GStwin.com GS500 Message Forum

K&N Drop in Filter with no restrictor, 40 non-bleeder pilot jets, 127.5 LARGE ROUND main jets, 3 turns out air screws, and float level at the top of the bowl. That is the ticket for smooth carburetion. I put the large round 127.5 main jets in tonight and it runs fine. So there is a difference between the small and large round jets. Don't use the small ones. :thumb:

Thanks for the update Ed,  :cheers:   What type of exhaust do you have on the bike?

Quote from: Ed_in_AzK&N Drop in Filter with no restrictor, 40 non-bleeder pilot jets, 127.5 LARGE ROUND main jets, 3 turns out air screws, and float level at the top of the bowl. That is the ticket for smooth carburetion. I put the large round 127.5 main jets in tonight and it runs fine. So there is a difference between the small and large round jets. Don't use the small ones. :thumb:

So, what exhaust are you running,  the elevation above sea level, and the humidity range there?  :cheers:

I've got the stock exhaust. Elevation 3,500ft. Humidity :dunno: Low. It's Arizona.

I guess I'm finally willing to consider this rejet on my nearly stock bike.

Since I've already got the K&N in-airbox filter and the stock pipe  ( :mrgreen: ) all I need is the jets.  Did you get 2 pair of each, Ed?  If so, would you consider swapping the extras for some cash?

Quote from: KerryI guess I'm finally willing to consider this rejet on my nearly stock bike.

Since I've already got the K&N in-airbox filter and the stock pipe  ( :mrgreen: ) all I need is the jets.  Did you get 2 pair of each, Ed?  If so, would you consider swapping the extras for some cash?

I only got a two pack of the mains, but I got a four pack of the 40 pilots. So I'll tell ya' what Kerry. You are so helpful to everyone on here if you'll PM me with your mailing address I'll send you the 40 pilots for free. :cheers:

Wow - thanks Ed!

The PM is "away"....

WOW :o   good deeds do payback :thumb:

Quote from: KerryI guess I'm finally willing to consider this rejet on my nearly stock bike.

Kerry, I might have a set of 127.5's... I'll check this weekend and get back to you.

Thanks, I appreciate it!

Where exactly would you buy these things?  would they work on a gs500f?

part numbers please and the website.  :mrgreen:

-Chino

This set up will not work on the 500f!!  The 2001 and newer models have different carbs and require different style jets and pilots.  

You can purchase the jets online or order them through your dealership.

Quote from: Hi-TThis set up will not work on the 500f!!  The 2001 and newer models have different carbs and require different style jets and pilots.  

You can purchase the jets online or order them through your dealership.

For the 2001 and up you need number 20 jets - different style, your suzuki dealer can order them for you - just a couple bucks each.  The mains are alredy 127.5 stock - but going up one size on the main to 130 sould not hurt a bit.  There is also a mid-main jet - cannot remember stock size, but bumping that one size is also a good idea (this has approximately the same effect as raising the needle with a number 2 washer on the pre-2001 models)

Of course if you are going to pods or an exhaust you need to go up more on the main jet I am at 150 - in my case the mid main does not seem to need changing - of course I raised the needle.

The pilot is a bleed type- it maybe wise for you to take the part with you so that they can see it, feel it, smell it, and sit on it when they order the wrong one.  I'll see if I can find the part number from mine- I actually picked it up from the Yamaha dealer for 7 bucks each.

The mid main starts at a 60 small round slotted mikuni- I've bumped it up to a 65 and have a shim under the needle- but I also have a full exhaust and pod filter.

Even a mild rejet will boost performance- bike warms up faster and typically runs a little smoother and faster.  

PLEASE NOTE: The numbers that I have referenced are for 2001 and newer.

Quote from: KerryThanks, I appreciate it!

Nope, no 127.5's... I have 125's (one size up from stock), 145's, and a set of 40 pilots.  Let me know if you're interested.

Sure, I'll try the 125's.  And if you could throw the extra 40s in, I'll pass them on to richard.  (Seing as how he's the Winter Rider Extraordinaire.... :roll: )

Please PM me any details about payment, address, etc.

Kerry Wrote:
I guess I'm finally willing to consider this rejet on my nearly stock bike.

