HuaSheng 142F vs Honda GXH50 vs Dax XC50s

Discussion in '4-Stroke Engines' started by Scootmeister, May 16, 2012.

  1. Scootmeister

    Scootmeister Member

    These three engines appear to be the same except for one important distinction. The HuaSheng is rated at 1.4KW or 1.88 horsepower, the Honda is rated at 2.5 horsepower and the Dax Super Titan is rated at 3 horsepower. These are substantial differences for no change in displacement. My guess is the Dax Super Titan has a different carb, a different cam, and maybe larger valves. This suggests that the output of the HuaSheng can be nearly doubled with the same upgrades. Has anyone found such upgrades for these engines? A fully adjustable diaphram carb would be nice.

  2. darwin

    darwin Well-Known Member

    The titan xc50 as rated at 2.5hp too. Its a powerful lil motor and you can tell the difference from a 35cc going up grades. I'm considering getting a super titan because that extra 1/2hp can mean alot when your talking 1.5 to 2.5 hp motors. From what I gather the super has a longer bore and stroke to get the xtra hp, correct me if i'm wrong. I'd like to hear what others have to say about the super titan vs the reg titan. As far as 4 strokes the choices are very limited in the near 50cc range. The honda is the motor to beat but with the clutch adapter $450 is pretty steep and it does hang way out there. Also with the honda changing to a diaphram carb is a bit tricky too, I like to use a big tank so refills aren't a worry on a 40 mile ride 1 way then 40 miles back.
    Last edited: May 17, 2012
  3. Scootmeister

    Scootmeister Member

    Hi Darwin. I got the 3 hp rating on the Super Dax from their website. I have a 3.5 hp Briggs 4 stoker on an edger with a diaphram carb and it works great. A fully adjustable carb is nice when you have varying operating conditions or when opening the engine up with porting, larger valves, or unrestricted exhaust. I don't know about the longer stroke on the Super, you may be right. I seem to have read somewhere that they bumped compression with a domed piston. I think I'll start out with a different carb, a different cam and see what difference that makes. It's so tempting to go with more displacement, but I want to stay legal.
  4. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Guys,

    It is next to impossible to install larger valves [no room]. Although several have supplied modified camshafts [reduced base circle method] , it isn't much help. If you stress the motor too many times above the redline [7800 RPms] you can remove the bottom of the rod. If you improve the carburation and increse the RPMs in the process [what would be the plan], you risk dropping the rod.

    We designed the Q-Matic to take advantage of the torque curve and avoid having the motor running above redline.

    The Honda motor has a higher compression ratio, and runs at a slightly lower redline compaired to the HS 142 series motor. In fact the main jet is larger in the HS 142 carburetor and it will rev higher than the Honda.

    We have tested hundreds of the HS 142 motors, and several of the Honda motors, and the motors are very close [not in price], and both gain the most power with exhaust upgrades.

    Have fun,
  5. Scootmeister

    Scootmeister Member

    Thanks for the input, Quenton. I think what folks are interested in is the major increase in HP in the Dax Super over the regular 142. Presumeably they have accomplished the increase without exceeding the rev capabilities of the engine, otherwise they would be swamped with engine failures and subsequent warranty claims. I agree that the standard 142 is a fine little engine, mine starts first time every time and runs great, however it is a little anemic compared to my other power plants. Any "Bump in Umph" would give a little edge, especially on takeoff. BTW, I have added lighting coils to my Huasheng and I can now run lights and recharge a battery. Total cost- $5.00 plus junk parts and lots of time in design.
  6. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Play around with the exhaust system to lite the motor up.

    Altering the exhaust can alter the torque curve and increase the torque.

    Have fun,
  7. Scootmeister

    Scootmeister Member

    Quenton, do these engines need back pressure to run optimally? I ran mine with a straight pipe for a bit and it seemed to rev quicker and the exhaust had a nice deep growl to it. I know 2 strokers need back pressure to facilitate fuel flow, not so sure about 4 strokers. I know Harleys run fine with straight pipes, but they have to be tuned properly.
  8. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Scootmeister,

    All types of IC motors benifit from tuned exhaust systems. Exhaust upgrades are called "cheap HP" because the gain is high in ratio to money spent.

    The reason I hold so many speed records is because of tuned exhaust and understanding drive ratios. My 1999 Whizzer will exceed 68 MPH with a reverse cone tuned exhaust pipe, and slows below 62 MPH with the factory system. This equates to an almost 10% increase in top end speeds due to the pipe.
    The Ducati "Desmo" singles I raced in the late 60's used the same type system and added almost 900 RPMs to the top end and is the reason I use a similar system on my high speed Whizzers.

    The 2 strokes I raced [Bult, Kaw, Yam, Carabela, AJS, etc] had "expansion" chambers, and of course added large amounts of power [cheap power].

