Page 1 of 3 1 2 3 LastLast
Results 1 to 10 of 27
  1. #1

    Gp1200 'popping' maybe misfire? Lil help!

    Hey guys, just a quick question.. I heard my ski 'pop' twice yesterday and once the other day.. All times was under pretty much full load hi rpms. It's maybe the 4th time it's been out (about 4 or 5hrs) since re-build (pistons, crank, shaved head,light port, new check valves) I also switched to premix 40:1 and have choke plates out. New br7hs plugs. Also got a few extra earth straps from battery to motor and also to electrical box just for good measure.

    Would u assume it's possibly a tad lean maybe to cause the pop? What do u think about me coming half a turn out on my low and hi-speed's?


  2. #2
    Pop.. As in like a misfire or back fire.. And came from under the seat..

  3. #3
    Flying Scotsman's Avatar
    Join Date
    May 2006
    Location
    IllINOIS
    Posts
    6,514
    +1
    4
    Check the rear seal is still seated
    You might have had it in ass backwards.

  4. #4
    Moderator OsideBill's Avatar
    Join Date
    Mar 2006
    Location
    United States
    Posts
    11,875
    +1
    30
    is the BR7HS a typo or is that the plug you are running? The BR8HS is what is recommended stock. The popping could be lean from not enough fuel, or air leak. either of these will definitely cause a backfire.

  5. #5
    john zigler's Avatar
    Join Date
    Aug 2006
    Location
    WI
    Posts
    2,545
    +1
    33
    Quote Originally Posted by OsideBill View Post
    is the BR7HS a typo or is that the plug you are running? The BR8HS is what is recommended stock. The popping could be lean from not enough fuel, or air leak. either of these will definitely cause a backfire.
    agreed. do a search on piston wash, and check yours...

  6. #6
    Quote Originally Posted by OsideBill View Post
    is the BR7HS a typo or is that the plug you are running? The BR8HS is what is recommended stock. The popping could be lean from not enough fuel, or air leak. either of these will definitely cause a backfire.

    no BR7HS is what i have in there, i read in many places that they run better with this plug..

  7. #7
    Quote Originally Posted by john zigler View Post
    agreed. do a search on piston wash, and check yours...

    WOW!!!! thanks sooo much john!! iv learnt ALOT by reading about piston wash.. lots more to read now!! im goin g to suss it out to morrow and also going to look at my old pistons too...


    i came out (was worryed for a bit trying to figure out which way richens it) half a turn on my hi-speed screws on the weekend and i think it made it feel better.. i may do another half turn our this weekend comming. i tryed to come out half a turn on my low speed screws but number two feels REAL LOOSE and feels like it would fall/vibrate out when i come out half a turn.. so couldnt do the lows and had to put lows back to how i had them previously...

  8. #8
    Well... Just did a comp test because i was board at work.... 145 psi, 145 psi, 000 psi. Sooo angry!!!!!! Only a few hours in on my fresh engine and i have no compression in cyl 3 at all.. Pulling the head off tonight

  9. #9
    Flying Scotsman's Avatar
    Join Date
    May 2006
    Location
    IllINOIS
    Posts
    6,514
    +1
    4
    Did you ever check that rear seal like I asked ?
    If it popped out you would have a massive air leak.
    What piston has 0 comp #3 ?

  10. #10
    Yamaha artisan Cutlass's Avatar
    Join Date
    Oct 2010
    Location
    Madison, WI, USA
    Posts
    2,500
    +1
    55
    Maybe that welded lower crankcase(if I remember correctly) is leaking. Did you pressure test the engine after you reassembled it?
    Rule number 1: pressure test after reassembly. The thing has to be really air tight.
    Rule number 2: Tune/make carb jetting and adjuster adjustments for your mods.

Page 1 of 3 1 2 3 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. oil hose popped off- no compression- Help!
    By darrengee in forum Yamaha PWC Performance (2-stroke)
    Replies: 7
    Last Post: 05-04-2009, 08:30 PM
  2. Lil help for an 06 NA GTX?
    By Cuisi in forum 4-Tec Performance
    Replies: 15
    Last Post: 05-03-2009, 07:53 PM
  3. 96 GSX no Start!!! Lil Help
    By GSXRYDER in forum 2-Stroke Performance
    Replies: 15
    Last Post: 11-03-2008, 08:19 AM
  4. need a lil help with Fercho's jetworks mod
    By MJE in forum Yamaha PWC Performance (2-stroke)
    Replies: 10
    Last Post: 05-25-2007, 09:57 PM
  5. 787 misfire - diagnostic help needed
    By javiert99 in forum 4-Tec Performance
    Replies: 3
    Last Post: 10-22-2006, 02:20 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •