[AgentX]

Does the sound of an Enfield pinging resemble this?

https://youtu.be/vlHRRO216dg

Is it clearly audible over engine and wind noise on the road?  I am worried that my Fireball won't like the local fuel around here; it was set for 91 octane and that's what I thought local stations sold; turns out it is not 91 US standard but some other standard that equates to 86ish.

Till now I have been mostly avoiding any situation likely to induce ping but would like to wring it out a bit more.  I can hear a regular sound at higher rpms (4000 or so, which I only hit/exceed for 5 seconds or so at a time ) but it seems like it might be part of the general valve clatter.

Yes, I am searching for an octane booster.

Appreciate any insight.  I just don't know how obvious the sound should be...or if it is a fast regular sound, or somewhat random. "Marbles rattling in the engine" is what I hear, but how fast is the rattling?  Rattlesnake?  Maraca? Slower?

Thx!

[ace.cafe]

It's a higher pitched rattle that has no relation to the rpm. That video is nothing like it.
If you open the throttle and hear something like jingling keys, then that's it. If it goes away when you let off the throttle,  that's it.

86 octane is a US equivalent of 91 RON, and is insufficient fuel for any Fireball level build. With a RON type fuel rating like that, you need to use 97 or 98 RON octane fuel. If you need an octane boost, try adding toluene or xylene by 10% volume to the gas.

[mattsz]

+1... I am intimately familiar with the sound of a (UCE) Enfield pinging... and that ain't it!

[AgentX]

It's a higher pitched rattle that has no relation to the rpm. That video is nothing like it.
If you open the throttle and hear something like jingling keys, then that's it. If it goes away when you let off the throttle,  that's it.

86 octane is a US equivalent of 91 RON, and is insufficient fuel for any Fireball level build. With a RON type fuel rating like that, you need to use 97 or 98 RON octane fuel. If you need an octane boost, try adding toluene or xylene by 10% volume to the gas.

Thanks, Tom...definitely not what I m hearing.  As you note the gas is inadequate and I have been avoiding higher-load situations because of it.

Trying to find either octane booster or pure toulene/xylene has been a bust so far.  Conversations in a mix of French and Bambara pretty much go "what paint do you need to strip?  This will work.  (Mineral spirits presented in used water bottle).  What?  For paint on a motorcycle tank?  Use this.  (Other bottle, same mineral spirits.). What, there is paint IN the tank?  What the hell are you talking about?"

It's just no use trying to explain and there is no assurance of what you are getting.  I do have a possible line on a real chemical supply place.

Other option is av-gas from the airport.  That's 100 octane I believe.  Any idea what would happen if mixed with normal 86?  Any issues blending them or will they just average per the ratios added to the mix?  I don't mind this but it does make my fill up options fairly restricted...

[ace.cafe]

Thanks, Tom...definitely not what I m hearing.  As you note the gas is inadequate and I have been avoiding higher-load situations because of it.

Trying to find either octane booster or pure toulene/xylene has been a bust so far.  Conversations in a mix of French and Bambara pretty much go "what paint do you need to strip?  This will work.  (Mineral spirits presented in used water bottle).  What?  For paint on a motorcycle tank?  Use this.  (Other bottle, same mineral spirits.). What, there is paint IN the tank?  What the hell are you talking about?"

It's just no use trying to explain and there is no assurance of what you are getting.  I do have a possible line on a real chemical supply place.

Other option is av-gas from the airport.  That's 100 octane I believe.  Any idea what would happen if mixed with normal 86?  Any issues blending them or will they just average per the ratios added to the mix?  I don't mind this but it does make my fill up options fairly restricted...

The AV gas is a good bet.
You can mix them, but I have no idea what the necessary ratio would be.
If you can afford to just fill it with AV gas, that would be the best bet. Good fuel is a worthwhile expense!
 

[AgentX]

More a matter of supply and storage than cost...but we'll see what I can wrangle.

Mixing would just be useful to keep the supply going longer.

[AgentX]

So that was it...finally heard it when I was about to lug the engine after a bad shift at low speed.

That was distinctly the sound... more of a ringing than a rattling.  And that is definitely not happening at the rpms to which I have taken the bike, which is comforting.  Mostly ride between 3-4.5k with constant acel/deceleration, so I am still hopefully breaking the bore in nicely.

[ace.cafe]

If it is going to happen, it is most likely to happen at rpms below torque peak,  and at larger throttle openings thanot usual,  indicating high load.

[1 Thump]

The AV gas is a good bet.
You can mix them, but I have no idea what the necessary ratio would be.
If you can afford to just fill it with AV gas, that would be the best bet. Good fuel is a worthwhile expense!
 

Does that influence jetting?

[ace.cafe]

Does that influence jetting?

No, octane rating doesn't affect jetting.

[SirStanley]

Ace, you’re certainly far, far more knowledgeable than I on such things, but speaking from personal experience, jetting might well need to be adjusted a bit when running 100% AvGas/100LL.

Since fuel might often stay in my bike's tank for 6 months or more, I now use 100LL  and definitely had to richen the mixture a bit over “pump gas" to keep everything happy.  A bit more than a 1/8 turn in on the idle, a notch on the needle and a wee bit more height on the float level. I believe this was due to differences in the specific gravities of the fuels.

That said, the bike runs wonderfully on AvGas and I’ve never had a fuel/ carb issue; even if the bike sits for months. Plus, the occasional whiff of it in the exhaust is magical.

[ace.cafe]

Ace, you’re certainly far, far more knowledgeable than I on such things, but speaking from personal experience, jetting might well need to be adjusted a bit when running 100% AvGas/100LL.

Since fuel might often stay in my bike's tank for 6 months or more, I now use 100LL  and definitely had to richen the mixture a bit over “pump gas" to keep everything happy.  A bit more than a 1/8 turn in on the idle, a notch on the needle and a wee bit more height on the float level. I believe this was due to differences in the specific gravities of the fuels.

That said, the bike runs wonderfully on AvGas and I’ve never had a fuel/ carb issue; even if the bike sits for months. Plus, the occasional whiff of it in the exhaust is magical.

Yes, in the US there is generally an ethanol additive to the pump gas, which is not in the AV gas.
This can affect the mixture. I probably should have mentioned that, but I still am having a hard time accepting that the gas in this country is tainted, even though it has been for some time now.
However, in Mali, where this bike is located, I don't think the ethanol is in the gas there.

[AgentX]

Definitely no ethanol here.

[Bullet Whisperer]

This might be of interest - it is my 350 Indian Bullet, which runs roughly 10:1 compression and uses a Meteor Minor sports piston with a shortened skirt and is a cast off from one of the 350 racer's engines. All other tuning mods aside, you can hear what is predominantly piston slap [due mainly to the shortened piston skirt] and, just occasionally, some 'pinking', or 'pinging' on some of the uphill work during the run [from about 18 minutes into the video is a good example]. The piston slap is very audible, the pinking less so, as it is only at a low level but neither are doing any harm to this machine, which has racked up thousands of miles in this form, although it sounds very rough when first started from cold 
 If anyone's Bullet sounds quieter than this one, it is very likely you have nothing to worry about 
 B.W.

https://www.youtube.com/watch?v=RBPg_Xj2X04