New Blaster vibrating under high revs

Discussion in 'General Support' started by chee_dee, May 16, 2019.

  1. chee_dee

    chee_dee Member

    Joined:
    Feb 26, 2019
    Messages:
    72
    Likes Received:
    15
    Trophy Points:
    44
    Gender:
    Male
    Location:
    South Africa
    So I am finishing my 3rd Blaster and this one feels really strong with nice clean revving except for the Vibration when revving past around 1/2 throttle.

    Stock Exhaust
    230 main jet.

    Previous owner installed 67mm Piston when the motor seized a year ago.

    This Blaster really feels strong in the rev range compared to the other 2 but the Vibration bothers me.

    I have checked the mounting bolts and they are secured.
    Will check counter balance timing tonight but if that is right, can it be that the oversized piston is causing the slight imbalance? and if that IS the case, how would I rebalance it?

    TIA
     
  2. Larry's Shee

    Larry's Shee Active Member

    Joined:
    May 23, 2009
    Messages:
    7,994
    Likes Received:
    723
    Trophy Points:
    149
    Occupation:
    Unemployed carpenter
    Location:
    Ortskaville, MI
    Well counter balancer would be my first choice. Don't know if you can peek at it to see if it has been shaved. Maybe shaved to much? Check pipe mounts and swing arm for tight, anything connected to the engine.
    Piston would have to be way over or underweight to affect balance that much.
    I'll mull it over some.
     
  3. Larry's Shee

    Larry's Shee Active Member

    Joined:
    May 23, 2009
    Messages:
    7,994
    Likes Received:
    723
    Trophy Points:
    149
    Occupation:
    Unemployed carpenter
    Location:
    Ortskaville, MI
    It's not banging or rattling is it?
     
  4. chee_dee

    chee_dee Member

    Joined:
    Feb 26, 2019
    Messages:
    72
    Likes Received:
    15
    Trophy Points:
    44
    Gender:
    Male
    Location:
    South Africa
    Nope. It's really small. More like a resonance when revving high.

    I am really not the expert but I don't know why the screaming on top revs and slight vibration gives me a feeling the engine is running lean.

    with the 67mm Piston added and no other mods, I have upped the Main Jet from 230 to 240 last night. Will take a ride this afternoon and feel if there is a difference. Plug chopping will happen soon though.

    PS: The vibration is very small.
     
  5. Larry's Shee

    Larry's Shee Active Member

    Joined:
    May 23, 2009
    Messages:
    7,994
    Likes Received:
    723
    Trophy Points:
    149
    Occupation:
    Unemployed carpenter
    Location:
    Ortskaville, MI
    Did you use a reputable shop for machine work?
    Do you have the rubber plugs between the find?

    What mods do you have?
     
  6. chee_dee

    chee_dee Member

    Joined:
    Feb 26, 2019
    Messages:
    72
    Likes Received:
    15
    Trophy Points:
    44
    Gender:
    Male
    Location:
    South Africa
    Nope, I do all work on my bikes myself. This one, however, I bought and the previous owner did the work. Good question though. Think I will touch base with him and ask who did the honing/boring of the cylinder.


    Out of the six, one is missing, front right.

    Bike has no mods, except for the oversized piston that was installed previously when engine seized.

    Airbox lid was missing when I got it. I got a new one and installed it because the bike has standard header and exhaust. Also upped the Main Jet to 240 from 230 out of fear of running lean. Havent done plug chops yet but since I upped the Main Jet, the engine temp became noticeably less so I think I am heading the right way.
     
    Larry's Shee likes this.
  7. Larry's Shee

    Larry's Shee Active Member

    Joined:
    May 23, 2009
    Messages:
    7,994
    Likes Received:
    723
    Trophy Points:
    149
    Occupation:
    Unemployed carpenter
    Location:
    Ortskaville, MI
    Do you know anyone else that has a Blaster? You can compare to?
    Have you ever ridden a 2stroke motor cycle to compare to?.

    I was thinking out loud about machine work on boreing/ hone.
     
  8. Larry's Shee

    Larry's Shee Active Member

    Joined:
    May 23, 2009
    Messages:
    7,994
    Likes Received:
    723
    Trophy Points:
    149
    Occupation:
    Unemployed carpenter
    Location:
    Ortskaville, MI
    Rubber plugs only reduce noise, but the extra noise might fool you. I took mine out for painting and didn't replace.
     
  9. chee_dee

    chee_dee Member

    Joined:
    Feb 26, 2019
    Messages:
    72
    Likes Received:
    15
    Trophy Points:
    44
    Gender:
    Male
    Location:
    South Africa
    That is exactly what I am doing. I have 3 blasters. 2 have been fixed up and busy with the 3rd.
     

Share This Page