replacing the cylinder

Discussion in '2-Stroke Engines' started by zippinaround, Sep 27, 2013.

  1. zippinaround

    zippinaround Active Member

    when i'm putting the cylinder back on which way should the conrod be or does it matter?

    Attached Files:

  2. crassius

    crassius Well-Known Member

    lock the crank with the rod at its highest is the usual way

    some folks like to put piston in cylinder before sliding wrist pin in, others like to attach piston, then slide cylinder over it - I do either depending on my mood and each requires some patience & skill
  3. HeadSmess

    HeadSmess Well-Known Member

    aforementioned technique is a great tip to know.

    insert piston and rings into cylinder FIRST.

    then drop cylinder down on studs, and insert gudgeon/wrist pin.

    having the rod at TDC helps.

    not so critical on the HT, but on an engine with thin rings, ie the oil scraper on a 4 stroke, it saves destroying a cylinder and rings ;)

    also helps on multicylinder jobs.

    replace the wrist pin clips if you do it this way.

    place rag over crank so as not to lose the clip. wear glasses.

    ensure rings are lined up with the locking pins in the grooves.

    same deal, i do it either way, depending on mood and engine. some engines have the wrist pin pressed into the piston :(

    some are pressed into the con rod and have the bearings in the piston! (mcculloch 10-10 for example)
  4. IbedaYank

    IbedaYank Member

    real techs use a piston ring compressor for each piston if the cylinders are connected togather
  5. HeadSmess

    HeadSmess Well-Known Member

    the same "real techs" get paid to work on multi cylinder jobs on a regular basis, find the need for the correct tools as they are constantly in use, and know that to find a single ring compressor for anything under 50mm, let alone a set of eight or so, is going to be hard to find.

    the same "real techs" that would use a hose clamp and a piece of drink can, if they bothered. not many of these "real techs" even bother with a compressor as only a moron needs them. a ring EXPANDER, now thats a different matter entirely.

    the same "real techs" that realise that theres almost no multicylinder jobs with pistons under 50mm, and if they were lucky enough to be working on one of them, would be charging through the nose, and would already have their workshop equipped or the job wouldnt have come through the door in the first place.

    ive read some fairly useless comments in my time but that ones up near the top of the list ;)
  6. IbedaYank

    IbedaYank Member

    shows just how little you really know as there is quite a few under 50mm bore

    honda 350cc inline 4 is just one example
  7. HeadSmess

    HeadSmess Well-Known Member

    theres plenty of examples. i was hoping an expert such as yourself would mention a real COLLECTORS ITEM, like the rc166.

    an engine so rare that its worth paying any price to get it rebuilt by the best workshop available.

    its not the type of engine to come in the door everyday.

    whereas your mediocre honda 350 is an obsolete POS that only a moron with too much money would bother rebuilding, unless its of one of those years that signifies "collectors piece", or a home enthusiast that just enjoys doing it. once again, a full set of ring compressors isnt going to be used that often, so MOST people would find alternatives on the rare occasion theyre necessary...

    go to any wrecker and see dozens of cb250 or zzr 250 with one dropped valve or similar, and why? its cheaper to sell the bike, and upgrade to a real bike....

    except for a few exceptions, noone BOTHERS working on multicylinder jobs with pistons under 50mm.

    yes, i can list many examples. but as a percentage of engines worked on worldwide? theres more with pistons at 6 inches than at 2 being rebuilt every day...
    some places rebuild twenty or more large diesels in a day. the ring compressors become a necessity at that point.

    this thread asked a question, for advice. i gave some advice, pretty simple, thats nice to know when your young and just starting.

    your comment didnt really add to the knowledge pool, now did it?

    go pester someone else or post something constructive.
  8. IbedaYank

    IbedaYank Member


    ok lets see how smart you are.. this is a sub 300cc 2stroke
  9. Fabian

    Fabian Well-Known Member

    Trying to get the jetting right on a 4 cylinder 2-stroke would be a serious exercise in frustration but it would be a walk in the park compared to a 24 cylinder or worse still a 48 cylinder 2-stroke engine:

    and 48 cylinders of madness - actually 49 cylinders if you count the single cylinder 2-stroke engine that's used as a starter motor:

    Last edited by a moderator: Dec 15, 2015
  10. HeadSmess

    HeadSmess Well-Known Member

    what exactly has this got to do with replacing a HT cylinder?

    i cant recall this thread being being titled "guess what obscure engine this is cus i cant actually post anything useful that helps with the subject at hand"

    its bert fruins 200cc racer why not buy one?

    so very common. only two made. hmmmmmm. so, an engine worth spending money on a full set of compressors?

    not that you actually need a full set, that is...
    Last edited: Oct 6, 2013
  11. HeadSmess

    HeadSmess Well-Known Member

  12. HeadSmess

    HeadSmess Well-Known Member

    hmmmm. ill give you that one. you chose a picture that was previously published on the internet. it made it fairly easy ;)

    so. heres a test.


    literally millions made, and thousands are in use, everyday.

    maybe not in my country, thats all...


  13. Bgard

    Bgard New Member

    It looks like a volkswagon block.
  14. HeadSmess

    HeadSmess Well-Known Member

    :jester: maybe not that common!

    2 cylinder 2 stroke....
  15. keatonx

    keatonx Member

    Snowmobile engine? I would say air cooled, but all the air cooled ones I know of are piston port
    Last edited: Oct 9, 2013
  16. keatonx

    keatonx Member

    Also air cooled ones usually have coolig find on the block and are more box-shaped (thinking of the air cooled rotax's)
  17. HeadSmess

    HeadSmess Well-Known Member

    water cooled, oil injected...

    snowmobiles the wrong climate ;)