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

All 2st Piston Sizing

Discussion in '2 Stroke' started by Aviduser, Jul 29, 2011.

  1. Aviduser Husqvarna
    AA Class

    Location:
    BC, Canada
    Husqvarna Motorcycle:
    08 cr 165
    Ok, so I had my cylinder replated a year or so ago. I gave the company the new piston to make sure the clearances were proper.

    The time has come for a new piston, I purchased a wiseco 54mm stock bore piston.

    I noted when I installed the old piston it was marked "E" behind the arrow. At the time I thought this was short for exhaust side. Looking at my service manual it appears there are pistons ranging in size from A-F. Starting at 53.940 to 53.970.

    Confused as to why there are different sizes when you can't hone/bore a nikasil cylinder anyway?

    Should I be concerned? Thanks.
    Aviduser, Jul 29, 2011
    #1

  2. Dirtdame Administrator

    Location:
    Rock Springs Wy
    Husqvarna Motorcycle:
    11 WR300,13 WR125,18 FE501
    Other Motorcycles:
    17 Beta Xtrainer
    Probably the size differences were made to fit discrepancies in tolerances in the final diameter of the cylinder bore. The range seems to span one and a half thousandths. If you are concerned and want to make sure that you have the most optimal tolerance, go with another stock E piston.
    Dirtdame, Jul 30, 2011
    #2

  3. Aviduser Husqvarna
    AA Class

    Location:
    BC, Canada
    Husqvarna Motorcycle:
    08 cr 165
    Thanks, I was wrong its actually a B sized piston.

    N e way I just did the ring for now, everything's still in spec.
    Aviduser, Jul 30, 2011
    #3

  4. Dirtdame Administrator

    Location:
    Rock Springs Wy
    Husqvarna Motorcycle:
    11 WR300,13 WR125,18 FE501
    Other Motorcycles:
    17 Beta Xtrainer
    And for the B size, you would be running good tolerances on an aftermarket piston.
    Dirtdame, Jul 31, 2011
    #4

  5. gixxer_gixxer Husqvarna
    B Class

    With the huskies 125 small bores, I would personally only used genuine pistons, but if you send a piston 'b' to get a cylinder fro replating etc then engineers should set this up correct, the problem maybe the exhaust bridge, it must be 'let back in' after replate, and also on genuine husky pistons they have two holes drilled for extra lubrication over the exhaust port, this will be the area to correct, assuming engineering by replating company is good!

    Gixx
    gixxer_gixxer, Aug 1, 2011
    #5

  6. Aviduser Husqvarna
    AA Class

    Location:
    BC, Canada
    Husqvarna Motorcycle:
    08 cr 165
    Was replated about 40 hrs ago. I have been using stock pistons so far, I went with the wiseco because I was ordering many other parts from 1 company. I see it has 3 holes for lubrication at the exhaust port. Vs the huskys 2.
    Aviduser, Aug 1, 2011
    #6

  7. gixxer_gixxer Husqvarna
    B Class

    Well that easy then, stick with what works ;-) stick with wiseco and stick with a 'b' next step maybe a 'c' when wear gets outside tolerences, my philosiphy is :- if it starts 1st/2nd kick hot/cold its good,
    gixxer_gixxer, Aug 1, 2011
    #7