hi nice site new to gas power bicycle i got a boy go fast kit having trouble getting it to run smooth at low speed have about 150 miles on it running 8oz to 1 gal of gas allso iam having trouble with rear motor mount keep breaking bolts motor the motor seam like it wont to turn to the left for bicycle when on seat then bolts break other then that i like it start good getting about 40 to a tank thanks for any help
can't find an answer then ask here someone may be able to help!!
- Thread starter Norman
- Start date
welcome to the forum
you are running a little thick on the mix it should be 6.5oz to a gallon for brake in not 8 oz the 16:1 in the book is for china they use regular motor oil and you need it then but with 2 stroke oil 20:1 for break in on regular oil then after 2 gallons 32-35:1 is a safe zone to run in some run real good synthetic oils that can be run at 50:1-751:1 but most of us are 30-40:1 regular oil or reasonable synthetic .
as far as you breaking mounts something has to be out of alignment or isnt tight enough
in your drive line you sprocket might not be 100% strait/level or could be offset to the front or back and yanking on the engine?
also how tight is your chain if its to tight it could be the issue
are you running anything in between the mount and the frame like rubber? this could be the cause
there are alot of things it could be we can start narrowing it down from here and get you all fixed up
you are running a little thick on the mix it should be 6.5oz to a gallon for brake in not 8 oz the 16:1 in the book is for china they use regular motor oil and you need it then but with 2 stroke oil 20:1 for break in on regular oil then after 2 gallons 32-35:1 is a safe zone to run in some run real good synthetic oils that can be run at 50:1-751:1 but most of us are 30-40:1 regular oil or reasonable synthetic .
as far as you breaking mounts something has to be out of alignment or isnt tight enough
in your drive line you sprocket might not be 100% strait/level or could be offset to the front or back and yanking on the engine?
also how tight is your chain if its to tight it could be the issue
are you running anything in between the mount and the frame like rubber? this could be the cause
there are alot of things it could be we can start narrowing it down from here and get you all fixed up
hi thanks for the help going to run the 6.5 oil to 1 gal of gas i have the 1 rubber on front and none on rear could not get it to fit have a bike with big frame no room on rear i have a lot of vibration from motor at half speed i am running to work every day 36 miles a day round trip thanks for the help
new to gas power bicycle have a boy go fast 80 cc motor having some trouble motor shacks bad at full speed and i lost end of muffler that keeps noise down now the shacking at top speed stop put motor to loud what can i do thanks for any help
ok, I'll give you the HACK method... and NOT really advised, but it will get you by and down the road.
Get a couple pot scrubber things made of metal from the dollar store and shove em loosely up into the muffler cannister. use some common bailing wire to hold 'em up in there.
..I ain;t sure what 'shack' means, but my guess is your motor is running to rich, or too lean because of carburetor jet adjustment wrong.
read through a buncha the threads for carb adjustment on whatever model carb you have.
You could also have an intake leak. It common.
..be cautious.. you can burn it up... fry the piston... by running it with the muffler opened up...
Good luck!
rc
Get a couple pot scrubber things made of metal from the dollar store and shove em loosely up into the muffler cannister. use some common bailing wire to hold 'em up in there.
..I ain;t sure what 'shack' means, but my guess is your motor is running to rich, or too lean because of carburetor jet adjustment wrong.
read through a buncha the threads for carb adjustment on whatever model carb you have.
You could also have an intake leak. It common.
..be cautious.. you can burn it up... fry the piston... by running it with the muffler opened up...
Good luck!
rc
new to this motor bicycle trying to get it right got a boy go fast got alot of help from every one one last thing at top speed i get a vibration that very bad what can it be also one more thing when vibration fixed how long can you run motor without turning it off to cool iam running 18 miles one way to work and stopping 3 times dont fell hot and its run ok no loss of power just dont wont to burn it up got about 540 miles on it going to mix oil at 4oz to 1 gal of gas or should i stay at 6oz to 1 gal thanks for help and a very good web sight
All the engines vibrate unless you are one of the lucky few that got a well balanced one. You have a better chance of winning the lottery though.
There should be a certain RPM range where the vibrations are nearly non-existent. That is known as the "sweet spot" and most folks just ride at that speed.
Above that speed, some vibrate so bad that folks are complaining of fear of loosing the fillings in their teeth.
The best way to combat it is to use a good quality spring seat and hand grips that will absorb the vibrations and not transfer them to your butt and hands.
Also, these vibrations are known for shaking loose all the nuts and bolts on the entire bike. Go over your bike after every ride and check them all. Don't tighten them unless they have come loose, you do not want to damage or strip any of them by over tightening them. Soon you will learn which ones rattle loose regularly and which ones are good for a while. Still check them regularly though, you don't want any unexpected surprises while out on a ride.
