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Post by wutzthedeal on Apr 26, 2014 17:17:05 GMT -5
When I sprayed starter fluid onto the outside of the right-hand side of the carb (idle adjust side) I noticed my rpms went down. Figured it was a fluke, but I tested it several times. I had read that rpms should INCREASE or do nothing; an increase in rpms would indicate an air intake leak. Is this gonna be a Rubixy Cubey type of deal or y'all know somethin' 'bout this? I'm still not satisfied with my reduced top speed from last year (now going between 25-30 avg.) so I keep poking 'round.
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Post by millsc on Apr 26, 2014 17:29:21 GMT -5
With over 5k miles your rings are possibly worn causing less compression and power output these China scoots don't come with top notch componets time for a rebuild.
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Post by millsc on Apr 26, 2014 17:31:56 GMT -5
You also could have a small hole in the piston seen it many times on scoots with half your mileage.
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Post by ramblinman on Apr 26, 2014 17:35:15 GMT -5
an increase in rpms would indicate an air intake leak. true... but may also indicate an air leak if rpms dropped. that would be my thought. |
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Post by justbuggin2 on Apr 26, 2014 17:44:51 GMT -5
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Post by wutzthedeal on Apr 26, 2014 18:55:51 GMT -5
Thanks all; that baffles me; I spray a highly flammable spray near intake areas, and the rpms decrease, meaning somehow you're saying the spray went on and essentially sealed the hole for a moment but did not make it into the engine to ignite. Now, if the rpms decreased, that would indicate a decrease in air in the a/f balance--is that right? So that would tell me that something on that right side is like a hairline-crack or something because the visuals all check out. Only other thing I could think of is torquing down the intake manifold even though it seems perfectly snug and tight.
EDIT: ordering new lines tomorrow for fuel and air.
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Post by jjoshua20213 on Apr 27, 2014 21:48:01 GMT -5
I think your problem might be you heavy slider weights with and without a bbk my weights had to have been between 5.5g-6.6g or my top speed was effected. Tried 8 gram weights once and the top was effected.
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Post by boostcrzy on Apr 28, 2014 15:42:05 GMT -5
if you spray on the outside of the carb and it affects the idle in anyway then you have established that you have an air leak. Now, if the idle goes down, then that would indicate a rich condition(obviously this depends on just how much fluid is being sprayed and getting into the motor). I would take the carb off and recheck all of the seals/couplings of your intake tract. What carb do you have exactly?...some pics or video would also help.
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Post by jjoshua20213 on Apr 29, 2014 12:35:56 GMT -5
I think your problem might be you heavy slider weights with and without a bbk my weights had to have been between 5.5g-6.6g or my top speed was effected. Tried 8 gram weights once and the top was effected. Sorry, misread the post, but this is a though for higher top speed |
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Post by wutzthedeal on Apr 30, 2014 11:37:39 GMT -5
I think your problem might be you heavy slider weights with and without a bbk my weights had to have been between 5.5g-6.6g or my top speed was effected. Tried 8 gram weights once and the top was effected. Sorry, misread the post, but this is a though for higher top speed I thought heavier weights made for higher top speed? Carb I got is here: carb |
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Post by jjoshua20213 on May 1, 2014 6:50:25 GMT -5
Sorry, misread the post, but this is a though for higher top speed I thought heavier weights made for higher top speed? Carb I got is here: carbToo heavy and the bike goes into high gear too early and the engine can't produce enough rpm to push it all. To light and it stays in low gear and over revs, tune right in the middle and you'll have good accel and top speed. I've tested this by putting heavy weights and too light of weights in. |
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Post by wutzthedeal on May 1, 2014 8:07:56 GMT -5
I might try to mix some 9s and 7s, or go back to my 7s. But this problem was present w/7's in. It sucks. I further isolated it to the rear area/low side of the carb. The leak is either at the bottom of the air intake hose coming from the air box to the carb or it is in the carb itself on the lower half, rear side. I tried putting my finger over various parts in that area and then using some RTV silicon to seal off possible leaks, but the only thing that would affect rpms is the spray in a short, heavy dose. Oddly, when I went to re-adjust my a/f, turning it fully clockwise did not stop the engine; still a bit baffled about that, but I once again adjusted for highest idle (which, on this one, is only about 1.25 turns out).
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Post by JerryScript on May 2, 2014 12:32:16 GMT -5
(oops, sorry)  |
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Post by jjoshua20213 on May 2, 2014 14:51:53 GMT -5
I might try to mix some 9s and 7s, or go back to my 7s. But this problem was present w/7's in. It sucks. I further isolated it to the rear area/low side of the carb. The leak is either at the bottom of the air intake hose coming from the air box to the carb or it is in the carb itself on the lower half, rear side. I tried putting my finger over various parts in that area and then using some RTV silicon to seal off possible leaks, but the only thing that would affect rpms is the spray in a short, heavy dose. Oddly, when I went to re-adjust my a/f, turning it fully clockwise did not stop the engine; still a bit baffled about that, but I once again adjusted for highest idle (which, on this one, is only about 1.25 turns out). I would do 7g sliders, but wouldn't worry about that until the current problem is fixed. If your bike was still running with the screw all they way in I would think the carb itself has a problem, but I really don't know. |
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Post by wutzthedeal on May 2, 2014 19:12:04 GMT -5
After replacing the fuel and main air line, the a/f screw anomaly went away. Now, twisting it all the way in stops the engine, as it should. So that's good. Idle is back down to 1800 rmp, idle is smooth, a/f was adjusted properly, but I'm still missing about 7mph off of my top end. Super sad about that. This has been a long battle (incl. replacing air filter then reverting back to original, replacing fuel and air lines, both tires, variator, sliders, belt, carb, and probably some other I'm not thinking of). Maybe I'm just expecting too much from a 49 cc and I should have expected it to lose 5-10 mph top end over the winter. I don't know. Tired of trying stuff at this point.
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