Motorized Bike Bullshit: Things your builds do that piss you off!

Discussion in 'General Questions' started by SEGACDX, May 18, 2016.


    SEGACDX Member

    We all have problems with our motorized bike projects, they are in constant need to attention and in other words tinker toys. Always needing adjustment constantly, these things from some people are a good way to learn mechanical acuity but for others can be just down right frustrating and annoying.

    Re-doing the same things over and over with no positive results can be discouraging at first but when you finally get it right it feels great, well until the next enviable thing goes wrong.

    Today I went to talk about a few things I find superbly annoying and I hope you share your frustration stories with me as well.

    First and most prevalent problem I have it simple. Air leaks, we all get them and we all know how hard they are to keep in check. My solution for it is simple but takes a lot more time and that's you use RTV ultra copper gasket maker since it offers maximum heat, gas and oil resistant over all the RTV gasket-makers.

    I find the gaskets the come with these engines to be to be nice lacking strength, I always find my gaskets leak no mater how tight and well maintained the engine bolts are. The only gaskets I cannot simply replace with RTV are the head, clutch and magneto simply because I need to adjust the clutch often, the magneto doesn't really need to be replaced often and the head gasket need to be metal to withstand the pressure. However I do RTV the bottom and top of the head gasket to keep leaks to a minimum.

    The next problem comes with the bad quality bolts the come with the engine simply put they are just not strong enough to resist tightening and maintenance you have to do in order to keep things leak tight, I recommend replacing all bolts with 40mm and 25mm 1.0 pitch 12.9 grade M6 socket cap bolts to keep them from snapping. I've used 8.8 hex cap bolts form home depot since I had no idea where to buy those bolts and they simply snap under the tension of the engine pushing back under high torque/ high pressurize/ high temperature conditions.

    I find the highest strength grade 12.9 bolts have been top notch with not one broken yet. If you want to know how many you may need of each you can get 20 of each so you have many spares since you may want to replace your sprocket bolts of even make studs to replace striped ones in the future, extra is always better.

    I've already had a few strip on me in resent times I've had to replace with studs I've made.

    I was working on a new build with used bet good shape parts and it's so frustrating to just have one little thing ruin a otherwise great job. I had a thread on the bottom end strip right out where the top end connect the the crack case, making me have to tear down the engine and replace the other half with another crank case half.

    It's just a pain to have to not only have to rebuild an engine twice because of bad quality parts.

    Clutch problems are frequent and oh so touchy every engine has a different amount of turns to get a strong grip on the pads. My old engine was 3 turns after hand tightening to max with the arm pulled in and the clutch cable removed, this is how I calibrate the clutch, but sometimes working with a new engine is a pain.
    I now know with my new build 5 turns is the needed amount to keep the clutch from slipping.

    I hate how downright simple but impossible they dam clutches are, you can spend hours dialing in the right settings and still have to go back for more, thankful I have air tools to keep my hands from falling off.

    Getting the god dam sprocket on straight, on my new wheels this was one of the most unnecessarily time consuming thing. The reason was my back wheel did not have the longer cylinder the sprocket fits on before tightening down. Because of this I had to rig a bunch of Popsicle sticks to keep the sprocket from moving from side to side wile tightening and it ended up working great but otherwise it will bob up and down making the chain get loose an then super tight and I just couldn't have that.

    This may just be my bike but I hate having my back wheel slip forwards it's due the the kind of bike I have rather than a problem with all builds but having to reset my wheel is very annoying.

    That's all I can think of for now, I hope you can share some things with your builds the annoy and frustrate you to no end.

    Happy Motoring!
    Dmar likes this.

  2. bakaneko

    bakaneko Active Member

    nice post. mine would be breaking a chain without chain breaker tool and with hammer and screw driver only. lol :p
  3. FurryOnTheInside

    FurryOnTheInside Well-Known Member

    Lmao! Did you lose your brick and nail?! XD
  4. butre

    butre Well-Known Member

    I have a tendency to destroy axles. that's the only consistent problem I have but it has more to do with riding style than anything else.
  5. Rob H

    Rob H Member

    Me me too bent axles and rear bearings
  6. crassius

    crassius Well-Known Member

    built properly, the listed problems are extremely rare
    Rico glover likes this.
  7. Timbone

    Timbone Active Member

    I am a good mechanic, but I have my issues.
    I really can't work on anything for very long without giving it a thorough cursing!

    Everything takes longer than I think it will. And somehow, my tools have a way of eluding me. I can use a wrench, change to a screwdriver, then go back to the wrench - GONE! Can't find it. Don't see it. I didn't move but it's GONE! Five minutes later - and after some rich cussing! - the wrench is behind me. Grrrr.