I am one of the believers in a product called Loctite. Some folks swear by it, some folks swear at it.
Loctite 242 Blue works very well.
Do not use Loctite on the factory kit screws and studs though. You need to upgrade to better quality hardware. The factory hardware can easily strip out the heads or snap before the Loctite looses it's grip.
SBP sells a great hardware kit at a very fair price.
http://www.sickbikeparts.com/catalo...ducts_id=43&osCsid=rbk3q31guvamv8kgacn25lks12
If the engine is not getting too hot or pinging, you don't have to worry about overheating.
A good "shade tree mechanic" test is to spit (or flick a little bit water) on the outer cylinder head fins immediately after a good long ride. It should evaporate quickly. If it sizzles the engine is too hot.
After 500 miles you are good to switch to a 4oz/ gal. ratio (32:1).
Expect to adjust the carburetor a little as the fuel will now be slightly thinner with less oil in it and therefore flow slightly more through the fuel jets inside the carburetor.
There should be a certain RPM range where the vibrations are nearly non-existent. That is known as the "sweet spot" and most folks just ride at that speed.
Above that speed, some vibrate so bad that folks are complaining of fear of loosing the fillings in their teeth.
The best way to combat it is to use a good quality spring seat and hand grips that will absorb the vibrations and not transfer them to your butt and hands.
Also, these vibrations are known for shaking loose all the nuts and bolts on the entire bike. Go over your bike after every ride and check them all. Don't tighten them unless they have come loose, you do not want to damage or strip any of them by over tightening them. Soon you will learn which ones rattle loose regularly and which ones are good for a while. Still check them regularly though, you don't want any unexpected surprises while out on a ride.
I am one of the believers in a product called Loctite. Some folks swear by it, some folks swear at it.
Loctite 242 Blue works very well.
Do not use Loctite on the factory kit screws and studs though. You need to upgrade to better quality hardware. The factory hardware can easily strip out the heads or snap before the Loctite looses it's grip.
SBP sells a great hardware kit at a very fair price.
http://www.sickbikeparts.com/catalo...ducts_id=43&osCsid=rbk3q31guvamv8kgacn25lks12
If the engine is not getting too hot or pinging, you don't have to worry about overheating.
A good "shade tree mechanic" test is to spit (or flick a little bit water) on the outer cylinder head fins immediately after a good long ride. It should evaporate quickly. If it sizzles the engine is too hot.
After 500 miles you are good to switch to a 4oz/ gal. ratio (32:1).
Expect to adjust the carburetor a little as the fuel will now be slightly thinner with less oil in it and therefore flow slightly more through the fuel jets inside the carburetor.
Last edited:
thanks for the help took it out today for a ride for something to do ran it out of gas going to go to 4oz now looks like a good time to start it thanks again
one more thing how to tell if the rpm are to high i have a 26 inch with a 41 tooth rear gear on it
The 2 strokes can rev to the moon!
The only way you'll over rev it is if you hold the throttle WFO while going down a steep hill.
The ignition system is a "fixed" system, it does not adjust for high or low RPM's which lets it act like a rev limiter.
All that said, do not rev it at max RPM for a long time. If you wring it's little neck it will fail.
The only way you'll over rev it is if you hold the throttle WFO while going down a steep hill.
The ignition system is a "fixed" system, it does not adjust for high or low RPM's which lets it act like a rev limiter.
All that said, do not rev it at max RPM for a long time. If you wring it's little neck it will fail.
thanks for the help i filled it up to day with 4oz oil to 1 gal of gas running better little smoother going to change plug its black cleaned every thing up today see how it gos this week thank again and have a good holladay
If the new plug gets black too, try raising the clip position on the slide needle one notch to lower the needle further in the needle jet. This will reduce the fuel being delivered from just off idle to 3/4 throttle. After a test ride, check the plug to see if it changed to a chocolate to leather brown color. If so you should be good to go.
new to motor bicycle got a boy go fast 80 cc ran great for about 500 miles now have trouble with fuel have to turn the fuel shut off almost off to keep it running iam going 36 mile a day to work and using a full tank of full iam mixing fuel and oil at 4oz oil to 1 gal of gas
It sounds like the float valve inside the carburetor has gotten some junk stuck in it. This will hold it open and not allow the float and valve assembly to properly regulate the fuel level inside the float bowl.
Are you using a quality in line fuel filter? If not you really should. The chintzy screen filter that installs on the top of the fuel tank valve is a very poor wanna be filter that clogs up easily but yet allows all sorts of carburetor clogging junk to pass through it.
