I Want Reliability

Discussion in 'Motorized Bicycle General Discussion' started by skyhawk66cc, May 4, 2011.

  1. skyhawk66cc

    skyhawk66cc New Member

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    I have a 66cc Grubee Skyhawk that I installed on a Mountain Bike. I want to know how to make this thing super reliable. The motor came with the CNS Gen B carb (the one with the red air filter housing) and I think I am going to get rid of that and order the NT carb that I have been reading a lot about. I will sacrifice speed for reliability in a heartbeat, what other parts or tips would help me with this build. I have about a 24 mile round trip that I would be commuting Mon-Fri there are some long hills (not super steep just long) which I would peddle assist. I junked the stock chain already because it broke in about 10 places and would kink up no matter how well it was lubed, I switched to a BMX chain made by ZChain. I am guessing I have a carb problem because it bogs down and doesn’t want to stay running after about 10 mins when it warms up and I always have to have the choke full on, but that should be eliminated once I get the NT carb. I want to seal the gaskets so I don’t have any air leaks or any leaks for that matter, anybody have a sealer that they recommend? Thanks for the help guys, can’t wait until I can come up with some tips to post.

    -skyhawk66cc .flg.
     
    #1 skyhawk66cc, May 4, 2011
    Last edited: May 4, 2011
  2. DaveC

    DaveC Member

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    Well, I hate to say for reliability the way to go is four stroke. Even the cheapest 4 stroke from Harbour Freight in more reliable than the best Chinese 2 stroke.

    The best and easiest way to double reliablity of a two stroke HT motor is to have a spare ready to go. At least that's the plan when I got touring :p
     
  3. skyhawk66cc

    skyhawk66cc New Member

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    LOL, wish I found this site b4 I ordered my 2-stroke then. That sucks, I knew it was to good to be true. I think im going electric and getting some extra batterys for my commute
     
  4. rohmell

    rohmell Active Member

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    ...And if your job is cool with it, you could have a spare battery at work charging overnight so that It is ready for you to use at quitting time to get home.
     
  5. 2door

    2door Moderator
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    DaveC and I usually agree on most things but I'm going to have to respectively disagree here. There are many of us who have accrued hundreds and in some cases, thousands of miles on our Chinese two stroke engines.
    Installed and maintained correctly they are (can be) just as reliable as any four stroke engine.

    As for your current problem, running for a short while then stopping, this could be the result of your fuel tank cap not venting or a defective CDI that performs when cool but developes a problem when warm. Try riding with the fuel tank cap loose for a while and see if that doesn't fix the problem. If not, replace the CDI and give it a try.

    If you're breaking chains it's a good bet you have an alignment or tension problem. Even the kit supplied #415 chain will suffice if installed correctly. Many of us use industrial #41 chain as a replacement.

    If you have to keep the choke closed for the engine to run, you have a massive air leak somewhere. When you replace that pos carb you now have with the NT, make sure the intake manifold gasket to the cylinder is good and seal the carb to the intake with SealAll. it is gasoline resistant, unlike silicone gasket sealers, and available at most auto parts stores.Good luck and don't give up on the little two stroker. Treat it right and it will serve you well.
    Tom
     
  6. skyhawk66cc

    skyhawk66cc New Member

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    My job promotes this type of transportation to its employees so they would have no problem at all. That was kind of my plan when I started looking for alternative modes of transportation, my problem with electric is that it rains fairly often where I live and I was worried about where water might get in and ruin, I planned on sealing everything I could think of but I know I would miss something.
     
  7. skyhawk66cc

    skyhawk66cc New Member

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    Thank you for the advice, I know that my tank vents well because fuel sloshes out all the time and makes a mess lol ( I am trying to come up with a fix for this that allows it to vent but not slosh all over me) as for the CDI I will order a another to try that out, I am going to try a different spark plug other than the one that came with the kit also since I see almost everybody uses an NGK. I haven’t broken a chain since I switched over but I did add a spacer behind the sprocket and I think that helped, I will try the #41 chain and save the BMX chain for a back up. This is a fun and fairly inexpensive hobby, so far I like it. Thanks for the help guys.

    -skyhawk66cc
     
  8. DaveC

    DaveC Member

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    The stock plug wire is suspect, too. It's made in a toy factory from 6 parts to replace what is made here from 3. The inside parts come apart very easily and can work intermittently.

    Spark plug, BP5HS "P" is for projected tip. "5" is the hottest recommended plug and the projected tip keeps it cooler. A B6HS is the coldest plug I'd run in a stock motor but there could be some fouling from there colder. Colder plugs are for when you start playing around with the compression. The higher the compression the colder the plug you need to prevent ping.

    I have very high compression. I use a NGK BR9HIX Iridium plug. There are reasons to use a Rare Earth plug, I won't go into them here but for your motor a BPR5HIX is what I'd recommended as far as a iridium plug would go.
     
