This is way more than enough wear to cause
overrich low speed problems
Top Left side
- This is a picture of the needle jet area of
an emulsion tube from a stock 38mm CV Mikuni carb
as installed on Ducati, Yamaha TDM/TRX 850, YZF750, FZR1000, etc..
It has approximately ~5000 miles or 8000k usage on a Ducati or TDM
850 - WITH A STOCK Aluminum NEEDLE.
Notice that the center hole is noticeably worn at the "V", the 12 o'clock
position, which would be towards the engine, as installed in the carburetor.
This causes 2 conditions. First, it allows more fuel to enter the carburetor,
as in using a needle with a small base diameter AND the fuel that enters
the carb - it enters in larger droplets, resulting in poor combustion.
We carefully check needle jet condition on the
vehicles when we create and install carb recalibration kits.
If you install a kit and it is much too rich at low rpm, and lowering the
fuel level 1mm doesn't fix it, check the needle jets
for any wear - it's not uncommon.
Additional: Eventually, in the 36mm horizontal mount and 38mm
downdraft Mik's, the carb body plastic insert, where it holds
and guides the slide from rattling back and forth, will wear out - allowing
the slide to rattle and bang the needle fore and aft in the needle jet orifice
- causing accelerated NJ wear. This wear is biased towards the lowered slide
position - as in idle and low rpm areas - as in "in-town", "stop and go"
driving.
The gist of that is that you may only get 5,000 miles out of your needle
jets in your VL / VS bike that you use for cruising 4th Street and
hanging out at McDonalds - but your long distance , highway cruising buddy
might get 25,000 miles before mileage deteriorates to 25mpg or worse.
I haven't heard of anybody who has got the "60,000 miles" that some Tech
Bulletin claims is normal with a stock needle...... I WILL change this if
I ever find that person who made it to 60,000 miles on his/her VS / VL and
has the original needle jets/emulsion tubes. In fact - I'll GIVE any carb
needle jet rebuild to any VL 1500 owner who makes it to 60,000 miles on
the original needle jets! Marc
Slide Guide Wear:
Example: The original needle jet lasted 5,000 miles in your usage. After
replacing the worn emulsion tube / needle jet, they only lasted 3,000 miles
or less. That's because the slide guide slot in the carb body is worn -
not because of the emulsion tube or needle is bad.
Even Suzuki knows that - even though their highly optimistic estimate of
60,000 mile life with a stock needle is based on perhaps a VL1500 or VS1400
run at high speed on a highway.
A "step" inside of the needle seat in the carb slide? It's there in virtually every Mikuni CV carb. It's supposed to be there.
It's to try to keep the needle bearing onto only one side of the needle
jet - otherwise, the needle bangs back and forth onto both sides of the
needle jet at idle and low rpm, instead on only one side.
Of course, if one "notches" the plastic needle shim, they are lowering the
needle about 2 clip positions and that will lean out the mixture, but that
doesn't really permanently fix anything.
Be famous! (for something besides
"that"!)
Have an emulsion tube that's worn? Send it in (in a padded envelope) with
make, model, mileage, usual use (in-town, commute or sport), your name and
the difference between running before and after replacement. We'll put some
of them at the bottom of this page.
US=USA
CA=California
CN=Canada
Aus=Australia
SW=Switzerland
FR=France
UK=United Kingdom
Euro=all European countries
These Factory Pro Design "Mikuni
style" needle jets are threaded for Genuine Mikuni and Factory
Pro "M221 and M604 Replica Series" main jets, but not dynojet.
Aprilia
Pegaso 650
36mm CV
~2.5mm
(.0985-.0990)
Factory Pro nickel plated replacements in stock
CRZ-EMU-100102k
$56 / 2pcs
2.
Ducati
Ducati
M600, M750, M900
900 ss/cs/sp 38mm CV
~3.00mm Ø
(.1175 kit)
Factory Pro nickel plated replacements in stock
CRZ-EMU-100120k
(nickel plated!)
$64 / 2pcs
2.
Suzuki
Suzuki
gsf 1200 "Bandit" 96-00
all countries
(does not fit the 01 and later Bandit
1200's - they are pressed in and not easily replaced)
Suzuki, rf600, 94-96
Suzuki, rf900, 94-97 yes, Suzuki used essentially the same part in both size carbs....
Suz pn:
09494-00810 (900)
09494-00872 (900)
09494-00854 (600)
09494-00814 (600)
These are all interchangeable. The top 3 are "O-9" and the bottom one is
an "O-8". The theoretical difference in size between an "O-8" and an "O-9"
is below any realistic manufacturing tolerance)
Factory Pro nickel plated replacements in
stock
CRZ-EMU-100195k
$112 / 4pcs
2.
Suzuki
VL1500
all carbureted
nickel
plated HDJ
Send in for
rapid turnaround repair / rebuild click here
Triumph
Triumph 900
3 cylinder, 36mm CV Mikuni carbs
~2.5mm
(.0985-.0990)
all countries
Factory Pro nickel plated
replacements in stock
CRZ-EMU-100102k
3pcs 2.
Triumph 1200
4 cylinder, 36mm CV Mikuni carbs
~2.5mm
(.0985-.0990)
Factory Pro
nickel plated replacements in stock
CRZ-EMU-100102
$112 / 4pcs
Yamaha
Yamaha
fzr400 - 1WG 88-90 USA and others, w/ 1WG carbs.
