Engine Trouble I've damaged my motor

Discussion in '2-Stroke Engines' started by jefuchs, Dec 4, 2012.

  1. jefuchs

    jefuchs Member

    I posted earlier about not being able to turn my motor enough to start it. After reading several posts in the archives here, I tried just about every suggestion. Nothing worked, and I was using an electric drill to turn the motor, as there are no hills to descend in my area, and judging by my results, a mountain would not have been high enough.

    Anyway, I did succeed at one thing. I stripped the bolt in the magneto. It's toast, and my new motor still hasn't run.

    I'm only a little discouraged, but very frustrated!

    Anyway, please look at this link, and tell me if this is what I need to replace it with, or is there a smaller part (just the bolt) I can buy. I'll also ask the seller.


    I'd ask for advice starting this thing, but you guys have shared all your advice already, and if I hadn't stripped the thing, I'm sure I'd succeed sooner or later.


  2. crassius

    crassius Well-Known Member

    That's the part, but you never know these days which crankshaft fits which engine. I'd work really hard at trying to get the threads repaired on the crank you have. Try a thread file, green loctite, threading the hole inside, then putting in a bolt with washers outside to hold the rotor, etc., etc.

    Seen this happen several times to folks, much better to keep a pull-start unit on the shelf to attach at times you need a hand start.

    I use a build bench that allows me to get on the bike & pedal start it, or just pull the back tire to turn the engine - not hard to build.
  3. motorpsycho

    motorpsycho Active Member

    if i were you, i'd just buy a new motor. I'm all for people diving in a tearing stuff apart to learn how to fix stuff, but
    replacing the crank shaft means TOTAL disassembly of the engine.
    this means that you'll have to split the case, buy all new gaskets, and i would also put new bearings on the connecting rod and crank shaft.
    It's a lot more work to replace the crank than to just buy a new engine (not a whole kit). sure the crank shaft is only $18.00 plus shipping, but add the cost of a gasket set, bearings, any tools that you need to buy(in case you have a limited amount of tools), the time and effort....buying a new engine and just replacing the whole thing woudl be a much easier route (in my opinion).
    BUT, there are ways of getting that stripped bolt out of there without damaging anything if you have the skills and the tools to do it.
  4. jefuchs

    jefuchs Member

    I've already thought of that. It would at least ensure that I'd have lots of replacement parts for the future. It's only $100, so that's $80 over what I'd be spending anyway, and after tool costs and aggravations, the cost might be a lot closer. As for new gaskets and bearings... They ARE new. I was trying to start the engine for the first time when I broke it.
  5. motorpsycho

    motorpsycho Active Member

    Yes, your current bearings are new, but thats not saying that they wont be damaged when you remove them. The bearings in these engine aren't the best to begin with.
    Yes, your current gaskets are new, but you can't re-use them.
  6. jefuchs

    jefuchs Member

    Okay, I decided I'd rather ride the bike than spend the rest of the winter tearing down a motor and figuring it out. I ordered a new motor for $80 plus shipping. I think I'll use two head gaskets (since I have all the extra parts now) to lower compression just to get the thing running easier. Maybe after break-in I can remove the extra one. Excessive compression was one of the reasons I broke the motor. The motor was too tight to roll-start, so I used the electric drill.
  7. BchCruizer

    BchCruizer New Member

    Sounds like you gonna be buying a new motor. unfortunatly. Can you get a replacement engine? My kit (the bee) you can get a replacement engine for 90$. I dont know what kinda deal's they have with those chain drives. How long did you kit last before it stopped running..its a hit or miss with those things. hope ya get her running!
  8. jefuchs

    jefuchs Member

    As I said above, I never got it running. It's my first build, and it was so hard to start that I broke it in the process. I found a new one from boygofast for $80.

    Rather than replace the broken part, I'll see if I can tap new threads, and maybe have a second build from the first motor someday. For now, I'm tired of not riding. I want one that runs.
  9. wan37

    wan37 Member

    Well here's and idea try putting some washer on the shaft to bring it out enough past the strip part then tighten down that way.I know you can put the piece of the pull start on there and it doesn't throw it out of balance,so the extra washers wouldn't either.
  10. jefuchs

    jefuchs Member

    It seems to be stripped to the end. But rather than lose a motor, I'll probably try to tap new threads on someday for a second build. That still won't make it any easier to start, though.
  11. wan37

    wan37 Member

    Well thats true I tried,I know I got mine to start easier with double head gaskets.
  12. motorpsycho

    motorpsycho Active Member

    using 2 head gaskets will lower compression to make it easier to start, but you will lose a little performance.
    these engines are low compression anyway, so adding a second head gasket shouldn't even be necessary.
    these engines are very easy to get started (if you get a good one, and you know how to work the choke.)
  13. wan37

    wan37 Member

    I didn't have to double it I email bgf and he sent me a thicker head gasket then the stock one yes it's better on starting,but did lose some performance.I'll know more as I break it in more I also order some jets from sick bike parts after I run a couple more tanks fuel I'll get her dialed.hope you get yours running Jeff.It runs better with the thicker gasket as to the double gasket I tried it too.