  9. yodar

    yodar New Member

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    ABSOLUTEL! as Hyman Kaplan would say. The ignition wiring, primary and secondary is suitable for toys. Replace all the primary and secondary wires with 18 ga. and automotive secondary (plug)wire and plug caps.
    and REPLACE THAT DARN CHAIN with an industrial chain and set up your pedal chain and drive chain to enable you t remove the darn tensioner. The newer industrial chain wont stretch.

    All the trouble I've had in my 1st year of motoring can be laid to those three areas. there were times when I had been put a-foot so frequently that I was afraid to ride the bike.

    Were it not for the encouragement a strong spirited mentor , I would be using public transportation.

    yodar
     
  10. skyhawk66cc

    skyhawk66cc New Member

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    The CDI that I got with my kit is one sealed unit, how do I replace the plug wire or any of the wires??? Its all sealed in the plastic case and the case is filled with some industrial strength plastic goo.. I spent an hour trying to open it up to put a better plug wire in and now the whole CDI is junk lol, time to order a new one i guess, it will probably be one that I can actually work on this time. Seems like the kit I ordered had a bunch of junk parts.


    -skyhawk66cc :-||
     
  11. rohmell

    rohmell Active Member

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    The wire should just unscrew from the CDI box.
     
  12. skyhawk66cc

    skyhawk66cc New Member

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    Ok, so I read on "Norm's 2 stroke repair center" about the whole Spark plug boot and the CDI and wire.. The CDI he had looks nothing like the one I broke trying to put a new plug wire in, Mine was not rectangle like his, mine was egg shaped and you could not unscrew the wire it had a metal ring crimped on it and was covered in a hard plastic goo???? Looks nothing like any CDI that I have seen on any of the websites even where I ordered it (gasbikes) "new design??" I try to do all the research I can before I post, so I don’t look stupid lol. I will post a picture of it when I get home if my wife didnt deside to put it in the trash already "GARBAGE DAY" cant keep her out of my stuff nomatter how many locks I put on stuff lol


    -skyhawk66cc :-||
     
  13. DaveC

    DaveC Member

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    I think the Chinese sold Grubee a bill of goods that is way under his usual standards. Sold on the idea that these new kits cost less and perform the same. The new CNS carbs were junk from the get-go and now a new ignition that a simple fix can't be done on?

    ....whee :/
     
  14. fall_down_stand_up

    fall_down_stand_up New Member

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    I think the best way to get reliability out of you HT engine is to never run it over 22mph and around half throttle,unless under load going up hills....If you baby these engines,they will be more reliable and last....
    John
     
  15. yodar

    yodar New Member

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    The plug wire sorta unscrews from the CDI.
    Me? I merely cut into the CDI-plug wire and solder-on a GOOD wire

    Yodar
     
  16. Allen_Wrench

    Allen_Wrench Resident Mad Scientist

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    Getting the new CDI is sounding like a good idea for you. And so far as two-stroke reliability goes, maybe I've been lucky on a number of levels, but mine has hundreds of miles on it and as long as I kept gas in the tank I could always just hop on and go. (And go further than the range of most E-bikes, I may add. I would own an electric myself, if only they could go further.)

    But for this kind of reliability I knew there would be things I'd have to do first. I set up the carb, the c-clip position, bit of port matching, NGK spark plug, etc. Then I tinkered some more when I had her running, until she was humming just the way I like. Then that was it. I started with a 415 chain, and I checked the allignment now and then. I always did a sort of Pre-Run Checklist before just taking off, but I never really did much actual work on the bike.

    My first bike was slammed in an accident (along with me). The engine survived just fine. Carb was cracked though. That same engine is mounted on my Higgins build with a new carb. Should run just fine.
     
  17. Tacomancini

    Tacomancini Member

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    Ditch that kill switch too. Or did someone mention that already?
     
  18. matthurd

    matthurd New Member

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    the cns carb works pretty well for me (although it's not great it does the job) flybytaco taught me how to get it running pretty well. take your fuel/air mix screw and tighten it all the way down. that will make it work well enough. if you unscrew it a bit you can get it to idle, but you'll take a hit in speed for sure, mine doesn't idle but it moves pretty quick.

    i haven't used an NT but i don't think the CNS is as bad as people make it out to be, i got a perfectly colored plug and a decent running bike out of my cns.

    as far as kit parts, the only things i didn't replace was the motor its self and the carb/exhaust ( i intend to get a better carb and an expansion chamber later though).

    the stuff in the kit is pretty bad from my experience.
     
  19. skyhawk66cc

    skyhawk66cc New Member

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  20. skyhawk66cc

    skyhawk66cc New Member

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    Nobody has told me this yet ( I Dont Think lol) but I dont really need it because the bike wont stay running anyway unless I give it alot of throttle and keep peddleing lol

    -skyhawk66cc
     

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