    4-stroke pipes can add a lot of power, however if done wrong it can reduce power. The most common mistake is size and length, and bigger isn't always better. If you look at the HS 142 motor, it is clear the exhaust has been "downsized" in the process to reduce the sound. Even the pipes we include in our EZM kits, while better than the "box" muffler, still reduces the output in a major way.

    Part of the tuning requires an understanding of "pulses" which are based on pipe I.D. and length. Once the correct I.D. is determined, the desired use will effect the length. As an example, when racing Ducatis I used a long pipe with a long reversed cone for long tracks [road racing], and a short pipe with a short reversed cone for short dirt track racing [short tracks, 1/2 miles, scrambles, etc]. Short pipes move the torque curve lower, add more mid range, but lower top end speeds. Long pipes will slow the RPM rate, move the torque curve upward, but adds top end speeds.
    Most often "tuned " exhaust systems are an average to make the motor more user friendly.

    The pipe construction is also critical, as the exhaust must exit smoothly, and the I.D. surface shouldn't disturb the "pulses". An example is using "LP" gas line, or water pipe, as the interior isn't smooth. Another issue is bending too sharply.

    To help you get started with the HS 142 motors, start with 7/8" I.D. pipe. Must be smooth interior pipe or automotive flex pipe. Some "back pressure" is helpful for mid range, and can be a straight tru muffler or a specially designed tip. Length will depend on desired useage.

    Have fun,
  9. chrisnbush

    chrisnbush Member

    I have super Titan with 6700 miles on it, have also owned 142F

    Have adjusted valves a number of times on the super titan, more recently as the power has started to drop off (at around 5500 miles). Have to say, the piston in mine anyway is not domed, at least from what I can see at TOC. I am not sure I am getting the valves quite right, going to make a tool (bolt with same threads as plug) to get to EXACT TOC before adjusting them.

    I put a new carb on it, the original was overflowing. Just lazy, probably needed a new float. DAX (Duane) claimed that the carbs were identical between Titan and super titan. My guess is the valve springs are stiffer in the Super ? If you look at the DAX site, he claims higher RPMs, which I think stiffer valve springs would allow. Not sure I trust Duane on the carb spec, though. Replacing the carb didn't restore power in any event.

    Anyway, my super titan now has the power of the 142F, which is not enough for the hills I have, even with a 50 tooth sprocket. I started noticing a difference probably around 5500 miles or so. I have religiously changed the oil every 1K, and also have used TufOil additive after the initial break in, in ALL oil changes.

    It goes well enough, and I love the motor - I changed my route a little (I commute 30 miles a day on it, have been for 1 1/2 years at this point). I think I have just lost some compression, 6700 (logged) miles is a lot for this little motor I think. Grubee clutch is great, although have to replace 11tooth freewheel every 1K miles, and I replace the T-belt every 3K miles (as i snapped when I had 3K on the clutch). THROW AWAY CHINESE CHAIN and get 41 chain from Trailer Supply Co. (TSC) ! It may still be Chinese but it DOES NOT STRETCH and really cuts down on chain adjustments, my big complaint. For a commuter, grease on clothes is your worst enemy - I wear shell pants over my clothes.

    I will get another motor shortly. My project bike is going to be the really cool 9HP 2cycle motor he is selling, I think I can have someone fabricate me a simple L shaped bracket, and drill some slots in the standard Grubee mounting plate to accomodate it - it's 49 cc, but 9HP - 50 mph up hills...

  10. Scootmeister

    Scootmeister Member

    Wow, Chris. It sounds like you are a true road warrior and have spent a good bit of time analyzing your Super Titan. Have you actually checked the compression, I would be interested to know if the rings have worn that much at your mileage. I have half that many miles on my HS and so far the compression is holding. Also, many of us agree with you advice on the kit chains. I have three and all of them have cracks on the side plate, bad enough that I cannot use them. I went to heavy duty KMC roller chains, they have been great so far. You might want to search the threads here on riders who have gone to high performance engines. They have experienced a good bit of component failure since bicycle parts aren't designed for that much stress. Some of us have gone to MC or Moped components for greate strength and durability, like double walled rims with 102g spokes, 203mm disc brakes, and better bearings. Frame flex is an issue on one of my builds, at higher speeds it increases the pucker/cringe factor a lot, especially when my springer starts working!!! My next build will be a vintage Huffy Tritan frame, it's built like a tank! A couple of other things on your HS, have you checked your carb for crud buildup, and what about the chance that the key on your flywheel has become deformed and changed your timing a couple of degrees, both of which would rob you of some power. Some keys are real soft, I have even seen aluminum keys which I automatically pitch in the trash. I'm assuming your air cleaner is clear and your plug is good. Let us know what you find and ride safe.
  11. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Remove the filter in the air breather and see if it helps. I have seen some of them restricted due to over filling the crankcase and causing the oil to feedback into the air breather.

    When we were testing the HS 142 motor on the DYNO it easily gained 1 MPH wth the air breather element removed.

    I don't suggest you remove it forever, just to see if it is causing issues.

