What's 'pinking' and do I have it?

[gabriel_gs]

Hi folks,

Probably been asked a lot and though I searched I couldn't 100% assure myself...

If I try to accelerate from low revs I sometime get a sort of rattle from the underside of the bike - sounds almost like a loose exhaust on a car -goes once the revs climb though.

Is that what 'pinking' is and if so, how do I overcome it?

 

[cookie]

pinking is a sort of tinkly noise from the cylinder heads. it occurs usually at low revs, under load.

usually a timing or fuelling issue.

 

[Dave Ett]

Could be yes. What octane fuel are you using?

Pinking is also known as pre ignition and happens when the fuel ignites before the spark plug has fired. Can be caused by the engine running too hot, too high compression or the octane rating being too low. or a combination or all these (and a few others I can't think of right now)

Have the plugs out and check the colour - you're looking for a tan / biscuit colour.

 

[gabriel_gs]

Thanks chaps.

I've only recently noticed it, so assume the recent hotter than normal conditions may be causing it.

Fuel-wise, it's what ever unleaded normal stuff BP and Jet sell I'll try filling up with the 'good stuff'

I'll take out the sparks this weekend and investigate.




PS... if I didn't know better, I'd say it was coming from under the bike.. could be wrong though...

 

[MikeP]

If you have engine bars fitted, check the mountings. Also check the bash plate is secure.

 

[sockpuppet]

If you have engine bars fitted, check the mountings. Also check the bash plate is secure.

Was just about the say that. The BMW engine bars have a habit of breaking at the top where they connect under the tank.

 

[brassmonkey001]

Most common cause of pinking is the timing is too far advanced. Unlikely to be the cause here though I would have thought.
Are you using the right spark plugs?

 

[Timolgra]

The most common cause of pinking on an 1150 in my experience is either poor fuel or a hot engine whilst the engine's under load.

 

[(RIP) Kaister]

Pinking is caused by the manufacturer not fitting a knock sensor linked to automatic timing retard.

HTH

 

[Greg Masters]

The guys have well described what pinking is and what causes it - but it's pretty rare in Surrey to experience it - so don't get too snared in this line of thinking.

It's more likely to be a rattle from the underside of the bike ...


Greg

 

[warmshed]

Have you changed you exhuast? this can lead to weaker fuelling and cause pinking.

 

[Tarka]

Another cause is people not changing down a gear when wanting to accelerate sharply...they load the engine up in too high a gear.

 

[John Armstrong]

Was just about the say that. The BMW engine bars have a habit of breaking at the top where they connect under the tank.

Had a strange rattle / vibration on a 1150 GSA, was one of the bars cracked where it joined the bash plate. Took a bit of finding

 

[gabriel_gs]

Another cause is people not changing down a gear when wanting to accelerate sharply...they load the engine up in too high a gear.

I know what you mean but I'm pretty aware of that.

It only a recent issue too.

 

[gabriel_gs]

Have you changed you exhuast? this can lead to weaker fuelling and cause pinking.

Nope standard exhaust.

Did have a BOS and y-piece fitted last year, but have been back to standard since October last year

 

[gabriel_gs]

Thanks all - I'll fill up with super, check loose bash-plate and anything else that might need a little tightening this weekend and report back.

 

[MattW]

I noticed my 1100 pinked slightly on a recent trip to Scotland.
It was warm (yes really, even in Scotland!) and it was two up and fully loaded. As expected, it tended to happen when I used the torque in the higher gears from lowish revs (as I tend to when solo). Using more revs in lower gears cured it.
I also have a suspicion that I picked up some slightly dodgy fuel from one of the little rural stations.

 

[Packer]

Hi folks,

Probably been asked a lot and though I searched I couldn't 100% assure myself...

If I try to accelerate from low revs I sometime get a sort of rattle from the underside of the bike - sounds almost like a loose exhaust on a car -goes once the revs climb though.

Is that what 'pinking' is and if so, how do I overcome it?

Define low rev's. Occasionally if I'm trying to make a fast getaway and am a bit too quick on the clutch the engine bogs and I get pinking. Avoid very large throttle opening below about 1500 revs.

Pinking is also called detonation and all the things others have correctly pointed out above can be the cause. What it actually is is the explosion of the fuel/air mix in the cylinder head rather than a progressive burn triggered by your spark plug(s).

It can cause damage to the engine so if you really do have it instead of a loose widget you need to sort it.

You don't need high octane fuel for your two wheeled tractor.

 

[(RIP) Kaister]

its caused mainly by the throttles going out of balance and one side is weak

i spent a long time balancing mine on the 1100 until i could ride it down to 1200 revs in top gear and pull away smoothly with no pinking on regular gas.

 

[MattW]

its caused mainly by the throttles going out of balance and one side is weak

i spent a long time balancing mine on the 1100 until i could ride it down to 1200 revs in top gear and pull away smoothly with no pinking on regular gas.

That's a very good point .
My TB's are slightly out of balance - I have a new cable to fit when I can get round to it (one of the stupid one piece affairs - balance is spot on at tickover but goes out at higher revs).