Rich after carb setup
Thread Starter
Senior Member
SuperSport
SuperSport
Joined: Aug 2007
Posts: 524
From: Tarpon Springs, FL
Rich after carb setup
All:
I've pored over every carb thread here, and I am still not sure what to do. I performed the stickied carb set up by 8451 Hawk, and now I am running very rich. After only 100 miles of riding my brand new pipes are sooty black and my garage smells rich, mpg is way down too. I leaned out the mixture screws to half turn in from the suggested 2.25 front and 2.5 rear; still rich, but this cured my stalling at abrupt deceleration, or at least made it better.
Haven't pulled plugs, but I know what richness smells like, lol. PAIR is deleted, and TPS is set. I am thinking about removing a shim on each needle, what do you think? Idle drop instead? I am riding the second full tank today, first tank was non-ethanol 90 octane. Would this make a difference? I filled up late last night with ethanol regular grade and I still only got 14 miles before the first block was gone from the fuel level indicator. I used to get about 20 to 25 miles before that happened. And I also used to get 115 miles before low level indicator flashed, first tank of non-ethanol got me 77. I wasn't heavy on the throttle, the beginning of that tank was used to dial in the MCCT's at warm up and sync the carbs.
All suggestions are appreciated.
I've pored over every carb thread here, and I am still not sure what to do. I performed the stickied carb set up by 8451 Hawk, and now I am running very rich. After only 100 miles of riding my brand new pipes are sooty black and my garage smells rich, mpg is way down too. I leaned out the mixture screws to half turn in from the suggested 2.25 front and 2.5 rear; still rich, but this cured my stalling at abrupt deceleration, or at least made it better.
Haven't pulled plugs, but I know what richness smells like, lol. PAIR is deleted, and TPS is set. I am thinking about removing a shim on each needle, what do you think? Idle drop instead? I am riding the second full tank today, first tank was non-ethanol 90 octane. Would this make a difference? I filled up late last night with ethanol regular grade and I still only got 14 miles before the first block was gone from the fuel level indicator. I used to get about 20 to 25 miles before that happened. And I also used to get 115 miles before low level indicator flashed, first tank of non-ethanol got me 77. I wasn't heavy on the throttle, the beginning of that tank was used to dial in the MCCT's at warm up and sync the carbs.
All suggestions are appreciated.
Former Superchicken Owner
SuperBike
Joined: Sep 2008
Posts: 1,607
From: Ft. Worth, TX
Yes, if the last thing you did was shim the needles, I would remove one possibly two. I believe that 8451Hawk has a disclaimer that this is a STARTING setup and that all bikes are different. Your idle should be 1200 per the service manual.
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MotoGP
Joined: Aug 2007
Posts: 5,942
From: Lake View Terrace, CA
Without knowing what your setting are I can only guess at what is causing the issues or where in the RPM range it is happening. (there is no listing of what jets you are running or how much you shimmed the needles)
So with the limited info I would guess that the needles are too high.
So with the limited info I would guess that the needles are too high.
Thread Starter
Senior Member
SuperSport
SuperSport
Joined: Aug 2007
Posts: 524
From: Tarpon Springs, FL
Sorry. Settings were front shimmed .050 total, 2.25 turns out. Rear .060 total shim stack, 2.5 turns out. 48 pilots and stock mains, slip on Leo's stock headers.
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Superstock
Joined: Oct 2011
Posts: 273
From: Pompano Beach, Fl.
Maybe the fuel in the float bowls is too high now. Maybe the float valves don't seal now and it will cause the rich condition you have. Maybe something happened to raise the fuel level in the carbs when they were out. I run the fuel screws at 1.5 turns out and there's no rich smell at all in the garage.
Last edited by zxbud; May 30, 2013 at 02:22 PM.
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MotoGP
Joined: Aug 2007
Posts: 5,942
From: Lake View Terrace, CA
Running different sized main will have a direct effect on how the pilots are set and also you can not adjust the float level in these carbs, if it is out of spec you replace the floats.
But none of these things should have suddenly gone bad..... work with the things you have changed already before you go off chasing phantom issues.
