Horrible ping...

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577-Jersey

577-Jersey

New Member
Mar 23, 2013
293
1
0
central western nj
New motor(67cc china girl) after warms up at half to full throttle has a horrible ping and loses power while its happening,,if I back the throttle down a bit that helps,,but its pretty bad,,I tried to tighten the gap on the plug,,that helps a little,,but its already at .15,,guess i could go a little tighter,,also tried to flip the head around,,maybe the cdi is causing this,there is no slop in the key at the crank to adjust,,any ideas would be great!

Thanks Tom
 
Kioshk

Kioshk

Active Member
Oct 21, 2012
1,152
10
38
Connecticut
Have you verified that that ping is indeed coming from contact with your sparkplug? (you allude to a wide-gap perhaps being a problem. Verify if the noise you're hearing is indeed caused by pysical contact, and not perhaps detonation. Sometime this can also be caused by a loose-head...the clicking is actually hot compressed gas escaping past the head-gasket. If you determine that the plug is NOT hitting the piston, I highly recommend that you increase the gap substantially...like 2X to about .30 .
 
577-Jersey

577-Jersey

New Member
Mar 23, 2013
293
1
0
central western nj
I'm sure its detonation,,only happens after its warm and under higher RPM,,nothing is hitting,, I'm very familiar with detonation,,I added another head gasket and that helped a little,,Ill try to open up the gap but it seems like it pings less with smaller gap.If I drill bigger holes in the magneto so I can move it CW a little that would retard the timing,,just don't want to bomb the magneto.

Thanks!
 
Last edited:
Mr. Minecraft

Mr. Minecraft

Visionary
Jan 13, 2012
349
0
0
San Diego
If adding head gaskets made the problem better, why not just run higher octane fuel? Im guessing right now you are running the lowest grade (87 in my area). Get a quart of the highest octane fuel available at the pump, and mix it with good quality oil at 32:1. Run the bike for a while and see if the pinging gets better or disappears completely. If it still doesn't go away, then let us know and we can explore other options.

The reason I bring this up is because when my HT pinged, I just got 96 octane gas instead of 87 and it went away.
 
Mr. Minecraft

Mr. Minecraft

Visionary
Jan 13, 2012
349
0
0
San Diego
Octane booster is a grey area. Some people claim it helps with predetonation, other say it is a complete scam. I have tried it in a few engines and never noticed any changes in how the engine runs. You can always try the octane booster, but just don't expect it to work very much if at all. The most effective way to raise octane is juts buying a higher octane gas. Try the 92 and see if it helps. If it does, we can try more things to get your engine running right.
 
maurtis

maurtis

New Member
Dec 14, 2011
707
0
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Kyle, TX
Are you sure it is pinging and not four stroking? I had what I thought was pinging under full throttle at anything over 35 MPH. A kind of a machine-gun pop-pop-pop and loss of power. After trying a new head and CDI, it was still there.

Once someone mentioned it might be four stroking (I had earlier ruled that out since it sounded different than when I ran my needle too rich), I changed out my jet to a 68. With the 68 jet, SBP HD air filter, and needle set on the leanest position, I would only get it to occur during the first half mile of a ride. Once properly warmed up, she would cruise at any throttle position without issue.

Then I blew up the wrist pin bearing... LOL

Good luck!
 
mapbike

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
maurtis said:
Are you sure it is pinging and not four stroking? I had what I thought was pinging under full throttle at anything over 35 MPH. A kind of a machine-gun pop-pop-pop and loss of power. After trying a new head and CDI, it was still there.

Once someone mentioned it might be four stroking (I had earlier ruled that out since it sounded different than when I ran my needle too rich), I changed out my jet to a 68. With the 68 jet, SBP HD air filter, and needle set on the leanest position, I would only get it to occur during the first half mile of a ride. Once properly warmed up, she would cruise at any throttle position without issue.

Then I blew up the wrist pin bearing... LOL

Good luck!
Click to expand...


LOL! I know your pain....maurtis, one of my engines was the same story, just when I got her running like a champ I was on my way home from about a 15mile round trip and just almost back home when the wrist pin bear gave up the ghost and destroyed my engine......

By the way just wanted to say you just gave some great advice here.


:-||
 
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