HPRE

Menu

Members Rides

7" Lucas Headlight


in
Members Rides

Welcome, Guest. Please login or register.
Did you miss your activation email?
October 22, 2014, 03:46:53 PM

Login with username, password and session length

 

Author Topic: Running a tad rich  (Read 5859 times)

RagMan

  • Bulleteer, Uralist &
  • Grand Gearhead
  • *****
  • Posts: 819
  • Karma: 0
Running a tad rich
« on: July 29, 2007, 03:22:56 AM »
Which way to tweak the carb, to lean it up a tad. clockwise or otherwise???
aka Indiana Bulleteer.
''99 Classic Bullet. '05 Ural Tourist sidecar rig, converted to 2wd. '05 Harley Davidson Sportster.
Jefferson County, WA

Leonard

  • Grand Gearhead
  • *****
  • Posts: 1278
  • Karma: 0
  • I love this bike!!
Re: Running a tad rich
« Reply #1 on: July 29, 2007, 11:41:00 AM »
Which way to tweak the carb, to lean it up a tad. clockwise or otherwise???

Are you talking about the idle/pilot jet?  If so this quote from Snidal"s manual would apply:
"The pilot jet is an "air bleed" - tightening it makes for richness, loosening leans it out."

Leonard
2009 Triumph Bonneville T100
2004 Royal Enfield Sixty-5 (RIP)
2001 Kawasaki W650 (going, going...gone)
http://www.romeoriders.com

RagMan

  • Bulleteer, Uralist &
  • Grand Gearhead
  • *****
  • Posts: 819
  • Karma: 0
Re: Running a tad rich
« Reply #2 on: July 29, 2007, 12:52:55 PM »
Thank you, that sounds like the thing.  Being somewhat ignorant of technical matters, and foreign, I have no clue what the correct names of things are. The idle is marginally high, which makes starting easier, but running tends to be a bit sooty, and deceleration causes minor soft 'pops'  Unless I am totally wrong, which is possible, such symptoms can be made by a rich running engine.
aka Indiana Bulleteer.
''99 Classic Bullet. '05 Ural Tourist sidecar rig, converted to 2wd. '05 Harley Davidson Sportster.
Jefferson County, WA

deejay

  • Guest
Re: Running a tad rich
« Reply #3 on: July 29, 2007, 12:55:06 PM »
You can lower your needle too.

RagMan

  • Bulleteer, Uralist &
  • Grand Gearhead
  • *****
  • Posts: 819
  • Karma: 0
Re: Running a tad rich
« Reply #4 on: July 29, 2007, 12:59:38 PM »
Thank you, deejay, how do I do that..  My P Snidal book has not arrived yet.
aka Indiana Bulleteer.
''99 Classic Bullet. '05 Ural Tourist sidecar rig, converted to 2wd. '05 Harley Davidson Sportster.
Jefferson County, WA

deejay

  • Guest
Re: Running a tad rich
« Reply #5 on: July 29, 2007, 01:06:34 PM »
I removed my tank to get to the top of the carb. Screw the top of the carb off by hand, then you can remove the cable, and the slide. Under the slide sits the needle, take it out, there is a clip on the needle that you can move up or down on 5 or 6 notches. If the clip is on the bottom notch, it is raised to the maximum, allowing more gas to pass by it. If the clip is at the top notch on the needle, it is at its lowest position, allowing less gas to pass by it.

This may seem confusing, but when you have the top of the carb off, it will become painfully obvious how it works.

RagMan

  • Bulleteer, Uralist &
  • Grand Gearhead
  • *****
  • Posts: 819
  • Karma: 0
Re: Running a tad rich
« Reply #6 on: July 29, 2007, 02:03:37 PM »
Thank you. That sounds logical. I will try the idle jet tweak, if it still pops, I will mess with the needle. If I am not careful, I will turn into a bike mechanic. :)
aka Indiana Bulleteer.
''99 Classic Bullet. '05 Ural Tourist sidecar rig, converted to 2wd. '05 Harley Davidson Sportster.
Jefferson County, WA

justin_o_guy

  • Bulleteer
  • ***
  • Posts: 112
  • Karma: 0
Re: Running a tad rich
« Reply #7 on: July 29, 2007, 05:49:31 PM »
I thought "Pops" were generally a lean burn indicator. If the inside of the exhaust is dark sooty, then rich it is, but if its got very little soot & its a lighter color, then rich it isnt. A look at the plug might be a good idea, too. Much less expensive then a scorched piston.