But none of these things should have suddenly gone bad..... work with the things you have changed already before you go off chasing phantom issues.
Former Superchicken Owner
SuperBike
Joined: Sep 2008
Posts: 1,607
From: Ft. Worth, TX
Running different sized main will have a direct effect on how the pilots are set and also you can not adjust the float level in these carbs, if it is out of spec you replace the floats.
But none of these things should have suddenly gone bad..... work with the things you have changed already before you go off chasing phantom issues.
But none of these things should have suddenly gone bad..... work with the things you have changed already before you go off chasing phantom issues.
Thread Starter
Senior Member
SuperSport
SuperSport
Joined: Aug 2007
Posts: 524
From: Tarpon Springs, FL
I'm not running different mains, just #48 pilots per the thread... Anyway, if my DIY float level gauge is to be believed, I am at the limit of spec, possibly a quarter to half millimeter out of apec! That being said...
The shims I had were various thicknesses, so I now have total shim stacks of: front .025 & rear .040 which seems ok, much better than previous. My mixture screws are at: front 1.75 turns out and the rear is a touch over 2, also much improved. Today's goal was to get my idle to be good, which it is. It's smooth and I can set it at 1,200 and it stays there, no hunting or surging, and pulls clean from just off idle. No stumble anywhere and some miniscule burbles on decel but definitely no more abrupt idle drop and stall when coming to a stop from normal speeds. I really was having lots of trouble at idle yesterday. Not just surging or hunting, I just had to turn it way up towards 1400 or more to keep her running good.
I just filled up and am leaving for my 60 mile round trip commute, let's see what I can see when I get her going as far as midrange and mpg.
Thanks guys! RWhisen, I really do think my floats are about ready for replacement, wouldn't have checked if not for your suggestion. Do the valves get replaced along with the plastic floats? I'd imagine so. The tip looks rubber and I'd guess the internal springs could wear too...
The shims I had were various thicknesses, so I now have total shim stacks of: front .025 & rear .040 which seems ok, much better than previous. My mixture screws are at: front 1.75 turns out and the rear is a touch over 2, also much improved. Today's goal was to get my idle to be good, which it is. It's smooth and I can set it at 1,200 and it stays there, no hunting or surging, and pulls clean from just off idle. No stumble anywhere and some miniscule burbles on decel but definitely no more abrupt idle drop and stall when coming to a stop from normal speeds. I really was having lots of trouble at idle yesterday. Not just surging or hunting, I just had to turn it way up towards 1400 or more to keep her running good.
I just filled up and am leaving for my 60 mile round trip commute, let's see what I can see when I get her going as far as midrange and mpg.
Thanks guys! RWhisen, I really do think my floats are about ready for replacement, wouldn't have checked if not for your suggestion. Do the valves get replaced along with the plastic floats? I'd imagine so. The tip looks rubber and I'd guess the internal springs could wear too...
Last edited by supermarto; Apr 29, 2013 at 10:23 AM.
Thread Starter
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SuperSport
SuperSport
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Posts: 524
From: Tarpon Springs, FL
Okay, still having problems down low. Meaning at idle... It runs pretty close to where I want it once it's warmed up, but getting there is a chore. It's much more cold blooded than I remember! Takes much choke, and if I shut the choke off before it's beyond 160 degrees, it's idles awfully low and wants to die. Once warm though, between 185 and 220, it's fantastic. I read all about Hawks that need no choke on start up and I am getting jealous! I also did MCCT's when I rejetted, could they be over tightened preventing a stall free idle? That would probably get worse though as it warmed up... I think it's my mixture screws. Gas economy is much improved, low level light still had yet to come on when I filled it up at almost 100 miles, where as it had started blinking at 77 miles previously. I almost feel like the front is now too lean and the rear is too rich. Next step will be to pull plugs when I can find the time to wrench.
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Superstock
Joined: Oct 2011
Posts: 273
From: Pompano Beach, Fl.
