1999 sporty 883 to 1200 jet sizes with 500 cam

[Dougiedoug]

Hey guys I’m running 45 little jet main jet 195 big jet. Will this work to run the bike off or is there a proper combo that can suit this set up?

Thank you

[JBinNC]

On slide type carbs with a metering needle, the needle is THE THING. Tuning the fixed jets is just nibbling around the edges.

Keihin makes jet and needle kits to tune the CV carb for modified motors. Those kits are offered by various distributors under different names. Other mfg. offer kits as well, but in my opinion, the Keihin kits work best as they have high quality OEM components. A jet kit for a 1200 XL will provide you with a good needle as well as some intermediate and main jets.

Jim

[SteveJ]

Start with big jets.

Make the engine 'blubber' under acceleration.

This is good. You now know where you are tuning wise.

Advance the ignition until it pings under acceleration and then back it off.

Now start leaning out the main jet until you start to feel the power coming on.

Its seat of the pants literally as you test ride.

Make ONE adjustment at a time to keep things clear.

You'll know pretty quickly when the power is coming on as you lean out the jets.

[Dragstews]

Harley Carburetor Tuning 101: The 88 Sportster Needle
by CV Performance


Harley tuners, mechanics, and those doing their own wrenching have long known about using the 1988 Sportster needle for tuning the Harley CV carburetor.

History

Harley Davidson motorcycles have a long history of carburetors used on their models over the years, but none as popular as the CV carburetor. Introduced in 1988 on Sportster models to replace the Keihin "butterfly" carburetor, the CV also from Keihin introduced a vacuum actuated slide and needle to regulate fuel delivery. As engine loads change the slide moves up or down allowing the suspended needle to meter fuel passing around it from a nozzle (needle jet). This innovative fuel metering system not only handles the air/fuel mixture throughout the mid range, but also provides a constantly changing venturi or throat size, hence the name CV or constant velocity.

The original CV carburetor in 1988 lacked an accelerator pump commonly used on most carburetors. To compensate for the lack of an accelerator pump and to eliminate lean flat spots, the factory produced the N65C needle whose length, diameter, and taper positions were designed to alleviate the off idle hesitation.

In 1989 an accelerator pump was added to the CV carburetor as all other models began to adopt the new carburetor, and the CV carb remained virtually unchanged until retired in 2006. The 88 needle (or N65C, HD #27094-88) became very popular after tuners and mechanics discovered its usefulness in tuning other models needing a richer off-idle and mid range mixture required with exhaust or intake upgrades. The N65C became a staple for tuners and is still used today even by Harley dealerships. Similar needles pulled from Buell variations and other special uses were used such as the N65B, NOKK, and NOKT however the N65C remained the most popular.

The 88 Needle Lives Again

Shortly after Harley Davidson discontinued use of the CV carburetor on factory models in 2006, the factory began discontinuing older components including the N65C needle. Having insight into these parts becoming obsolete, CV Performance began producing our own N65C "Sportster" needle (fits Big Twins too) to meet the needs of those wanting to continue using them. Based on the original specs from Keihin, the N65 needle was added to our line of velocity needles using our unique precision CNC machining process and billet aluminum material.

[SteveJ]

Or you can just put the needle in a lathe and turn to spec.
We did that in the beginning too.

[DustyDave]

Or you can just put the needle in a lathe and turn to spec.
We did that in the beginning too.

Or file small flat spots like old Triumph tuners used to.
Dusty

[Dougiedoug]

On slide type carbs with a metering needle, the needle is THE THING. Tuning the fixed jets is just nibbling around the edges.

Keihin makes jet and needle kits to tune the CV carb for modified motors. Those kits are offered by various distributors under different names. Other mfg. offer kits as well, but in my opinion, the Keihin kits work best as they have high quality OEM components. A jet kit for a 1200 XL will provide you with a good needle as well as some intermediate and main jets.

Jim

Hey Jim, so we threw a 47 jet and 185 jet in there and it runs better. But it still won’t really idle and coughs and dies out. My guess is might be a timing thing so we’ll time it again today. But those jets really helped it breathe better. But still won’t fully idle even with the idle adjusted good and like I said still kinda backfired or wants to die when we blip the throttle and then coughs and the bike dies…

[Dougiedoug]

Or you can just put the needle in a lathe and turn to spec.
We did that in the beginning too.

I need to get a lathe, that’s on the list!

[Dougiedoug]

Start with big jets.

Make the engine 'blubber' under acceleration.

This is good. You now know where you are tuning wise.

Advance the ignition until it pings under acceleration and then back it off.

Now start leaning out the main jet until you start to feel the power coming on.

Its seat of the pants literally as you test ride.

Make ONE adjustment at a time to keep things clear.

You'll know pretty quickly when the power is coming on as you lean out the jets.

So I threw in some bigger jets. Went from a 45 to a 47 and from a 195 to a 185 and the 47-185 is the best combo out of them all. But the bike still coughs and dies. Under correct tuning of the idle screw. As to what you mentioned, I don’t get what you mean by “until it (pings)”. Pings as in the light will go off? Or what did you mean by pings? And leaning out the main jet as in put a smaller jet in it kind of thing?

Thanks Steve

[SteveJ]

So I threw in some bigger jets. Went from a 45 to a 47 and from a 195 to a 185 and the 47-185 is the best combo out of them all. But the bike still coughs and dies. Under correct tuning of the idle screw. As to what you mentioned, I don’t get what you mean by “until it (pings)”. Pings as in the light will go off? Or what did you mean by pings? And leaning out the main jet as in put a smaller jet in it kind of thing?

Thanks Steve

Advancing the ignition timing is where the ping comes in , you are now tuning by listening to the engine and feeling the power difference as you test ride the bike.
Advance until it pings when you accelerate. Dont make it ping all the fuckin live long day you only need to hear it once. then back off the timing , this is your optimal timing setting. Set it and leave it alone.
Now go to the carb and richen the main up until you hear the engine blubber under acceleration.
If you guys wanna play at tuner you will have to learn to listen to the engine and differentiate the sounds it makes as you tune the bike. Either that or pay a guy like me to tune the bike.
It cant really be done with a buncha stupid typing and descriptions.
Good ;uck !

[dianawelch123]

Allow the engine to 'blubber' as it accelerates. Harley tuners, mechanics, and DIY mechanics have long known that the 1988 Sportster needle can be used to tune the Harley CV carburetor.

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[SteveJ]

No need for an '88 needle in a '99 carb. lol
Blubbering indicates a rich condition.WHEN YOU HEAR IT YOU KNOW WHERE YOU ARE IN THE TUNING RANGE. Its called a - base line
Like I say- listening to the engine rather than forum answers is how to tune a bike.

[Dougiedoug]

No need for an '88 needle in a '99 carb. lol
Blubbering indicates a rich condition.WHEN YOU HEAR IT YOU KNOW WHERE YOU ARE IN THE TUNING RANGE. Its called a - base line
Like I say- listening to the engine rather than forum answers is how to tune a bike.

Got it dialed. Threw in a bigger idle jet and it’s money! That new cam threw everything off! Thanks Steve I appreciate the info!

[SteveJ]

Got it dialed. Threw in a bigger idle jet and it’s money! That new cam threw everything off! Thanks Steve I appreciate the info!

No worries bikes on the road is what counts.

[thecarfarmer]

Just a question... have you verified, beyond a fucking shadow of a doubt that the intake seals and/or carb base don't leak?

Impossible to get good idle with.a leak - can't tune around that.

If that's done, then disregard...