RagMan

  • Bulleteer, Uralist &
  • Grand Gearhead
  • *****
  • Posts: 819
  • Karma: 0
Re: Running a tad rich
« Reply #8 on: July 29, 2007, 07:19:50 PM »
Real sooty exhaust...  someday, when it arrives, I will read the Snidal book cover to cover, at least 10 times, so that I turn into a knowledgeable person..  I unfortunately have limited mechanical experience, most of which was over 30 years ago.
aka Indiana Bulleteer.
''99 Classic Bullet. '05 Ural Tourist sidecar rig, converted to 2wd. '05 Harley Davidson Sportster.
Jefferson County, WA

deejay

  • Guest
Re: Running a tad rich
« Reply #9 on: July 29, 2007, 11:51:12 PM »
Best way to tell is a plug chop. Make sure the plug is new.

RagMan

  • Bulleteer, Uralist &
  • Grand Gearhead
  • *****
  • Posts: 819
  • Karma: 0
Re: Running a tad rich
« Reply #10 on: July 30, 2007, 12:14:24 AM »
I will be getting a box of plugs this week so will have me a look see then.
aka Indiana Bulleteer.
''99 Classic Bullet. '05 Ural Tourist sidecar rig, converted to 2wd. '05 Harley Davidson Sportster.
Jefferson County, WA

gapl53

  • Guest
Re: Running a tad rich
« Reply #11 on: July 31, 2007, 03:47:05 PM »
Remember;
Idle adjustment affects how the engine runs from idle to midrange, changing the needle clip position affects the midrange. The high speed jet effect the engine from 3/4 to full throttle.
The high speed jet should be correct before making any other adjustment to the carburetor.
If the high speed is correct, then adjust the midrange, low speed mixture and idle speed in that order. Just don't have the idle set over 1200RPM when adjusting the low speed mixture. At about this point, depending on needle height, you will start the transition to midrange.

RagMan

  • Bulleteer, Uralist &
  • Grand Gearhead
  • *****
  • Posts: 819
  • Karma: 0
Re: Running a tad rich
« Reply #12 on: July 31, 2007, 07:25:16 PM »
Thank you for that clarification - I have the Snidal manual on hand so I will be reading a lot from now on.
aka Indiana Bulleteer.
''99 Classic Bullet. '05 Ural Tourist sidecar rig, converted to 2wd. '05 Harley Davidson Sportster.
Jefferson County, WA

gapl53

  • Guest
Re: Running a tad rich
« Reply #13 on: August 01, 2007, 04:19:27 PM »
For future reference, popping or a backfire in the carburetor is an indication of a lean running, or to far advance timing. Popping or a backfire in the muffler indicates a overly rich condition. But a single back fire in the exhaust when you suddenly close the throttle is normal. This is due to the fact that when the carburetor is suddenly closed for an instant it causes an overly rich mixture because the slide blocks the air flow. The overly rich mixture will not combust in the cylinder under compression due to the lack of oxygen needed. But once that mixture is moved to the exhaust pipe where there is more oxygen available, it has a chance to ignite from the following combustion stroke.
 
I love the art and science of tuning.

RagMan

  • Bulleteer, Uralist &
  • Grand Gearhead
  • *****
  • Posts: 819
  • Karma: 0
Re: Running a tad rich
« Reply #14 on: August 01, 2007, 06:40:21 PM »
Reading this manual is giving me a warm feeling.. sounds silly, but I think I am going to be able to do this stuff without too much problem.
aka Indiana Bulleteer.
''99 Classic Bullet. '05 Ural Tourist sidecar rig, converted to 2wd. '05 Harley Davidson Sportster.
Jefferson County, WA

Leonard

  • Grand Gearhead
  • *****
  • Posts: 1278
  • Karma: 0
  • I love this bike!!
Re: Running a tad rich
« Reply #15 on: August 01, 2007, 10:43:21 PM »
But a single back fire in the exhaust when you suddenly close the throttle is normal.

I don't have any facts or theories to back me up but I respectfully disagree. ???  It just doesn't seem right that you would normally get an exhaust backfire when you suddenly close the throttle.  Maybe someone with more knowledge than I can argue my gut feeling.

Leonard
2009 Triumph Bonneville T100
2004 Royal Enfield Sixty-5 (RIP)
2001 Kawasaki W650 (going, going...gone)
http://www.romeoriders.com

gapl53

  • Guest
Re: Running a tad rich
« Reply #16 on: August 02, 2007, 03:28:46 AM »
But a single back fire in the exhaust when you suddenly close the throttle is normal.

