seems to miss then long return to idle

GoldenMotor.com

thegnu

New Member
Sep 15, 2011
982
1
0
freedom pa
OK still breaking in my 66 cc china 2 stroke , its displaying a couple things that I cant seem to get figured out an I have been searching threads for some possible causes , first problem at a moderate rev its begun to seemingly miss or go a lil flat but comes up an runs normal if you hold it there an it seems to just happen at random.
could this be an air leak ? or something I am missing ? all new gaskets an checked tourque on bolts twice.
second if you quickly blip the throttle at idle the revs come right up but take a lil longer to return to idle , I am currently going into the carb to check out the things that I have found here like a sticking barrel or missaligned barrel or a sticking throttle cable .
I love this thing its definately a tinkers bike !
ps. I have been letting it run out of gas when I shut it off an it seems to run significantly better right before it stalls, running too rich maybe ?
 
Last edited:

2door

Moderator
Staff member
Sep 15, 2008
16,302
175
63
Littleton, Colorado
You probably have an air leak somewhere. The carburetor to intake manifold is the most common place. Many of us never rely on the metal to metal connection, or even ones with a plastic bushing to get a good seal. Use a gasoline resistant sealer such as Seal All to seal the carb.

Any engine will increase rpm when leaned out (running it out of fuel). That doesn't necessarily mean you're running rich. Check your spark plug color to determine your air/fuel mixture. A dark plug will indicate a rich mix, a light one is running leaner. For engine longivity, a rich mix is preferable to a lean run.
Check that carburetor and intake manifold for leaks and let us know what you find.
There are other places to look for leaks. Use the search feature, key words 'air leak' and you'll have plenty to read on the subject. http://www.google.com/cse?cx=partne...4/seems-miss-then-long-return-idle-35701.html
Tom
 

thegnu

New Member
Sep 15, 2011
982
1
0
freedom pa
Ok , I started checking things at the throttle an worked my way down , found a lil burr of plastic in the throttle cleared that an added a small amt. of lube also a thin coat of lube on the bar, an inside of the grip was rough gave that a quick sand with 400 wet or dry paper then gave it a thin coat of lube an reinstalled the grip , dropped some airtool oil into the cable housing an while that soaked in checked the manifold to jug gasket an the carb to manifold fit both fit well , but wrapped the carb end of manifold with a few wraps of plumbers tape temporarily (carefull not to let any loose tape enter the motor) , the barrol is moving free an shows no signs of binding an moves smoothly to the bottom of the throat .
After all of that I got the best dead cold start ever made about 1 full rev of the cranks an it lit right up an idles much better ,an returns to a smooth ide after a quick blip on the throttle a bit faster , my plug is a bit oily , I am attributing that to the richer oil mix I am using for break in ,after break in I think if I still have probs with a seemingly rich mix or air fuel mix I will adjust the needle or rejet the carb .
theres the findings an results . I hope if anyone else has a similar prob this helps .
Gary