Broken Engine Mount Problem

Discussion in 'Frame Mounted Engines' started by Soundplot, Aug 7, 2011.

  1. Soundplot

    Soundplot New Member

    I have a great little 2 stroke here that has been running great for months now. I have had minor problems but nothing that I couldn't easily fix.... until now. I would like to keep using the engine considering the little guy runs like a thief but I just can figure this situation out so I bow down in humble genius of MotoredBikes.comm. As you can kind of see in this poorly lite picture taken with my phone the screw that attaches the engine to the bike has broken in two. It snapped right at the engine block. I have no clue how to get the broken piece out or the engine block or how I might circumvent this situation and still use the engine. Any thoughts or fixes out there that I don't know about? You have always been so good to me in the past with so much help, Thank you in advance for any help!


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  2. Al.Fisherman

    Al.Fisherman Active Member

    When are people going to learn..first the correct mounting is critical, the trash hardware the Chinese needs to be replace..with that said, since it broke off flush, you have a couple of options, search will find 100's like your problem. So the's like [​IMG],,, Have you searched for your solutions?
  3. impression

    impression Member

  4. Lazieboy

    Lazieboy Member

    Been there Done that

    I brang mine to a lawn mower place they were able to back it out with a tool.
    Yey hardware is ****. I got some new stuff at Fastenal. I dont use the factory stud bolts, just goot bolts with some washers.
  5. dougsr.874

    dougsr.874 Active Member

    You will have to take the engine off of the bike......go to a parts house and buy a set of left=hand drill bits, also a screw extractor of the proper size...some extractors come with a drill bit the correct size...don't damage the threads when you drilling out the stud...
  6. joshua97

    joshua97 Member

    I found left hand bits very useles from my experiences haha. I used a dremel cutting disc (like a 2cm long by1mm angle grinding disc) cut a slot in shaft of screw (may have to graze engine block tho :-/ so careful. Then use a screwdriver to unscrew it from the groce u cut, after google "the jake bike" and look at his custom mounts :)
  7. dougsr.874

    dougsr.874 Active Member

    HOW can a left handed drill bit be useless?.....It just drills a hole when the bit turns to the left.....
  8. Big Red

    Big Red Active Member

    And sometimes it'll even screw the stud out before you get the hole drilled all the way. BUT, It don't HAVE to be a left hand bit. Any bit of the proper size will work. I've done A LOT of these. All ya gotta do is center punch the stud so the drill bit goes down the CENTER of the stud. Ya DON'T want to mess up the threads. Then drill a hole in the stud, get the matching size easy out, (bolt extractor,) and spin it out. Then make sure you use better quality studs and replace them both. Also, Make sure the drill bit isn't too big, All ya need is a hole in the stud without hitting the threads in the case. Easy stuff. I don't see why there's even a debate on this subject. (Left or right drill bit? LOL.) IT DON'T MATTER. Drill the hole and extract it. DONE!!!
    Big Red.
    P.S. It's A LOT easier to do with the engine OFF the bike.
    And Al is right, There's a LOT of posts on broken studs. Ask the question AFTER you've done a search. Just proper etiquette.
    Last edited: Jun 22, 2013
  9. joshua97

    joshua97 Member

    i tend to find when drilling out screw shafts less than .8mm the left bit tends to slip and it bite the thread, but mabey its just my bad luck
  10. Big Red

    Big Red Active Member

    Did ya read the part where I said, All ya gotta do is CENTER PUNCH the stud. That will keep the bit from drifting.
    Big Red.
  11. joshua97

    joshua97 Member

    last case dremel, or drill it right thru and helical kit, or force big bolt in there that usually hold, better yet=new crankcase or motor :(
  12. Big Red

