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Spada Fuel Mixture

Discussion in 'Technical and Troubleshooting Torque' started by gre03, Sep 14, 2015.

  1. Hi All,
    I've heard that its better to run rich than lean so i set my pilot mixture screw as such, the bike started fine (after 1sec) and idled great but the fuel consumption was horrible. I was getting 150-170km per 9L tank.

    So i set the carbs to a bit leaner (1/2 turn in), this didn't change the idle or running but its harder to start (needs full choke even warmed up) and i'm at 180km/tank and still going.

    which is better? rich and bad economy or lean and good economy?
  2. It's better to be SLIGHTLY rich than lean. Too rich can be bad as well, resulting in oil film washed off the bores (premature wear) carbon build up (pre-ignition and possible bore scoring), fuel in the oil (general engine wear) and general crappy running. Your pilot mixture only affects the low end of the rev range. For the mid range and top end you need to make sure the float level is right and the jets are both clean and the right size. If you haven't touched either then it's time to either learn how or take that to a decent mechanic for a tune up.
    • Agree Agree x 2
  3. thanks, i'll put it back to slightly rich when i get home (1/4 turn out) i've had a look at the floats and jets and they look fine to an untrained eye, but i'll be going over them with streetmaster soon.

    also how do i link members' in posts?
  4. Just use the "at" symbol and their name. ie gre03gre03 (which I typed as @ followed by your name, no spaces).

    re the idle mix, just put it back to whatever it is supposed to be stock. It would have already been the correct mixture. The stock setting is between 1/2 and 1 turn out (assuming we're talking about the VTR250)
  5. Idle mixture will make bugger all difference to range. It should be set in conjunction with idle stop. So you set the the mixture screw so you are getting a good strong fire and then adjust the idle back to where it should be. You will have to do this a few times as you approach the optimium point.

    The fact that you are getting such bad economy would suggest to me the carbies need some attention. Maybe the plugs too.

    You should only set the mixture after you are confident the float levels are correct. and the balance.
    • Agree Agree x 1