36 miles out of approx. 1/2 gallon? That sounds like the carburetor is definitely running rich/ adding too much fuel to the intake air. A stuck float valve could certainly cause that as well as a good running carb that just needs a tune up.
Check out the float valve situation before fiddling with tuning the carb.
Are you using a quality in line fuel filter? If not you really should. The chintzy screen filter that installs on the top of the fuel tank valve is a very poor wanna be filter that clogs up easily but yet allows all sorts of carburetor clogging junk to pass through it.
36 miles out of approx. 1/2 gallon? That sounds like the carburetor is definitely running rich/ adding too much fuel to the intake air. A stuck float valve could certainly cause that as well as a good running carb that just needs a tune up.
Check out the float valve situation before fiddling with tuning the carb.
worked on float today every thing looks clean bent the to fingers that the float push up to stop fuel put it all together but fuel runs out of carburetor non stop the carburetor the one that cam with kit from boy go fast
If there is fuel pouring out of the carburetor then there definitely is something wrong with the float valve.
I am assuming here (careful now) that you have a NT carburetor.
If this is true, did you slightly bend the two float fork arms down towards the float or up towards the carburetor body?
Bending them down will lower the fuel level.
Also when you reinstalled the valve needle did you put the sharp pointy end up into the valve seat (which is correct) or did you put the end with the teeny spring loaded plunger up into the valve seat (which is up-side-down).
I am assuming here (careful now) that you have a NT carburetor.
If this is true, did you slightly bend the two float fork arms down towards the float or up towards the carburetor body?
Bending them down will lower the fuel level.
Also when you reinstalled the valve needle did you put the sharp pointy end up into the valve seat (which is correct) or did you put the end with the teeny spring loaded plunger up into the valve seat (which is up-side-down).
think you are right it a nt carburetor i bent them down i did nothing with any needle was riding and it started to flood motor with gas had to us fuel shut off to slow fuel to make it home just can not get it to stop
took the needle out and looked it over and no spring on it did not see any place there one looked under float nothing there the float round the 
that pushes on it half round with a needle that hooked to it it square with round point going up seen no dirt any where starting to think about getting a new carburetor but dont know what to get i use bike to get around and to work thanks for all the help
that pushes on it half round with a needle that hooked to it it square with round point going up seen no dirt any where starting to think about getting a new carburetor but dont know what to get i use bike to get around and to work thanks for all the help
If there is any dirt or other debris stuck in the needle valve, simply removing the needle half will not clean it or be a positive method for ensuring that it is truly clean. The other half, the brass seat could have the dirt stuck in it.
You don't even need to remove the carb from the engine or remove the float bowl from the carb either.
You can remove the brass seat by unscrewing it from the carb body. Just be careful of the red paper gasket. You don't want to tear it.
There really is no reason to replace an NT carb just because the float valve is misbehaving. They are the most simplest of carbs to work on and tune.
Clean the valve assembly with carb cleaner and a Q-Tip stem. Cut the fuzz ball off of the Q-tip with a razor blade. Spray carb cleaner through the valve seat and stick the Q-tip stem through the valve from the needle side in and spin it with your fingertips to "scrub" the seat clean. Spray a little more carb cleaner through the seat through both ends to be sure that it is totally clean, and re-instal it. Be careful to guide the needle back up into the seat when re installing the seat. You don't want to have needle going in crooked and getting forced down when screwing the seat back into the carb body. You can use either the little red straw that comes with the can of carb cleaner or the Q-Tip stem. Just stick it through the seat to gently catch the point of the needle and guide the needle in to the seat as you thread the seat in.
You don't even need to remove the carb from the engine or remove the float bowl from the carb either.
You can remove the brass seat by unscrewing it from the carb body. Just be careful of the red paper gasket. You don't want to tear it.
There really is no reason to replace an NT carb just because the float valve is misbehaving. They are the most simplest of carbs to work on and tune.
Clean the valve assembly with carb cleaner and a Q-Tip stem. Cut the fuzz ball off of the Q-tip with a razor blade. Spray carb cleaner through the valve seat and stick the Q-tip stem through the valve from the needle side in and spin it with your fingertips to "scrub" the seat clean. Spray a little more carb cleaner through the seat through both ends to be sure that it is totally clean, and re-instal it. Be careful to guide the needle back up into the seat when re installing the seat. You don't want to have needle going in crooked and getting forced down when screwing the seat back into the carb body. You can use either the little red straw that comes with the can of carb cleaner or the Q-Tip stem. Just stick it through the seat to gently catch the point of the needle and guide the needle in to the seat as you thread the seat in.
thanks going to work on it this week end bike has not ran all week no spark took cover off and fond that the magneto can apart the rivets broke and made a mess order new one waiting for it to get here not shore how to get old one off
