Throttle cable just won't snap back

scootertrash

New Member
Aug 25, 2020
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Hi

My first ever motorized bicycle & am much grayer now from this darn thing.

I cannot get the throttle to snap back once i get the bike moving, ( don't think i have gone more than 100 metres now in 4 weeks, problems after problems.... sheesh)

Have taken apart right from the carb, reinstalled... works great... start pedalling, pop clutch ...
DEAR GOD ... THROTTLES STUCK WIDE OPEN ... and throttle is now sloppy with no snap.

Have lubed the inner wire & now discovered the cable wants to catch on the inside of that silver L shaped thing that connects to bottom of kill switch housing ..ya that doesn't work either

Pls help an old gal out ... our neighbors just roll their eyes cause we are at 4 weeks now & still NO rides.
My husband is too busy to do this & his hands shake too much so I am building 2 bikes.

By bike 2 i will be a bicycle & small engine mechanic
 

Tyler6357

Well-Known Member
Mar 15, 2012
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Santa Barbara, CA
Ha! Okay, calm, you can do this, frustrations happen to all of us. There is a learning curve with these things before you work all the kinks out. The cable for the throttle has to be tight enough and not get caught on anything. It must slide smoothly through the cable housing. Also, check the spring in the carb to make sure it is providing enough tension to close when you release the throttle. Post pictures if you can to help us diagnose your problems.
 

scootertrash

New Member
Aug 25, 2020
19
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Ha! Okay, calm, you can do this, frustrations happen to all of us. There is a learning curve with these things before you work all the kinks out. The cable for the throttle has to be tight enough and not get caught on anything. It must slide smoothly through the cable housing. Also, check the spring in the carb to make sure it is providing enough tension to close when you release the throttle. Post pictures if you can to help us diagnose your problems.
How do I check the spring in the carb for proper tension?
Will take pics tomorrow, it's dark now.
 

scootertrash

New Member
Aug 25, 2020
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Watch these videos

Good vids, thank you. Actually had the carb apart today looking for a clog, we finished got the muffler bent & put on but the engine is being starved of gas ( took it off & it started) regardless everything installed like the vids & even lined up with the pin on the inside.
 
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Tyler6357

Well-Known Member
Mar 15, 2012
1,143
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Santa Barbara, CA
The throttle should pull the carb slide up and when you release the throttle the spring should push it back down. Take the carb off the engine and look in hole and twist the throttle, you should be able to see the slide going up and down.
 

wolframore

New Member
Nov 10, 2016
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Illinois
Check your cable. I’ve seen permanent bends in the cable that causes binding in the cable housing. The same bike had dried mud in the plastic throttle which caused binding. Changed the throttle tube, cable and custom shorted it for a MTB and guy was super happy.
 

scootertrash

New Member
Aug 25, 2020
19
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No kinks. I saw a 2016 thread where the white plastic in the kill switch housing had plastic preventing the full range of throttle. Had some burrs so sanded smooth, hooked everything back up, got bike running & had some throttle response for the first time, when I pulled in the clutch the engine went full blast, always happens & the choke is off, today full choke wouldn't kill it i had to pop the clutch.
 

Tyler6357

Well-Known Member
Mar 15, 2012
1,143
170
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Santa Barbara, CA
Have never adjust the carb it's factory set still.
These are things you can do to adjust your carb.
-Adjust the idle screw once you got it running
-Adjust the needle clip, I recommend that you move it to the lowest/leanest setting
-Replace the jet, these carbs come with a #70 sized jet. You could purchase a set of jets and try different ones, usually a size from #60-#70 will be the best one.
Also, make certain you don't have any air leaks where the carb connects to the intake and where the intake connects to the cylinder. An air leak will screw up your ability to idle properly. Another thing to consider is the gas/oil mix, you should be at 24 to 1 until the engine is broken in and then 32 to 1 after. Do not mix at 16 to 1. I know MFG recommends 16 to 1 but everyone pretty much agrees that is too much oil. Too much oil will get messy and clog up your exhaust pipe.
 
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scootertrash

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Aug 25, 2020
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The silver throttle housing won't sit properly, if i tighten all the way the arm sticks out to the right causing angle on the cable, and the cable keeps pulling out of the barrel regardless, have a piece of old shower hose on there to keep the cable from jamming.
How do I test for an air leak? Dish soap trick?
 

scootertrash

New Member
Aug 25, 2020
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Yes my gas/oil is 16/1 & most of it has hit the ground lol, only mixed a 2 litre batch (1/2 gallon) and not filling up tank until I get this bike sorted.
So thanks for that advice
 
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Tyler6357

Well-Known Member
Mar 15, 2012
1,143
170
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Santa Barbara, CA
The silver throttle housing won't sit properly, if i tighten all the way the arm sticks out to the right causing angle on the cable, and the cable keeps pulling out of the barrel regardless, have a piece of old shower hose on there to keep the cable from jamming.
How do I test for an air leak? Dish soap trick?
The cable MUST run smoothly when pulled and released. If you can't get that to happen, just get a new one, they are only $5 here-----> https://www.ebay.com/itm/Throttle-C...245497?hash=item41f27e6b39:g:8EwAAOSwn1FbPsrc

Yep, dish soap/water is a good way, also, make sure no fuel is leaking, make sure you have an intake gasket on the intake/cylinder connection. Also, make sure the air filter is not clogged with oil, a good way to check it is to take it off and start the engine, see if it is running differently.
 
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scootertrash

New Member
Aug 25, 2020
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Will not having the muffler on affect anything? I just noticed the carb isn't quite all the way on, need to give another shove.
Will work my way down the list.
And will report back
 

Tyler6357

Well-Known Member
Mar 15, 2012
1,143
170
63
Santa Barbara, CA
Will not having the muffler on affect anything? I just noticed the carb isn't quite all the way on, need to give another shove.
Will work my way down the list.
And will report back
The carb must be on tightly, even if it don't leak, vibrations will eventually cause leaks if it's not tight. If you don't have an exhaust pipe on, your engine will be extremely loud.
 
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