Been trying figure this out but no luck so far. Let my blaster warm up a few minutes then take off it runs rough. Not a miss fire or sputter sort of an extra vibration. After goin for about 2 min of riding it would go away smooth out run as normal. It felt like when a plug loads upnd then crack throttle it cleans out . Not the case plug was fine. Did a plug chop and was light chocolate color. So not sure what it could be. Now it doesn't smooth out. Any ideas?
running rough
- Thread starter resurrected89
- Start date
Also changed pet weiner, fuel filter, did carb rebuild kit, put in fresh fuel, and checked reeds. None helped.
how bout the float height and airscrew/pilot jet settings ??
http://www.blasterforum.com/carburetor-138/float-heights-how-adjust-them-50565/
http://www.blasterforum.com/carburetor-138/adjusting-your-airscrew-pilot-jet-51060/
mixing or injecting your oil ?
if mixing, is the oil injection nipple blocked off good ?
check your intake boot for cracks too.
has it been verified leak proof with a leakdown test ?
https://www.google.com/url?q=http:/...ds-cse&usg=AFQjCNGE4_UApOQ430CitSH5I2KBsaRL7A
this could very possibly be electrical in nature too,
have you checked/cleaned the ground connection at the coil ?
checked all other connections to be good and clean ?
checked the plug wire with an ohm meter as covered in the manual ?
plug boot connection to the plug good, tight and clean ?
try a new plug, they can be fouled or partially fouled yet show good spark when tested against the cylinder and not fire when under the pressure inside the cylinder.
check a few or all of these and get back to us with your results
http://www.blasterforum.com/carburetor-138/float-heights-how-adjust-them-50565/
http://www.blasterforum.com/carburetor-138/adjusting-your-airscrew-pilot-jet-51060/
mixing or injecting your oil ?
if mixing, is the oil injection nipple blocked off good ?
check your intake boot for cracks too.
has it been verified leak proof with a leakdown test ?
https://www.google.com/url?q=http:/...ds-cse&usg=AFQjCNGE4_UApOQ430CitSH5I2KBsaRL7A
this could very possibly be electrical in nature too,
have you checked/cleaned the ground connection at the coil ?
checked all other connections to be good and clean ?
checked the plug wire with an ohm meter as covered in the manual ?
plug boot connection to the plug good, tight and clean ?
try a new plug, they can be fouled or partially fouled yet show good spark when tested against the cylinder and not fire when under the pressure inside the cylinder.
check a few or all of these and get back to us with your results
To me it seems like you are not warming up enough, before you even think of putting it into gear it must be close to operating temperature.
I have the problem with my lad wanting to shortcut the warm up period and it runs like crap until it gets up to the heat.
I have the problem with my lad wanting to shortcut the warm up period and it runs like crap until it gets up to the heat.
haven't done a leak down yet but, not oil injected properly blocked off. yes did plug chop tried dif plug, the electrical connections are clean, no air leeks at the carb boot, and I warm it up til the engine is warm to the touch. I will do a ohm test on the coil and do a leak down test. I followed both of those guides when setting up carb float is good and it idles fine. air screw is about 1/3 turn out
Problem child here.
Air screw should be 1 1/2 turns out, what size is the pilot jet?
Warm up period should really be called "hot" up period, the motor should be hot to the touch.
I would not ride again until I was satisfied that it was airtight.
if you're positive it's not carb related ?
get it leakdown tested !
if it's producing highest idle at 1/3 turns out on the airscrew, might havean airleak ?
like mentioned, on a stock set-up, it should be around 1.5 turns out.
then.....
keep checking electrical as described in the troubleshooting section of the manual
also....try disconnecting both kill/key switches and see if it makes a difference
(you'll need to hold the brake on and stall it to kill the engine when done)
get it leakdown tested !
if it's producing highest idle at 1/3 turns out on the airscrew, might havean airleak ?
like mentioned, on a stock set-up, it should be around 1.5 turns out.
then.....
keep checking electrical as described in the troubleshooting section of the manual
also....try disconnecting both kill/key switches and see if it makes a difference
(you'll need to hold the brake on and stall it to kill the engine when done)
Highest idle isn't 1/3 out. That's where it idles well. It's got stock pilot and a 340 main. I will havta confirm that though. Iirc I'm one spot down from middle on the needle. I rebuilt carb its all new everything and it made no difference. I should be up at the garage in the morning working on it. Will post up what I find!
Ports have been smoothed out not really opened up though. It's .06 over boar, has full fmf, and open box top. Tors is long gone and so is oil injection. My jetting may not be spot on but with the way the weather has been lately not much riding has been done. It ran fine with that set up in the fall though. I dropped the clip a spot because idle screw had be way out to idle. It was 4 turns out. I dropped a spot and it idle fine now.
I would guess air leak. If you had good plug chop results with a 340 main there is something's wrong. I ride at sea level and my bike has the same exact mods as yours. I run a 270 with the clip in the middle of the stock needle. Do a leak test post results. What is your elevation?
Set the float level and try again.
You do not adjust the idle by moving the clip position on the needle, the needle comes into action at approx 1/4 to 3/4 throttle.
This is the wasy to adjust the idle.
Idle adjusting.
Start with air screw 1.5 turns out.
Set idle screw so that it has some sort of idle. With TORS it is the big screw under seat on top of unit. With no TORS is is the brass screw midway down carb body.
Warm up motor and then set idle screw for a faster idle, 2000rpm+
Adjust air screw either way to get the fastest idle.
Adjust air screw a little at a time leaving 10 secs or until the motor to responds.
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The main jet is way too big, drop a #300 in there , put the clip back to middle slot, and make sure there is a 32.5 pilot jet in there.
Adjust the idle, and do a plug chop.
Before you make the plug chop run it is important that the float level is correct, the idle is set correctly and there are no air leaks in the system, otherwise the smoke ring may lie about the AFR.
WHEN ALL OF THE ABOVE ARE CORRECT PROCEED WITH THE FOLLOWING.
Warm up motor to operating temp.
Fit new B8ES plug, ride through the gears and hold WOT in 5th or 6th gear for 10 seconds, or as long as you can safely.
Switch off the motor and pull in the clutch, apply brakes to come to a stop quickly.
Take the plug out and replace the old one for the ride home.
Carefully cut the threaded end off the plug to expose the insulator.
There should be a smoke ring of a cardboard or biscuit colour around the insulator.
If it is non existant or a very light colour, you are lean and require a larger main jet.
If it is a lot darker you are rich and may go down a size in main.
I prefer to run a little on the darker side, I may loose a little power but it is worth it for the peace of mind that I won't need a rebuild so soon.
http://www.blasterforum.com/do-yourself-20/how-plug-chop-38674/
http://www.blasterforum.com/engine-13/plug-chop-how-vid-48226/
This is a good to go plug.
This one is a little rich, but I would run it, I like to be on the safe side.
You have to get up a reasonable speed so that you can get the motor to pull strongly.
Then hold it Wide Open Throttle (WOT) for 10 secs or as long as you can.
The idea is not to get speed but to make it pull strong at full throttle to get onto the main jet curcuit.
I find I can safely do it on a short run by applying the brakes some.
If you have not enough room you can use 4th or 5th gear with good results.
my idle screw is all the way in as far as it will go just to get it to idle at all if I back off on idle screw it falls on its face. maybe some of the boss needs to be filed off? it seems to be drilled and tapped pretty good. it has been filed flat. thanks for the info guys. looking like I most likely have my carb set up all sorts of wrong.
