New 4-stroke 49cc HuaSheng (142F) Build

[bakaneko]

Yep, I use that plug in every 4-stroke build, they make a difference you can feel.

Anything is better than the stock can exhaust but there is no 'performance' exhaust on a 4-stroke engine like a 2-stroke engine. All you can do is make it as free flowing as possible.

KC take a look at this build for the HuaSheng 49cc. The guy has what I think is about $100 in upgrades with a 7G transmission and 44T sprocket (I think). The video has the exact mods that he listed and I found the site where I think he got his performance parts. My engine is pretty tight on my bike; I need to make sure an exhaust will actually fit first. LOL

NT Carb with a #78 Dellorto SHA main jet
race pipe from AGK
Venice Motor Bikes billet intake
NGK Iridium plug

This is his exhaust. https://www.affordablegokarts.com/m...de=A&Product_Code=22110&Category_Code=MTRBK49

 

[bakaneko]

So, listed below is what I've done from stock thus far and the next upgrade. Cruising at around 30-33 in calm conditions but torque is low due to my gearing. A car was following me today; I think he or she was curious about my speed, lol.

Changes from stock engine / settings
- Adjusted the idle and mixture screw to improve performance and idle
- NGK 7544 Iridium IX CR7HIX spark plug provided more torque and mid range speed via better ignition. It feels like 3-5mph more speed for optimal torque and ~3-5 mid range speed improvements. I love this small upgrade ($10) and I think it is on sale at sickbikeparts for $7 atm. Idling has improve too
- Replaced the defective flyweight. It was revving higher with new flyweight but after a few miles the revvs seem to come down a bit

Upcoming Changes
- I might eventually pull the 36T sprocket and put in the stock 44T. I am a lighter rider but the torque is so low. I will see
- Get a long/short exhaust or just regular 2-stroke exhaust for better air flow
- Putting on the duo 3L + 1.5/2L gas tank setup (not really a performance mod)

Any comments from 4-stroke owners would be appreciated as I get this girl up to her potential.

 

[skyash]

Have you tried oil additives? Newways makes a great one called roil for use in everything bikes drag cars my skyline got 10kmh more per gear if you're oil can take 100kg stran then with this it will take 200kg

 

[Deleted member 25783]

Bakaneko,
My co-worker built a Huffy Cruiser-HuaSheng 49cc bike in January and commutes 3 miles 5 days a week.
Has never complained of jetting causing lack of power. Empirically found that a modification of the Bikeberry muffler made a noticeable difference in top end and overall performance. The only thing I have seen him do was give the engine a bit of warmup. His build is stock Bikeberry and this is no advertisement as I am into a Bikeberry build inspired by his.
I used to build Ultralight Aircraft, these are a different cat. For the record my co-worker set his up with a 31 tooth rear sprocket and I did the same. I don't need a 30mph+ top end. In this Kettle Moraine country hill climbing is more valuable, so I am going to order a laced coaster brake wheel from Shimano for safety sake and clam shell a 44 tooth rear.
Tom from Rubicon, WI

 

[bakaneko]

thanks for your inputs. i probably am not going to add an additive to the oil though that seems like an interesting idea. i think there is still some mechanical power i can get out of the kit.

tom, i have the cheapest transmission on this bike. i opened up the transmission and the gears and chain is so small. bikeberry has a double chain system and bigger transmission, which is probably providing enough power for your co-worker. i think i am going to eventually change out the transmission.

 

[bakaneko]

I tried placing my exhaust from my 2-stroke on the 4-stroke HuaSheng and it was almost a disaster... The hex bolt rounded and was stuck. Plus, I didn't realize the exhaust prevented me from pedaling, LOL. It was dark but it seemed like there was some more bottom end power, but I couldn't say for certain.

Luckily, the heat or vibrations from the ride loosened up the nut and I was able to put the stock exhaust back on there. I think I will need the exhaust with the bendable neck for my bike as I don't want to install the wide crank on there.

I think I am fine with what I have at the moment. It goes about 30-35mph at half throttle. It can take off from a stop but due to the low torque (low gearing) I like to help it get going to about 15-17mph then let it take over.

So, this seems like my only option for a muffler.

http://www.ebay.com/itm/66-80cc-bik...406467?hash=item1eada6c443:g:EhIAAOSw9mFWMUD-

 

[KCvale]

KC take a look at this build for the HuaSheng 49cc.

Yep, that scoots right along.
To bad he didn't show what the bike looks like ;-}

I don't waste money on oil additives, just good oil, and change it often.
And I like gears so I don't need to run wide open all the time.

 

[bakaneko]

Yep, that scoots right along.
To bad he didn't show what the bike looks like ;-}

I found it in another video. Here is his mods again. Obviously, you are building top notch 4-strokes but maybe we will all learn a few things from this guys build.



the GasBike.net Ghost Racer 7G kit.
NT Carb with a #78 Dellorto SHA main jet,
race pipe from AGK,
Venice Motor Bikes billet intake,
NGK Iridium plug.

 

[KCvale]

I found it in another video. Here is his mods again. Obviously, you are building top notch 4-strokes but maybe we will all learn a few things from this guys build.

There are a few lessons.

You don't need to use whole chain that comes with the kit.
Cut it down so your chain don't flop around like a fish on land ;-}

The 7G is for long shaft HS engines.
The clutch bell rides on the output shaft with a lousy bushing in between.

See how the back wheel wheel spins at idle?
That is because the clutch bell is not isolated from the engine output.
The drag from the bushing is causing enough friction to spin the back wheel at idle!

When the wheel is on the ground not enough friction to move you, but friction non the less and all that friction simply wears the clutch bell bushing.

I am not fond of that 7G design and not fond of people that can't even break a chain to fit right.

Maybe we all learned something, maybe not, but that's my 2¢ worth ;-}

 

[bakaneko]

There are a few lessons.
You don't need to use whole chain that comes with the kit.
Cut it down so your chain don't flop around like a fish on land ;-}

It isn't that bad. It looks like he has room to tighten it on the chain tensioner too. I like a looser chain with around 1-2 inches of play; it is easier to pedal around.