Huasheng 142 Crank Shaft Swap

Discussion in '4-Stroke Engines' started by Stoltzee, Jul 13, 2013.

  1. Stoltzee

    Stoltzee Member

    Does anyone know if I can replace a tapered shaft crank shaft with a regular one. Just take out the tapered, and put a straight shaft in.

  2. dougsr.874

    dougsr.874 Active Member

    I was told it could be done....I shipped my engine to in Bristish have it done by him.....He is a good guy , but the cost of shipping into Canada is prohibitive....You can proably just replace the engine cheaper.
  3. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    You would also need a new motor side cover as the straight shaft motor
    uses a different cover.
  4. Stoltzee

    Stoltzee Member

    Your talking about the side with the pull start I gather. The other side I'll be using the Q-Matic from ezm, which I have already.

    If I was smart I should just go with a new tapered shaft ($28), (First the bolt breaks, and then the EZ out. Spent $25 on Carbon Drill Bits, $9 on a tungsten Dremel bit (grinding).

    Then to be even smarter:
    I'll get this engine going again, and then plan on using a 212 Cc OHV Horizontal Shaft Gas Engine - EPA & CARB $119.00 from Harbor freight, and slap a 49cc sticker on it. Then I can go up hills, cruise all day long, it will idle right, take the governor off, and it will probably last me for 5 years with just simple maintenance, and also order a set of heavy duty wheels from "Custom Motored Bicycles" with 11 gauge spokes for $88.00, yes a set.
  5. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    I am talking about the output shaft side motor cover which is totally different on the straight shaft versus the tapered shaft.

    Now that I look at it it is the cylinder block and and bearing support that is different
    with the straight and tapered shaft.

    Never done it so I don't know if the straight shaft crank would work with the tapered
    shaft block?

  6. Stoltzee

    Stoltzee Member

    Thanks for the advice. I think I read another thread also that said something about them being different, so to play it safe I'll stick with the tapered shaft. Thanks again.
  7. HeadSmess

    HeadSmess Well-Known Member

    are we sure its the case thats different and not just the adaptor plate stuck to the case? cause i cant see any difference between the types, fullstop. it also makes no economic sense to change more than just a crank shaft for a chinese company!

    but i have seen three different adaptor plates and a few different engines...none,ie a lone plain straightshaft engine, one to take the chain shs or rhs or something chain reduxes, one for the hoot, and one for the tapered shafts like the qmatics...

    unfortunately, theres also several configs of engine depending on use, country and supplier so i cant really say yes or no.

    from what ive seen there should be no problem. you may have to check shaft/bearing sizes, as there may be selective assembly making one set incompatible with another set that appears to be identical until micrometers are used! without a stockpile of engines outback to play with, its probably best just to get a new engine. sticking with one type or style of engine ensures a stockpile of parts :)

    avoid the temptation to "legalise" an illegal engine. it only makes it worse for yourself when you do get caught. you obviously knew the rules or wouldnt have bothered...
  8. Stoltzee

    Stoltzee Member

    Your right about the legalism. I'll just order a replacement shaft (found one already). Then when this engines finished I'll probably switch to a 79cc Predator from HF. The HS 142 has to many issues, but the Predators seem to be more application specific. I can order the engine parts from my state, and has the after market parts for a MB cheap.

    Exhaust pipes, performance head
    2 Max torque torque clutches
    Bored and reworked carb
    12 different carb jets
    jack shaft parts Pretty Much Everything.
  9. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Straight shaft will work in place of tapered version. The bolt pattern is different where the drive system attaches, however the Q-Matic drive plate can simply be re-drilled to fit.

    If you use the 79 CC HF you won't need any speed parts as it has lots of torque to handle taller gearing [11.55 X 1 is standard on the Q-Matic for the HF motors].

    Most of our HF test motors easily traveled at 45 MPH or higher. One of our test bikes with the 99 CC version topped out at 54 MPH.

    Have fun,
  10. Stoltzee

    Stoltzee Member

    Wont be needing a new drive shaft. Bought some new tools, and a couple of Dremel bits, and some Cobalt bits. Spent a gang of hours getting through a broken Easy Out, and then re-drilled and tapped the hole. Modified the air filter to increase air flow a bit also. Now I have more tools in place of a new crank shaft.
    It was the Diamond Dremel bit in a regular drill that cut through the Easy Out. Next time I have work like this to do I'll have a drill press, or just buy a new engine.:sweatdrop:
    20130728134927.jpg 20130728134953.jpg
  11. Stoltzee

    Stoltzee Member

    Well the first adapter was a bit wobbly, and I probably hadn't torqued the bolt properly. With the weight of my bike there seems to be some lugging taking place at take offs, so I bet the HF 79cc would be good partner for the stock Q-matic. I have no intention of doing 50 mph hour on a bicycle ever. I can screw myself up just fine on a 10-speed, and I have the knots to prove it.
  12. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Stoltzee,

    The HF 79 and 99 CC 4 stroke motors provide a lot of torque. If "geared" correctly they are really smooth between 30 and 35 MPH. Your Q-Matic drive simply needs new mounting holes and a new larger primary pulley. We suggest either the 2.5" or better the adjustable drive pulley. Both are available from Grainger or EZM. It is important to drill the new mounting holes in a certain pattern as the drive must miss hitting the valve cover, be low enough to clear the exhaust port, and the idler pivot bolt must be relocated to miss the oil dip stick.

    If you need a pattern, just contact us and we can make one for you.

    Always remember, you don't have to run at full throttle to cruise at 35 MPH

    Have fun,
  13. HeadSmess

    HeadSmess Well-Known Member

    more tools! a smart man! just more tools always means...more shelves!

    yep, a diamond bit is about all ive found will get an ezi out out. and yes, they take a long time. use plenty of lube, try and get a coarse grade bit, and come from side on, so it actually cuts. they dont "drill" so well :( something to be aware of if using a drill press. (make a plasticine "tub" full of lube, hang a weight on the drill arm, and just walk away for a few hours)

    other methods are to heat the case around the broken stud, along with some wd40 (panther pi$$!).

    hopefully the heat will burn any thread locking goop, and the difference in expansion rates will free up the stud.

    and then, theres always a plug cutter... basically a skinny hole saw. drill out the old stud and retap to the next thread size or helicoil it...

    tools are great, cus they always get used. just at a certain point, you get so many you forget where they are! at least i know where my magnetic chuck is. and ive never even used it!
  14. Stoltzee

    Stoltzee Member

    Hi Quenton, I fixed the old crank, and ready to reassemble everything. I think I'll wait for another build to use an HF Predator. I'm already toying with heavy duty wheels, and a 6 volt hub,which is more readily available along with parts n pieces. Thanks.
  15. Stoltzee

    Stoltzee Member