    Have fun,
  12. Scootmeister

    Scootmeister Member

    Hey Quenton, somehow I missed your July 7 post. Must admit I suffer from being an old Go Kart racer where we focused on everything BUT the exhaust. For my 2-strokers I have been using 1" thick walled conduit because it is available, it's cheap, and it is easy to weld. Both bikes run great but I'm going to be experiementing with some expansion chambers for some boost. I like the old vintage ones that came on the 2-stroke bikes you raced ( I rode Bultacos, Matese, Bridgestone, and Suzuki 2-smokers), the newer ones look like an alien's intestines!!! My HuaSheng is on the bench at the moment. I've been fabricating lighting coils to charge a battery and run lights. I'll either install it on my Schwinn Spoiler or an old Huffy Triton that's in storage. At that point based on your suggestions I'll probably install a 7/8" straight pipe and go from there. I'm thinking about playing with a CVT to see if I can make it work with some top end. Thanks for your input.
  13. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Scootmeister,

    In the day, I raced many 2-strokes including Bultacos, Ossa, Yamaha [twin flat tracker], Kawaski, AJS [ 2-stroke], and even Carabela [2 stroke] from Mexico, and they all had tuned expansion chambers. All the 4-strokes I raced also had tuned exhaust [Triumph, Ducati, HD, BSA, Norton, etc].

    I wouldn't spend too much time adapting a CVT to the HS motor as they eat a lot of power. When starting with 2 HP you won't have much to give up for the CVT needs.

    If you want the maximum setup for your motor, make a header pipe 28.5" long and weld a reversed cone to the end. Cone need to be 14" long and the exit must be 5/8". The cone needs to be 11" before it tapers down.

    Although it is very possible to increase the RPMs on these motors [Honda GXH50, HS 142], if run at higher RPMs too long it will drop the rod from the crankshaft.

    We found it more important to increase the torque than the RPMs, and the correct exhaust will do just that. A correctly tuned system will advance the torque curve between 500 and 700 RPMs and increase it slightly.

    Have fun,
  14. Scootmeister

    Scootmeister Member

    Quenton, I'm trying to picture the exhaust. I understand that the overall length is 28.5", the reversed cone is 14" long and the exit is 5/8", but I don't understand where the 11" dimension comes in. You aren't saying the front of the reversed cone is 11" in diameter are you? Thanks for the clarification.
  15. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    The distance from the front of the cone to where it reverses is 11", and the rear of the cone is 3".

    I will attach a picture of my 1999 Whizzer's version of the reversed cone [68 MPH @ Portland, IN 2005] so you can get an idea of how to contruct one for the 49 CC motor.

    Have fun,

    Attached Files:

  16. Scootmeister

    Scootmeister Member

    Got it, Quenton. Thanks. BTW, when is the Plainfield meet each year?
  17. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Plainfield ??????????

    Not aware of any event in Plainfield.

    Have fun,
  18. Scootmeister

    Scootmeister Member

    sorry, I meant Portland.
  19. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Just returned from the Portland show a few weeks ago. Is planned for July 5th week in 2013.

    My 1951 Schwinn S4 Whizzers won 1st place best restored motorbike senior class this year

    Have fun,
  20. chrisnbush

    chrisnbush Member

    Scootmeister -

    Thanks for the help.

    I got a compression tester from Harbor Freight, nice kit as it has the 10mm fitting (1.00 mm thread, fine) that you need for the Hua sheng / Titan / Super Titan to fit the spark plug threads.

    Ran the motor for 5 min, then checked compression - about 40 psi. Then adjusted the valves AGAIN using a trick I came up with to be more certain on TOC - simply a 10mm bolt that I advance until I can stop the movement of the piston, then I back it off, get the TOC stroke, then advance it again - to just stop the piston. Now I adjusted the valves to .004, forgot what DAX said to do in terms of thousandths - "thickness of a piece of paper" doesnt' work for me (what kind of paper ?). Anyway the TOC bolt gives me some confidence.

    Ran the motor for 5 min again, now my compression is 50 psi (pic attached). How does that compare with your younger Super Titan - have you measured it ?

    Thinking maybe that what was happening with me was that the input valve, being loose, was not opening for enough time to let all the air/gas in - so my "compression" was lower, not having enough of anything to compress.

    Anyway, it is better now at 50 psi - more power - but still not up to what it was when I got the motor. Again I have 6700 miles on the motor, so I would be interested in what the compression is on a new one.

    By the way, I attached some pictures of the 142F valve springs, compared to the Super titan springs (I have an old blown 142F on the shelf). Look identical, you can see the bolt I am using to estimate TOC in the lower part on the pic of the Super Titan.

    So, it must me higher compression on the super titan ? Again, I don't see any doming on the piston thru the plug hole, but it might be more subtle than this. Maybe I will check the flywheel at some point, I can do it on my 142F.


    Chris super titan compression.jpg super titan.jpg Titan (Hua sheng 142F).jpg
    Last edited: Aug 13, 2012