Jetting help needed

Discussion in 'Jetting' started by ToddsToys, May 28, 2019.

  1. ToddsToys

    ToddsToys New Member

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    I am new to the forum, so I would like to 1st say thank you to everyone who has contributed by taking the time to share their knowledge and experience,it has been very helpful for me,and many others I am sure. I have a 2004 blaster with brand new weisco bottom end and top end ,bored out to 66.5, FMF exhaust with fatty pipe, after market air cleaner with lid off of box. 32:1 mix, oil pump deleted.tors wires cut and spliced into a loop. What type of jetting is needed? There is currently a 290 main jet in now. I am going through the engine break in process and it feels like it's not getting enough fuel or maybe too much. I don't know a lot about jetting but if I am taught or told the right things I can do it right.
     
  2. Awk08

    Awk08 Administrator Staff Member Technician

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    assuming the engine is ..... 120-ish + compression for a fresh rebuild, proven leak free with a proper leakdown test, float level set correctly, stock 32.5 pilot, airscrew tuned for highest idle between 1/2 and 2 turns out, stock needle is on the middle clip position ? (DIY threads on a lot of those are in the carb section)
    290 should be in the range your looking for with that setup your running, FMF/lid off, mix fuel is usually in the 270 - 310 range depending on elevation, sea level requires more fuel (richer jetting) than higher elevations.
    the best way to fine tune that main jetting is plug chops .....
    https://www.blasterforum.com/threads/how-to-plug-chop.53237/

    buy 270 thru 310 mains and a six pack of plugs, start large and jet down to slightly darker than cardboard colored smoke ring

    I've run a similar setup here across the state @ 1800' elevation with a 300 main jet
     
  3. ToddsToys

    ToddsToys New Member

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    Basically what is happening is it feels like it is bogging out when I 1st get on the throttle but then when I get to higher rpm it kicks in like normal
     
  4. Awk08

    Awk08 Administrator Staff Member Technician

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    that sounds like the transition from pilot to needle, or needle to main jet.
    double check everything I listed above
     
  5. ToddsToys

    ToddsToys New Member

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    OK I will do a good thorough check to make sure everything is where you said it needs to be I will get back to you when it is all checked thank you for your advice I really appreciate it
     
  6. ToddsToys

    ToddsToys New Member

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    So I did a leak down test today and I am losing about 1.5 per minute and I cannot find a leak anywhere. The plug I used in the exhaust port may not be holding tight enough though so I am going to get a better one and try again.
     
    Last edited: May 29, 2019
  7. ToddsToys

    ToddsToys New Member

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    So I got the right plug for the exhaust port did the test again and it still reads I have a leak and I cannot find it anywhere how can I tell if my crank seals are not installed correctly? I had them done from a Yamaha dealer in my area
     
  8. Awk08

    Awk08 Administrator Staff Member Technician

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    are you spraying soapy water everywhere ?
    have you checked the tester itself for leaks ?

    you can check the clutch side by holding the end of the vent tube in a cup of soapy water, it's up under the hood if still stock ?
    or pop it off the nipple and add your own short piece for the test

    the stator side may show bubbles around the gasket or where the stator wires go in

    otherwise you'll need to pull both covers, and the stator out on that side and spray the seals themselves
     
  9. ToddsToys

    ToddsToys New Member

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    I am getting air bubbles in the soapy water from the vent tube so does that mean the crank seals are badd? I just had them installed from a professional dealership I take it this means they screwed up?
     
  10. Awk08

    Awk08 Administrator Staff Member Technician

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    it's either the new crank seal, the collar the seal rides on, or broken/cracked cases between the crank and trans areas.
    hope not the last :(
    I'd pull the clutch cover and spray the seal itself while pressurizing

    here's a vid on sealing the collar............
    https://www.blasterforum.com/threads/crank-collar-seal-vid.50433/
     
  11. ToddsToys

    ToddsToys New Member

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    I cannot find this air leak anywhere and it is killing me
     
  12. Larry's Shee

    Larry's Shee Active Member

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    Did you pull flywheel and spray seal with soapy water while pressurized ?
    Right crank seal area?
    Vent hose before talking cover off ?
     
  13. ToddsToys

    ToddsToys New Member

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    The leak is between the right side seal and the outside of the collar. It's a brand new seal. Should I get a new collar.Or should I put yamabond between seal and collar?
     
  14. Larry's Shee

    Larry's Shee Active Member

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    If the collar looks worn, see if flipping it end for end gives a new wear surface. Be sure to reseal collar and key to cranl and retest
    If it still leaks get a different seal.
    Where did you get the seal you have now? Link?

    Be sure to lube seal while collar is out.
     

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