HPRE

Menu

Members Rides

Prof's new Moto Guzzi Breva 750


in
Members Rides

Welcome, Guest. Please login or register.
Did you miss your activation email?
October 25, 2014, 10:27:06 AM

Login with username, password and session length

 

Author Topic: Little Bit of Hunting when Accellerating  (Read 1573 times)

fredgold52

  • Grease Monkey
  • ****
  • Posts: 352
  • Karma: 0
  • Macomb, IL Flatlands Rule
Little Bit of Hunting when Accellerating
« on: April 17, 2008, 09:51:59 PM »
At this point my valves are set properly, and so is the ignition timing.  This is a 65 so there are points involved.  The carb is a little rich with a 27.5 pilot jet, 115 main jet and the needle set all the way rich (clip in lowest position).  It has a K&N filter, no PAV, and the stock muffler is drilled.

The bike starts and runs well.  Cruises nicely.  When I accelerate in like 4th gear at 1/2 or better throttle it seems to hunt a bit.  Hunt means it surges a little, then backs off, then surges, then backs off.  This is not a pronounced surge and backing off, but it is easily felt.

It almost feels like the spark advance mechanism is binding - actually I'm not sure it isn't.  Any ideas about what could cause this condition?  If I have a choice, I'd like more of the 'surge' and less of the 'backing off' feeling.  I am hoping some of you have encountered this sort of thing before.

Thanks,
Fred
2006 '65' and a 200cc Stella, Indian all the way

Charro

  • Bulleteer
  • ***
  • Posts: 104
  • Karma: 0
Re: Little Bit of Hunting when Accellerating
« Reply #1 on: April 18, 2008, 01:09:31 AM »
How does the plug look? You might be too rich.

Andy
2014 Continental GT (on order)
2004 Triumph Sprint RS
2004 Triumph Speed Four
2001 Triumph Bonneville
2006 Triumph Scrambler
2010 Vespa GTS
"Tell me what kind of horse you want to ride. I'll tell you what kind of rider you are." (Old Mexican proverb)

stipa

  • Grease Monkey
  • ****
  • Posts: 254
  • Karma: 0
Re: Little Bit of Hunting when Accellerating
« Reply #2 on: April 18, 2008, 04:36:37 AM »
Is it a continuous surging or is it a once or twice thing?  Sure your clutch isn't slippling a bit?  Especially when you romp on it?


fredgold52

  • Grease Monkey
  • ****
  • Posts: 352
  • Karma: 0
  • Macomb, IL Flatlands Rule
Re: Little Bit of Hunting when Accellerating
« Reply #3 on: April 18, 2008, 12:37:26 PM »
The plug is black around the metal part but light grey on the porcelain.  It is a bit too rich, but I don't think it's badly so.

Stipa, I generally roll the throttle on up to 1/2 or 3/4.  The hunting occurs during acceleration.
2006 '65' and a 200cc Stella, Indian all the way

Charro

  • Bulleteer
  • ***
  • Posts: 104
  • Karma: 0
Re: Little Bit of Hunting when Accellerating
« Reply #4 on: April 18, 2008, 05:36:30 PM »
Fred, try moving the needle c-clip up 1 to 2 notches see if it helps. At 1/2 throttle that might be your over richness.

Andy
2014 Continental GT (on order)
2004 Triumph Sprint RS
2004 Triumph Speed Four
2001 Triumph Bonneville
2006 Triumph Scrambler
2010 Vespa GTS
"Tell me what kind of horse you want to ride. I'll tell you what kind of rider you are." (Old Mexican proverb)

fredgold52

  • Grease Monkey
  • ****
  • Posts: 352
  • Karma: 0
  • Macomb, IL Flatlands Rule
Re: Little Bit of Hunting when Accellerating
« Reply #5 on: April 18, 2008, 09:28:02 PM »
I'll try it at one notch up from the bottom to see how it does.  At 2 up from the bottom or the center position, it has no power in mid range at all.
2006 '65' and a 200cc Stella, Indian all the way

Spitting Bull

  • Grand Gearhead
  • *****
  • Posts: 535
  • Karma: 0
Re: Little Bit of Hunting when Accellerating
« Reply #6 on: April 19, 2008, 11:30:59 PM »
I had a very similar problem not long ago.  I got the hunting when the bike was held at a steady speed, with not too may revs.

This didn't happen on accelleration like your problem, but I wonder if it's the same thing?  The instant cure was a new battery.

Tom
One cylinder is enough for anyone.

bob bezin

  • Grand Gearhead
  • *****
  • Posts: 1172
  • Karma: 0
  • I ride therefore I am.
Re: Little Bit of Hunting when Accellerating
« Reply #7 on: April 20, 2008, 12:01:46 PM »
there were some other threads  that talked about  a new battery curing several kinds of simptoms of bad running, my jeep started running poorly so i got new plugs wires and cap it only got worse, then the battery would go dead if it sat a day or two, i tried two other batteries i had kept charged on a battery tender all winter no help then suspecting that these batteries wernt good i tried one from my tractor that was very new and thet i knew was good, wallah! started right up ideled fine ran good , went to town and bought a new battery for it .
2000 RE classic ,              56 matchless g80
2006 RE delux fireball       86 yamaha SRX 600
65 500cctriumph
04 bonnie black
71 750 norton.
48 whizzer

fredgold52

  • Grease Monkey
  • ****
  • Posts: 352
  • Karma: 0
  • Macomb, IL Flatlands Rule
Re: Little Bit of Hunting when Accellerating
« Reply #8 on: April 20, 2008, 05:43:50 PM »
I just spent maybe an hour messing with the carb tuning.  I did each of these things one at a time and test rode in between.  Moved the needle clip up one notch to the 2 up from the bottom position.  Changed from a 120 main to a 125 main.  Changed from a 125 main to a 130 main. 

The result of these changes is that the hunting is gone.  Throttle responce at low speeds is much improved.  Top end is essentially unchanged at slightly more than indicated 70.  At this point I am very satisfied with how it runs.  I may try to raise the needle clip to the center position and go back to the 125 main.  For right now, it runs good and I'm tired of taking the carb off and putting it back on.

So, in summary; My engine was in fact hunting - hunting for gas that is.  A richer main jet was all that was needed to straighten this out.  More fine tuning to come later - of course.    :)
2006 '65' and a 200cc Stella, Indian all the way

Charro

  • Bulleteer
  • ***
  • Posts: 104
  • Karma: 0
Re: Little Bit of Hunting when Accellerating
« Reply #9 on: April 21, 2008, 12:28:30 AM »
Good job Fred, looks like your close.

Andy
2014 Continental GT (on order)
2004 Triumph Sprint RS
2004 Triumph Speed Four
2001 Triumph Bonneville
2006 Triumph Scrambler
2010 Vespa GTS
"Tell me what kind of horse you want to ride. I'll tell you what kind of rider you are." (Old Mexican proverb)

fredgold52

  • Grease Monkey
  • ****
  • Posts: 352
  • Karma: 0
  • Macomb, IL Flatlands Rule
Re: Little Bit of Hunting when Accellerating
« Reply #10 on: April 21, 2008, 03:49:51 PM »
OH YEAH!!!  Now it's got much more mid range poop.  I don't care much about the top end but the new acceleration ability is much welcomed.
2006 '65' and a 200cc Stella, Indian all the way