Lets talk bearings / bearing soloutions

Discussion in '2-Stroke Engines' started by 210061741, Nov 13, 2009.

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  1. 210061741

    210061741 Guest

    Ok the 6202 bearings are easy to get and all over the place.
    6202-2RS 6202-ZZ and many other flavors.

    Honestly as dry as my mainbearings were and as crappy as the seals are i think i want to replace my mainbearings with good quality double shielded / double sealed bearings.

    Is there any reason that wouldn't be a good idea?
    Will the seals take the heat in the crankcase?


    Now the needle bearings aren't as common.
    Allthough available from some kit vendors.

    Anyone find a super high quality set of needle bearings for the HT ?

    I'm thinking part of the problem is the amount of space they have to slide back and fourth on the crank and piston pin.

    Alot of the bearing actually can make it's way freely out of the conrod.

    Why not put some wider ones in there?

    Suggestions are appreciated.

  2. Fabian

    Fabian Well-Known Member

    Hi Rich

    You need to remove the dust seals from the bearings used on the crankshaft shafts as they need to recieve a supply of lubricating oil.
    A few people have mentioned INA-F.A.G bearings are very high quality; obtaining the crankshaft bearings is not a problem but they don't make a K16x21x10 dimension needle roller bearing for the connecting rod big end.
    The K16x21x10 is an impossibly difficult bearing to source because of it's odd size.

    K16x20x10, K17x21x10 and K18x22x10 are readilly available and my solution was to be drilling out the big end to 22mm and sleeving it down to 20mm, so being able to use an INA-F.A.G K16x20x10

    The company i've sourced my K16x21x10 neddle roller bearing is from the company, UBC Bearing.
    Unfortunately they are a Chinese company so the quality may or may not be good.

    It's a gamble using any Chinese bearing.

    Interestingly, the Rock Solid Engines, engine that i have purchased uses a 17mm crankshaft pin (instead of the 16mm pin used in the Chinese engines) and a 22mm big end I.D connecting rod.
    This allows the use of a K17x22x10 bearing from any quality bearing manufacturer.

    The small end bearing problem can be solved by using a wider K10x14x15.
    It's 15mm wide and has approx 1mm of play between the bearing and the piston - just perfect as the bearing cannot side out from the small end.

    Link to UBC product catalogue: http://www.ubc-bearing.com/Products/show.php?itemid-4.html


    Attached Files:

    Last edited: Nov 14, 2009
  3. 210061741

    210061741 Guest


    Very nice my friend.
    How difficult is it to get the crank pressed apart.
    Could it be done without taking it to a shop?

    I'm hoping i can build a jig to hold the crank assy and use a hydraulic bottle jack to press the crank pin out.

    Is that the right way.

    Press that crank pin out?

    I have a new Jet PK 66cc showing up by tuesday.
    I want to tear it down and build it up before it ever sees the bike.

    On a second note i like the idea of offseting that hole to increase the stroke.
    The amount of travel the piston has past the exhaust port "Power Stroke"
    largely influnces the total output of the motor.

    The other thing i'm pondering is i'v heard that the porting is too low on the HT engines. If you raise the port you would loose some of that power stroke which may actually make things woorse not better.

    So if you can get the piston to travel higher by re machining the conrod and crank you could use a spacer and overcome this.

    I want to make the HT as close to optimal as possable.

    Did you end up using the ConRod for the HT or is it a replacement for another motorcycle.

    I wonder what brand the RockSolid is.

    Hopefully my PK has that 17mm bearing.

    But how about the little end.
    It seems that bearing could be much wider also.

    Did you make any changes there?