86 Elite 150 quest for 70mpg

Discussion in 'Battle Scooters' started by outofcontrol, Jul 26, 2012.

  1. Süsser Tod

    Süsser Tod Long timer

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    My 175cc Chinese scooter averages 43mpg, the absolute best tank was 54mpg. Do you still want a Chinese carb? I think the biggest bang for the buck mod on GY6 scoots is a new carb, replacing that Chinese junk carb with a good carb does wonders for them.
    #21
  2. outofcontrol

    outofcontrol Been here awhile

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    Filled up today finally: 1.68g, 93miles = 55.4mpg. :cry

    Moving on now.
    Checked compression: 178psi. spec was 175-185, so OK there. ( Edit: spec is 184 +/- 28psi )

    When I pulled the plug I noticed that it was black and sooty. I cleaned it off, and suck it back in and started the scooter; instantly sooty again. Tell me I'm not crazy, and this is a rich running plug indication.
    So what can cause rich running?
    1. clogged air jets - verified clear
    2. faulty float valve - brand new and tested
    3. float level too high - brand new float, verified level
    4. auto bystarter faulty - bench tested OK.???
    5. dirty air cleaner - New and checked whole airbox for blockage
    [​IMG]

    I'm a little confused: I drilled out the idle mixture screw to clean it, and set to 1-3/8 turns out when I boiled the carb. So after I saw that the plug was so sooty, I started playing with the mixture screw. Scooter ran best with it screwed all the way in tight??? I've always thought that if it runs best < 1 turn out, go with a smaller pilot jet as it's rich. Runs best > 2 turns out, go to a larger pilot as it's lean. So the air mixture screw is also telling me I'm rich. But I have stock everything; stock jets, stock pipe, stock air box, I'm at 250' elevation. (Sometimes just writing these posts out helps me to figure out WTF I'm talking about, but I'l love any corroboration)
    Can I assume that there's another fuel circuit that's making this run rich at idle? Like the bystarter?
    I guess I'm going to take this carb off for the 5th time and do more testing on the auto bystarter while it's connected to the carb like the manual says to do.

    [​IMG]
    #22
  3. hayasakiman

    hayasakiman Been here awhile

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    Is the plug correct for the engine?
    Is thermostat installed and working porperly?
    Does ex pipe flow good?

    I don't know, I'm thinking out loud.
    #23
  4. hexnut

    hexnut Been here awhile

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  5. outofcontrol

    outofcontrol Been here awhile

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    Great questions, and thanks for the ideas.

    Plug is NGK DPR7EA-9 which is correct, and gap is correct. (looks newer than stock, but no idea of age).
    Temp comes up after 5-10 min run time and then levels out. (only verified by gauge on dash).
    Exhaust pipe: I don't really have a way to bench test this, but WFO performance is good. (I hit indicated 70mph)

    So when I cold start this scooter, it idles high for about 60-90 seconds, then settles down into a nice idle. It just seems like the bystarter is working. I think I'm also going to buy a new main jet, main jet needle, and pilot jet. They look like they're 25 years old, so I'm assuming they're stock, but there's no #s on them. Who knows, but those are cheap parts. I might just buy a new bystarter as well, but I absolutely just hate buying parts on a whim. I like to prove they're faulty first.

    Thanks,
    Kevin
    #25
  6. outofcontrol

    outofcontrol Been here awhile

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    That's the directions that I'm accustomed to. The CH150 idle mixture screw modulates fuel delivery right? not air?

    My scooter wouldn't die if I screwed the pilot/idle screw in all the way. Maybe I just have too big of a pilot jet? OR, maybe someone in years past cleaned it with a tool instead of fluid and reamed it out a little?

    Most of the problems I find with fine machinery are user error. I shouldn't discount 24yrs of exposure to ill hands.
    I also went out on some high speed WOT runs on the freeway today and she definitely was intermittently missing at 60+ mph. I'm going to re-check all my electrical connections in the ignition. Maybe a new CDI is in my future.