(yam pn: 1WG-14141-90-00)
Discontinued by Yamaha at last suggested retail of about
$180 for 4 pcs.
Factory Pro used to do a lot of race work (3rd OA in
24 Hour) for the venerable fzr400, so we tooled up and made a limited
run of emulsion tubes to keep these classic bikes running right.
Factory Pro
nickel plated replacements in stock
CRZ-EMU-100105k
$148 / 4pcs 2.
NEW!
Yamaha
fzr400 - 3EN & (3TJ?)
(yam pn: 3EN-14141-90 or 92)
Factory Pro
nickel plated replacements in stock
CRZ-EMU-100160k
$132 / 4pcs 2.
Yamaha
fzr600,
89-99 USA 89-93 rest of the world (not for yzf Thundercat)
Factory Pro also used to do a lot of race work for the
long running fzr600,. We used that knowledge and built a stronger,
longer lasting, "better than original" emulsion tube.
Factory Pro
nickel plated replacements in stock
CRZ-EMU-100160k
$132 / 4pcs 2.
Yamaha
yzf750, 93-99
Yam pn: 3GM-14141-90-00
Yam pn: 3GM-14141-92-00
Yam pn: 3GM-14141-94-00
and all 3GM
(aprox. Yam price $40 to $60 each)
38mm CV
~3.00mm
(.1175 kit)
Factory Pro
nickel plated replacements in stock
In the
original carbs, there are tiny differences in the "size", but, if you know
what I'm talking about, a Y-2 and a Y-4 are the equiv. of <1/3mm difference
in float height (translate to "insignificant").
Also same part used in all Ducati 600,
750 and 900cc bikes. Fits early Mikuni 38mm downdraft CV carb.
(does not fit 99-00 TDM's)
(does NOT fit 90-92ish gsxr750 horizontally mounted 38mm carbs -
email for those)
Factory Pro nickel plated replacements in
stock
In the original carbs, there are tiny differences
in the "size", but, if you know what I'm talking about, a Y-2 and a Y-4
are the equiv. of <1/3mm difference in float height (translate to
"insignificant").
~3.00mm (.1175 kit)
CRZ-EMU-100120k
$74 / 2pcs 2.
Yamaha
fj1100, 84-85
84 1100 Yam pn: 16H-14141-90-00
85 1100 Yam pn: 50h-14141-92-00
(same part number as the fj1200)
84 1100 models are upgradeable to the later style
"50H" 1200 parts.
Factory Pro
nickel plated replaces stock parts seamlessly - atomizes fuel
better for better mileage and power.
HDJ style!
for better fuel atomization and response
CRZ-EMU-100112k
$168 / 4pcs 2.
Yamaha
fj1200, 89-93
HDJ style!
Yam pn: 50H-14941-92-00
Factory Pro
nickel plated replaces stock parts seamlessly - atomizes fuel
better for better mileage and power.
HDJ style!
for better fuel atomization and response
CRZ-EMU-100112k
$168 / 4pcs
Emulsion Tube / Needle jet
Yamaha
V Max and VMX1200 -
85-07
replaces Yam pn: 26H-14941-90-00
Factory Pro
HDJ
replaces stock Yamaha tube nickel plated replaces stock parts seamlessly - atomizes fuel
better for better mileage and power.
CRZ-EMU-100110k
HDJ Hi Dispersement Jet style
$120 / 4pcs
Intro Special 2.
Emulsion Tube / Needle jet
Yamaha
Venture Royal - XVZ1200, 85
Yam pn: 26H-14941-90-00
Factory Pro
HDJ
replaces stock Yamaha tube nickel plated replaces stock parts seamlessly - atomizes fuel
better for better mileage and power.
CRZ-EMU-100110k
HDJ Hi Dispersement Jet style
$168 / 4pcs 2.
Emulsion Tube / Needle jet
Yamaha
Venture - XVZ1300, 86-93
Yam pn: 26H-14941-90-00
Factory Pro
HDJ
replaces stock Yamaha tube nickel plated replaces stock parts seamlessly - atomizes fuel
better for better mileage and power.
CRZ-EMU-110k
HDJ Hi Dispersement Jet style
$168 / 4pcs 2.
xv250,95-11
fzr400,88,89 (1WG-14141-90-00??)
xj600, Seca, 92-98
V-Star xvs650, 98-05
fz750, 85-86
fzx700,86-87
Royal Star, xvz1300 96-01
Royal Star, xv13,98-01
I got really tired of
trying to use the original Keihin numbering / profile codes, so I made
my own.
Very nice if you have everything perfect at every throttle position
except for 1/4 and only want to change that 1 thing!
Flatslides are super easy to tune on the
EC997 dynos and not easy on anything
else for many different reasons.
patented High Dispersal Jet System HDJ available for licensing Easily retrofitable in many OEM Keihin, Mikuni
and aftermarket carbs and simple to make minor modifications in manufacturing
process to incorporate.
Significantly better fuel atomization, runs without misfire at leaner fuel
delivery rates, better power from the same amount of fuel, more consistent,
smooth running, as verified on EC997 Low Inertia dyne
FLUX value engine smoothness testing. I can explain that if you are not
using that dyne system and cannot get that data.
All what an MJN promised, but it can run cleanly at all rpms and, because
it still used a tapered needle, is easy to tune properly.
