Pinking; mixture or advance curve?

  • Thread starter Thread starter Reggie3cl
  • Start date Start date
Hmmmm. Think I'll stay with curve 2, been running well for the last umpteen years. Only more confused after following this thread :D :D
 
nick7 said:
Yup  cant argue with that Simon! Where were you yesterday ? Hope your bike is hoing well?
Click to expand...

Bike going great Nick!

Back on topic - I always use the 'How Much?' BP Ultimate.
Never had a problem with it - ever!
Only problem I had was with Highlands out of the way garage fuel (No BP out there).
 
The bulk fuel supply up here comes out of Grangemouth and is mixed with each retailers additive pack.

Last year I topped a D****i up with V-Power at a station I've used before, within a couple of miles it was down on power.
Struggled to run clean and wouldn't idle. Checked everything over and no sign of any component failures.
Drained the fuel and refilled with local Supermarket unleaded, ran fine, fully restored.
Conversely on holiday in Spain last year filled the car up in the Picos and it zipped along very much better than it had all the way there.

Suppose you are at the mercy of the station operator getting the mix correct.
 
Bugger all to do with the station operator.
They get what they are given  :(  from the depot.

Tanker drivers drop the fuel into the wrong tanks (Shandy) on the odd occasion  :o
Hoooman error ! "she will be rite the punter wont know"  :'(

Hit n Miss now days, and our old Laverdas that are higher comp dont like a Shandy  :(

Best ya all start ridin 750,s they will run on a Shandy fine  8)
 
Just to add my 2p worth.....

Pinking also known as detonation is caused by either fuelling or ignition:

  • Too much advance
  • Too lean fuel mixture

As Reggie leaned off the mixture on the needle I would suspect it was this that caused the pinking.

In an ideal world we always want a very small amount of "pinking" to ensure that optimum performance is met. It takes a long time to set up an engine on a dyno to find the ideal setting for ignition and fuelling.
For example: The engine may perform much better with big amounts of ignition advance but this causes pinking, to overcome this pinking you can richen the mixture. (Typically changing the ignition settings will lean or richen the mixture anyway, good practise when changing one thing is to double check the other).

Hope it helps and happy to discuss further....
 
Also....

To clean up the initial pick up of the throttle 1/2 turn adjustment of the air screw should fix it. As mentioned earlier the needle has very little effect at initial throttle opening.

If on the initial throttle opening the response is delayed and all of a sudden chimes in this would typically indicate a lean mixture at that point.
 
Thanks for the input.  Hopefully I'll be able to get out soonish to test properly the current setup, but at the moment I'm dealing with a rather large pair of windows and a joiner who has a holiday booked...
 
Well the bike seems to like curve 11 - feels better than it ever has, midrange very strong and smoother too.  Pulling away improved by winding back the pumper.  Slightly surprised that it still need 3/4 of a turn on the mixture screw even with 20 pilots.  Speaking of jets, found this in someone's garden today....

P4230159.jpg
 
Good news on the advance curve.
Hey, what's happened to your blue filter??????
 
Yeah, I think I may have to go back and do something about the colour of the grass in that shot.

Funny, I never thought to check the curve.  The box Keith fitted crapped out, so Witt sent a replacement and I didn't even think to check the setting when I fitted it, dummy that I am.  Anyway, all good now, even the forks feel pretty good!
 
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