engine head gaskest is not sufficent

Discussion in '2-Stroke Engines' started by peppy, Feb 13, 2011.

  1. peppy

    peppy New Member

    please help gang, new grubiee 66 , and im geting air and oil leak from the head gasket, resulting in loss of compression and thus power.I have changed the head gasket to a new one , its better than the first but still not completly sealed.I i used a torque wrench and tightened the nuts to 10 lbs of foot tourqe as specified in my manual,and used loktite (blue) for added strength,this bike has less than an hour of running time, its my first build and it hasnt run properly since day one , is there a suitable gasket maker that will seal and last or am i s.o.l ? i would appreciate any helpful suggestions. thanks ahead of time.:confused::ack2:

  2. wildemere

    wildemere Member

    How do you know its a air leak?

    Have you tested it properly?

    With smoke or gas? for example a lit cigarette or propane gas.

    All HT's ooze unused and spent/used oil from most gaskets. They are not engineered like Honda or Yamaha or Morini ect.

    For that matter all the early designed Japanese and European small bore 2 strokes also oozed out oil everywhere.

    Its actually the sign of a heathy engine.

    Either get used to it or buy a quality four stroke.

    Also, loctite will not add strength.
    Last edited: Feb 13, 2011
  3. Dave C

    Dave C Member

    My head gasket leaked from the begining, too. I used Permatex Copper Spray-A-Gasket. Spray both sides and let it set for 15 minutes and install. Did you use any kind of torque pattern? I use a "Z" shaped pattern and tighten in stages starting at 2 1/2 lb and going up 2 1/2 lbs at a time. My instructions say 12 1/2 lbs. is your target. Get rid of the acorn nuts, you can't see if the stud has backed out and they can cause a lot of problems.

    I don't locktite the nuts but you can locktite the studs into the block. I raced and used ARP bolts and studs many times and they use a molybdnum disulfide assembly lube on the nuts and stud tops. This was to make sure your torques are right. These head studs is one place you need to trust lockwashers. Blue Locktite everything else, though.
  4. motorpsycho

    motorpsycho Active Member

    man, you guys buying thses grubee engines have nothing but problems.
    I got my engines (4th one so far) from boy go fast and i have not had any problems.
    I always see people posting problems, and 9 times out of 10, it's on a grubee engine.

    my guess with your leaking head gasket is either the surface of the cylinder, or the surface of the head is not flat (where the gasket goes).

    as far as the quote "All HT's ooze unused and spent/used oil from most gaskets.", i have not had any leaks like this with my engines other than at the exhaust gaskets (which are junk). I replaced the exhaust gaskets with aluminum ones last year, and have not had a leak from them since.
    My headgaskets do not leak, and my engines are as clean as the day i put them on my bikes.
    No oil residue on my engines, except for inside the exhaust.
    Last edited: Feb 13, 2011
  5. Dave C

    Dave C Member

    I had to send back my first motor from BGF. It would not fire, no matter what. I put the second one on and it fired right off. Wasted my summer working out the bugs.

    It ain't all rosie at BGF...Yet I have bought from them since.
  6. Skyliner70cc

    Skyliner70cc Active Member

    I never had a head gasket leak and here is what I do on ALL engines I purchase (dozens and dozens to date)

    1. pull OEM headstuds and replace them with better quality ones.
    2. JB weld the new studs into the engine
    3. Flat sand the head and cylinder on glass with fine emory paper to ensure sealing surfaces are flat
    4. Use copper gasket spray and spray both sides of aluminum gasket with about 3 coats, waiting a while for each coat to dry.
    5. Install all parts and torque the heck out of the bolts holding the head down. I don't use a torque wrench I just tighten things down much higher than factory settings.
    6. Ride and never have to worry about loose heads and head bolts pulling out of block again!
    Dustmonkey likes this.
  7. motorpsycho

    motorpsycho Active Member

    my guess is that you got a bad magneto or cdi box with that engine.
    I'm just saying that i've had good luck buying from bgf.
    I have no idea who manufactures the engines that bgf sells, but they seem to be pretty solid from what i've experienced.
    Every engine manufacturer has issues, no matter who makes the engine or the parts.
  8. Skyliner70cc

