The Sportster and Buell Motorcycle Forum Lickscycles  

Go Back   The Sportster and Buell Motorcycle Forum > SPORTSTER MOTORCYCLE ZONE > Sportster Motorcycle Intake and Exhaust > Sportster Motorcycle Air intake, Carburetor, EFI, Fuel, and Exhaust
XLF Gallery XLF Classifieds XLF Blogs XLF Shout XLF Arcade XLF Disclaimer/Privacy Statement/Terms Of Use

Sportster Motorcycle Air intake, Carburetor, EFI, Fuel, and Exhaust Problems, advice and/or how tos for Sporster and Buell motorcycle carburators, Electronic Fuel Injection (EFI), Air Intake, Fuel and Exhaust.

Members Birthdays
seajay, Hugh Betcha (68), jimhd89 (65), JayFL459 (65), Big Al (58), dakota_dj (57), 10walt (55), kiltbill (55), timsvalk (54), horsewriter (49), Benetampa (37)
Figure Machine
Biltwell
Energy One Clutches
Foxcreek Leather

Licks Cycles
Reply
 
Share Thread Tools Display Modes
  #1  
Old 7th May 2012
MONTY MONTY is offline
Biker
 
Join Date: Aug 2009
Location: Warrington, UK
Posts: 16
Sportster/Buell Model: XL883
Sportster/Buell Year: 1991
Other Motorcycle Model: FL1200
Other Motorcycle Year: 1960
Reputation: 10
MONTY is an unknown quantity at this point
Default CV carb - spitting fuel back?

Ok, i never messed with an Evo CV before but since i got them working on Big Twins OK, what's the diff, right?

So i finally get round to "staging" my old '91 XL hack bike by swapping the stock air cleaner for a SE ham-can arrangement with a K&N filter in it and flat back-plate (like the old days, LOL).

I asked a mate for jetting suggestions and he said 48/185 which sounded a little thick (i have a Evo BT with the same jets, but a whole lot more cubes!), but he's more experienced than me so i went with it.

SO: bike runs fine, starts so easy and comes off the enricher a bit too quick, suggesting it's a bit rich. But what i don't understand is the puddle of fuel that keeps forming under the carb, inbetween the tappet blocks! First i thought i'd forgotten to tighten the hose clamp on the fuel line, but no - when i was checking that i could see the fuel was coming out of the carb itself, via the air cleaner. But, i thinks, if it were flooding (maybe got some shit in the float bowl and float valve isn't shutting properly) then fuel would come out of the overflow tube as well, and if i left the fuel on it would run out on the floor ... but it doesn't.

The bike does pop a little though the mufflers on overrun (but actually less than it used to), but i haven't heard it spit back in the carb, so where the hell is the fuel coming from, and how do i stop it? Is it the jetting, or have i screwed up something else?

Any help/suggestions appreciated!!

Cheers

p.s. i re-directed the breather away from the air cleaner - dunno what diff that would make but thought i'd mention it anyway!
__________________
MONTY

Work to ride, ride to work!
Reply With Quote
  #2  
Old 7th May 2012
LuxBlue's Avatar
LuxBlue LuxBlue is offline
Senior Master Custom Bike Builder
 
Join Date: Nov 2004
Location: South of Lancaster, PA
Posts: 4,051
Sportster/Buell Model: XL 1200 Custom
Sportster/Buell Year: 2004
Reputation: 285593
LuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond repute
Default

883? Try jetting at 42/165 or maybe 45/170. As far as the puddle...most likely crap in the needle valve or your accelerator pump diaphram is leaking.
__________________
Jester Mafia Member * TC88A Ignition With Rico's Jester III Map *
Reply With Quote
  #3  
Old 7th May 2012
nmbillb's Avatar
nmbillb nmbillb is offline
Senior Chief Know It All 1st Class
 
Join Date: Aug 2006
Location: Vado, NM
Posts: 1,134
Sportster/Buell Model: XL883C
Sportster/Buell Year: 1999
Other Motorcycle Model: Kawasaki Vulcan 500
Other Motorcycle Year: 1996
Reputation: 64508
nmbillb has much to be proud ofnmbillb has much to be proud ofnmbillb has much to be proud ofnmbillb has much to be proud ofnmbillb has much to be proud ofnmbillb has much to be proud ofnmbillb has much to be proud ofnmbillb has much to be proud ofnmbillb has much to be proud ofnmbillb has much to be proud ofnmbillb has much to be proud of
Default

I have the same problem...here's a vid I made a couple of years ago...fuel blows back out of the carb on accel. Probably jetted too rich.