Okay, still having problems down low. Meaning at idle... It runs pretty close to where I want it once it's warmed up, but getting there is a chore. It's much more cold blooded than I remember! Takes much choke, and if I shut the choke off before it's beyond 160 degrees, it's idles awfully low and wants to die. Once warm though, between 185 and 220, it's fantastic. I read all about Hawks that need no choke on start up and I am getting jealous! I also did MCCT's when I rejetted, could they be over tightened preventing a stall free idle? That would probably get worse though as it warmed up... I think it's my mixture screws. Gas economy is much improved, low level light still had yet to come on when I filled it up at almost 100 miles, where as it had started blinking at 77 miles previously. I almost feel like the front is now too lean and the rear is too rich. Next step will be to pull plugs when I can find the time to wrench.
With #48 pilots and 2 turns out on the FS I'd be plenty rich in the low end and we're in the same climate, etc. There may be some dirt/obstruction in the low speed circuits causing a lean condition. In a few minutes I'm going to post a vid of the Hawk below to compare with. Engine will be cold started and choke is shut off within 100 yards of the house. Towards the end of the vid is a 3rd gear rollon. The sound is bad due to a vibration in the camera induced by the tank mount.
Senior Member
Superstock
Joined: Oct 2011
Posts: 273
From: Pompano Beach, Fl.
Vid
Here's the vid I mentioned. Cold start, choke off soon after but generally it's a right tuned Superhawk if not a fast one. It runs right in 3rd bottom to top and returned 46mpg at the next fillup. At the 4:45 mark is the roll on. I have a couple things yet to try concerning the top end but they don't involve pulling the carbs again. One of these days I'm going to install the high bars and then I won't know how to act 
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SuperBike
Joined: Aug 2005
Posts: 1,864
From: Fort Wayne, IN
First thing - switch back to stock #45 pilots. Every VTR I've ever tuned needed those. That includes just slip-ons, ones with full systems, and ones that were highly modified. Don't be afraid to draw down the screws to 1-1.5 turns if you need to also.
I would not shim the needles any more than 0.5mm/0.020in. Good luck!
I would not shim the needles any more than 0.5mm/0.020in. Good luck!
Senior Member
Superstock
Joined: May 2012
Posts: 397
From: UK
Out of curiosity do you guys mainly have 45 pilots as standard over there. In the UK we mainly have 48's as standard. It's only the early models 98 and 99 that had 45's, from 2000 onwards they came with 48's.
(:-})
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Thread Starter
Senior Member
SuperSport
SuperSport
Joined: Aug 2007
Posts: 524
From: Tarpon Springs, FL
First thing - switch back to stock #45 pilots. Every VTR I've ever tuned needed those. That includes just slip-ons, ones with full systems, and ones that were highly modified. Don't be afraid to draw down the screws to 1-1.5 turns if you need to also.
I would not shim the needles any more than 0.5mm/0.020in. Good luck!
I would not shim the needles any more than 0.5mm/0.020in. Good luck!
And I was thinking about going back to the #45 slows. I'll try to go low on the mixture screws... I also thought about that. I managed to pull the plugs, but I didn't do a true "chop" reading. Regardless, just as I suspected the rear looks kinda rich and the front looks pretty lean still. MPG has improved, but I am not getting ANYWHERE near 46 MPG. That's crazy, mang...
Thread Starter
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SuperSport
SuperSport
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Posts: 524
From: Tarpon Springs, FL
Bud, I suspect that was also true... this bike sat for almost three years with no stabilizer. I am cruel. It's now on it's fourth fill up and it's running better with each tank I run through it but it still needs help. I think I am gonna try to keep the #48 slow jets but dial back the mixture screws and see what happens. Would it be better to be rich on the pilots/lean on the screws, or better to be rich on the shims/leaner on the pilots by using the #45's? Or am I completely guessing and making a mockery of dynoing by "feel" LOL?
Last edited by supermarto; May 30, 2013 at 09:56 PM.
Member
Squid
Joined: May 2011
Posts: 64
From: SoCal
All:
I've pored over every carb thread here, and I am still not sure what to do. I performed the stickied carb set up by 8451 Hawk, and now I am running very rich. After only 100 miles of riding my brand new pipes are sooty black and my garage smells rich, mpg is way down too. I leaned out the mixture screws to half turn in from the suggested 2.25 front and 2.5 rear; still rich, but this cured my stalling at abrupt deceleration, or at least made it better.