    Skyliner70cc Active Member

    MY BFG engines have been pretty solid too but customer service from them is god-awful. They often don't get their order correct, e.g. order a slant and get a non-slant or get something that looks completely different from the picture on the ebay listing. Returns and warranty work are unlikely. Most of my BFG had some sort of damage, broken head fins or damaged gas tanks. Never did get them to send replacement parts and email replys were hostile.
  9. Fletch

    Fletch Member

    If you want you can use Permatex Indian Head Gasket Shellac instead of a head gasket (or base gasket). If you use it instead of a head gasket I would definitely have a base gasket. The stuff is messy, but seals tight and holds well. This would boost your compression by not using a head gasket, but make sure there is no piston contact. Sanding first to even the surfaces of both the head and cylinder is great advice too. If you replace the studs with good ones, torque to 12 ft lbs.
  10. motorpsycho

    motorpsycho Active Member

    I have never had to deal with bgf for anything customer service related, other than when i sent him an e-mail looking for a black 66 c.c. slant head.
    he replied right away and said that he had then, but he just didn't have them listed.
    I haven't had any problems with bgf at all.
  11. motorpsycho

    motorpsycho Active Member

    huh? I'm stll running my stock head studs, nuts, washers, and head gaskets.
    been over 2 years on one of my engines and a year on one of my other engines.
    still no leaks and tons of compression both of them.
    I even took the head off of my 50 c.c. slant and turned it around for clearance after i had been running it for about a year. I used the original head gasket when i put it back together, and that was about 150 miles or so ago.
  12. Dave C

    Dave C Member

    I sent back the basic motor, the same as if you bought just a replacement motor. I don't know because I haven't had one of these apart, yet:evilgrin:, so I dont know but I think they pressed the crank together with the woodruf key indexed to the crank incorrectally. When I tore it down to ship there was a black oily residue in the port. Lead me to believe the index thing. Motor was fireing but not at the right place.
  13. Loup Garou

    Loup Garou New Member

    I also have bought 2 engines from BGF and have not had any problems except a weak cdi on one.
  14. peppy

    peppy New Member

    while i appreciate your attempt at advice wildmere,i am a little confused by your tone ? You seemed a bit irritated and and pompus, and in order for oil to escape from the head gasket air would also be escaping, i thought this would have been obvious ,and your comment about loctite not adding strength ,i found that very snarky and contrite. Perhaps i misunderstood your tone but maybe in the future use a little more cortesy in your responses.
  15. peppy

    peppy New Member

    and to everyone else i greatly appriciate your helpful suggestions and plan on applying your advice to my bike , thanks again.
  16. retromike3

    retromike3 Member

    boy wont go

    the first of three motors I have bought was a Boy Go Fast from Ebay and I had problems from the start. After a while I had to replace all of the components. I will admit that this was three years ago and things might have changed.

    I believe that the main problem is that with these kits you are never sure what is correct and for the price that they cost its amazing that they work at all.

    I have bought engines and kits from three different companies Boy Go fast,Zoom(only got the engine there) and Gas Bike. I finally got my latest up and running (a Skyhawk 66cc) but only after working on it for about two weeks(on and off). turns out that it was a combination of a bad plug wire and a defective CDI unit. But in the meantime I did learned a whole lot about two stroke motors and I can successfully tare down and rebuild all of the parts on these little guys.

    The sense of accomplishment you get when your on your way with these things is hard to explain. And with the complexity of most things in todays world its hard to put a price on that.

  17. Alson

    Alson Member

    Head leak

    I have a friene that bought a crome head, so he had to take the other off.So he put only one warsher on all the studs abd big air leak. I told him theres four more warshers, he didnt believe me, there stuck on very hard abd there hard to tell there on there. So he did see them, were going to try tommarow to put them on. I believe the acorn nuts were bottom out without thoses extra warshers
  18. Dave C

    Dave C Member

    Yeah, if your not going to replace the head studs you should replace the acorn nuts with regular open nuts. At least you won't bottom out and you can see if things are holding together.