I don't have any facts or theories to back me up but I respectfully disagree. ???  It just doesn't seem right that you would normally get an exhaust backfire when you suddenly close the throttle.  Maybe someone with more knowledge than I can argue my gut feeling.

Leonard
All air cooled engines will do this do to the higher heat factors, (most air cooled engines cylinder heads will normally run between 260 and 340 degrees Fahrenheit, depending on design. For reference paper ignites at 400 degrees Fahrenheit), being transfered to the overly rich mixture  which does not have enough oxygen to ignite in the combustion chamber. This rich mixture will ignite when reaching the exhaust pipe due to the fact that energy wave from the previous combustion episode has collapsed at the open end of the exhaust pipe. When this collapse occurs the energy wave will return back up the exhaust pipe bringing with it additional oxygen in the form of air. This additional oxygen mixes with the rich mixture in the pipe to so to speak lean the mixture enough to cause ignition when the next combustion event spill high heat into the pipe during exhaust.
At the other end of the engine you have the carburetor which works on the venturi principle of air passing over the passages leading to the diffrent mixture circuits and related jets which meter the fuel. This causes a lower pressure or vacuum to occur which pulls fuel into the air stream and down to the engine and into the cylinder where combustion can occur. Air has weight, in fact when they say the proper air fuel ratio is 15 to 1 the proper measurement is 15lbs of air to 1lbs of fuel. The mixture once in motion down the intake channel does not like to turn corners or stop. This is key to the fact that when you shut the throttle quickly the mixture that is between the throttle slide and the combustion chamber keeps moving which cause a vacuum behind it at the carburetor. This in turn draws a larger than normal amount of fuel into the combustion chamber causing the overly rich mixture which cannot be ignited due to the lack of the proper amount of oxygen. We are now back at the beginning where the unburnt mixture enters the exhaust pipe where the returning energy wave brings with it oxygen in the form of air from out side the pipe.
In fact if you read up on RAM tuning it will explain how these pressure waves work.
You always need to keep these in mind when tuning an engine for maximum performance.

Leonard

  • Grand Gearhead
  • *****
  • Posts: 1278
  • Karma: 0
  • I love this bike!!
Re: Running a tad rich
« Reply #17 on: August 03, 2007, 09:46:29 AM »
So would the backfire be more likely to occur with an overly rich mixture?  I'm still trying to wrap my mind around the normal condition.  Would a by the book tuned bike with minimal upgrades (less restrictive exhaust and K & N filter, larger main) be likely to backfire when shutting off the throttle?

REgards,
Leonard
2009 Triumph Bonneville T100
2004 Royal Enfield Sixty-5 (RIP)
2001 Kawasaki W650 (going, going...gone)
http://www.romeoriders.com

hutch

  • Grease Monkey
  • ****
  • Posts: 380
  • Karma: 0
  • Til death do us part
Re: Running a tad rich
« Reply #18 on: August 03, 2007, 02:10:45 PM »
On a Suzuki Savage they backfire on deceleration in the pipe due to a lean condition. To make them quit backfiring you richen them up and seal any loose exhuast to head fittings so they don't get extra air in the pipe and cause a backfire. The same goes for Harley and Triumph. My 05 Bullet backfired out the pipe when I put a KN air filter on and free flowing pipe. After putting in larger pilot and main jets the backfire went away, and I still get 80mpg.       Hutch
« Last Edit: August 03, 2007, 02:16:20 PM by hutch »
You learn from your mistakes, and I have LEARNED a lot.

gapl53

  • Guest
Re: Running a tad rich
« Reply #19 on: August 05, 2007, 02:00:07 PM »
So would the backfire be more likely to occur with an overly rich mixture?  I'm still trying to wrap my mind around the normal condition.  Would a by the book tuned bike with minimal upgrades (less restrictive exhaust and K & N filter, larger main) be likely to backfire when shutting off the throttle?

