hey everyone...been a while! (popping/pinging question)

[ERM83]

ok...so, i've been riding my whip EVERYWHERE since getting it running. i've only touched my car 3 times in the past month and a half...even when i did (rain), i'd haul ass home from work when the rain stopped, JUST to get the bike, and meet up with my coworkers at whatever respective place they wanted to go out to. i'm OBSESSED with this thing. there's just one slight problem...

i'm getting a slight ping on idle (after it's warmed up), and some popping on decel sometimes. other than that, it RIPS through all gears/RPMS just fine. i checked and changed the plugs, and honestly, the old ones looked PERFECT...no fouling whatsoever. probably could've kept using them. here's my thoughts on the problem:

- timing slightly off
- carb boots leaking (will oil-test later tonight)
- cam chain? (It has the venture mod)

everything else is GREAT...ignition wires are fine (got new ones for the hell of it that i'm going to put on when i have time), haven't had any significant electrical problems at all...the thing is a TANK. despite it not being the most beautiful aesthetically at the moment, people come up to me daily, look and at and ask "MAN...WHAT THE HELL IS THAT?!", haha. a huge inline four does look pretty nasty and intimidating...

[TopCatGr58]

Hey there,

You've got 2 bikes listed in your profile, and you didn't specify which one you're talking about here, so I'm going to assume it's the 80 SG/dottie!?from your photos, it has an OEM airbox, but aftermarket pipes. Aftermarket pipes are not as restrictive,and can cause a slight lean condition which causes the decel pop. The bike might be jetted a little too lean or adjusted a little too lean . You could try turning the pilot/idle screws out a 1/4 turn each and test run it to see how it behaves on decel....or you can adjust the idle speed a little higher which will keep it from being so lean when you slam the throttle shut on decel since it keeps the butterflies opened just little bit more.

However, pinging or detonation is usually sensed and occurs under a bit of a load with too low of an octane of fuel, or too advanced ignition timing. Being able to hear the ping at idle doesn't sound right?? The vacuum advance unit can make a similar sound when it's vacuum hose is connected to the wrong port...the intake boot synch port instead of the #2 carb body metered port.

T.C.

[ERM83]

T.C.....here's what I'm running jet-wise: 140 mains, 45 pilots. I'm running 89 octane. I went with the 140's as a starting point, as i rebuilt the carbs for the 79' originally. I remember reading on here that going up a step at a time on the mains is a good starting point, being that gas is different nowadays. It IS the 80' sg, by the way...sorry i didn't specify! The vacuum advance is DEFINITELY set up correctly, and I've tried turning the pilots out a quarter turn...still pops....yet another another thing I forgot to specify. Should I go up a size or two on the mains, or check the timing first??? I'm in distance of getting the necessary things to solve both possible problems...I'm thinking maybe going up in the main jet size first??? I probably could use a timing strobe though, anyway...

[ERM83]

Also, it's DEFINITELY. more prominent in the left exhaust. I synched the carbs, and I'm STILL getting the pop/pinging. Pretty sure it's the no. 1 carb boot, or the timing...

[ERM83]

While synching, no. 1 DID give me a hard time. Maybe I just answered my own question. Will report back, and thanks for the help, for sure!