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sunbear |
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sunbear Could Be A Chat Bot
Joined: 12 Jul 2005 Karma :
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Posted: 14:54 - 13 Apr 2010 Post subject: Info needed on running lean / rich |
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Hey fellas,
This might sound thick, but it's something that I just can't grasp ...........
Can someone tell me the exact symptons of a bike running rich or lean ? And why it does this ?
Cheers ____________________ Bikes had : BMW F650, suzuki tr50, gt125, SV400, GSXR600 SRAD. Honda CBR900RRP, CBR600FX, CBR1000F, VT600, Transalp 600, mtx125, nsr125r, CB500T, Yamaha fy50, tzr125, tdr125, XV535, Diversion 600, Fazer 600, TDM850 MK1 & MK2, Majesty 400, XV 1100. Cagiva mito evolution, Aprilia rs125, Piaggio x9 125. DNA 125 . Suzuki Bandit 600, GZ125 Marauder, RF600 , RF900RS2, Kawasaki ZZR400, ZX6R Ninja, ZZR600 . Ducati 750 Sport . Triumph Tiger 955i. CURRENT : 2004 Kawasaki Z750 and LOVIN IT ! |
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P. |
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P. Red Rocket
Joined: 14 Feb 2008 Karma :
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Posted: 16:11 - 13 Apr 2010 Post subject: |
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my GS was running rich, basically dumping too much petrol into the cylinder.
Caused spark plugs to get ruined, wasted petrol and cost me more money
running lean is too much air/not enough fuel. I think lean is more dangerous than running an engine rich. |
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sunbear |
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sunbear Could Be A Chat Bot
Joined: 12 Jul 2005 Karma :
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Posted: 16:17 - 13 Apr 2010 Post subject: |
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Ok
But what are the actual physical symptons of each that you notice when riding ie.... popping on the overun, bogging down at certain revs....etc... ? ____________________ Bikes had : BMW F650, suzuki tr50, gt125, SV400, GSXR600 SRAD. Honda CBR900RRP, CBR600FX, CBR1000F, VT600, Transalp 600, mtx125, nsr125r, CB500T, Yamaha fy50, tzr125, tdr125, XV535, Diversion 600, Fazer 600, TDM850 MK1 & MK2, Majesty 400, XV 1100. Cagiva mito evolution, Aprilia rs125, Piaggio x9 125. DNA 125 . Suzuki Bandit 600, GZ125 Marauder, RF600 , RF900RS2, Kawasaki ZZR400, ZX6R Ninja, ZZR600 . Ducati 750 Sport . Triumph Tiger 955i. CURRENT : 2004 Kawasaki Z750 and LOVIN IT ! |
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P. |
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P. Red Rocket
Joined: 14 Feb 2008 Karma :
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cb1rocket |
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cb1rocket World Chat Champion
Joined: 30 Jan 2010 Karma :
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Howling Terror |
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Howling Terror Super Spammer
Joined: 05 Dec 2008 Karma :
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Odie |
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Odie World Chat Champion
Joined: 24 Jul 2004 Karma :
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Posted: 20:07 - 13 Apr 2010 Post subject: |
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Follow steps in order....First, dial in:
1. Top end (full throttle / 7.5k to redline - Best Main Jet be selected before starting step 2!
Select Best Main Jet
To get the best, most even top end power (full throttle/after 7500 rpm), select the main jet that produces the highest top speed / pulls hardest at high rpm.
If the bike pulls harder at high rpm when cold and less hard when fully warmed up, the main jet is too large. Install a smaller main jet and retest until you find the main jet that pulls the hardest at high rpm when fully warmed up. This must be done first - before moving on to the other tuning ranges.
If the bike doesn't pull well at high rpm when cold and gets only slightly better when fully warmed up, the main jet is too small.
In order to properly tune the midrange and low rpm carburetion, THE MAIN JET MUST FIRST BE PROPERLY SELECTED after 10 to 15 minutes of hard use!
Do not pay too much attention to the low-end richness when you are changing main jets - you still need to be using the main jets that produce the best power at high rpm. You will deal with the low-end / cruise later - after step 2.
2. Midrange (full throttle /5k-7k)
Select best needle clip position
To get the best power at full throttle / 5k-7k rpm, after you have already selected the best main jet,
If the engine pulls better on a full throttle roll-on starting at <3k, when cool but soft when at full operating temperature, it is too rich in the midrange and the needle should be lowered.
If the engine pulls better when fully warmed up but still not great between 5k-7k, try raising the needle to richen 5k-7k.
If the engine pulls equally well between 5k-7k when cooler as compared to fully warmed up, the needle height is probably properly set.
Do not pay too much attention to the low-end richness when you are changing needle clip positions - you still need to be using the clip position that produces the best full throttle / 5k-7k power in conjunction with the main jets that produce the best power at high rpm. You will deal with the low-end / cruise next.
3. Low end (full throttle / 2k-3k)
Float height (AKA fuel level & how to..)
To get best low-end power, set float height (fuel level) so that the engine will accept full throttle, without missing or stumbling, in 2nd gear from 2.5k to 3k rpm at minimum.
