Help!!! Bottom Studs Snapped Right Off

Discussion in '2-Stroke Engines' started by israel_ny, May 30, 2010.

  1. israel_ny

    israel_ny New Member

    Hello everybody,
    Yesterday I rode my bike to the gas station and on the way home i realized sounds coming from the chain so I stopped immediately. Then I found out that the bottom studs from the engine mount snapped off and that the engine tilted a bit. Now I can't get the remnants of the studs out of the engine :veryangry:. Any ideas?
    Thanks a lot!

  2. retromike3

    retromike3 Member

    Had the same problem

    I had the same thing happen to me What I did the first time was to get a small Easy-out. You have to file the bolt section sticking out of the case flat and then very carefully center punch a divot in the middle of the bolt, then drill a small hole in the center of the piece. Then insert the right size easy out into the hole and then turn it counterclockwise. You should be able to get it out without to much fuss. Later because the stock I replaced it with was weak it broke again. I could not get those out so I drilled and tapped two new holes about 5 mm lower. They seem to work ok, but I am replacing them with some new grade 8 bolts on my next set up. I will let you know how they work out.

  3. Al.Fisherman

    Al.Fisherman Active Member

    The first question should be.... NOT how to fix this, but why did this happen in the first place, so when you fix it, it won't happen again. IF you have used the studs that came with the kit, that is part of the problem. I wouldn't take a kit out of the box, mount it on a bike and ride it around the block.

    The BEST way of removing a broken stud is to center punch a spot as close to the center of the broken stud as you can (as stated file flat if you can). Second drill a small hole through the remaining stud. Then take the largest "LEFT" handed drill bit that can be drilled through the stud without drilling the threads out. Then onto a easy out.

    When replacing the studs use a metric grade 8.8 which is equivalent of a US grade 5.....NOTHING MORE. The cast aluminum can't even take the torque that a grade 8.8/5 will take. Use the proper amount of torque...don't guess. A 6mm @ 50-60 INCH pounds and a 8mm @ 150-200 INCH pounds.

    Now as to why they broke in the first place... three words... "improper engine instillation" will be my first bet. Were BOTH front and rear engine mounts completely flush with the tubes? I'd venture to say NO!

    Here is some good reading for a NOOB.... My profile has plenty of pictures in the photo albums. Sum Up prep checklist? Happy Time Mounts and Sprockets Hard Clutch non working Kill Switch Rear mount studs broke,... fix??? Huffy Cranebrook Best way to secure a gas tank... bike? Leaking Head/Gasket Cranbrook Coaster Brake INSTALL much to break in? I need a tutorial on putting a cylinder back together Solution to torquing China HT engine mounts. No power with Skyhawk 49cc (same for 66cc) First build Were can I get a clutch pin? Clutch roller (a must have item) ok to ride long time?
    Last edited: May 31, 2010
  4. israel_ny

    israel_ny New Member

    Thanks for the valuable answers.. I knew from the beginning that the studs that came with the kit were crappy and that something was going to happen to them sooner or later.. so the best option would be to drill a small hole through the center and then use an easy out?

    thanks again
  5. Al.Fisherman

    Al.Fisherman Active Member

    Drill a small hole first then a larger hole after which use the easy out. If you knew about the studs, why did you ignore the obvious? Also mount the engine to the frame, not the frame to the engine...
  6. israel_ny

    israel_ny New Member

    I just ordered a set of easy outs, I'll keep you updated about whether it worked for me asap (without a promise lol :goofy: ).. Also, may you please direct me with which studs I should purchase from McMaster and link it to me? Here are the options:

    Thanks Fisherman and Retromike
    Last edited: May 30, 2010
  7. Al.Fisherman

    Al.Fisherman Active Member

    Head studs ($2.75ea) Part Number: 93275A034 8mm X 110mm (4.5”)

    Front Mount ($2.98ea) Part Number: 93275A014 6mm X 40mm (1.5”)

    Rear Mount ($3.23ea) Part Number: 93275A019 6mm X 80mm (3”)

    They don’t have 6mm X 25mm (you can use a 6mm X 50 or 80mm bolt and cut to 25mm (1”)
    I'm sure Lowe's/Home Depot has 6mm X 30mm...cut or grind head off.
    6mm nuts ($0.93ea)…
    8mm nuts ($1.50ea)
    Last edited: May 31, 2010
  8. Pablo

    Pablo Motored Bikes Sponsor