Keihin CV carb. Stage 1 or stock jets and emulsion tube (jet holder)
#1
10-31-2011, 01:30 PM
Keihin CV carb. Stage 1 or stock jets and emulsion tube (jet holder)
Keihin CV carb
For first time removed float bowl on '99 FLHTC carburetor to remove jets to clean them and the accelerator pump. A month after new in 1998 a Stage 1 kit was added along with HD free-er flowing mufflers. Stage 1 may have been Dyno-Jet or Screamin Eagle version.
Main jet stubborn to remove, screwdrivers kept spinning out; when main jet came out it was stuck in jet holder/emulsion tube, the jets screwdriver slot somewhat stripped. Jet still couldn't be removed from tube. No big deal, been 12 years, will get replacements if it doesn't run right.
Looking at the HD repair manual it shows the emulsion tube with several to a dozen bleed holes. Mine has 2. Jet doesn't have the jet size that you can see.
Might get new main jet and emulsion tube and need to figure? try stock HD jet size and stock jet holder, or different size or ? are there different jet holder tube sizes. Don't know if what I removed was stock or what came in Stage 1 kit. Welsh plug for access to air idle screw is removed and idle air mix is adjustable. Engine stock. Altitude about 100'. Somewhere in garage are extra parts and/or original parts from when Stage 1 was installed. Never been 100% happy with the tune on it, seemed to backfire too often on sudden deceleration even when warm.
What about 4 screws to replace the four phillips but with allen or torx wrench fit. And the 3 accelerator pump screws.
For first time removed float bowl on '99 FLHTC carburetor to remove jets to clean them and the accelerator pump. A month after new in 1998 a Stage 1 kit was added along with HD free-er flowing mufflers. Stage 1 may have been Dyno-Jet or Screamin Eagle version.
Main jet stubborn to remove, screwdrivers kept spinning out; when main jet came out it was stuck in jet holder/emulsion tube, the jets screwdriver slot somewhat stripped. Jet still couldn't be removed from tube. No big deal, been 12 years, will get replacements if it doesn't run right.
Looking at the HD repair manual it shows the emulsion tube with several to a dozen bleed holes. Mine has 2. Jet doesn't have the jet size that you can see.
Might get new main jet and emulsion tube and need to figure? try stock HD jet size and stock jet holder, or different size or ? are there different jet holder tube sizes. Don't know if what I removed was stock or what came in Stage 1 kit. Welsh plug for access to air idle screw is removed and idle air mix is adjustable. Engine stock. Altitude about 100'. Somewhere in garage are extra parts and/or original parts from when Stage 1 was installed. Never been 100% happy with the tune on it, seemed to backfire too often on sudden deceleration even when warm.
What about 4 screws to replace the four phillips but with allen or torx wrench fit. And the 3 accelerator pump screws.
#2
10-31-2011, 02:01 PM
Keihin CV carb
For first time removed float bowl on '99 FLHTC carburetor to remove jets to clean them and the accelerator pump. A month after new in 1998 a Stage 1 kit was added along with HD free-er flowing mufflers. Stage 1 may have been Dyno-Jet or Screamin Eagle version.
Main jet stubborn to remove, screwdrivers kept spinning out; when main jet came out it was stuck in jet holder/emulsion tube, the jets screwdriver slot somewhat stripped. Jet still couldn't be removed from tube. No big deal, been 12 years, will get replacements if it doesn't run right.
Looking at the HD repair manual it shows the emulsion tube with several to a dozen bleed holes. Mine has 2. Jet doesn't have the jet size that you can see.
Might get new main jet and emulsion tube and need to figure? try stock HD jet size and stock jet holder, or different size or ? are there different jet holder tube sizes. Don't know if what I removed was stock or what came in Stage 1 kit. Welsh plug for access to air idle screw is removed and idle air mix is adjustable. Engine stock. Altitude about 100'. Somewhere in garage are extra parts and/or original parts from when Stage 1 was installed. Never been 100% happy with the tune on it, seemed to backfire too often on sudden deceleration even when warm.
What about 4 screws to replace the four phillips but with allen or torx wrench fit. And the 3 accelerator pump screws.
For first time removed float bowl on '99 FLHTC carburetor to remove jets to clean them and the accelerator pump. A month after new in 1998 a Stage 1 kit was added along with HD free-er flowing mufflers. Stage 1 may have been Dyno-Jet or Screamin Eagle version.
Main jet stubborn to remove, screwdrivers kept spinning out; when main jet came out it was stuck in jet holder/emulsion tube, the jets screwdriver slot somewhat stripped. Jet still couldn't be removed from tube. No big deal, been 12 years, will get replacements if it doesn't run right.
Looking at the HD repair manual it shows the emulsion tube with several to a dozen bleed holes. Mine has 2. Jet doesn't have the jet size that you can see.
Might get new main jet and emulsion tube and need to figure? try stock HD jet size and stock jet holder, or different size or ? are there different jet holder tube sizes. Don't know if what I removed was stock or what came in Stage 1 kit. Welsh plug for access to air idle screw is removed and idle air mix is adjustable. Engine stock. Altitude about 100'. Somewhere in garage are extra parts and/or original parts from when Stage 1 was installed. Never been 100% happy with the tune on it, seemed to backfire too often on sudden deceleration even when warm.