Kerry: Did you do the rejet?  Did you include the #4 washer on the pilot jet?  How does the bike run?

I've got the same almost-stock setup near sea level in NYC.  Thinking I'll give it a try...

I'm postally inept, so he just received the mains yesterday.

Kerry, please take lots of pictures!  :)

I wouldn't mind taking pictures, but miket has already done a bang-up job with his Poor Man's Rejetting Pictorial (http://www.angelfire.com/mt2/mikesgs500/rejetting/).  See what you think.

I dunno - does the world need yet another page for this mod?  :dunno:

ahh soo!

thanks for the link Kerry... i've read quite a few rejet threads and even googled, but i've never seen that page  :thumb:

Where to order Mikuni jets online?

As my engine doesn't like high RPMs (ie. above 9000RPM), I'd like to experiment with main jet sizes, so I'd like to get jets from 115 - 150 (in pairs).

I can't seem to get them from Suzuki dealers around here as they all want my VIN and then they order the 'factory default' jets...

Thx, D.

PS: My spark plugs have white-ish electrodes and isolator... That is too lean, right?

Quote from: danci1973My spark plugs have white-ish electrodes and isolator... That is too lean, right?

I can't help with the jets; I've been "ordering" them through other GStwin members.  :mrgreen:

As for the plugs, are they even whiter than the "Normal condition" sample on this Haynes Spark Plug Chart?

For a second opinion, read the SPARK PLUGS page from Dan's Online Motorcycle Repair Course.

Quote from: Kerry

Quote from: danci1973My spark plugs have white-ish electrodes and isolator... That is too lean, right?

I can't help with the jets; I've been "ordering" them through other GStwin members.  :mrgreen:

:dunno: Oh my...

Quote
As for the plugs, are they even whiter than the "Normal condition" sample on this Haynes Spark Plug Chart?

Yeah. Here is one:



and the other:

Quote
For a second opinion, read the SPARK PLUGS page from Dan's Online Motorcycle Repair Course.

I'm reading...  :)

Thanks, D.

Yup its lean... I have seen very very very pretty looking bikes that were so lean they wrinkled the front fender from the heat. Lean enough to have the pipes glow red... Maybe. You want jets, get 125's for a all stock bike, and if you made mods tell us what the mods are and we'll suggest the jets.
Cool.
Srinath.

Quote from: seshadri_srinathYup its lean... I have seen very very very pretty looking bikes that were so lean they wrinkled the front fender from the heat. Lean enough to have the pipes glow red... Maybe. You want jets, get 125's for a all stock bike, and if you made mods tell us what the mods are and we'll suggest the jets.
Cool.
Srinath.

Now we're talking! :)

OK, the only mod I have is an open exhaust can - and I have that on because the bike actually runs better than with the stock one (stock exhaust somehow makes the bike run terrible at 6000-7000RPM and anything over 9000RPM).

With the open can the 6000RPM hole is almost completely gone, the bike feels stronger throughout 4000-9000RPM, but still doesn't like to go higher (but not as bad as with stock can).

Originally I had 125 (left carb) and 115 (right carb) main jets, together with slider travel restriction (yeah, my bike was factory restricted to 34PS).

I removed the slider restriction and replaced the main jets with 127.5's (in both carbs) so far, but I haven't noticed much of a difference.

I haven't done the float level (don't quite know how to) and I haven't synced the carbs - yet (don't have the equipment).

I have a pair of 130 main jets and 127.5/122.5 (Suzuki recommendation) I can try...

 Thx, D.

PS: I know my bike isn't running well as my top speed is only ~140km/h (~88mph - measured with a GPS and Sigma bike computer).

PPS: The 127 I use now and 130 jets were 'made' by a mechanic (actually, he took some smaller jets and enlarged them - I don't know if they are 100% what they should be...). And they have a smaller head than original jets.

Quote from: danci1973I haven't done the float level (don't quite know how to)[...]

See my Float Height page.  CAVEAT: This page tells you how to CHECK the level, but doesn't include the procedure to CORRECT it.

Quote from: danci1973[...]and I haven't synced the carbs - yet (don't have the equipment).

