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Post by onceler on Sept 28, 2014 10:04:48 GMT -5
I finished installing my new parts and I'm seeing a stronger spark, but it still won't start. Here's what I've checked today:
1.) spark. Checked at valve cover- looks good and strong
2.) compression. Showed 160psi max.
3.) fuel. I've been spraying starting fluid in the carb and even removed the carb and sprayed starting fluid in the intake.
4.) after trying to start it I remove the plug and it's wet but doesn't have any carbon on it.
I'm ready to haul this thing to the shed and be done with it. Any advice? Ideas?
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Post by tvnacman on Sept 28, 2014 10:13:37 GMT -5
recheck your mechanical timing ? your missing something , are you getting a strong cranking ?
John
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Post by onceler on Sept 28, 2014 10:19:20 GMT -5
K I'll recheck cam timing. My starter wasn't cranking for very long before fading out but I took it apart and cleaned it and shined up the portion where the brushes ride and it cranks for about 5 seconds now before losing power
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Post by onceler on Sept 28, 2014 15:58:35 GMT -5
I hate to ask this, but is there anyone out there who can post a video of their spark plug sparking on a running scooter? Or hook up a timing light to their running scooter?
My timing light will not flash and the scooter has no signs of even wanting to start.
I did play with cam timing moving it forward and backward a tooth, but now I'm back to suspecting a spark issue again.
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Post by onceler on Oct 7, 2014 19:22:55 GMT -5
So today I removed the BBK, and re-installed my original 49cc piston, cylinder, and head. After a few cranks it fired up and revved and idled fine on the stand  Hopefully, this tells me that I do not have a fuel or spark issue. It seems odd, though, because my compression test with the BBK was at >150psi, unless that is not enough compression for a BBK. I might check compression on the stock setup before I tear it down. Anyway, I'm gonna lightly hone the big bore cylinder and install the new rings I bought a while back and see what happens. |
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Post by tvnacman on Oct 8, 2014 6:24:13 GMT -5
Maybe the valves are not sealing . Put a spark plug in the head turn it up side down . Put some gas in and see if it leaks past the valves .
John
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Post by onceler on Oct 14, 2014 10:01:29 GMT -5
I did the test you recommended, John. And I saw 2 small bubbles coming out of the intake and exhaust valves. So I removed and relapped the valves again and also lightly honed and installed new rings. And finally it started  It needs some tuning on the carb and everything put back together, but it finally is able to run  Thank you everyone for all of your help! |
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Post by tvnacman on Oct 14, 2014 12:21:59 GMT -5
I did the test you recommended, John. And I saw 2 small bubbles coming out of the intake and exhaust valves. So I removed and relapped the valves again and also lightly honed and installed new rings. And finally it started It needs some tuning on the carb and everything put back together, but it finally is able to run Thank you everyone for all of your help! This is a bitter sweet post . I'm very happy you got it sorted out . Did you lap the valves and then recheck for bubbles ? John |
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Post by onceler on Oct 14, 2014 19:13:48 GMT -5
Yep, no bubbles. I tried this a few weeks ago but I used water. Using gasoline was the tidbit of knowledge that revealed the problem, again thanks for hanging in there with me
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Post by tvnacman on Oct 15, 2014 6:03:56 GMT -5
Is it laboring while cranking or kicking back ? What type CDI are you using ?
John
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Post by onceler on Jun 5, 2015 13:06:07 GMT -5
Well here it is almost a year later and turns out I don't have this damn thing figured out, yet. After throwing the in the shed for the winter, I've been monkeying around with it again. Since the BBK swap I probably have about 30 miles on it. It runs fine at wot it does have some hesitation from idle. But still the biggest problem I have is it usually won't start. Sometimes it will start after a couple minutes of fiddling with the throttle and then sometimes I'll mess around with it for an hour and it doesn't start. Any ideas? I've pretty much replaced everything (twice) at this point: -new carb. (stock size, upjetted to a  I think) -new head -new stator -new Casoli CDI -new intake and spacer -new plug -new fuel petcock I've checked for spark = ok compression = ok spark plug is wet if i've been cranking it for a while and giving it throttle have turned the air/fuel screw everywhich way including loose. any thing I haven't mentioned I'm sure I've tried in the past. (Sorry my attitude sucks right now) |
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Post by tvnacman on Jun 5, 2015 13:15:04 GMT -5
recheck the valve lash.
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Post by onceler on Jun 5, 2015 13:23:29 GMT -5
Hi John, thanks, once I get home I'll re-check the valve lash and clean the carb
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Post by ital on Jun 5, 2015 13:47:00 GMT -5
Good luck! I feel for you man. You need a Chinese scooter mechanic contact. I have a contact that bales me out when I am in a jam..
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Post by murkyapricot on Jun 5, 2015 16:41:50 GMT -5
Im no expert and i didn't read all the old posts but did you put a more powerful starter in it? From what I've read when installing a bbk you usually need more power to get it going
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I think)