    -Kevin
    #26
  7. outofcontrol

    outofcontrol Been here awhile

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    I bought a new Iridium plug today and threw it in. Took a quick run 5 miles and plug was not sooty, and a nice brown.
    With the last plug is was sooty in 30 seconds.

    If this pushes me up over 70mpg and solves my problems.... $8 plug and 5 min of work???

    It'll take me another week to find out driving 12 miles a day to work and back.

    -Kevin
    #27
  8. Süsser Tod

    Süsser Tod Long timer

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    I was wondering...

    Are you sure it is even possible to achieve 70mpg in your commute? I mean, there are several factors involved that will take their toll on MPG even if the scooter is running perfectly. I know for a fact that I will never be able to achieve 70mpg on my AN125 because my commute is on very hilly terrain with lot's of stop and go, I'll be happy if I can average 60mpg.
    #28
  9. hexnut

    hexnut Been here awhile

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    The last time I checked my Kymco S 250 I got 70 MPG. That was around town. stop and go and 30 to 45 MPH. That was also being easy on the take off.
    #29
  10. outofcontrol

    outofcontrol Been here awhile

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    No, not sure.

    I have a very hilly, stop and go commute.

    But I don't think I have a perfectly running machine. I had a leaky petcock and float valve, and somehow a rich fuel mixture.
    If I can verify it's running perfectly, and I still don't hit 70mpg, then my quest is over I guess.

    I saw reports of 70-90mpg depending on the owner's right wrist, on a finely tuned machine. That's my goal.

    Once I get it running as good as I can, I'll take her out for a whole tank at 45-50mph on flat terrain and see what happens.

    I did crack 100 miles for this tank today. (that's a first) I'll fill up again today and report in.

    -Kevin
    #30
  11. hayasakiman

    hayasakiman Been here awhile

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    If it was my scoot showing that much improvement with iridium plug over regular plug provided the heat range is correct, I would review all of connections and components related with ignition system. Make sure there's no corrosion or crud build up preventing proper flow of electrons. :norton
    #31
  12. outofcontrol

    outofcontrol Been here awhile

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    I did this once before, but it makes complete sense. Maybe I missed something. When I did some high speed runs it was just a little bit cutting out. Not a lot, but it would stumble every once in a while. Like 3-4 times for a blip in 5 miles of WOT. I might not have noticed if I wasn't paying attention. Sometimes I magically fix stuff just by playing with it. (wiggling wires) Also, maybe I'm just breaking in this motor again after sitting for 21yrs? I keep adding a couple ozs. of Seafoam to every tank. Thanks for all the advice!

    Filled up today: 60.3mpg.

    History:
    51.0
    50.3
    53.9 fixed float valve and petcock leaks. adjusted brakes so they don't drag. :1drink
    53.8
    55.4 deep cleaned carb.
    60.3
    ??? Iridium plug?
    #32
  13. BuzzJ

    BuzzJ n00b

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    I have an 85 Elite 150 which I have been getting about 60 mpg using 87 octaine gas. My question should I use regular or high octaine gas in this bike?
    #33
  14. outofcontrol

    outofcontrol Been here awhile

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    My theory is that unless you're getting a lot of knocking, 87 is fine. That being said, try 92 and see if it changes.

    Today I lowered the oil level to 3/4 on the dipstick. I read some post somewhere that having too much oil in the crankcase caused a guy poor economy. I think he said that the manual even says to do that... doesn't sound right, but I'll try it.

    -Kevin
    #34
  15. hexnut

    hexnut Been here awhile

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    I believe I would rather have poor economy than low oil, but thats just me...My scooter only holds .9 mils of oil and I want it all in there.:D
    #35
  16. outofcontrol

    outofcontrol Been here awhile

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    100% agreed. I think mine holds 910 mL as well. Not even a full quart.

