chucklbowen. When you did your valves did you notice if the crank case breather pipe was getting pinched by the storage box under the seat? Mine was. It wasn't totally squashed and still allowed the engine to work normally. It's worth checking, it should be routed below the box mounting bracket.

If the breather pipe is blocked/squashed for some reason would this cause a vacuum in the crank case? That would have some interesting consequences. I found this on the web -

ENGINE - BREATHER SYSTEM
Good ‘engine breathing’ is usually associated with efficient intake systems e.g. high flow air filter, a well designed manifold, etc. However, efficient ‘crankcase breathing’ is an equally important function of any engine whether Ford or not. Even in a new engine, the combustion pressure will inevitably pass the piston rings into the crankcase. If an engine’s breathing system should become blocked or restricted, the crankcase will pressurise causing any one or more of the following problems:

The oil/air mix will force its way out through any other convenient exit e.g. oil seals, dip stick, filler cap, etc.
The efficiency of the oil control rings will be reduced creating increased oil consumption.
Impurities such as water vapour and acids (by products of combustion) will build up and contaminate the oil causing sludging and increased engine wear.
The adverse affect on the air/fuel mixture will result in starting problems and rough idling conditions.
As a consequence of the weakened fuel charge, detonation or ‘pinking’ will ensue. To compensate, the ignition will need retarding resulting in further power loss.

[Chucklbowen]

I will definitely check the hose.

I was not expecting great things from this bike, but 35mpg less and 55mph does not add up to the experience that I am hearing from everyone else (not to mention, I know what it was like before the service, as it worked flawlessly from the dealer) or the money spent. Yes, there are other scooters that will go faster etc., but I bought a "quality" scooter from a "quality" company. I am not asking for a shoulder to cry on, just a little advise or direction. Thanks to all who have responded.

[gn2]

Take it to the dealer and get them to sort it under warranty.

[maddiedog]

Take it to the dealer and get them to sort it under warranty.

^ Seconded. You paid for a good, quality bike. It's still under warranty, have them fix it!

How far is your ride? The shorter the ride, the less fuel economy you will have, because a lot of efficiency is lost to the initial heating up of the engine.

[Cookie]

How far is your ride? The shorter the ride, the less fuel economy you will have, because a lot of efficiency is lost to the initial heating up of the engine.

That's very true Maddiedog. I used to consistently get 130mpg on my PCX but now I'm using a Silverwing for the longer runs and the PCX for shorter runs (between 5 and 35 miles) the consumption has dropped by 10 to 15 mpg.
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