Author Topic: K&N RU-2970 & Re-Jetting Question / 20/65/142.5 jet set?  (Read 836 times)

Offline Carltheproducer

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K&N RU-2970 & Re-Jetting Question / 20/65/142.5 jet set?
« on: May 15, 2019, 08:31:50 PM »
K&N RU-2970 & Re-Jetting Question. There is so much information out there about re-jetting for a K&N RU-2970 and aftermarket exhaust slip on but I do not see any specific manufacturer jet set to buy, just to buy this set for a K&N Pod or Lunchbox Air Filter + Sports Exhaust = 20/65/145 but does my aftermarket exhaust slip on qualify as a Sports Exhaust? If not, then I need a K&N Pod or Lunchbox Air Filter Only = 20/65/142.5 jet set. I have called DynoJet and they do not have this 20/65/145 set for a 2009 GS500. Where/what jet set should I be buying exactly to then finesse the jetting process once installed. I am aware I need to buy 2 jet sets. Should I install new spark plugs too, if so which is the best? Thanks in advance and primary season I am doing this is to get a bit more performance but ultimately more physical space under the tank for R6 rear shock and move over some wires, gak over.
Here was my favorite re-jetting website, http://www.gstwins.com/wiki/index.php?n=Upgrades.Rejetting




Offline Bluesmudge

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Re: K&N RU-2970 & Re-Jetting Question / 20/65/142.5 jet set?
« Reply #1 on: May 15, 2019, 09:17:37 PM »
Yes slip on counts as sport exhaust. It's completely open right?

You dont want anything from dynojet. You want actual Mikuni jets. The Buddah on this forum used to sell pre made jet kites with Allen head replacements for the JIS carb screws. He may still sell them -- makes it easier than trying to figure out what exact carb parts to buy. Send The Buddah a PM if he doesnt show up in this thread.
« Last Edit: May 15, 2019, 09:18:57 PM by Bluesmudge »

Offline Carltheproducer

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Re: K&N RU-2970 & Re-Jetting Question / 20/65/142.5 jet set?
« Reply #2 on: May 15, 2019, 09:49:25 PM »
Yes slip on counts as sport exhaust. It's completely open right?

You dont want anything from dynojet. You want actual Mikuni jets. The Buddah on this forum used to sell pre made jet kites with Allen head replacements for the JIS carb screws. He may still sell them -- makes it easier than trying to figure out what exact carb parts to buy. Send The Buddah a PM if he doesnt show up in this thread.

Thanks for this intel, hitting up The Buddha now. Here's photos of my exhaust. Idk is it open? haha, what does open mean?




Offline Carltheproducer

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Re: K&N RU-2970 & Re-Jetting Question / 20/65/142.5 jet set?
« Reply #3 on: May 17, 2019, 07:20:58 PM »
No response from The Buddha yet but I called Van Nuys, CA Suzuki and rep needs the other jet size to a pilot 20/mid main 65/ main 145? Supposedly pilot 20 comes in 2 sizes? Any clarification, I can't find a small or large size of pilot 20s on forums/links. Rep said its simply to get out one carburetor w/ screwdriver & wrench to take a photo of the bottom to see sizes. I have a 07 GS500 engine in my 09 frame. Thanks!
« Last Edit: May 17, 2019, 07:23:30 PM by Carltheproducer »

Offline BikerBoy

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Re: K&N RU-2970 & Re-Jetting Question / 20/65/142.5 jet set?
« Reply #4 on: May 17, 2019, 10:54:06 PM »
GENUINE Mikuni jet size 20 ( N224.103)
GENUINE Mikuni jet size 65 ( N102.221)
GENUINE Mikuni jet size 142.5 ( N102.221)

You can search just the part number in parentheses. I recently ordered jets for my 08 500f.

Offline herennow

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Re: K&N RU-2970 & Re-Jetting Question / 20/65/142.5 jet set?
« Reply #5 on: May 18, 2019, 06:59:57 AM »
As I said over on the other recent posts, don't worry about the mid (Choke) jet, you will just mess up your choke operation.

Going 5 times higher on the main (see table below) seems A LOT to me even for free air filter and open exhaust....

