Pinking; mixture or advance curve?

  • Thread starter Thread starter Reggie3cl
  • Start date Start date
Same inverse logic as those who say they drop the forks when in fact they are dropping the yokes and raising the stanchions.
Dropping the needle means raising the clip in the notch on the needle.
Therefore dropping the needle leans off the mixture, and vice versa.
 
Hi Grant, Clem
I can assure you my logic is fine; if you re read Reggies post he says he Dropped the needles a notch...then he goes on to express concerns about leaness. If he had droed to a lower notch, the needle would be raised, the mixture richened. So as he says, he misexpressed that.he had lowered tge needle by using a higher ie raised notch.I thank you!😂thank god we are not in the hands of you engineers too often eh, genetally fucking things up😁
 
nick7 said:
Hi Grant, Clem
I can assure you my logic is fine; if you re read Reggies post he says he Dropped the needles a notch...then he goes on to express concerns about leaness. If he had droed to a lower notch, the needle would be raised, the mixture richened. So as he says, he misexpressed that.he had lowered tge needle by using a higher ie raised notch.I thank you!😂thank god we are not in the hands of you engineers too often eh, genetally fucking things up😁
Click to expand...

Discussion is futile - lawers always win      ;)
 
I use 10 on my RGS with good results (hi comp / 4C cams - sadly!).  All things being equal, higher compression means the flame front can travel quicker and so less advance than stock is required.  Certainly 36 deg advance is going the wrong way IMHO.  Curve 6 also whacks in 4 deg more advance just where you probably don't want it - at 2500rpm.

Graph courtesy of Cam's excellent DMC spreadsheet
 

Attachments

  • Curve 6 vs 10.jpg
    Curve 6 vs 10.jpg
    84.9 KB · Views: 25
Yeah, have the high compression pistons.  It seemed good on curve 10, possibly a bit 'creamier' if you see what I mean  ::)
 
I do know what you mean Richard, my current setup on TOG (rode her this am) is pretty well spot on, with yet another dyno run to confirm or deny, but she feels "harsh" mid range, idle to a quarter and from three quarters to flat out (not tried a sustained WOT yet) she does feel "creamy" I want to remove that "harsh" feeling, but its only while revs climb, at cruising around 3500/4000 she is loverly.
CLEM
 
Is the problem the same no matter which fuel supplier you use or is it more prevalent with one specific brand.

Dots' A2 adjusts its fuel and ignition settings quite noticably when she fills it up at either Tesco or Shell stations. 
 
Usually I've got a mixture of Tesco and Shell swilling around in the tank.  I would expect it to pink less on the Shell V Power (or whatever it's called - the HOW MUCH??? stuff).  I think what happened is that I noticed it once and kept an ear out for it, and was also being a bit lazy with the gearchanges making it pull harder up hill in a high gear - possibly too much advance at low revs was making it pink a bit?

Reason I wanted to know if mixture could have caused it was because that was the only change I made (going slightly leaner on the needle), however, having looked at the no. 6 curve (henceforth known as the Embassy curve, one for our younger readers there...) I suspect that going leaner may have exposed the shortcomings of this curve. 
 
Reggie
Now, while Clem may assert that i know fuck all about it 😁I can tell you that pinking is NOTgood! I dont think it should pink under any realistic load...my Jota doesnt ...but when it used to do that it wasnt long before it melted a piston. Great detective work...yes by that fella Clem...found shorting at the original btz pickups which caused overadvancing. Now run the Sachse redax...so i cannot help but feel you need to get the timing checked.unless your bores or pistons are shagged which might be giving you piston rattles/ slap? Nuff said.
 
Hey Nick, yeah, pinking definitely not desirable.  Certainly no harm in checking the timing if I can remember how my timing light works, but it's unlikely to be out as His Keithness set it up.  Bike only did it a couple of times, same circs: up hill in too high a gear for the road speed. Reckon I've got a better setup now, hopefully I'll be able to fully test it soon.  All engine internals should be fine as it's only done 11000km after the rebuild.  Never thought to check the curve, dunno why it was on 'Embassy', the manual reckons an even lower advance (30 degrees) for 1200 hi comp motors like mine.
 
no 6 was no 6
Embassy was Embassy
not the same oily rags, two different brands
my favourite  (until 30/06/1973 was Guards, or pack of cards if you savvy.
CLEM
 
Only the rainbow ones :-*
May be the cause of your Pinking.

Sorry, my bad, Cocktail, wouldn't want to be pulled up by the purists :D
 

Attachments

  • 87d8d949d86ab6fec7193f67d67ad5ff.jpg
    87d8d949d86ab6fec7193f67d67ad5ff.jpg
    33.2 KB · Views: 8
danger just because it said 99 oct on the pump doesn't mean thats what it gave you, due to economics if a delivery driver as 1000 lts of ron 95 that won't go in a filling station tank he will not take it back he will put it in the other tank(99oct) otherwise somebody will have to pay haulage.
  drain tank and refill.
 
laverdas said:
danger just because it said 99 oct on the pump doesn't mean thats what it gave you, due to economics if a delivery driver as 1000 lts of ron 95 that won't go in a filling station tank he will not take it back he will put it in the other tank(99oct) otherwise somebody will have to pay haulage.
  drain tank and refill.
Click to expand...
More commonly nown as a Shandy in the game  >:D
 
You must log in or register to reply here.
Back
Top