    These little two strokes are so finicky - they never wanna start the same way. Sometimes choke works - other times not so much. Some days, the thing revs up fast and it's smoking - some days it seems sluggish. WTF?

    And my hands. My poor hands! Sometimes just looking at the bike and they are filthy with lines of black under the ends of the nails. Oil gets everywhere. Even locking the bike and funk gets on my hands. Ugh.

    I cuss. A lot.

    Holly, Jay dee and Hello Moto! like this.
  8. KCvale

    KCvale Motorized Bicycle Vendor

    Is this your first build?
    And did you start with the cheapest bike and kit you could get?

    Either will screw ya bud, both insures a problem child, and if you are a Rookie, well that is another factor as the first build is always the hardest.

    Rest assured a good kit on a good bike can run for thousands of miles with medium maintenance.
    Heck, I have 45 of them out
    And that is just the stock kit builds.

    In short, not everyone has your problems but I'll bet many others do ;-}
  9. 45u

    45u Active Member

    I am happy to say after over 2 1/2 gallons I have had very few problems. I have had some very nice 30 plus mile rides. Most of mine where things breaking and coming loose from vibration. After putting lock nuts, sometimes double nut and welding and bracing things I have very few problems now. I do have to fix my headlight bracket now. I will all so be balancing the crankshaft which I am sure will help a lot. On build two this will all be done before I ever start the motor or ride it.
  10. Rob H

    Rob H Member

    I'm getting ready to do the same on build 2 as well all stock no problems
  11. 45u

    45u Active Member

    For my second build I have a genuine Grubee engine. The engine every one else copied. So far from what I have looked at much better quality. This build is going to be my hot rod.
  12. rjs1617

    rjs1617 Guest

    i agree with crassius. if you use better quality parts to start with and properly adjust them you will have few if any problems with parts breaking or striping. if your stripping bolts and threads it means your over tightening them in the first place. i bought a used bike from my local bike shop for ten dollars about 20 years ago. now this bike was incomplete so i got it cheap but had most of the parts i needed here at home and ended up with a $40.10 bike that to this day runs great even motorized. to those who are getting into motorizing your bike be smart and have someone who is good at building wheels go through it and properly tension the spokes and clean and regrease the hubs. it is vitally important to adjust them properly and lock the nuts down to each other and not to the bearings this will get you a long way in your future riding. also ditch those heavy steel hubs, it is Pure B.S. that they are better than aluminum. the steel gets hot and stays hot whereas the aluminum dissipates the heat as you ride. i've ridden mine about 4 miles WOT then jumped off and touched the hub with my bare finger and found them to be barely warm to the touch. proper adjustments will do that not steel hubs and rims. lighter is better and by no means do i mean the most expensive out there. my rims and hubs were low end at the time they were sold on bikes at bike shops not walmart or kmart.
  13. Hello Moto!

    Hello Moto! Active Member

    Biggest problem I have had was due to my own lack of attention. Forgot to fasten the coaster arm one day and destroyed my rear wheel. Bent axle, bearings falling out and the whole shabang! Other than that My bike is reliable. I do check it out often for any loosening of critical parts like the hub adapter, chains and the muffler and stuff but loc-tite and nylock nuts are good at keeping that in check. I think it's better to be safe than sorry as the old adage goes. I enjoy this hobby :)

    I also cuss a lot. :D
    Last edited: May 20, 2016
  14. 45u

    45u Active Member

    Yep on this things thread lock and lock nuts are mandatory.
    Timbone likes this.
  15. gus.

    gus. New Member

    The only problem I have is the constant a just of the head nuts. (175).ebry 40 miles. The blue tread lock don't do nothing
    WINDY CITY BOB likes this.
  16. 45u

    45u Active Member

    Are you using the aluminum head gasket? Make sure the head and head cylinder gasket surface are flat then get a copper gasket. Not only are the copper much better you can anneal them and us them over and over and over and over. I had the same problem till I went to the copper gasket. All so make sure you studs are not pulling out. Make sure you torque them properly as well.
    Torque 8mm to 120 to 175 INCH POUNDS
    Torque 6mm to 60-70 INCH POUNDS
    Last edited: May 20, 2016
    Timbone likes this.
  17. gus.

    gus. New Member

    I'm using Teflon gasket and flater the head and cylinder with sandpaper 220 and a glass.
    Timbone likes this.
  18. 45u

    45u Active Member

    And you still have to keep re-torqueing???? Try a cooper one and you will only have torque 2 times. Once when you install it and once after riding it for about 30 minutes let it cool all the way down and torque. I even check it once after that just to be sure but did not have to tighten it any. Al so like I said you can reuse it over and over and over. All so you can get them it two different thickness which is a easy way to up the compression a little.
    Last edited: May 20, 2016
  19. gus.

    gus. New Member

    Thanks I will try it.
  20. 45u

    45u Active Member