i aplogise that some of this is covered in other threads, but i wanted to ask a specific question about fuel...

i know there are a million discussions about whether or not high octane fuel is worth it, but has anyone actually had a negative experience putting it in your harley?

i've owned my bike (2004 1200custom, 8.6k miles) for about a month and i i've only taken it on a dozen or so short rides, so i've only filled up with gas 3 or 4 times max. the previous owner said he used to fill up every 130 miles, so to play it safe i've been filling it up every 100 miles (so obviously there's still a bit of fuel left in the tank). anyway, for the first few weeks it was spot on, but recently it started to develop a strange sound above approx 20mph - it's hard to explain but it sounds a bit like a small metal ball running around the inside of a cylinder and making a kind of ringing sound. it started off really quiet, but it's gradually become more noticable and i think my bike may also be starting to develop a bit of a knocking sound. at the same time, it's started to spit and splutter on the odd occassion, in particular at slow speeds. i THINK it also feels like the engine is getting hotter, but i'm not 100% sure about this (because the harley's are so loud and hot anyway it's difficult to know 100% what's a new fault and what's 'normal' when you're a newbie!!!)

i started to read online about carb settings, dodgy spark plugs, engine lubrication, battery, etc which could all lead to problems, but one thing i've kinda overlooked is the fuel! i've filled it every time at my local shell garage with their top fuel - shell v-power nitro which i think is 99 RON, or at the very least 97 RON. in my manual it says to use 95 RON, which is pretty much regular unleaded in the UK as far as i understand it

it seems a real coincidence that as the old fuel from the previous owner has obviously been gradually burned off, the bike has started to develop these symptoms. from reading online i understand that higher octane fuel generally helps to prevent knocking etc, but for a 1200 harley engine do you think it could actually be causing my problems???!!! has anyone had a similar experience???

thanks guys

 

If your bike is actually "knocking" (detonation) then you should be using a mixture of race gas and regular. The symptoms you describe (ringing, metal ball, sputtering, etc.) sound more like a mechanical issue and unless you have mechanical knowledge, I would recommend a visit to the local dealership. Not enough info to try and give good advice on this forum.

 

Are you giving the bike enough RPM's and not lugging the bike?

 

thanks

i've not changed my riding style. the only thing that's changed is the fuel

i would film the bike on my phone and upload, but the ringing noise only starts when riding above 20mph

i guess it could well be a mechanical fault, it just seems a coincidence. i'm just wondering if it's worth burning off all the high octane stuff and switching back to regular before taking it in to a garage???

 

Higher octane pump gas should not be making that kind of difference in your bike. Your only talking about a few octane points. You may be getting some bad gas.....

 

In short, NO. You're bike's motor design requires premium gas, going to lower octane will likely make your "pinging" worse, if that's what the noise is.

It's not unheard of a gas station (intentionally or accidentally) to have regular gas in their premium (underground) tank. Have you switched gas stations?

If your gas station pump has a single hose for the different grades of gas, the first quart or so out of the hose will be whatever grade the previous customer pumped. Frequent (early) fill-ups, like filling at 100 miles instead of 150 miles, can increase the ratio of regular to premium pumped into your tank if the previous customer pumped regular octane.

You might try emptying the current tank of fuel and refilling with a full tank of fresh premium gas from a different brand station.

Edit: It's also the start of summer and air temps are rising. As temps increase, so does the the risk of detonation (pinging), so this might be related to your increase in ping. Are you experiencing the noise more when your in stop & go traffic (motor hotter)?

 

Well, if it were me, I'd put regular gas in it and ride it for a hundred miles or so to see if the noise changed etc. It sounds mechanical to me - not gas related. I've run regular in my two Sportsters for years (in fact all of my bikes) without any problem. Sounds like the primary chain to me - and that is a normal noise - so check the fluids and chain tensioner. I know you say it doesn't start until 20mph or so but do the simple things first to rule them out. Then panic!

 

I would not put regular gas in it for any reason, I made that mistake last summer in SandBridge, Va. Out of habit I grabbed the 87 octane hose. It was about 102 that day. On the slightest hills I had to drop to 4th gear to keep it from pinging heavily. I was glad when a 100 miles went by so I could put some 93 in it.

 

Over the 50+ years the Sporty has been in production, Harley has produced many models that were designed for regular octane fuel. Since you don't bother to list what Sportster models and year you actually own, I guess we have to assume it's one of those.

 

After my recent round sound effects I started using octane booster. Sound effects left. No more detonation.

I only use premium gas, unless I cant find it.

I blame florida heat and ethanol.