XB12R Rattle noise when I get on the throttle

[canadahippie]

My Firebolt makes an unsettling metallic rattling sound when I get on the throttle. This only happens when I've been riding for a while (20-30 minutes in hot weather) and the engine is hot. What could be causing this?

 

[buellxb9rs]

What bike, mods, exhaust etc

 

[nicholas900]

Hard to tell from your comments. Is it spark ping (pre-detonation)? Have you ever heard that noise before? Try higher octane fuel see if it goes away.

 

[canadahippie]

It's a 2004 xb12r with a race ecm, drummer exhaust, and it's been lowered with a lightning rear end and lowered on the stock forks (previous owners). It has had this noise for a while. It sort of sounds like metal screws being rattled in a metal can. I can accelerate slower and ride at any rev it doesn't make the noise. It's only under moderate to hard acceleration that the bike makes the noise. I just looked up some videos of spark ping but it doesn't sound like this https://www.youtube.com/watch?v=VjlL3C4EsNM it's more metalic sounding.

 

[go cytocis]

Try higher octane fuel see if it goes away.

[up]
You may also have carbon build up for which you could try a detergent fuel additive. If that fails, you might try a set of cooler plugs.
If the knocking persists, I'd check that the CPS is operating & set correctly.

 

[canadahippie]

I'm running 91 octane, but I can't find any higher. Where do people get 93?

 

[Alien]

It might just be normal. All my Buells make a sound similar to hitting the motor w a ball peen hammer.

 

[50dro]

I'm getting the same noise too! No loss in performance but "pings" under hard acceleration. 2004XB12 with NGK Irridium 9 plugs (which I believe are cooler than the 8 plugs that the XB calls for). Always run 93 in it. I used to hear it with my Hawk and still hear it with the Torque Hammer so I don't think it's something loose in the exhaust. It would be nice to cure this...

 

[ReadyXB]

I'm running 91 octane, but I can't find any higher. Where do people get 93

If you want to rule out pre-ignition as the cause, you could buy a bottle of Octane booster at an automotive store and run with that for a while. You should easily be able to get above 100 octane.

 

[Theycallmecrash]

You should easily be able to get above 100 octane.

This isnt exactly true. Most of those octane boosters are garbage and increase your detenation point hardly anything.

If you have ecmspy and a cablr, increase the AFV by 10 to 15 percent once the noise starts and go for a ride. If its detenation should go away.

 

[ReadyXB]

In a scientific evaluation, just 0.8 fl oz of a 12 oz bottle NOS brand Racing Formula Octane Booster was added to 1 gall. of Shell 91 octane (which was measured to be 91.2). The AKI increased from 91.2 to 93.7. These are real octane numbers (RON+MON/2). I don't where or if there is a point of diminishing returns is, but even 2.5 points increase makes it a valid detonation test for canadahippie if he can't find 93 octane.

 

[canadahippie]

I just got all the oil changed and the weather has been cooler so it hasn't been making the noise. The bike has to be so hot that it's uncomfortable to sit on before it starts making the noise. If the noise starts up again I'll try some of these suggestions and report back.

 

[303xb]

Have you checked primary tension?

 

[canadahippie]

No, but I'll do that. What makes you think I should check the primary tension? I'm young and inexperienced so I'm just curious what your reasoning is.

 

[303xb]

My only reasoning is your explanation of metallic rattling. It would increase with an increase in throttle (as long as you are in gear).

I recently had an issue where my bike sounded like someone was shaking a can of ball bearings near my engine...it was a primary chain out of tolerance.

It's something easy to check. If you could post a video of the issue that will help.

 

[WIGGLE2]

Detonation....almost guaranteed. Its at a 'low', almost lugging RPM as well? Any 'race'/performance shops up there sell UNLEADED race fuel? A gallon of race fuel FAR exceeds ANY 'booster' by ANY name. Do NOT try leaded fuel....it will kill your O2 sensor in short order. This little experiment will eliminate your noise IF it is detonation. Now.....even with 91 it SHOULDN'T try to ping UNLESS it's super hot, (like in the city) and you're lugging it a bit. Mine CAN do this even with 93. It isn't bad, and it's only if I'm pulling it down hard or starting out from a stoplite at low RPM. That being said, you will want to look at (or have someone help you), other variables like your timing, etc.

 

[canadahippie]

Primary tension is within spec, thanks for the explanation 303. Wiggle2, it sounds like your bike is doing the same thing as mine. I do run at lower revs than most other Buell riders I've met and lug it a bit. Do you think it's worth worrying about? It normally doesn't ping and it's easy for me to avoid.

 

[DualSportDad]

I had the same problem with my Uly. I can send you you my map if you want. It has stock timing map with the fuel maps adjusted. My bike no longer detonates with k&n, race muffler and my map.

 

[thrstrmech]

had the same issue with the noise...turned out to be the horn bracket was loose against the headlight bracket causing the rattling sound. could be your horn is loose rattling against the stay, just something to look at, maybe rule it out as the issue.

 

[303xb]

Funny you say that...I installed shorty front turn signals and riding I heard what I thought was a rattle or knocking. It was simply the longer wire from the new signal vibrating against the windscreen. I swore it was engine knock.