REgards,
Leonard
Well will your air cooled lawn mower pop when you suddenly close the throttle from fast to slow in a hurry after mowing for awhile. It's is caused by the same dynamics and considered perfectly normal. It is always more pronounced in a single cylinder engine, and the larger the engine or the freer flowing the exhaust the larger the pop.

dewjantim

  • Grease Monkey
  • ****
  • Posts: 430
  • Karma: 0
Re: Running a tad rich
« Reply #20 on: August 05, 2007, 04:49:49 PM »
My bike pops when I let off the throttle. Usually it seems that my bikes do this with a straight through exhaust or drag pipes. The bike runs really good so Im not messing with the jets anymore, it also gets fantastic gas mileage and the plug looks perfect.  I kinda like the backfiring, hehehe........Dew.
If it hurts, you're not dead yet!!!!!

Leonard

  • Grand Gearhead
  • *****
  • Posts: 1278
  • Karma: 0
  • I love this bike!!
Re: Running a tad rich
« Reply #21 on: August 05, 2007, 11:11:03 PM »
So would the backfire be more likely to occur with an overly rich mixture?  I'm still trying to wrap my mind around the normal condition.  Would a by the book tuned bike with minimal upgrades (less restrictive exhaust and K & N filter, larger main) be likely to backfire when shutting off the throttle?

REgards,
Leonard
Well will your air cooled lawn mower pop when you suddenly close the throttle from fast to slow in a hurry after mowing for awhile. It's is caused by the same dynamics and considered perfectly normal. It is always more pronounced in a single cylinder engine, and the larger the engine or the freer flowing the exhaust the larger the pop.

  Can't say that it ever has, no.  It does sometime backfire if I turn off the ignition too quickly before it idles down a little bit.  Same thing I suppose.
  I don't want to belabor the subject, my bike doesn't normally backfire when I shut off the throttle and I like it that way.  I was just trying to understand why it would be considered normal when everything I have ever heard claims that a backfire is not a good thing to happen.

Best,
Leonard
--Leonard
2009 Triumph Bonneville T100
2004 Royal Enfield Sixty-5 (RIP)
2001 Kawasaki W650 (going, going...gone)
http://www.romeoriders.com

RagMan

  • Bulleteer, Uralist &
  • Grand Gearhead
  • *****
  • Posts: 819
  • Karma: 0
Re: Running a tad rich
« Reply #22 on: August 06, 2007, 01:25:44 AM »
The noise mine makes is not a backfire, exactly  - just a repetitious pop.
aka Indiana Bulleteer.
''99 Classic Bullet. '05 Ural Tourist sidecar rig, converted to 2wd. '05 Harley Davidson Sportster.
Jefferson County, WA

gapl53

  • Guest
Re: Running a tad rich
« Reply #23 on: August 06, 2007, 04:18:14 PM »
So would the backfire be more likely to occur with an overly rich mixture?  I'm still trying to wrap my mind around the normal condition.  Would a by the book tuned bike with minimal upgrades (less restrictive exhaust and K & N filter, larger main) be likely to backfire when shutting off the throttle?

REgards,
Leonard
Well will your air cooled lawn mower pop when you suddenly close the throttle from fast to slow in a hurry after mowing for awhile. It's is caused by the same dynamics and considered perfectly normal. It is always more pronounced in a single cylinder engine, and the larger the engine or the freer flowing the exhaust the larger the pop.

  Can't say that it ever has, no.  It does sometime backfire if I turn off the ignition too quickly before it idles down a little bit.  Same thing I suppose.
  I don't want to belabor the subject, my bike doesn't normally backfire when I shut off the throttle and I like it that way.  I was just trying to understand why it would be considered normal when everything I have ever heard claims that a backfire is not a good thing to happen.

Best,
Leonard
--Leonard
Trust me, I'm not saying there is anything wrong with the bike not back firing. If it is a stock Enfield, you wouldn't hear it if it did due to the over enthusiastic silencer that is in place. If you put a free flowing exhaust on don't be surprised if you hear an pop through the exhaust pipe. That is normal. But normal is a relative term, every engine is different, as with anything in life moderation is a good thing. If it is continuous, better check your ignition timing (overly retarded, firing way after TDC ), exhaust valve clearance (not enough clearance can hold open the exhaust valve), or your valve timing, which can be change slightly on the Enfield's by adjusting the valve gear backlash (if the valve backlash is improperly adjusted it can cause the exhaust valve to open to soon).
If you watch NASCAR on television, during the short track races (they back off the throttle a lot more than on the super speedways) you will notice flames coming out the exhaust, watch the shots of the right side of the race car, when they enter the corner and back off the throttle. You will see flames coming out the exhaust headers, that is in reality a backfire. If you were standing at that point in the track, you will hear the popping. Which is more like a rumble with multiple cylinders being exhausted so close together