Modified Chinese motors?

Discussion in 'Dealer Advertisements' started by JoelC707, Apr 3, 2009.

  1. JoelC707

    JoelC707 New Member

    I'm not sure if this would be the right place for it but it looks like a good spot. If not please move it where it needs to be.

    I'm sure all this info is out there scattered around but I was curious if we could get it all in one place. What are your biggest complaints about the Chinese two stroke motors? If you could change ANYTHING on the motor what would it be? How much extra might you be willing to pay for those changes?

    One thing I've been kicking around is taking the motors I have (Star Fire Gen II's, Gen II-A's and GT4's) and reboxing them and sorta rebadging them as a "modified" motor kit. The biggest thing I had in mind to replace were the bolts. I know everyone (including myself) says the Grubee motors have Japanese fasteners that are better than the Chinese parts but lets face it, they still aren't a match for a good old American bolt, even a low grade one. I know there are kits out there for this purpose but would you consider buying a kit that has the same modification already done?

    The other thing that needs to be fixed is the muffler. I'm not sure about others but the screw that holds on the end cap of my mufflers flat out SUCKS. The hole it screws into doesn't give it much bite to begin with and ultimately loosens itself to the point the screw no longer holds. what we have been doing it taking a short stud (about the length of the exhaust stud on the enging), and welding it in place then you can put a nut on the outside with a lock washer, nylock or double nutted if you want.

    So what else would you like to see changed for the better? I would of course continue to offer both the original, unmodified kit for those that prefer to do the work themselves or just don't care. But I suspect most would welcome an "upgraded" kit even if it costs a little more. What are your thoughts?


  2. kallsop

    kallsop Member

    Longer front engine mounting bolts, and better still, wider spacing. The front mount seems to be a common area of aggravation. A decent spark plug (NGK) and external fuel filter. An inline kill switch rather than shorting out the coil to ground (duh). Automatic chain tensioner.
  3. arceeguy

    arceeguy Active Member

  4. JoelC707

    JoelC707 New Member

    Thanks for the suggestions guys. Lets see what we have here.

    On the longer mounting bolts and wider spacing I think we can cover you there, with two options even. We are currently building a "universal" front engine mount that also has an adjustment on it to pitch the front of the engine side to side. About the only type of frame it won't fit on is the oddball shaped ones, the ones that look more like a rectangle than an oval or round one. The other option we have is from a friend that works at Boeing. He has developed a solid rubber engine mount (front and back) that in our testing took out 80% of the vibration easily.

    Decent spark plug. Have you really found aftermarket plugs to work better than the factory ones? I've always heard they foul out much quicker.

    External fuel filter. I completely forgot about this. We put them on every bike we build for our own use or as a show bike. It only costs about a buck retail at an auto parts store and just makes good sense.

    Inline kill switch. Got any links to those? I personally haven't seen a kill switch that doesn't short to ground.

    Automatic chain tensioner. This is something we are brainstorming about now. Not sure how it is going to come out though.
  5. Gene

    Gene Member

    Hi Joel
    I think balancing the motor would be a big plus and a tear down and inspection of the entire assembly would go a long way to avoid early failures. I know I would pay for a engine that was gone over in that way. Torqued properly and had beefed up hardware and superior gaskets.
  6. JoelC707

    JoelC707 New Member

    That's a good idea but one little problem. I'd lose the 90 day factory warranty by opening up the motor. The advantage to it is the warranty wouldn't be of much use anymore because any potential failure points would be spotted and fixed or tossed back. If we did this the most we could offer warranty wise would be a DOA warranty, say 7 or maybe 30 days tops.
  7. BoltsMissing

    BoltsMissing Active Member

    I would like to see the entire motor copied and Made In Australia and sold back to you.
  8. jlebh1

    jlebh1 Member

    that would be the best idea "Now made in Australia" im in brisbane by the way
  9. HybriDude

    HybriDude Motored Bikes Sponsor

    Ambitious idea to think about upgrading quality of HTs.

    What brought you to this conclusion that there might be a market in it?

    I actually think that the HT has heeps going for it, except questionable quality. The market potential is huge for a good quality lightweight motor that mirrors the function of the HT so that it can be fitted to a commuter bicycles. I'd be interested to find out if anyone is doing it.
  10. thescooterguy

    thescooterguy Member

    i have been upgrading motors for awhile now , and building a few from the ground up . i like to ad ported heads , advance the timing with a key , use larger intake manifolds , and carbs with v stack and nicer air cleaners , replace all the bolts with upgraded harder Allen heads and use locking washers , , motors don't rattle apart , and better performance. all pretty cheap stuff but makes a world of difference , the ported head is the spendy part but not too bad $50,00 bucks or so . and yes there is a market for it . there is nothing like a motor that starts on the first pull even on a cold start, your pull start last forever .
  11. JoelC707

    JoelC707 New Member

    In some cases it's things that should have been fixed from the start, and we are going to pressure Don into fixing before we make our next order sometime in the Fall or so. There's another, more recent discovery that needs to be changed, the clutch plate. It's pressed together but that's all that's holding it and we've already had one come apart on us (luckily it was a demo motor we were testing) and several were fairly loose out of the box. We've started tack welding them together and everything seems to be happier that way.

