RentAGuzzi Motorcycle Rentals & Tours – Los Angeles CA
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Do I have a problem?

Discussion in 'Loop & Tonti' started by Gappy, Apr 16, 2019 at 10:27 PM.

  1. Gappy

    Gappy Just got it firing!

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    I am finally putting the bike on the road. I have taken the carburators apart cleaned and replaced the gaskets and o rings. NOTE: I did not replace the rubber diaphragm, There was not one in my kit only the rubber gasket that goes under it. Also note that in the diagrams I have seen of my carburators, there is a spring that goes between the diaphragm housing cap and the diaphragm itself which mine did not have or is missing? I put them back together as I found them. I have put new plugs in, set the valves and syniced the carbs.

    The bike starts and idles nicely. ( this is my first experience with one of these bike and I don’t know how they are supposed to behave ). The bike spins or should I say thumps up to 3500 - 4200 rpm rather slowly imo, where in 1,2,3 and 4th gears, it runs surprisingly smooth! I am delighted, now I shift to 5th gear and rpms drop and it immediately begins to thump and pound so hard trying to climb back up to the 35-42 hundred rpm range. When achieved it does not run smooth like the other 4 gears. Is this normal ? I can’t go anywhere with it running like this! Could this situation have anything to do with the diaphragm fuel pump and possible missing springs? I have put 100 miles on it hoping things would straighten out, but it just keeps thumping and pounding away in 5th gear and shaking me to pieces , so disappointing. Riding in 4th gear at 59 mph across the country is not going to work. I need your help guys.
     
  2. john zibell

    john zibell Moderator Staff Member GT Famiglia

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  3. Amboman

    Amboman Cruisin' Guzzisti

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  4. john zibell

    john zibell Moderator Staff Member GT Famiglia

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    Thanks Charlie, I seem to have lost the bookmark Herdan Corp. and a web search came up empty for them. BTW, I did find theses guys in California, but I'm not sure if they do motorcycle carbs. http://usacarbs.com/
     
  5. Gappy

    Gappy Just got it firing!

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    Thanks guys, I used the link to mgcycles and they had the springs and fuel accelerator pumps in stock and I ordered them. Once installed we will see if that will cure my problem. I stumbled across a company that deals with Dellorto carbs and sells all the parts to them but mainly for Ducati, some models use the same carb as Guzzi, Bevel Heaven Products out of California.
     
  6. john zibell

    john zibell Moderator Staff Member GT Famiglia

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    Again I'm going to say that you are shifting to 5th too soon. If you are trying to get up to 35-42 hundred rpm range. That is what your rpm should drop to after making the shift. Guzzi engines like to rev. Don't ride it like a low rpm Harley engine.
     
    Mikko likes this.
  7. Nordicnorm

    Nordicnorm Cruisin' Guzzisti GT Contributor

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    John has a good point.
    If I were to ride my '01 Jackal (FI) across the country at 59 MPH, I would do most of it in 4th gear. These bikes are geared for European speed limits, and the speedo is normally about 10+% optimistic. If you find smooth running at about 75 MPH (indicated) in 5th (check your speedo against a GPS), we are on the same page. Personally I love that tall gearing. If your fueling (carburation) is not correct, vibration will be more prevalent.
     
    Trout and john zibell like this.
  8. Trout

    Trout GT Reference

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    Just here to agree with John & Nordicnorm.
    Worst abuse of a Guzzi is lugging the engine.
    Even my Victory likes higher RPM's. If running along at 60/65 I'm in 4th running around 3200 rpm.

    My old Mille GT still loves to hum along at 5000 rpm / 80 mph.
    Keep her above 4500 & she will love you for a long time.
     

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