Float heights, unless otherwise specified in the installation guide, are measured from the "gasket surface" of the carb body to the highest part of the top of the float - with the float tang touching but not compressing the float valve spring.
If the engine has a "wet" rhythmic, soggy area at full throttle / 3k-4k rpm, that gets worse as the engine heats up, lower the fuel level by resetting the float height 1mm greater (if the original was 13mm - go to 14mm). This will lower the fuel level, making full throttle / 2k-3k rpm leaner.
If the engine is "dry" and flat between 2k to 3k rpm, raise the fuel level.
Example: change float height from 15mm to 14mm to richen up that area.
REMEMBER, since the main jet WILL affect low speed operation, the MAIN JET has to be within 1 or 2 sizes of correct before final float setting.
Warning: If the engine is left with the fuel level too high,, the engine may foul plugs on the street and will be "soft" and boggy at part throttle operation. Adjust Floats to raise/ lower the Fuel Level.
Base settings are usually given if a particular application has a history of fuel level criticalness. The Fuel level height in the float bowl affects full throttle/low rpm and, also, richness or leanness at cruise/low rpm.
Reference: a bike that runs cleanly at small throttle openings when cold, but starts to show signs of richness as it heats up to full operating temperature, will usually be leaned out enough to be correct if the fuel level is LOWERED 1mm. Check out and RESET all: Suzuki (all), Yamaha (all) and Kawasaki (if low speed problems occur). Needless to say, FUEL LEVEL IS EXTREMELY IMPORTANT!!!
If there are low-end richness problems, even after lowering the fuel level much more than 1.5mm from our initial settings, also check for needle wear and needle jet (part of the emulsion tube). See Worn Needle and Worn Needle Jet diagram. It is VERY common for the brass needle jets (in the top of the "emulsion tube") in 36mm, 38mm and 40mm Mikuni CV carbs to wear out in as little as 5,000 miles. Check them for "oblong" wear - the needle jet orifice starts out round! Factory Pro produces stock replacement needle jets / emulsion tubes for 36mm and 38mm Mikuni carbs.
4. Idle and low rpm cruise
Fuel Screw setting (AKA mixture screws)
There is usually a machined brass or aluminum cap over the fuel screws on all but newer Honda. It's about the diameter of a pencil. Cap removal details. Newer Honda carbs use a special "D" shaped driver, usually supplied in the carb recal kit.
Set for smoothest idle and 2nd gear, 4k rpm, steady state cruise operation. Set mixture screws at recommended settings, as a starting point. For smoothest idle, 2nd gear 4000 rpm steady state cruise , and 1/8 throttle high rpm operation.
Pilot fuel mixture screw settings, float level AND pilot jet size are the primary sources of mixture delivery during 4000 rpm steady state cruise operation.
If lean surging is encountered, richen mixture screws (turn out) in 1/2 turn increments. Alternative pilot jets are supplied when normally required.
Pilot fuel mixture screw settings, float level and pilot jet size also affect high-rpm, 0 to 1/8 throttle maneuvers. Too lean, will cause surging problems when the engine is operated at high rpm at small throttle openings! Opening the mixture screws and/or increasing pilot jet size will usually cure the problem.
NOTE: A rich problem gets worse as the engine heats up.
If the throttle is lightly "blipped" at idle, and the rpm drops below the set idle speed, then rises up to the set idle speed, the low speed mixture screws are probably set too rich: try 1/2 turn in, to lean the idle mixture.
NOTE: A lean problem gets better as the engine heats up.
If the throttle is lightly "blipped" at idle, and the rpm "hangs up" before dropping to the set idle speed, and there are no intake leaks and the idle speed is set at less than 1000 rpm, the mixture screws are probably too lean: try 1/2 turn out, to richen mixture. Be sure there are no intake leaks and the idle speed is set at less than 1000 rpm ____________________ You are so ugly when you were born the doctor said "I?m gonna drop it, if it falls is a rat, if it flies is a bat." |
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sunbear |
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sunbear Could Be A Chat Bot
Joined: 12 Jul 2005 Karma :
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Posted: 07:39 - 14 Apr 2010 Post subject: |
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Thanks for the replies fellas ____________________ Bikes had : BMW F650, suzuki tr50, gt125, SV400, GSXR600 SRAD. Honda CBR900RRP, CBR600FX, CBR1000F, VT600, Transalp 600, mtx125, nsr125r, CB500T, Yamaha fy50, tzr125, tdr125, XV535, Diversion 600, Fazer 600, TDM850 MK1 & MK2, Majesty 400, XV 1100. Cagiva mito evolution, Aprilia rs125, Piaggio x9 125. DNA 125 . Suzuki Bandit 600, GZ125 Marauder, RF600 , RF900RS2, Kawasaki ZZR400, ZX6R Ninja, ZZR600 . Ducati 750 Sport . Triumph Tiger 955i. CURRENT : 2004 Kawasaki Z750 and LOVIN IT ! |
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temeluchus |
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temeluchus World Chat Champion
Joined: 01 Oct 2008 Karma :
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Old Thread Alert!
The last post was made 14 years, 16 days ago. Instead of replying here, would creating a new thread be more useful? |
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