__________________
Bill in Southern New Mexico - '99 XL883c
I miss Mr. Jimi!
RIP BryanEOD
When I carry a gun, I donít do so because Iím looking for a fight, but
because Iím looking to be left alone. - Marko Kloos

XLF Road Help [URL]http://xlforum.net/vbportal/forums/showthread.php?t=670716[/URL]

My recent accident [URL]http://xlforum.net/vbportal/forums/showthread.php?p=4397043#poststop[/URL]
Reply With Quote
  #4  
Old 8th May 2012
CharlieB's Avatar
CharlieB CharlieB is offline
Senior Chief Master Mechanic
 
Join Date: Jun 2009
Location: Deeply embedded in Florida swampland
Posts: 932
Sportster/Buell Model: XLH 1200
Sportster/Buell Year: 1994
Sportster/Buell Model #2: XLH 883 Deluxe - sold now
Sportster/Buell Year #2: 1986
Other Motorcycle Model: FXDWGi
Other Motorcycle Year: 2004
Reputation: 4114
CharlieB is just really niceCharlieB is just really niceCharlieB is just really niceCharlieB is just really niceCharlieB is just really niceCharlieB is just really niceCharlieB is just really niceCharlieB is just really niceCharlieB is just really niceCharlieB is just really niceCharlieB is just really nice
Default

Too rich? Reversion is more likely. What exhaust?
Reply With Quote
  #5  
Old 8th May 2012
MONTY MONTY is offline
Biker
 
Join Date: Aug 2009
Location: Warrington, UK
Posts: 16
Sportster/Buell Model: XL883
Sportster/Buell Year: 1991
Other Motorcycle Model: FL1200
Other Motorcycle Year: 1960
Reputation: 10
MONTY is an unknown quantity at this point
Default

Thanks for the replies guys.

Yes it's an 883, pipes are stock headers (with balance pipe under carb - doh!) and stock mufflers "messed up a bit". I've pretty much convinced myself it's not the needle valve as i can leave it standing with the fuel on and nothing happens, but the accel pump diaphragm sound possible, though i didn't mess with it at all so not sure why it would suddenly start leaking so bad ...

Lux, that jetting sounds pretty lean, in fact i think the first option you suggest (42/165) is leaner than the factory jets i took out! I'd have to check in the workshop when i get home (at work right now) but i think it was 42/170 (UK spec., as that's where i am).

Bill, that's an interesting video!! I can't for the life of me understand how opening the throttle makes fuel spray outwards that way, but if that's what's happening on mine then it would explain everything. I never thought to try running it with the filter off, but that's the first thing i'm gonna do tonight!

Thanks again
Reply With Quote
Know Thy Hog

  #6  
Old 8th May 2012
LuxBlue's Avatar
LuxBlue LuxBlue is offline
Senior Master Custom Bike Builder
 
Join Date: Nov 2004
Location: South of Lancaster, PA
Posts: 4,051
Sportster/Buell Model: XL 1200 Custom
Sportster/Buell Year: 2004
Reputation: 285593
LuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond reputeLuxBlue has a reputation beyond repute
Default

My 1200 with taxes paid...V&H short shots and Hurricane air filter is running 45/180. Your 883 doesn't need that much fuel.
Reply With Quote
  #7  
Old 8th May 2012
beuz's Avatar
beuz beuz is offline
Senior Master Custom Bike Builder
 
Join Date: Dec 2006
Location: Mennecy
Posts: 4,017
Sportster/Buell Model: SPORTSTER "old boy"
Sportster/Buell Year: 1997
Sportster/Buell Model #2: SPORTSTER CR (sold)
Sportster/Buell Year #2: 1998
Other Motorcycle Model: Suzuki GSF 650 Bandit
Other Motorcycle Year: 2006
Reputation: 324148
beuz has a reputation beyond reputebeuz has a reputation beyond reputebeuz has a reputation beyond reputebeuz has a reputation beyond reputebeuz has a reputation beyond reputebeuz has a reputation beyond reputebeuz has a reputation beyond reputebeuz has a reputation beyond reputebeuz has a reputation beyond reputebeuz has a reputation beyond reputebeuz has a reputation beyond repute
Default

