HS 142f bucks and cuts out when cruising

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worksuxxx

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Jul 16, 2013
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Well I seem to have been mistaken about the exhaust valve. Upon closer inspection I realized movement was the same as the intake. Sure wish I could find the cause of this little motor not revving to its potential. I was going to order another cdi in the morning but after swapping cdi earlier from the bike that's revs to redline only for the engine to run poorly their is no use. I am still stumped why the cdi off that engine won't work. Anybody have any ideas why this would happen?
 

jburr36

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Jul 17, 2008
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Idaho
Have you tried a different muffler? Could it be plugged up for some reason? Is the timing correct? If it idles properly I say the timing might be ok.
 

worksuxxx

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Jul 16, 2013
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well, I think I found the problem with the rpm limit. I didn't notice until just now the cdi on this 4 stroke is different than the others. Look at the attached pic. I am guessing the new builds have a limiter, since it is a new coil design. I looked on all the vendor sites for cdi replacement, all look like the old ones. These don't even show up looking like this. And bike runs very poorly with old version cdi. When accelerating no load, it barely revs up. What needs to be changed to be able to use an older version cdi? I would think just swapping them would be all you need to do.
 

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jburr36

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Jul 17, 2008
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yeah. That's definitely different than the one I have. Maybe that one messes with the timing electronically.

I have the one with the round coil like in the pic below on both of my engines.

My engine runs really well with this CDI. No hesitation and no RPM limiting.
 

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worksuxxx

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Jul 16, 2013
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Yeah swapping out with that cdi doesn't work. I need to find out if I need to change timing gear or flywheel also. Just out of curiosity, who would just try to return the motor and go with a different vendor? For real, I would have never made this purchase if I knew I was limited to 6900 rpm. I have countless hours on these two builds trouble shooting this problem.
 

worksuxxx

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Jul 16, 2013
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Revving up to 8000 rpm!!! Changed the flywheel along with the coil. That fixed it. Looking at the flywheel compared to the other one, the half moon key is positioned differently. Almost like the timing was advanced/retarded. Now wondering about valve adjustments. If the timing was set up differently, would that alter the old version valve adjustments of .004/.006? Will have to play with the adjustments to see the differences. Gonna go ride at 30 mph for a while....
 

jburr36

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Jul 17, 2008
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Grats! I'm really glad you got that figured out!!! Sometimes it really pays to stick with it and not give up!
 
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worksuxxx

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Jul 16, 2013
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Got it up to 32 mph, at least per my GPS. But boy is it slow getting there. Definitely will have to do some different settings on the valves. First am going to try the new carb I order a couple days ago on this bike. I am guessing it may be possible if they lowered the rpm, ran with a different timing setup, that the new carbs may have a smaller jet. So before adjusting the valves I will slap on the other carb and give it a try. I am hoping the carb is the same though. Already will have to shell out for two new cdi's and a flywheel to get the results I expected in the first place. Would hate to add carb's in the mix as well.
 

worksuxxx

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Jul 16, 2013
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Well I never did do the carb first. I adjusted the valves .008/.012 and it seemed to run the best there. Although valve tap was horrific. Any tighter and the engine just didn't breathe right. I just swapped out the carb with the new one I ordered from BikeBerry, and I tell you now, the bike ran like a spotted ape! It was noticeably more power all the way thru the rpms, and accelerated on hills that before might only hold speed. So, apparently not just the flywheel, cdi are different on these new engines, but the carburator has some differences too. I am not sure if it may only be a jet size difference or not, I will check them later. But I am now believing the reason for such a "loose" setting on the valves is to create more pressure buildup and vaccuum to make up for the carb difference. I knew off the bat these engines felt less powerful, and the last two problem motors just wouldn't run right. One was flooding out, the other hesitated at low throttle and bucked and jerked holding any rpm. The two new motors, one was flooding out (reason for new carb) and the other one had very slight hesitation but would cut out over bumps. Thinking smaller jet size, vaccuum issue and float causing an issue when any jarring occured. I could lift the front wheel and drop it and it would kill the engine. Now with new carb, no such problem. Now I have to adjust valves with the new carb on it, but boy I can't wait to get this one dialed in. It feels powerful enough to now go from a 48t to a 44t.
 

GearNut

Active Member
Aug 19, 2009
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I am glad to read that you are working out the bugs in these "new" engines. I also thank you for sharing the differences you have found between the "old" and "new" engines.
I wonder why the factory felt that they had to take something so reliable and well respected and change it into something less desirable (IE the issues you are having with the "new" ones) and incompatible wit the "old" design.
I guess the old adage "leave well enough alone" does not apply here.