What about 4 screws to replace the four phillips but with allen or torx wrench fit. And the 3 accelerator pump screws.
I have replaced the four bowl screws and three accel pump screws with allen heads on every CV carb I have worked. Lowes, Home Depot or any hardware store has them. Backfiring on decel could be leaking exhaust manifolds or loose muffler to head pipe joints. Some hi temp RTC silicone at the muffler slip joint will help. Check exhaust flanges,maybe install new exhaust gaskets. Backfire could also indicate rich or lean condition but I would suspect rich first; unspent fuel hitting hi temps in the muffler and igniting.
#3
10-31-2011, 02:04 PM
#4
10-31-2011, 02:05 PM
Not knowing exactly what you have in there now or just guessing at it, I would suggest that you purchase a new dyno-jet kit for approx. $100 bucks and follow the directions. ....but I have listed the stock parts for your convenience. These are still available and the prices listed are for each piece.
27146-89 Accelerator pump screws $1.50 MSRP (3) needed
27579-88A Fuel Bowl screws $2.00 (4) needed
27101-88 Emulsifier Tube $8.00
27100-88 "Collett" actually "needle jet" sits above emulsion tube $8.00
27090-89 Main Jet Stock 1.75mm $6.75
27146-89 Accelerator pump screws $1.50 MSRP (3) needed
27579-88A Fuel Bowl screws $2.00 (4) needed
27101-88 Emulsifier Tube $8.00
27100-88 "Collett" actually "needle jet" sits above emulsion tube $8.00
27090-89 Main Jet Stock 1.75mm $6.75
#5
10-31-2011, 02:33 PM
NO
the dyno jet kit is junk
the yost kit is junk ( which may be your emulsion tube, I won't bother pulling a carb apart to count, but I'd guess the emulsion tube has 12 to 16 holes)
4mm allens make for easy bowl dropping with carb in place, use a hand mirror to see when changing the jets. use antisieze on the screws.
The very common sportster needle and drilled .125" slide work well, in addition I chamfer the leading edge of the slide and polishit as best i can by hand the 2 guide fins.
with that I ran a 42 low speed jet and a 170 main jet delivering great power from sea level to 8000' and 45 MPG at 65 MPH ( 1995 FLHTC---- my Hipo FXR is 45/180) and larger main jet just decreased fuel mileage with out any power benefit that's 80", your 88" may need a little larger
good info on tuning and modding the CV carb at nightrider.com under bike tech
But if you have a linkert on the '58, then you are probably pretty good at feel and adjustments
backfire: when the throttle is closed the motor has very high vacuum, this will pull extra fuel from the float bowl--- so don't worry about some noise of decel---
-- listen to the NASCAR cars going into a turn --- backfire/flame/farting & burbling--- totally normal--- and I rely on that to help other traffic know that I'm there.
mike
the dyno jet kit is junk
the yost kit is junk ( which may be your emulsion tube, I won't bother pulling a carb apart to count, but I'd guess the emulsion tube has 12 to 16 holes)
4mm allens make for easy bowl dropping with carb in place, use a hand mirror to see when changing the jets. use antisieze on the screws.
The very common sportster needle and drilled .125" slide work well, in addition I chamfer the leading edge of the slide and polishit as best i can by hand the 2 guide fins.
with that I ran a 42 low speed jet and a 170 main jet delivering great power from sea level to 8000' and 45 MPG at 65 MPH ( 1995 FLHTC---- my Hipo FXR is 45/180) and larger main jet just decreased fuel mileage with out any power benefit that's 80", your 88" may need a little larger
good info on tuning and modding the CV carb at nightrider.com under bike tech
But if you have a linkert on the '58, then you are probably pretty good at feel and adjustments
backfire: when the throttle is closed the motor has very high vacuum, this will pull extra fuel from the float bowl--- so don't worry about some noise of decel---
-- listen to the NASCAR cars going into a turn --- backfire/flame/farting & burbling--- totally normal--- and I rely on that to help other traffic know that I'm there.
mike
Last edited by mkguitar; 10-31-2011 at 02:42 PM.
#6
10-31-2011, 04:41 PM
Agree completely on the DJ and Yost kits; not worth the money, more difficult to tune and mileage will suffer.
However, I do not agree that one has to live with decel backfiring. I run a 44mm CV on my 104" '02 FLHT, moderate compression at 10:1, worked heads and have run a variety of TMans cams though Rinehart true duals. I wouldn't consider a carb tuned that was backfiring on decel; may be OK for NASCAR but not OK for a vtwin touring motorcycle. It the fuel and spark are tuned properly and there are no intake or exhaust leaks, the motor will not backfire on decel no matter how quick you close the throttle.
However, I do not agree that one has to live with decel backfiring. I run a 44mm CV on my 104" '02 FLHT, moderate compression at 10:1, worked heads and have run a variety of TMans cams though Rinehart true duals. I wouldn't consider a carb tuned that was backfiring on decel; may be OK for NASCAR but not OK for a vtwin touring motorcycle. It the fuel and spark are tuned properly and there are no intake or exhaust leaks, the motor will not backfire on decel no matter how quick you close the throttle.
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