BTW, i tried the cheap chinese jets out and i was surprised by their quality. They ALL measured perfectly with my pin gauges. For 6 bucks you get 6 jets, so 2 each of three different sizes. Shipping can take up to a month though...  Although your mileage may vary depending on your country (Trump and tariffs and all that Jazz)

https://www.aliexpress.com/item/Mikuni-carb-N102-221-Main-Jet-PWC-High-Speed-Jets-Kawasaki-KSF-KXF-Polaris-Predator-and/32274435837.html?spm=a2g0s.9042311.0.0.27424c4dZSirQ6







Offline Carltheproducer

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Re: K&N RU-2970 & Re-Jetting Question / 20/65/142.5 jet set?
« Reply #6 on: May 22, 2019, 05:48:22 PM »
Apologizes to ask the same question(s) in previous posts but I am not getting a straight answer or I am getting more confused since I am a noob. Thank you in advance for your patience.

I am sorting though this conflicting information to order the right size(d)(s) of jets for my particular situation.

The GS Twins' Jetting website, http://wiki.gstwins.com/index.php?n=Upgrades.Rejetting, does not have 2009's stock jets' sizes and I am referring these stock sizes.

2004+ Stock - 17.5 Pilots / 60 Mid Main / 130.0 Main

However on the Van Nuys' Suzuki micro fish website, https://shop.suzukiofvannuys.com/fiche_section_detail.asp?section=989747&category=Motorcycles&make=Suzuki&year=2009&fveh=27496, it states my stock sizes are;

JET,PILOT,17.5
JET,MAIN(60)
* I can not seem to find the 3rd size

It seems per my situation, GSTwins' suggest, "K&N Pod or Lunchbox Air Filter + Sports Exhaust = 20/65/145 jet sizes." I have a K&N RU-2970 filter & Core Engineering Slip On. When I showed these jet sizes to the Van Nuys Suzuki guys, they said, "well what sized 20, 65 & 145 do you need? Because I can give you three different 20 and 65 and 145s?" WHAT IS HE TALKING ABOUT? He wants me to pull out the jets so he can get the diameter size (i think) as the service manual supposedly does not list them as each carburetor is different? Again, what he is really saying to me?

@BikerBoy, did you install those GENUINE Mikuni jets? If so, how is it? Especially swapping out mid's? Did it mess up your choking operation?

@herenow, what am I suppose to be pulling from your table? I am reading under 2008 section the following below, clarificaiton as your posts suggests I replace main & pilot jets only correct?

main jet - 130
jet needle - 5DH60

Please and thanks.

As I said over on the other recent posts, don't worry about the mid (Choke) jet, you will just mess up your choke operation.

Going 5 times higher on the main (see table below) seems A LOT to me even for free air filter and open exhaust....

BTW, i tried the cheap chinese jets out and i was surprised by their quality. They ALL measured perfectly with my pin gauges. For 6 bucks you get 6 jets, so 2 each of three different sizes. Shipping can take up to a month though...  Although your mileage may vary depending on your country (Trump and tariffs and all that Jazz)

https://www.aliexpress.com/item/Mikuni-carb-N102-221-Main-Jet-PWC-High-Speed-Jets-Kawasaki-KSF-KXF-Polaris-Predator-and/32274435837.html?spm=a2g0s.9042311.0.0.27424c4dZSirQ6




Offline BikerBoy

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Re: K&N RU-2970 & Re-Jetting Question / 20/65/142.5 jet set?
« Reply #7 on: May 22, 2019, 10:13:13 PM »
Apologizes to ask the same question(s) in previous posts but I am not getting a straight answer or I am getting more confused since I am a noob. Thank you in advance for your patience.

I am sorting though this conflicting information to order the right size(d)(s) of jets for my particular situation.

The GS Twins' Jetting website, http://wiki.gstwins.com/index.php?n=Upgrades.Rejetting, does not have 2009's stock jets' sizes and I am referring these stock sizes.

2004+ Stock - 17.5 Pilots / 60 Mid Main / 130.0 Main

However on the Van Nuys' Suzuki micro fish website, https://shop.suzukiofvannuys.com/fiche_section_detail.asp?section=989747&category=Motorcycles&make=Suzuki&year=2009&fveh=27496, it states my stock sizes are;

JET,PILOT,17.5
JET,MAIN(60)
* I can not seem to find the 3rd size

It seems per my situation, GSTwins' suggest, "K&N Pod or Lunchbox Air Filter + Sports Exhaust = 20/65/145 jet sizes." I have a K&N RU-2970 filter & Core Engineering Slip On. When I showed these jet sizes to the Van Nuys Suzuki guys, they said, "well what sized 20, 65 & 145 do you need? Because I can give you three different 20 and 65 and 145s?" WHAT IS HE TALKING ABOUT? He wants me to pull out the jets so he can get the diameter size (i think) as the service manual supposedly does not list them as each carburetor is different? Again, what he is really saying to me?