Regarding the old and new flywheels, is the keyway cut in a different position in relation to the magnets? Are there diameter differences between the two?
 

worksuxxx

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Jul 16, 2013
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Omaha
Yes the keyway is vut in a different position. The diameter of the flywheel looks the same. I will post pis of the two flywheels side by side tomorrow. I am almost afraid to think I may not be able to get the valves set just right due to the difference of the timing with the other flywheel. The best adjustment to allow the motor to breathe just right just makes the valves too noisy. Without tearing it down, I couldn,t say if the cam was different.
 

worksuxxx

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Jul 16, 2013
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Omaha
I don't know about bicycle-engines, but do know bikeberry was out of stock a month ago. So it's possible they now have the newer Huasheng motors with their kits. I liked the Huasheng motors too. For the price they fit the bill. But now that out of the box they don't even compare to the previous engines without spending at least $100 additionally (assuming cam is the same), I don't know what direction yet I will be taking on future builds. I know Gasbike probably didn't know themselves about the changes, and have tried to speak with them multiple times. Since my findings though, I have tried to contact them to educate them on the differences, but now they won't take my calls. I would have never bought these motors with the knowledge I have now. I have given up trying to call them, wanted to give them a chance to allow for the return of these motors. At best the only valid dispute is the fact the motors do not meet the 8500 no load rpm as stated under the product description. I have disputed the charges on my credit card for that fact, and hope for a positive conclusion. If not, my next step will be to tear into the motor and check the cam and valves. I would rather the dispute go in my favor, so I can look into alternative motors. It would sicken me to have to spend the additional time and money just to get the motor to run the same as the earlier versions. I am betting the Honda motors will be popular now...
 
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worksuxxx

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Jul 16, 2013
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Omaha
Yeah I think everyone will be affected. I know a lot of people go with the predator motors. I just don't like the looks of the motor on the bike. Noise is also my second issue. Honda motors are just so expensive. The problem I see going forward, is parts. I have yet to see the new parts available. If I order a carb, flywheel or cdi, I will get a part not compatible to this new motor. Now we have to be careful ordering parts, by making sure we order the correct part by build date. Many people such as first time builders are going to havee a headache with this. Vendoors will have to stock two versions of parts. I do want to throw out there that I don't know if this is an isolated issue with Gasbike.net motors only. I have only experienced this with my order from them. I can't say every vendor will have the same motors. It could be something new they offer, such as a cheaper buy for them. Or it could very well be a design change. Only time will tell.
 

worksuxxx

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Jul 16, 2013
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Omaha
Well, I have found two websites showing the no load rpm ratings of these Huasheng motors. I am guessing these sites have updated the description as the vendors on here have not. I don't know if the vendors know the difference or not, but here are two sites I found.

http://www.chinabestexporter.com/page/page_jl.asp

http://chinagas.en.alibaba.com/prod...cycle_engine_kit_for_4_stroke_gas_engine.html

I have just sent an email to Grubee.Inc inquiring about the changes for the 2013 engines. Hopefully I will get some form of response.

I am currently putting the motor I have back to stock today. I only dug into it to determine the RPM concern I had. Now I know, so I will await the results of my dispute with the CC company. Guess I need to start looking for alternative 50cc motors.

P.S. Last concern of bad valve tap was never corrected. The gap on the valves to eliminate the valve tap noise was so tight the engine just would not perform satisfactory at all. Best performance only made the valve tap noise unbearable. I could set the valves on the "old version" motor to .007/.009 with very minimal tap noise. The difference in the tap noise between "old" and "new" engine is unbelievable. In fact, the "new" motor set to .004/.006 was still louder than the "old" motor at .010/.012. At idle, the tap noise overpowered the exhaust note, especially from a distance. At a distance, all you hear is tap tap tap tap. Made it sound like you had an engine problem.
 
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worksuxxx

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Jul 16, 2013
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Omaha
Here is a pic of the flywheel showing the key cut in a different position. I put the "new" flywheel on top of the "old" flywheel. Looks like at least a 20 degree advance to me.
One would have to assume a change like this required a new cam... Advance in timing would also move the torque curve to a lower rpm and possibly require the use of a colder plug.
 

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GearNut

Active Member
Aug 19, 2009
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San Diego, Kaliforgnia
Considering how loose you need to set the valve lash for good performance, I wonder if the new cam timing is too far advanced.
This could be done with either a different lobe profile, cam clock position in relation to the cam lobe and timing mark and/ or a different cam follower design... or all of the above.