You can get pretty close by using one of the "no fancy equipment" methods described in the How to sync the carbs? thread.  Especially read Srinath's and scratch's first posts and the later post by Lars.

I would almost swear that someone posted yet another "no tool" method recently, but I can't think of what to search on.   :o

For more info on "cheap tool" methods, see the Carb Synchronization ! thread.

[quote="danci1973]
Originally I had 125 (left carb) and 115 (right carb) main jets, together with slider travel restriction (yeah, my bike was factory restricted to 34PS)....
I removed the slider restriction and replaced the main jets with 127.5's (in both carbs) so far, but I haven't noticed much of a difference.

I have a pair of 130 main jets and 127.5/122.5 (Suzuki recommendation) I can try...
PPS: The 127 I use now and 130 jets were 'made' by a mechanic (actually, he took some smaller jets and enlarged them - I don't know if they are 100% what they should be...). And they have a smaller head than original jets.[/quote]

On 4 cylinder and on V twin bikes it is quite common for carb jets to differ - The inside cylinders or the back cylinders get different cooling air flow and they compensate by changing the jetting to reflect operating temperature.  I have never seen any recommendations, nor can I think of a justification for an air cooled  parallel twin to have different jets right and left.  Also, while it is possible to change the size of jets by drilling, there is a lot more to the flow of a viscous fluid through an orifice than the largest cross section of the hole - the most common effect of making the hole slightly larger would be to ruin the profile and reduce fuel flow - not increase it.  This could cause yur lean condition.  The way around the restriction is to drill a bigger hole - at some point the larger size makes up for the increased friction - or (so you know what is going on) get the right jets.

Your plugs are so white (at least on my monitor) that I would be very concerned about causing damage to the engine by running it --  You should know that the lean jetting causes high enough internal engine temperatures to cause your engine to sieze.  Now, if you did not pull these immediatly after a 10-15 second full throttle run followed by hitting the kill switch and coasting to a stop, it is possible that they just reflect your idle mixture - still too lean - but not a huge problem, just open up the mixture screws about 1/2 turn and try it again.  Then do the proper full throttle run and re-post pictures of what they look like then.

The 9000 rpm and up problem can be caused by a bunch of things that are not jetting related as well as things that are jetting related.  

Are you sure that the slides are free to rise all the way up in the carb bodies?  Are you sure that the little "o" ring on the top of the carb is in place?  Are you sure that the diaphrams in the carb are OK?  Are the valves adjusted properly?

GET PROPER JETS - PUT THEM IN If you have stock airbox and filter with the exhaust drilled start with 132.5 or so.  If you have K&N in the box make that 140.  These may be too big - take full throttle plug readings and adjust sizes as needed.

The smaller head jets ok Ed_in_Az recently tried them... and hated them... Look at post "Rejetting - Follow gstwin exactly" for more info. You need the big slotted round mikuni's, not the little slotted round mikuni's...
Cool.
Srinath.

Ok this is that thread  :?  ... OK...  :dunno:
Cool.
Srinath.

So far I have learned that I need to do valve adjustment... Even though I took my bike to the dealer a couple of times, I don't think this has been done.

Bigger/different jets are next - but where to buy jets? I called up several local (and not so local) Suzuki shops and they are all either stupid or unwilling to help.

Are there any 'online' shops, where one can order any number of any kind of jets?

  D.

Quote from: seshadri_srinathOk this is that thread  :?  ... OK...  :dunno:
Cool.
Srinath.

_I_ wasn't going to say anything....  :roll:

I have done this and my bike runs sweeeeeet!  :mrgreen:

Quote from: danci1973So far I have learned that I need to do valve adjustment... Even though I took my bike to the dealer a couple of times, I don't think this has been done.

Bigger/different jets are next - but where to buy jets? I called up several local (and not so local) Suzuki shops and they are all either stupid or unwilling to help.

Are there any 'online' shops, where one can order any number of any kind of jets?

  D.

Large round Mikuni main jets - order by size .  Almost any motorcycle or snowmobile or outboard  shop has a box full sitting in the back - does not need to be a Suzuki dealer. If the parts guy is an ass (and many are) try talking to a mechanic.   If none of your local dealers are cooperative try Bike Bandit, Ron Ayers, Dennis Kirk - petty much any on-line parts store.