@BikerBoy, did you install those GENUINE Mikuni jets? If so, how is it? Especially swapping out mid's? Did it mess up your choking operation?

@herenow, what am I suppose to be pulling from your table? I am reading under 2008 section the following below, clarificaiton as your posts suggests I replace main & pilot jets only correct?

main jet - 130
jet needle - 5DH60

Please and thanks.

As I said over on the other recent posts, don't worry about the mid (Choke) jet, you will just mess up your choke operation.

Going 5 times higher on the main (see table below) seems A LOT to me even for free air filter and open exhaust....

BTW, i tried the cheap chinese jets out and i was surprised by their quality. They ALL measured perfectly with my pin gauges. For 6 bucks you get 6 jets, so 2 each of three different sizes. Shipping can take up to a month though...  Although your mileage may vary depending on your country (Trump and tariffs and all that Jazz)

https://www.aliexpress.com/item/Mikuni-carb-N102-221-Main-Jet-PWC-High-Speed-Jets-Kawasaki-KSF-KXF-Polaris-Predator-and/32274435837.html?spm=a2g0s.9042311.0.0.27424c4dZSirQ6



Those other sizes are for older carbed models. The carbs changed around 2000 or so I believe.

If you show him the part number in the post I linked above, the guy at the store will definitely know which ones.

And yes, replacing the mid did mess up my choke badly lol. I didnt have an exhaust installed then. It was so rich it flooded my airbox. After I switched it back (and played with the idle and fuel mixture screws) my bike was beyond fucky, so I took it to a shop for them to fix (hey, I never said I was good!). They quoted me only 100-200 bucks for examining the carbs and syncing them so its not too bad. I got my bike in the beginning to be reliable and comfortable, not to try and make it fast, because its already plenty fast for my skill level.

Offline herennow

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Re: K&N RU-2970 & Re-Jetting Question / 20/65/142.5 jet set?
« Reply #8 on: May 23, 2019, 03:52:33 PM »
There are handreds of differnt types of jets, these all come in different sizes.

our main and choke jets are this model

N102.221

Based on this you choose the sizes you want. I'd start with only the main jets and go with 6 jets, two each of the next three jets up from stock.

I'd not even bother about the idle, its almost spot on and you hardly ever use that circuit.....

Offline Carltheproducer

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Re: K&N RU-2970 & Re-Jetting Question / 20/65/142.5 jet set?
« Reply #9 on: June 15, 2019, 02:40:59 PM »
i finally re-jetted my baby and here's my experience. Thanks for all your help on this thread. Here's what I recommend for a '09 Suzuki GS500F carb though.



I emailed Jetsrus' Mike to get the GSTwin recommendation sets and it takes forever to get a message back. Must be a 1 man shop there so I went down to Sudco, in South Central Los Angeles, and they have like every jet size/set. Eric helped me on a memorial day weekend and stayed later for me to pick up. He’s the owner supposedly, i thought that was wicked cool. I am a noob and honestly to clean them, clean the carbs, replace the seals, and put them in takes at least 1 hour and putting on the K&N RU-2970 airbox was like an additionally 30 mins. I have a lot more loose rubber tubes now to clean up but wow, I gained so much space under seat now.




The bike fired right up, but sounded shitty & cut out eventually after a rough start sitting out overnights, so you should definitely replace the spark plugs & tweak fuel mixture screws, easy to access once you find them, i am currently at one full turn. I definitely feel some additional power and boy is she louder but maybe I still need to tweak carbs. Hear how she sounds now, she pops hard when you let off the throttle, https://youtu.be/DjhBSN3Err0. Should I check to see if carbs are balanced (synced)? I made this just in case after seeing this video, kinda want to try it out https://www.youtube.com/watch?v=7D_f05_a74Y.


« Last Edit: June 15, 2019, 02:51:21 PM by Carltheproducer »