Ok heres the deal. At 6800-6900 rpm engined starts cutting out. Feels like a rev limiter would not allowing any more spark. It wont hit 6900 rpm even with a tail wind, have to be on a downhill. Ratio is 19.20:1. Valves set intake tight 4 exhaust tight 6. Carb adjustment didnt help. Ngk irridium plug, stock plug did same thing. Engine is paired with the 4g 80t belt drive. Idles and accelerates good. Anybody know why its cuts off at 6900 rpm?
Hs 142f 49cc feels like rev limiter
- Thread starter worksuxxx
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New Huasheng 142f 49cc motors seem to have a rev limiter now. The flywheel and cdi are different on the new builds to my knowledge as of (3-25-13). In order to achieve higher rpm's you will need to replace the cdi and flywheel with the older version. As I write this post I am not sure of any difference with the carburator, although will check on it tonight. Also at this time do I know if different settings for the valve adjustments will be required. I plan on swapping the carb out for an older version and test riding tonight, as well as test different gaps for the valves. I will post as more testing is complete.
Marginal valve springs causing valve float at top rpm?
If it's not ignition limited, check valve spring pressure.
If it's not ignition limited, check valve spring pressure.
After dialing in the best gap for the valve adjustment (.008/.012) although valve tap noise was terrible, with the flywheel and cdi changed, I put on a new carb ordered from BikeBerry. BIG DIFFERENCE! Apparently the cdi, flywheel and carb are different on the new Huasheng 142f engines. So with that, I am now going to redo the valves to see what the best settings are with the new carb on it. So in a nutshell, if you order a new Huasheng 142f and it's a newer build, it will not run up to it's potential. You will have to change the cdi, flywheel and carburator. I hope that my experience with these motors this past month and my findings will help someone from a lot of headache. I will post the valve adjustment settings soon.
I'm sorry to bump this old thread, but I think I might be running into the same problem. I have a HS 142f and it idles fine, but only wants to rev up to about 3k RPM. Measuring with a tach the highest I've seen is about 3200 RPM, going downhill. This engine was purchased in a kit on eBay in Dec 2013, and after reading this (and several other threads about recently-made HS 142f engines having problems with the top end) I can only wonder if this is what's troubling my engine. I'm confident my tach is reporting the correct RPM (every other rotation, as it's a 4-stroke) and it sounds nothing like the YouTube videos out there with people redlining their HS 142f.
If this is the case, whereabouts can I get the parts necessary to "fix" my engine? Carb from BikeBerry, and then CDI and flywheel from...?
If this is the case, whereabouts can I get the parts necessary to "fix" my engine? Carb from BikeBerry, and then CDI and flywheel from...?
Bicycle-engines.com has the parts, but I can't say for sure if they'd work or not. Might want to give them a call.I'm sorry to bump this old thread, but I think I might be running into the same problem. I have a HS 142f and it idles fine, but only wants to rev up to about 3k RPM. Measuring with a tach the highest I've seen is about 3200 RPM, going downhill. This engine was purchased in a kit on eBay in Dec 2013, and after reading this (and several other threads about recently-made HS 142f engines having problems with the top end) I can only wonder if this is what's troubling my engine. I'm confident my tach is reporting the correct RPM (every other rotation, as it's a 4-stroke) and it sounds nothing like the YouTube videos out there with people redlining their HS 142f.
If this is the case, whereabouts can I get the parts necessary to "fix" my engine? Carb from BikeBerry, and then CDI and flywheel from...?
http://www.bicycle-engines.com/49cc-Engine-Parts/
Thatsdax sells a carburetor that should work:
http://thatsdax.com/ENGINE_KIT_PARTS_PAGE_1.html
He also sells a diaphragm carburetor and kit that should work also:
http://thatsdax.com/ENGINE_KIT_PARTS_PAGE_3.html
This would be good so you don't have to rejet your carburetor.
Good Luck,
Chris
AKA: BigBlue
I have been there, done that... too many times...Oops............sorry!
It's the thought that counts, it's all good.
