Help....stripped Intake studs

Discussion in '2-Stroke Engines' started by hammer5312, Oct 21, 2011.

  1. hammer5312

    hammer5312 Member

    Okay I bought the engine from I assume, the original buyer (now I'm wondering:shout:)...and so have been working off and on the little beast.
    Well today decided to take the carb & intake off...well in doing so I noticed the nuts were different and that one of the studs appeared stripped.
    So in removing the studs, I found the right side stud to be stripped inside the cylinder.

    So my question?...can I just thread the hole with a bigger tap? :idea:
    I found the existing size was a metric if I went up to a 7, I should be good or should I go up to a metric 8?

  2. Padovani

    Padovani New Member

    Just asking: Are you sure that the threads of the cylinder are really stripped? Did you try to carefully screw the good stud on the right hole just to check?

    I´m asking because most china bolts are really ****! If you press with your fingers you can strip it! And for me it seems that the engine threads are stronger than mouting studs...

    It happened to me too when mounting the mount studs on the front tube. When I torked the stud on the engine, I stripped it. Then I bought a 6 mm thread bar, sawed to size and mount it again with no problems...
  3. blue 48

    blue 48 Member

    yep same here but i had the 3 clutch actuator screws strip replaced them with good hex key types and added locktite works great
  4. HeadSmess

    HeadSmess Well-Known Member

    tap that hole out to M7 (not standard) or M8, and all i can say is "good luck getting a nut on with the manifold in place"

    theres not much space even with the M6 threads....

    helicoil...either fork out on a kit (not cheap...try ebay) or go see a mechanic.

    a helicoil is basic but you have to do a few to work out the technique of insertion... practise makes perfect. and theres nothing worse than a helicoil inserted by an idiot!

    (has memories of working on his mates kwaka...with every cam bearing bolt stripped, helicoiled, and even some of those stripped, and tapped out the next size up, stripped again! then helicoiled again at the next size up...a complete nightmare! over 16 helicoils in two different sizes! the idiot that did it obviously had no idea of how to reassemble a head... or how to use a helicoil!)

    a kits only worth it if you can get one cheap or expect to be replacing a lot of threads.

    on that note, i got a full kit...M3 up to M12 for $120. that was cheap, and then the refills on inserts is cheap. the initial cost is mainly in the special tap they use.(and DONT mix that tap up with your normal ones!) once you have the tap, your laughing.

    meh. theres only one...take it to a mechanic/machinist... :D
  5. richirich1113

    richirich1113 Member

    check out the Time-sert thread repair kits on amazon and their installation video on youtube. very easy to use, ive had to use them and would swear to the repair.
  6. Skyliner70cc

    Skyliner70cc Active Member

    Second timesert inserts! I love them and have used them numerous times on HT engines. I go a step further with the timesert and apply a light coat of JB weld on them before I screw in the insert.
  7. hammer5312

    hammer5312 Member

    First off...thanks to any and everyone who replied!

    Second, yeah I'm sure the threads are stripped on the cylinder...looks smooth as a Chinese baby's butt....

    Prolly going to tap it, which means tapping the other hole too....I had bought some M6 bolts to use instead of the studs, looks like I need to buy some M7's...oh well.

    Thx again.
  8. motorpsycho

    motorpsycho Active Member

    like headsmess said...good luck getting an m-7 nut on with the intake in place.
    There's a gnats hair of room between the intake tube and the stock m-6 nuts, so going up to an m-7 will make the nuts hit the intake tube and you won't be able to tighten them up.
    helicoil or time-sert is the only answer...or just buy a new cylinder....they're cheaper than a helicoil kit.
  9. Barnfresh

    Barnfresh Member

    How about tapping to m7 and using a step down stud to m6?
  10. hammer5312

    hammer5312 Member

    the problem with buying a new cylinder....I bought a head for it and found out that it may be a 60/88 cause the head was for a 49cc and didn't fit....
  11. richirich1113

    richirich1113 Member

    Ther time-sert mite be spendy at first but in the long run.. the intake, exhaust and mounting studs and possibly the head studs(depends on motor) all use the same 6mm so it would most likly come in handy down the road. and you cant beat the ease and solidness of the time-sert repair.
  12. Al.Fisherman

    Al.Fisherman Active Member

    Solution, works on all the 6mm, 1/4", and 7mm studs.

    Last edited: Oct 25, 2011
  13. motorpsycho

    motorpsycho Active Member

    EXCELLENT idea!!!
    yeah this would do the trick for sure with the m-7 studs and nuts.
  14. Al.Fisherman

    Al.Fisherman Active Member

    Why....thank you. I use them on 6mm studs. This way I can use a socket to torque the nuts. Otherwise there isn't enough room for the socket on some applications.
    Last edited: Oct 25, 2011
  15. HeadSmess

    HeadSmess Well-Known Member

    theres also replacing studs with unbrakos or allen key screw thingies. usually have a 8-10mm head thats round... :whistling: can even get sockets for them! a 10mm nut is a lot wider from point to point... about 13. m8 unbrakos around about a 12mm diameter head. and can always be made a lil bit smaller.

    in all my time...while i have an m7 tap...ive only ever found one m7 thread in real life. and i think someone had been at that before me :thinking: the tap came from a cheap kit i wouldnt buy myself... they come in sets of three per size and anything else is cheap and dodgy, and will probably break at the best time possible :shout:

    maybe its more common in the US, but here... never seen it for sale, never needed it, wouldnt want it either. hard enough dealing with whitworth, unc, unf, unef, iso fine, bsp,bspt,unt, what else? theres more...lots more... :(
    Last edited: Oct 26, 2011