Haven't pulled plugs, but I know what richness smells like, lol. PAIR is deleted, and TPS is set. I am thinking about removing a shim on each needle, what do you think? Idle drop instead? I am riding the second full tank today, first tank was non-ethanol 90 octane. Would this make a difference? I filled up late last night with ethanol regular grade and I still only got 14 miles before the first block was gone from the fuel level indicator. I used to get about 20 to 25 miles before that happened. And I also used to get 115 miles before low level indicator flashed, first tank of non-ethanol got me 77. I wasn't heavy on the throttle, the beginning of that tank was used to dial in the MCCT's at warm up and sync the carbs.
All suggestions are appreciated.
I've pored over every carb thread here, and I am still not sure what to do. I performed the stickied carb set up by 8451 Hawk, and now I am running very rich. After only 100 miles of riding my brand new pipes are sooty black and my garage smells rich, mpg is way down too. I leaned out the mixture screws to half turn in from the suggested 2.25 front and 2.5 rear; still rich, but this cured my stalling at abrupt deceleration, or at least made it better.
Haven't pulled plugs, but I know what richness smells like, lol. PAIR is deleted, and TPS is set. I am thinking about removing a shim on each needle, what do you think? Idle drop instead? I am riding the second full tank today, first tank was non-ethanol 90 octane. Would this make a difference? I filled up late last night with ethanol regular grade and I still only got 14 miles before the first block was gone from the fuel level indicator. I used to get about 20 to 25 miles before that happened. And I also used to get 115 miles before low level indicator flashed, first tank of non-ethanol got me 77. I wasn't heavy on the throttle, the beginning of that tank was used to dial in the MCCT's at warm up and sync the carbs.
All suggestions are appreciated.
I had the same problem. i removed stock shim from the front needle and messed with my fuel screw until it stopped the lean situation on the bottom end. also if your smelling fuel after you ride and then stop at a light then i would first try the fuel screw, start at 1.5 turns out like i did and go from there, im sure if im wrong then someone will chime in.
Senior Member
Superstock
Joined: Oct 2011
Posts: 273
From: Pompano Beach, Fl.
Pilots
Without a wideband exhaust sniffer it's guesswork. But, 48s with one turn out on f/s might be ok at 1/8 throttle cruising. You may also want to run fuel system cleaner through it for a while. I would. My setup is as perfect as anything I've ever owned and that includes several FI bikes. Heck, that VTX1800 weighs 800lb plus me and the windshield and it always turns 45mpg.
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Superstock
Joined: May 2012
Posts: 397
From: UK
48s with one turn out on f/s might be ok
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Thread Starter
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SuperSport
SuperSport
Joined: Aug 2007
Posts: 524
From: Tarpon Springs, FL
If you only have 1 turn out on the fuel screw then it's time to go up a size on the pilot jet. As for whether you use a 45 or 48 or even 50 will depend on what the settings are with mains and needles. With tunning CV carbs you start at the top with the mains and work you way down through the circuits finding what gives you the best speed and smooth pull. So get you needles sorted frst before moving onto the pilot circuit.
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Superstock
Joined: May 2012
Posts: 397
From: UK
Yep you right, sorry my mistake I got that the wrong way around. If only one turn out your at the minimum so go down a size which allows you to add more fuel by unscrewing the Fuel mixture screw more. If up to 3 turns out you want to go up a size which allows you to lean of the fuel mixture screw
Just another note, you will find the approximate Fuel screw settings according to pilots as follows give or take half a turn.
50's 1.5 turns out
48's 2.5 ---- ---
45's 3.5 ---- ---
you ideally want to be between 1 and 3 turns. Somewhere around the middle would be perfect. But like I said earlier get the needles right first.
(:-})
Just another note, you will find the approximate Fuel screw settings according to pilots as follows give or take half a turn.
50's 1.5 turns out
48's 2.5 ---- ---
45's 3.5 ---- ---
you ideally want to be between 1 and 3 turns. Somewhere around the middle would be perfect. But like I said earlier get the needles right first.
(:-})
Last edited by cybercarl; May 31, 2013 at 04:26 PM.
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