Two tanks of 93 octane and there's no difference whatsoever in the character of my bike, which is: Sounds like a blue-printed hot rod for the first 10 minutes, then it knocks quite loudly under a light load
It's pretty sad sounding, really.
As someone alluded to, with the woman on the back it's worse because the only way the bike sounds good is ON the gas or OFF....not exactly the way I like to ride with my lady on the back. So, I just sit there right in that zone where the knock is banging away at its loudest. Depressing, but there's no good alternative. Down shift and rev it higher....makes no difference, just more knocks-per-minute. It's related to the load my engine is under, not the RPM so much.

Anyway, back to the octane, makes no difference. Oil makes no difference.

One thing I thought I might try is a colder plug. Could my plugs be retaining too much heat? I know many will say that a colder plug would be begging for SVS, but for God's sake something must be making this thing pre-ignite and it just isn't normal. I've been riding close to 40 years and I've ridden an enormous number of motorcycles (used to work in the industry) and no bike....EVER.....has made this kind of racket when warm.

Docs take is probably right with the further heating of "superheated" gases, combined with lower octane fuel. Unlike out west, here in the southeast we have extremely high humidity which will literally knock you aback immediatley upon walking outside; does anyone know if that has harder effects on an engine and/or fuel atomization. I drove out west one time and was in Phoenix and my vehicle just didn't seem to work as hard as it did here??

The big V-twins air cooled do get hot and noisy like at thrashing machine when hot..

Syn oil helps but only a little..

When sitting the motor being air cooled does radiate heat..and of course you are sitting directly on top of this heat... and the noise is normal...not deadened by a water jacket..but actually transmitted along the cooling fins...

An oil cooler does work when not moving...oil is still being pumped through the cooler and the heat simply leaves by radiation...movement or a fan hastens this process..

I put an oil cooler on the Harley because it was an easy and attractive location and the cooler has a thermostat which opens at 187 deg F
It does work and keeps the oil about 15-20 deg F cooler.. (I have an oil temp guage..) which only helps keep the crank area and the oil itself cooler..

Like older Harleys the oil tank is remote in the dry sump system on the R* and the oil travelling along the lines to the tank under the seat gets cooled ..more so than if the oil tank is tucked closer to the engine..

as well the oil in the R* is shared with the transmission and clutch and so larger exposed areas...and volume..keeps oil cooler..
For these reasons an oil cooler helps but is not as needed on the R*..but it does help..

Since most of the rest of the motor is air cooled the oil has little effect cooling those areas..

So living with the clatter and the heat is why the air cooled V_twin gives us the real motorcycle experience we so much enjoy..

Pop Rivet wrote:
The big V-twins air cooled do get hot and noisy like at thrashing machine when hot..

AND>>>>>

So living with the clatter and the heat is why the air cooled V_twin gives us the real motorcycle experience we so much enjoy..


Hi Pop,

With the above statements, should we assume that your Harley makes clatter/knock/ping sounds after ten minutes or so, like many Road Stars do?

I've ridden a lot of Harleys over the years, and none of them did this.

MidStar07 wrote:
Pop Rivet wrote:
The big V-twins air cooled do get hot and noisy like at thrashing machine when hot..

AND>>>>>

So living with the clatter and the heat is why the air cooled V_twin gives us the real motorcycle experience we so much enjoy..


Hi Pop,

With the above statements, should we assume that your Harley makes clatter/knock/ping sounds after ten minutes or so, like many Road Stars do?

I've ridden a lot of Harleys over the years, and none of them did this.

I have heard a lot of complaints about the noise of the R* and the Harley both...so yes my Harley is a little bit less noisy than the top end of the R* but you have to remember the valve train is more massive in the R* hence should be noiser...
you have to listen to other R* and compare so maybe there is something wrong with yer bike...
what does the dealer think or have you had them listen to it...??

you should know with your experience...rods bearings timing..

IMO, this isn't valve noise. Valve noise typically occurs when engines are cold, when clearances are large. Hydraulic lifters are supposed to cure this anyway, but yes I know all about the unusual link between our left and right valves.

Still, no one seems to be listening to the Road Star Knock Club when we say that this noise is something that happens at a particular throttle setting. Why would the valves make more or less noise when a tiny, very tiny change was made in throttle setting?

If the rod bearings are bad, then they were bad when the bike came out of the crate, and keep in mind that the bike sounds like a million $$ piece of perfection when run for 10 minutes or less People say "yeah, but the oil is thicker then." Are they kidding me or themselves? If thick oil could make a troubled engine sound so much better it would be a cure-all for every guy trying to unload a POS used car/bike/boat.

This is a combustion problem, period.

Since my first experience with pinging, I have been convinced that it is heat related on my R*. Only does it on hot days when low or no airflow over engine. High octane fuel has cured the problem for me. I know some say high octane will cause carbon build up. Not buying that one. One other consideration. Fuel with the Ethanol mix will run hotter as well.

Road_Hawg wrote:
Since my first experience with pinging, I have been convinced that it is heat related on my R*. Only does it on hot days when low or no airflow over engine. High octane fuel has cured the problem for me. I know some say high octane will cause carbon build up. Not buying that one. One other consideration. Fuel with the Ethanol mix will run hotter as well.

This Ethanol myth busters site claims ethanol runs cooler. Go figure. Myth busters

I too have just recently heard this knock on my "R" that I have had for 3 months now. I live on beachside Ormond Beach and ride mine to work for 13 miles one way. Never heard the knock until a trip to Pasco Count this past weekend. An hour into my ride (Silver Springs) having to stop at lights, I noticed the sound taking off from stop signs and lights. Only hear it on takeoff...dont hear it when riding. Parked the bike in Dade City at father in laws house for the night and went for a ride Saturday morning. After 20 minutes of riding, the noise returned on stops only. Both days were 90+ degree days in the Florida heat. I was hoping this would be a case of changing the oil to a thicker one.

DocShadow wrote:
SoonerFlash wrote:
I wonder now if a higher octane fuel might have stopped this knock? Normally I run 87 octane fuel and did so while I was there. Afterward we all felt like the knock was fuel related. Who knows?????

Interesting comment.

The knock or pinging is usually due to pre-ignition. I wonder if the result of overheating produces areas within the ignition chamber which are 'superheated' and result in variable detonation within the chamber.

It would be interesting to see if some of you folks in the hotter parts of the country find the 'knocking' is diminished by running higher octane fuel.

Dco

You are right on the mark. It does create hot spots in the cylinder. Under compression these hot spots detonate the air/fuel mixture before the spark. Premium fuel does help reduce the detonation because it has a higher flash point than regular. However, there are times here in Texas that it still pings some with premium fuel, but is is not as bad as when I have regular fuel.