    I guess I should have been more clear: If the oil is overfilled, the crank can splash in the oil and froth it up just like a milkshake or a Latte. That's when the damage happens. Aerated oil is a poor lubricant. I think the guy who posted up about lowering the oil amount also had a rich fuel mixture from the high oil. I'm not sure about the connection there, but whatever.

    And I did have way too much in there. Right up to the bottom of the dipstick threads, which is too much. I might have dumped out about 1.5oz. And it's still reading 75% on the dipstick. I honestly don't think it will make a difference, but I'm keeping an open mind to all advice.

    -KM
    #36
  17. Wentwest

    Wentwest How's that work?

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    Maybe I missed it, but to really assess mileage, I'd need to know how much you weigh, how much the stuff you carry weighs, how long your average trip is and how fast you accelerate. There are lots of things that can change your mileage a few miles either way. On my 150 I get about 63 mpg, but if I use it on the freeway much that goes down a bit. If you ride around at 40-45 and rarely stop, you'll get great mileage. A worn belt will lower your mileage, worn rollers in the variator will too. If you weigh 250, your mileage will be lower by a lot compared to a 130 pound person.

    Finally, I know it's an old story, but every time I find I can't change the idle much with the pilot screw it's because of a faulty bystarter. Make sure the gaskets on it are sound, so it's not leaking air around it. On one scooter I finally took the brass ferrule and needle and spring off a broken bystarter, dropped it into place, plugged up the large opening fully with gas resistant foam, capped it with a piece of plastic screwed down with the 2 screws that held the bystarter clip down and just eliminated the whole bystarter circuit altogether. The scooter runs great, the mileage went up a lot, and starting it, even after sitting for several months, is pretty easy. Probably would be bad at 30 degrees, but it's not 30 degrees here and if it was, I wouldn't ride for fear of ice.

    Bob
    #37
  18. outofcontrol

    outofcontrol Been here awhile

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    203lbs.
    Sometimes a laptop in my backpack, but just rider and scoot most commutes.
    6.5 miles to work, 6.5 miles home, 15-20 min each way. Over a large urban mountain range: 250' to 800' back down to 250'.
    25-40 mph with 5-6 stops each way, and yes WOT to get going most of the time.
    I don't think the rollers/variator are worn, but I don't know. Bought the bike with 3700 miles, and I have about 4300 now in a month. I just assumed that they're ok. I took the belt off, and it looks new, but what do I know. It was 18mm wide, and looked fine. I think that's the spec for a new one, and 16mm means replace. The rollers were buried in grease so I assumed they're fine too. I was able to hit 70mph on a slight downhill freeway stretch, but that's my only basis for assuming the belt is fine, or wide enough to get to the outside diameter of the variator.

    I love the solution for just eliminating the bystarter. I was thinking that it would be wonderful to just eliminate that component from the equation. Unfortunately unplugging it doesn't do the job, rather the opposite.

    I am actually pleased as punch to get 50mpg and have so much fun doing it. But at the same time, I really enjoy tearing into this thing to see if I can make it better. Thanks so much for the perspective, and some more ideas for me to entertain.

    I'll keep posting my results, if for nothing else, my own record. Cheers!

    -Kevin
    #38
  19. outofcontrol

    outofcontrol Been here awhile

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    I went to sleep last night thinking about this. I don't have a spare bystarter to sacrifice. Would it be just as effective to plug the bystarter pickup right next to the jets? Use either a tiny screw, or some fuel resistant glue, or a tiny little rubber cork? Something I could easily reverse down the road?

    It's below the main and pilots jets in this picture. It's a pressed in brass tube. (as far as I know)
    [​IMG]

    Aired up my tires to 38psi rear, 28psi front.

    -Kevin
    #39
  20. Wentwest

    Wentwest How's that work?

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    That's the pickup jet for fuel. If you plug it, you won't get fuel, but you will still get a lot of air through the port that runs around the side of the main venturi. You can see a hole on the intake side and another in the manifold side. Air flows right through there, and shuts off when the bystarter heats up and extends. So you have to plug up that passage, too.

    Bob
    #40