    As for the upgraded bolts, we happen to be lucky, there is a Fastenal store behind us in the office complex where we are. They may not be the cheapest in the world but still. We've got upgraded bolts/studs for every spot on the motor. So far we've only replaced them on a few in-house motors and they look GOOD actually. They're allen head as phillips and flat can wear out, phillips especially. they're also the highest grade we could get. The factory grade is metric 4.8, the new ones are 10.9 or 12.9 depending on the size. Yes, we are still using 6mm head studs but in our experience if they pull out, it is the head side that gives problems, not the bottom end. That tells us the block itself is stronger than the stud and higher grade components should be the answer. Besides, if we had to drill and tap larger holes the price would probably more than double simply because of all the labor involved.

    I'm going to be listing some "upgraded" models on ebay soon and see how well they do. The price will be higher obviously but there will be other thing done to it as well that we feel should have been "standard". We're considering several "models". We'll still offer the motor as is with no changes done to it for those that want to shop on price alone. We'll offer the modified version for those that want a better kit right from the start. And we're considering a DIY version, where we send you a bolt kit with the motor kit and you change them out yourself. I know there is already a place you can get your own bolt kits so people seem to be OK with this option.

    We're working on getting other upgraded parts as well, such as different air filters, larger carbs, velocity stacks, boost bottles, etc. We should know more about these options in about two weeks or so.

  12. wavygravy

    wavygravy Guest

    it whoud be nice to see someone address the connecting rod berrings , upper & lower , also a balanced flywheel/lower end, & consistant port placement!! larger carbs & boost bottles may add to a shorter engine life unless someone address these issues first! one can only hope that the manufactures will pay attention , but so far all our suggestions & pleas have fallen on deaf ears! i so love the looks of my happytimes! lets hope the motoredbike gods shine down upon us someday & add precision to the chinese language!
  13. Pablo

    Pablo Motored Bikes Sponsor

    wavy - I think that's what the Manic Mechanic is all about. He's basically making a whole new engine.
  14. impression

    impression Member

    mmm, quality components and a balanced engine so no more vibrating engine mounts and sheared bolts....

    these are nice motors but really flawed in quality :(
  15. BoltsMissing

    BoltsMissing Active Member

    It's about the humble single cylinder internal combustion engine when technolgy came about in the 1900's of it's inception and now we are in 2009, surely anything less in today's engineering knowhow/standards is an insult !
  16. HybriDude

    HybriDude Motored Bikes Sponsor

    We need to be thinking Direct Injection. That's the direction that the EPA wants the industry to head.

    There is a niche for an emission compliant, very light weight, fuel efficient, dedicated bicycle engine. Whoever cracks that one will be the money. The closest engine currently available is dear old HT.
  17. BoltsMissing

    BoltsMissing Active Member

    And who the heck is this EPA ?

    But there is a dark hidden risk from an investors point of view.

    Three elements HybriDude


    1 & 2 is most of us here but can't do 3 all that well.

    3 can't do 1 & 2.

    Usually is seems 2 & 3 team up and leave 1 out when 1 and 2 had it good.

    Eventually the fad will fade away, 3 will divorce 2 and 2 will reconcile with 1, but 1 is much the wiser.

    3 will look for another 1 & 2, and on it goes.

    There is 4, that entity controls 1,2 and 3. hence a probable risk, cos 4 could be the Govs. and the Govs. know many many 3's
    And all want a piece of the action.
    Last edited: May 6, 2009
  18. bamabikeguy

    bamabikeguy Active Member

    The image I have is Burt Munro down there in New Zealand, casting his own valves and cylinders, making THE modification that rockets the bike at 100+ mph.

    It does seem that the century old design could be modernized, get them into the $400-500 range, and be marketable.

    There are so many of the cheapies out there gathering dust in garages and basements, souring the purchaser to the whole idea.
  19. Mountainman

    Mountainman Active Member

    start with someTHING that may save a life

    a good chain tensioner may save a life -- great place to start

    you state -- not sure how it is going to come out though
    if you do just a little homework
    there are many many good solid alteratives
    check search

    as we ride those motor bike THINGS
  20. furament

    furament New Member

    ? has aney one had trouble with the stock needle bearing melting ?