PK-80 or SD stinger

Discussion in '2-Stroke Engines' started by alec, Apr 29, 2012.

  1. alec

    alec Member

    I have to choose between an SD stinger and a pk-80. Which engine is better? the sd kit from has alot of upgraded stuff i guess.

  2. Skyliner70cc

    Skyliner70cc Active Member

    I got a PK80 last month that I finally got to install on a bike this weekend.

    I thought they were built better; here is what I found.

    1. Engine would not turn over. I took it apart and found the following:
    (a) Large chunks of plastic in the crankcase.
    (b) Engine missing upper wrist pin bearing (not kidding).
    (c) Head studs were loose

    2. Same crappy hardware that all HT engines have.

    3 Intake had manufacturing flashing that partially blocked the intake. Removed it when I did some mild porting

    4. Broken solder tab on magneto

    5. Carb is NOT an NT carb. I have about 9 non-NT carbs in my collection...they are junk.

    6. Enigine had bent fins (not quite as bad as when I buy from Boy Go Fast but I thought Pirate Cycles sold better HT stuff)

    7. Crank seal behind drive gear on clutch side is torn. I'm glad I pulled the gear to install a centrifugal utch.

    8. Engine kit did not come with a gear puller.

    9. 48mm front engine mount spacing....had to modify commercial engine mount designed for oversized bike tube.

    10. Had to grind down spacer on SBP shifter kit so 15 link 415 chain would fit the shifter engine assembly. I never had this problem before with any other engine.

    It better be worth it when I fire up the engine later this week. I bought it from Pirate Cycles because the PK80 engine has reputation of being more powerful than other happy time engines and manic mechanic's pirated head design fits on te PK 80.
    Last edited: Apr 29, 2012
  3. Skyliner70cc

    Skyliner70cc Active Member

    I looked a the SD engine on your weblink, its nothing special or upgraded. At least the PK80 has a slant high compression head....granted the headgasket on it is about 1/2 foot thick......
  4. alec

    alec Member

    So should I get the sd stinger or the pk? I am gonna buy a slant head for about 20 bucks if I get the sd. I havent heard anything bad of the sd's accept some dying at 500 miles because the guy didnt use synthetic oil or ran too lean or something stupid
  5. vermhot

    vermhot Member

    Dude That guy is wacked !!!!! I bought a PK80 , pulled it apart and put it back together ,was perfect ! NT carb and runs great !!!!! I have pics on here ,no bent fins and such !!!! I would buy from them again and treated me good and gave me candy !!!!!
    Hamzsim likes this.
  6. Skyliner70cc

    Skyliner70cc Active Member

    Yeah, I'm wacked. I've built and sold more motorized bikes in the past 7 years than you'll ever in a lifetime.

    My pirate cycle PK 80 carb says NT etched on the black airfilter but if you look on the side just above the idle adjustment screw, it says WH. WH is not an NT carb......mail me postage money and I send it to you....its garbage to me and will never be used.

    I'd buy a PK 80 again but I'm not very impressed, its not much different than any other crappy time engine. As for **** inside the engine, not unusual and fairly common. I was expecting to see casting sand an other **** left over from the manufacturing process but instead found plastic and a missing wrist pin roller bearing.

    Hey, about 4 years ago, I got an engine from a very reputable vendor that was missing a piston ring. Stuff happens.

    I'm not very worried about the problems I've found. My PK80 already has gotten a new head, new CDI, new reedvalve intake from Australia (thank you rock solid), new seals, new bearings, a dellorto clone carb, a torquer II exhaust pipe, and a shifter kit.

    I'll eventually add a ceramic piston and a more aggressivly ported head later down the road.

    As for the bent fin, its very odd that it is exactly the same fin that is bent on almost every boygo fast kit I've gotten in the past.

    Vermhot, did you keep that very thick stock PK80 headgasket or did you put a normal thickness one in? Or do you even know what a normal thickness headgasket looks like?
    Last edited: Apr 29, 2012
  7. alec

    alec Member

    So pk80 from piratecycles or Sd stinger from bikemotorkit? I need to know because im probably order it tomorrow
  8. chainmaker

    chainmaker Member

    without a doubt I would go with the PK from Pirates.
  9. alec

    alec Member

    I just found out that I can get a grubee and a jet from piston cycles because they are located close to me. Are those better choices? I like the idea of looking at the kit before I buy it.
  10. Lunardog

    Lunardog Member

    Gave me candy?!?! wtf?????
  11. vermhot

    vermhot Member

    Ya dude you were right !!! It was the crappy carb but it dose run good !!!! Want to up grade to a better one later this summer !!!
  12. Skyliner70cc

    Skyliner70cc Active Member

    I live at 6600 feet elevation and the WH carbs don't work well for me...they all stumble when accelerating. If your WH at your elevation works well, no need to replace it. I've had better luck with NT carbs. I think it is BS that the carbs with the PK 80 kit say NT on the aircleaner assembly but are WH labled....gotta love it.
  13. Waxxumus

    Waxxumus Member

    I dont see what peoples problems are with SD stingers.
    Mine has been fine to me.
  14. crassius

    crassius Well-Known Member

    all engines I've seen, no matter where they are from, end up on a scale from crappy to great at an almost random position - 4 motors from same place at same time will vary a lot in how they run

    seems just luck of the draw
  15. Waxxumus

    Waxxumus Member

    so that means 3/4 china motors are not built correctly.