Huasheng bogging problem

OgreVorbis

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Joined
May 26, 2019
Messages
16
Hi,

I am new to this whole motor biking thing and I just finished my first build today. It was pretty fun for about an hour or two and then I began having problems with the Huasheng 49cc. I have it mounted on the back of the bike with a friction drive from Staton Inc. I road it around for an hour and at first, it was fine. I think I may need a larger size drive wheel though because the top speed is really low and I am practically giving full throttle and going maybe 20 mph, but I'd guess more like 15 mph, but that's beside the point.

Anyway, that's not the problem though. After an hour, I noticed the engine was producing less and less power as I would rev it. It was also going at a slightly lower rpm, but not much. I let off of it for a while and then tried the throttle again and it died. After this, I could not get the engine to start again. I was eventually able to get it started by raising the idle speed, but it died again, so adjusted it more and it would stay running, but now whenever I give it any throttle, it just bogs down and dies in a few seconds.

I've been running with the oil that came with it and it wasn't completely full maybe 2/3, so I added some more oil, but it didn't help. Hopefully I didn't ruin it with too little oil.

To me it seems like the engine is over-heating. It has that working hard sound as it slows down. Why is it doing this? I don't know much about engines, but I am an engineer, so I can understand most things. Any suggestions?

I am going to try it again after it cools down and see if the problem still occurs. Hopefully it does LOL, because I really don't know what to do if it's over heating so easy. I probably went only 2-3 miles and I was using the engine about 50% of the time - most of that time was nearly full throttle.

Thanks.
 


Old Busted Hotness

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Jul 2, 2018
Messages
314
Bogging down is usually due to a fuel-flow problem. It's possible there's an internal carb problem, but check for adequate fuel first.
 

darwin

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May 26, 2008
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3,279
Your HS has a rev limiter built into the cdi/flywheel and about 22mph is the fastest I could get mine to go, 2 of them in fact using a 1-1/8th roller. On the older models I could at least go 30mph I swear using the same roller. As far as you losing power and it dying while increasing throttle your idle jet needs cleaning. Its a black plastic thingy under your black plastic idle adjustment screw. It just twists to come out. Try to be careful with it and not booger it up cuzz you can't just buy them anywhere. I use a bristle from a fine brass brush I had to clean out the jet hole It's tiny and nothing else around the house worked. Also make sure the orings are nice and not all cut up when you reinstall the jet. Use a fuel filter in your gas line to help keep the carb clean.
 

Spare_Parts

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Nov 29, 2017
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Your HS has a rev limiter built into the cdi/flywheel and about 22mph is the fastest I could get mine to go, 2 of them in fact using a 1-1/8th roller. On the older models I could at least go 30mph I swear using the same roller. As far as you losing power and it dying while increasing throttle your idle jet needs cleaning. Its a black plastic thingy under your black plastic idle adjustment screw. It just twists to come out. Try to be careful with it and not booger it up cuzz you can't just buy them anywhere. I use a bristle from a fine brass brush I had to clean out the jet hole It's tiny and nothing else around the house worked. Also make sure the orings are nice and not all cut up when you reinstall the jet. Use a fuel filter in your gas line to help keep the carb clean.
The older ones had a different cdi without the rev limiter. Grubee has new engines with the old style cdi now.
 

OgreVorbis

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Joined
May 26, 2019
Messages
16
Thanks everyone for the replies. Today, I disassembled the carb and cleaned everything out. I used a small wire to clean the main jet. The idle jet I didn't have anything small enough for the hole, but I blasted canned air into it, so it should be clean. Also, the idle is fine, it's when I apply throttle. After cleaning the carb with isopropanol and canned air (don't have carb cleaner), it still doesn't work.

It idled ok for a half hour -I left it running and it was fine. The engine seems to work harder as I apply the throttle, but begins to slow down. It shakes harder as it's trying to speed up, but it can't and eventually dies. Maybe I should drain the old oil and replace all of it. I just topped it off before, but I didn't drain the shipping oil.

Do you normally just drain the shipping oil before running or do you run with it for the first couple hours? I used to think the shipping oil was meant for breaking in.
 
Last edited:

Will'smotobikes19

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Apr 9, 2018
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1,653
No alot of people say to drain the shipping oil that's for rust prevention casting sand will be in there especially on the predators. Plus who knows what quality Chinese oil will be. Aren't they the ones that say to use 10w30 car oil for the mix in the booklet?
 
Last edited:

The_Aleman

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May 2, 2007
Messages
1,010
Sounds like the carb is screwed up still. My first 3 Huasheng carbs all did the same thing eventually, not even rebuilds would help anymore. These Huasheng carbs don't seem to like American fuel, especially when it has ethanol. It seems to degrade the carb internally. I recommend removing the factory carb and intake and replacing with a 2-stroke carb adapter intake and NT carb.

Also, they are shipping engines with oil in em now? And you didn't drain that oil out? *shudders
 

OgreVorbis

New Member
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May 26, 2019
Messages
16
Sounds like the carb is screwed up still. My first 3 Huasheng carbs all did the same thing eventually, not even rebuilds would help anymore. These Huasheng carbs don't seem to like American fuel, especially when it has ethanol. It seems to degrade the carb internally. I recommend removing the factory carb and intake and replacing with a 2-stroke carb adapter intake and NT carb.

Also, they are shipping engines with oil in em now? And you didn't drain that oil out? *shudders
OK, well I do have a new engine though. I don't think there is a high chance of this being a problem so early on. Maybe I'm wrong though. have you had this problem on any engines with only a few hours use?
If not, I really think I just busted the engine by not draining the original oil. :rolleyes:

Do you think I'd be better off with a different engine? I want something that is reliable. I am not really in this for racing or as hobby (it will probably inevitably become that haha). I just want something for efficient transportation. I do have a lot of hills in my area though, so I do need some power too. I looked at the original Honda version of this Huasheng, but there is no built in clutch, so it would require an extra assembly causing more cantilever. I'm just curious what you more experinced people would reccomend for an engine.
 

darwin

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May 26, 2008
Messages
3,279
Once you get the 142f/144f dialed in it is very reliable. The carb is the weakest point getting trash in it. Just use a good filter and then only issue will be if it sits for 5/6 months with no use cuzz of the carb clogging up due to ethanol in the fuel. Even that can be minimized by draining it properly for storage. For the money HS's are the best bang for the buck for a MAB, in the 4 stroke category.
 
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