    Big Red Active Member

    Why would you dremel it or drill all the way through when ya can just drill a hole and "easyout" it. If the case is stripped out then ya just tap it to the next size up. And there's LOTS of things you can do before ya buy a case and rebuild the entire bottom end because of a stripped out stud. If you CENTER PUNCH the stud, Drill it straight, Spin it out with a easyout. It's the easiest way to do it. It doesn't scar the case and is the proper, professional way to do it. Any other way is what you might do if you don't have the proper tools or experience. (Force a big bolt in there, REALLY?) C'mon bro, Even a 15 years old ya gotta know THAT ain't right.
    Big Red.
  13. joshua97

    joshua97 Member

    from my 4 years of motorize biking i have had snapped studs 4 times, (now use high tensile haha) easy outs were for me a big fail (i used cheap ones etc so may be my luck) the other 2 i dremeled a grove and used a flat head screwdriver (barely even marked the crankcase) The last i nothing worked as i used red loctite lol so i drilled it at 7mm then used a drill bit with a thread (like a rough threader bit) thin tightened a bolt into it (one that matches the rough thread job) still works after over a year fine. i guess my suggestion o new case or motor was pretty stupid, so apologies for that. if not take to professionals i guess? :)
  14. Big Red

    Big Red Active Member

    I think the only reason you had bad luck with the easyouts is because ya REALLY gotta center punch the stud to keep the drill bit centered on the stud. Otherwise yer gonna "drift" off to the side and mess up the casing threads. This really is the easiest way to remove a broken stud, That is unless it breaks above the case. Then ya just grab it with vice grips or whatever and screw it out.
    Now, I've busted cheap easyouts off inside the studs and THEN YER SCREWED and I have no good solution for that dilemma. So first of all ya gotta buy the good easyouts, Not the dollar store ones. Ya can't drill out even the cheap easyouts once it's busted inside the stud. In this case YOUR solution might work. Dremmel a slot and use a screwdriver. If this ever happens to me again I will strongly consider slotting it with a dremmel.
    Big Red.
    P.S. I've got almost 8 years of MB's behind me, 5 of that running a small motorized bike business. Not to brag or anything, but since ya brought up your 4 years. And I've had A LOT more than 4 broken studs. Like 20 or 30 on customer bikes.
    Last edited: Jun 26, 2013
  15. IbedaYank

    IbedaYank Member

    another PRO way is to weld a washer to the stud and then a nut to the washer.

    And this works with broken easyouts and drillbits if not busted to far off down in the hole
  16. Big Red

    Big Red Active Member

    And yer right, IF ya got a welder. Like I said somewhere before, Not everyone has a welder. And if ya take it to someone else to do it ya might as well take it to a machine shop and let 'em do it all. But yer right. If ya got a welder and decent welding skills then this would work just fine.
    Big Red.
  17. Skyliner70cc

    Skyliner70cc Active Member

    Don't waste you time. Drill two holes thru the mount 90 degrees to the original studs and then bolt and attach angle iron or a steel "L" to it for a new engine mount...much more strdy
  18. Big Red

    Big Red Active Member

    I'm not saying I've never done it like that before skyliner, but only as a last resort. There are all kinds of better mounts you can make or buy. None I can think of require you to drill into the case to achieve putting a sturdier mount on a bike. The only time I will do this is when there is no hope of saving the original mount. And it's a LOT more work than simply extracting a broken stud.
    But, As I've always said.
  19. KCvale

    KCvale Motorized Bicycle Vendor

    What has worked for me a couple of times was just blocking the motor in my little drill press and after running a bolt that size up to hardware store and bought a brand new drill bit and easy-out, it worked like a champ but the trick as mentioned is drill the stud and not letting the bit slip into the cheap soft case metal.

    One other note is unless you snapped it off tightening it your motor had to be loose to snap it off. One simple test you should do before you take a ride is grab the top of your motor with one hand, your top bar just behind the gas tank and try to push you motor back and forth, if it moves AT ALL it's need tightening.
  20. Big Red

    Big Red Active Member

    Yeah KC, Ya tell em and tell em, Then they just jump on the thing and ride without checking anything. I don't trust ANYTHING made in China THAT much. It's only happend once, But my baby tells me if my motor is getting a little loose. The vibration starts tickling me in my neither places and makes my rear go numb. I check for engine tight every 3 or 4 times I ride it, Don't know what happend the one time. I do check wheels and brakes along with lights EVERY time.
    Big Red.