1. 2 Stroke Husqvarna Motorcycles Made In Italy - About 1989 to 2014
     WR = 2st Enduro & CR = 2st Cross

All 2st Piston Diagnosis

Discussion in '2 Stroke' started by ohmygewd, Mar 14, 2011.

  1. ohmygewd Husqvarna
    Pro Class

    Location:
    Melbourne, Australia
    Husqvarna Motorcycle:
    13'Berg FE350, 96'WR360, 01 WR250
    Other Motorcycles:
    Aprilia RSV1000
    OK, the bike has had 100 odd hrs since it's full rebuild and after a compression test (158), l knew it's time for either rings or piston and rings but after opinions on the piston.
    The cylinder is within spec as is the "A" Wossner piston but the ring gap and ring groove are out of spec but judging the blow by, should l replace piston.
    [IMG][IMG][IMG]

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    ohmygewd, Mar 14, 2011
    #1

  2. Vinduro Husqvarna
    Pro Class

    Location:
    Mississippi
    Personally, I would. Not absolutely nessessary but it will last longer if you do.
    Vinduro, Mar 14, 2011
    #2

  3. Motosportz CH Sponsor

    Location:
    Vancouver WA
    Husqvarna Motorcycle:
    2021 TE250i, 570 Berg, 500 KTM, 790R
    Other Motorcycles:
    many
    100 hours is right about where my buddies 07 WR250 always needs piston and rings with the Wiesco. That is about 1200-1500 miles of our trails. His bike starts to feel weak at that point. He has about 6000 miles on it now, 4th or 5th piston, cylinder still looks great. Weisco piston and rings are about $150 so he does the whole thing each time.
    Motosportz, Mar 14, 2011
    #3

  4. R-J van Hulst Husqvarna
    Pro Class

    Location:
    Cambodia
    Husqvarna Motorcycle:
    WR 125 + 40 = WB 165 and a SM165
    Other Motorcycles:
    Honda CB 400 Vtec 3
    I had a better looking piston but the rings where gone.

    after measure all the dimentions the piston rod whas also out of spec.

    asking the price for the piston rod together with the little bearing and piston rings, it came to a marginal cheaper price than a complete piston kit.
    so in my opinion for the few $ more buy the whole new piston and put the old one in your trophy cabinet.

    Robert-Jan
    R-J van Hulst, Apr 21, 2011
    #4

  5. Bench Racer 117 Husqvarna
    A Class

    Location:
    Oregon
    Husqvarna Motorcycle:
    2007 WR250
    I just replaced my Wiseco piston and rings with about 100hrs on my 07WR250. I went with another Wiseco and I'm glad I did. That thing looks great and the cylinder is perfect. That thing sounds sweet. Starts easier and seems to run smoother too.
    Bench Racer 117, Apr 21, 2011
    #5

  6. lankydoug Husqvarna
    Pro Class

    Location:
    MO
    Husqvarna Motorcycle:
    WR
    Other Motorcycles:
    TM 300en
    Just from looking at the pics and not measuring it looks like the ring groove is worn and rings only won't do the job. It appears the blow-by was caused by the rings rocking up and down in the groove and not being held square to the cylinder. Replace piston and rings.
    lankydoug, Apr 22, 2011
    #6

  7. ohmygewd Husqvarna
    Pro Class

    Location:
    Melbourne, Australia
    Husqvarna Motorcycle:
    13'Berg FE350, 96'WR360, 01 WR250
    Other Motorcycles:
    Aprilia RSV1000
    Correct LD, l replaced the base gasket 6 months prior after a leak and l noticed a hint then but all good now!!

    After doing the top end, l've forgotten how much torque the 360 has especially with Wallybean's airboot mod..KTMCRFKXFWRFRMZ450 whaaat :)
    ohmygewd, Apr 25, 2011
    #7