HS 142f won’t idle or start without starter fluid

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#1
Stock carb cleaned, SBP air filter, new head gasket, valves clearance checked, clutch looks okay? (copper bushing chipped off a little on the rim area but lubed)... I can’t seem to adjust air screw to help it idle. Carb issue? Clutch maybe?

Starter fluid fires it up but very quickly dies with no gas. Won’t idle at all. Thanks for ideas
 


CrazyDan

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#2
You gotta pull the brass plug out on the left side of the carb closest to the engine. Carefully drill a small hole in the plug and screw a wood screw in there. Twist the screw while pulling out with a pair of vice grips. You should uncover your idle mixture screw underneath.
 
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#3
Indeed. Yes, so to clarify I have done that drilling out previously but this time the small screw adjustments aren’t helping much. I have that screw at about 2 turns out from lightly seated. Can’t dial it up correctly yet..
 

CrazyDan

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#4
You might have an air leak between the carb and engine. Try spraying the starter fluid around where the carb attaches to the engine. If it revs up you got an air leak.
 
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#6
I think I checked for leaks with the starter fluid and didn’t notice any rpm revving. I’ll double check.

I don’t believe I scrubbed that idle jet since I didn’t have the right gauge but it looked clean through before. I’ll go find some and scrub just to be sure. Gauge #?

More info: My problem started when riding along full throttle normally and came to a stop. Bike idled way down and then died. Hasn’t idled since.
 
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#8
These damn carbs! Boxier than an 80s Volvo and almost as fun. Okay, so the carb’s the only real culprit ay? Fuel is in bowl and the float and needle/spring seem normal
 

MotorBicycleRacing

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#9
I don’t believe I scrubbed that idle jet since I didn’t have the right gauge but it looked clean through before. I’ll go find some and scrub just to be sure. Gauge #?
.
Believe? Looked clean?? Scrub? LOL
There is no way to see if that small opening is not blocked.
Use a thin piece of wire to clean the jet.
I have a jet cleaner from a Svea 123 stove that works great.
 
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#11
I’ll get at another cleaning then. Thanks

Actually.. if you look up in the sun at a 49 degree angle and stand on your head you can see the other side of the jet. But wire seems legit I guess :rolleyes:
 
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#13
These damn carbs! Boxier than an 80s Volvo and almost as fun. Okay, so the carb’s the only real culprit ay? Fuel is in bowl and the float and needle/spring seem normal
But did you check the float setting to see if its set correctly.. 21mm from gasket surface to top of float.. Measured with carb upside down float setting on brass tabs?
 
M

Milkedglass

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#14
Measured floats on two stock carbs and finally poked all jets with wire. Flushed with carb cleaner and used backup carb. Still can’t get an idle. Throttle responds fine with no load but will not run under load. Starting to think it isn’t a carb issue but the clutch looks fine. ???
 
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#15
Is this off a plain start/idle or when your trying to start it? Mine tends to idle a lil diffrent also daily but from temperature adjustments an the gas sitting gets dull and takes on moisture which dulls combustion. Could it be the gas or a weak cdi.. Cheap dirty plug.. Either to much load from clutch bogging it out maybe bad piston seals? Do you give it throttle to rev it up and it still dies when loads applied? Im lost after that lol
 

darwin

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#16
O ring seal on the idle jet needs to be pliable and sealing correctly for it to run optimally. Don't know exactly why it's so darn important but it IS. Thatsdax.com has those orings on parts page 1 if needed.
 

CrazyDan

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#17
I had a horrible time trying to figure out a carb issue a while back and found the chock lever was worn enough to allow it to rattle back and forth from open to closed and back again when riding. Gave me a hell of a hard time trying to figure out how a clean carb with no air leaks was acting that way. I melted that mofo wide open. Starting is a little harder but no more issues while riding.
 

darwin

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#18
Now that I remember correctly it was a piece of brass wire from a cleaning brush that worked to open the jet hole up, steel wire from a brush was too big to work.
 
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#19
How can I test 8mm spark plug compression with a kit that only goes down to 10mm. Can’t find an 8mm adapter anywhere! How do folks test HS engines?
 

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