big said:
...valve train noise or piston slap...when in fact it's detination occuring BTDC.
Disagree. Det happens at peak TDC. I'm going to walk dishit out the bag if both ends were open say to find a way out? I'm running down some tube so you can see the piston moving up the cylinder is the idea. So you get the whole picture about BTD and T. So, here I'm running down some tube and it sure is going to end soon is the det appears. So before I get there, do you hear any noise? No, of course not. I'm still running smack into wall, but do you hear the noise yet = BTDC? You have to ask yourself, if before that split second your nose has a gap of air between that wall, and that to me is still a cushion of no sound? Now your nose is the tree that fell in the forest no one was around to hear it the fuk. Now, do you understand where det is at TDC, not still rearing it up BTDC? LOLike slamming a door: Slam + Air + Distance [time getting it reared up] to hit the door jam = Bang the drum slowly is I change from a door slamming to a hand with a stick instead. We Get WATT and where Det's POSITION LANDS, now IS THE NOISE? Not before top? Hello? I though you knew this stuff? My post makes noise. Yours make wind. That make sense?
Valve train noise or piston slap occurs every stroke up, then every stroke down. The trick here is a constant 2 time-noiseslap and this one is tricky to the ear... Listen to how it occurs:
When a valve lash is out of tolerance, the cam lobe smacks open a lost valve train lash and it taps maybe inconstant when hot or almost constant when cold. Some can tick when tight too. However, once you thing that the valve lash was off, confirmed it wasn't, the next noise of a tick or slap is now chasing the piston skirt clearance.
This too could be related to top end noise. To follow this tick, notice how small the gap is between piston skirt clearance and cylinder wall? This is a cold clearance. Once expanded, we have a different number. And if that numbered gap expands too wide, galls material off the piston skirt, a gap enlarges.
When this excessive gap occurs, a tick will be heard like a valve lash is too wide/too tight. So this tick happens on the thrust up is a slap. When the piston comes around, changes direction at TDC, you hear the other slap or tick. So if it was a top end noise tick, this too like the lifter, would be a constant noise at start up, rev, idle, or @ 75mph.
Again, this occurs @ 75 mph. And if the OP has mentioned no knock, but a noise @ 75mph, home he has no slap but to slap the posts that do not think thishit out. Then, Sven/Hub/cntrhub/Shovelicious/PazYearazzUp comes up with the empirical generic is to paz year azz up once again. Like the diagnostics is going this way and not zoning in on 75mph is the harmonic/noise/internet sounds like?
This can be caused from a number of things including> Out of time, bad fuel, wrong octane fuel (less than 92) motor running too hot or lean....ect.
Almost. The ping is under load, no? I run 87 octane in a 12:1 compression ration kind of bike. Where the gas tank sticker recommends 92 octane or better. I setup my bike to run @ 15.3:1 AFR. Where is my knock @ static 220psi is the last time I checked my OTTO's cylinders. Book called for 228psi being the high. High think I'm close enough that the bike's life of 87 octane was the juice of choice. See any damage using the cheap chit? My bike liked it.
Combine both the fuel and the compression ratio for this real world scenario. You have one situation scenario being in the wrong rpm range under cruise; in the wrong gear going up a steep hill or incline: this is called a load of pressure happening under the kinetic. And you mix that scenario with octane, they still use spark knocks to sense the harmonics and squash the advance curve down some to stop it. So knock in the OTTO is forever.
This [92] octane is more like squid juice. Racers use 87 octane. If there was a knocking noise, wouldn't they stop using it? Back to load based situations is the knocking scenario of the OTTO. So, will it tick down the road all at 75mph on the sustained? I haven't a clue of a lot of things, but common sense tells me I'd be riding at 75mph is the knocking tick? I doubt it. Is the OP in the wrong gear? If he was out of time, as soon as he'd leave a light he'd be under such loade loady watt he say?
Like I said, what type of noise is it?
Like I said, he said it ticks ONLY @ 75mph. Narrow it down is the tick @ 75mph. Who brings in all this baggage, if 75mph is the ticking/harmonic, and at no other time is that happening, right? I'm not trying to get on your case, fella. Do you understand where I have to clean up these 'runner upper' kind of posts and the schooling begins? No offense guy, but dishere is the 3rd time I'm running down the OP's suggestions witchew. I know it's a hunting party, but cheeze is. This stuff is confusing enough, you get them running in circles. How many hours you billing the customer you talking like dis on some wild goose of a chase.
. I had a few minutes yesterday and the weather was decent so I took it out to really do some searching as far as the sound I am hearing is coming from and really try to listen for rattle or tick sound while the traffic was light. If I am just tooling around in through the country side around here I don't notice it much. Right off the bat before the heads got hot I just barely got it to the rpm's that makes it sound off and put my left hand on the very top of the head. In that range where it makes the noise it feels more like the tick sound on the top of the rocker boxs. I did check the tank and found nothing lose, rattling etc. It does it just in that higher rpm range no matter which gear it is in. The lower rpm range I can't hear it at all. Several times I put my hand on the top of the motor and could fell the ticking even after it got warmer into hot. 