175/42 with between 2.1/4 and 2.1/2 turns is perfect for a 883 carb.
__________________
You live more in 5 minutes flat out on a bike like this than most people do in a lifetime...
Burt Munro.
Reply With Quote
  #8  
Old 8th May 2012
MONTY MONTY is offline
Biker
 
Join Date: Aug 2009
Location: Warrington, UK
Posts: 16
Sportster/Buell Model: XL883
Sportster/Buell Year: 1991
Other Motorcycle Model: FL1200
Other Motorcycle Year: 1960
Reputation: 10
MONTY is an unknown quantity at this point
Default

Quote:
Originally Posted by LuxBlue View Post
My 1200 with taxes paid...V&H short shots and Hurricane air filter is running 45/180. Your 883 doesn't need that much fuel.
Yeah, it's certainly looking that way! Like i said though, i'm pretty sure it was a 42/170 combo i took out (need to check) so maybe i'll try something like 45/175.
Reply With Quote
  #9  
Old 8th May 2012
wedge's Avatar
wedge wedge is offline
Whitworth Products
 
Join Date: Jun 2010
Posts: 9,261
Sportster/Buell Model: 1200R
Sportster/Buell Year: 2005
Other Motorcycle Model: 5 bikes and 1 quad
Reputation: 680592
wedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond reputewedge has a reputation beyond repute
Default

Quote:
Originally Posted by MONTY View Post
Yeah, it's certainly looking that way! Like i said though, i'm pretty sure it was a 42/170 combo i took out (need to check) so maybe i'll try something like 45/175.
This is not how you determine jetting. It's much more of an exact science. You need to learn how to read plugs accurately (try reading "plug reading 101" in the sticky's), then you need to jet accordingly. There is a CV 101 in the sticky's (or a name similar to that) that will help you tune the carb once you know what the plugs are telling you.

First off, the main jet can be a 175 to start with because as long as it's more than you need you will be fine until you get to WOT, and that doesn't happen all that often in daily riding. You could throw the main jet away and the bike would run the same until you got to around 3/4 throttle.

The 42 pilot may be just fine, but if the plugs and the "feel" of the bike is asking for the 45 then you can tune to that pilot, but a 48 is way too big.

I would start with 42/175 and then read plugs, take some test runs, read plugs again, and tune it from there.

What you never want to do is just throw in jets that some dyno jockey says are right, because every engine and pipe/air cleaner combination is different.

I also think you need to open up that exhaust, because without doing that, your performance over stock will be almost the same as stock. Which means that you probably didn't need to alter the carb at all.

Oh, look back at Beuz's post. He suggested the 42/175 also. Sounds like a good starting point to me.
__________________
A Biker is not just any guy who rides... that's a motorist.
A guy that gets up and rides again after every crash... that's a Biker.

Whitworth Fork Brace: http://xlforum.net/vbportal/forums/m...outme&simple=1

Reply With Quote
  #10  
Old 8th May 2012
MONTY MONTY is offline
Biker
 
Join Date: Aug 2009
Location: Warrington, UK
Posts: 16
Sportster/Buell Model: XL883
Sportster/Buell Year: 1991
Other Motorcycle Model: FL1200
Other Motorcycle Year: 1960
Reputation: 10
MONTY is an unknown quantity at this point
Default

OK, did a quick look at running with filter off, blip the throttle but none of that spraying back in Bill's video, so at least that's a relief. Too damn tired to mess much else tonight, but i did check the jets i took out - my memory was wrong, they were 45/175!! So i checked in the Clymer manual, and sure enough, just for that one year (1991), all non-California 883s got 45/175 as stock.

I already checked the plugs couple days ago (yea i can read plugs, been riding and wrenching my own bikes 30+ years) after a coupla days riding on new set up, and actually they look OK, certainly no sign of being overly rich, not sooty or anything like that.

Wonder about even putting back the stock jets and seeing if that's not too lean but actually might be OK ...!
Reply With Quote
Know Thy Hog

Reply

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


Custom Search

All times are GMT +1. The time now is 06:12.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
XL Forum - Linson Media LLC