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Main Area => General GS500 Discussion => Topic started by: FD3S on September 24, 2003, 10:35:04 AM

Title: Jetting Help/Advice for '01 GS
Post by: FD3S on September 24, 2003, 10:35:04 AM
I've searched the board on this and came up confused, so I thought I'd just ask...

I have an '01 GS. Stock intake, V&H supersport full exhaust. It currently has the stock jetting. Also, I do not have an ignition advancer and don't
plan to fool with it unless I absolutely have to.

The bike doesn't want to take much throttle at low rpm until you've ridden it a few miles, but it starts up easily. It also seems down on power in the low rpm  range, but picks up when you get above 2500 to 3000 rpm.

Anyway, does anyone know of a proven jetting setup for my bike (remember, 2001 GS)?

How 'bout if I lose the airbox and put K&Ns on it? Any proven jetting
setup for that combo?

I just want to get the jetting right the first time... I don't want to have to keep pulling it apart a fiddling with it. I'm just looking for good, smooth power across the whole rpm range.

What kind of jets do I need for an '01? (large, round, small, etc.)

Where is the best place to get them? Local dealer? On-Line?

Thanks
Title: Jetting Help/Advice for '01 GS
Post by: dmp221 on September 24, 2003, 11:38:31 AM
I have the '01 and did the jets about 2-3 months ago.  Bike runs great, just like you describe it.

You want a "Factory Pro" stage 1 jet kit for 01 Suz GS-500.  I ordered from 2 brothers racing.  Try www.2bros.com

Good luck.
Title: Jetting Help/Advice for '01 GS
Post by: dmp221 on September 24, 2003, 11:41:53 AM
Sorry bout the bad website. Try this:

www.twobros.com
Title: Commercial Kits
Post by: FD3S on September 24, 2003, 12:24:21 PM
What is in the commercial (Factory Pro & Dynojet) kits that makes them cost so much more? (vs buying the individual jets from somewhere)

Should I just go ahead and buy the K&N filters and go stage 3 while I have it apart? Any disadvantages to that? Remember, more power is great, but I don't want to sacrifice smoothness, throttle response, or low rpm torque for a few top end hp.

Also, people keep mentioning washers... do the people who sell the jets also sell the washers? How do I know if I'm getting the right washer?

Thanks again for all the advice.
Title: Funny thing...
Post by: The Buddha on September 24, 2003, 12:51:45 PM
Well with a well jetted bike you never give up anything. Well naver give up anything good...You do lose the cold starting blues, the top end leanness woes, the mid range lean surging worries, the occassional Hot starting problems...and more.
The real reason to jet the bike is to get it running cooler...power and driveability are just an aside. Having said that to jet it to the spot it should be in under diverse conditions will take time, effort and patience. The tips of those that did it will leave you close but to get the spot...you need to listen to it and do what it says. Manjul posted a formula for the 01...induvidual jets and pretty cheap...that should be a start for your bike too.
Cool.
Srinath.
Title: Re: Funny thing...
Post by: TheGoodGuy on September 24, 2003, 08:35:00 PM
Quote from: seshadri_srinathManjul posted a formula for the 01...induvidual jets and pretty cheap...that should be a start for your bike too.
Cool.
Srinath.

well it was piper who posted the formula.. look for a thread that starts with "did some testing today"..

its got the stuff in there.
Title: Jetting Help/Advice for '01 GS
Post by: FD3S on September 26, 2003, 10:43:18 AM
Hey guys... I've decided try try the following on my GS (V&H Full system, stock intake).

Pilot #20
Mid-Main #62.5
Main #132.5 or #137.5

Anyone see a problem with that?

Also, I tried to order them from my local dealer. He showed the stock pilot as a 17.5 (correct) and the main as a 60 (kinda correct, at least I know thats the mid-main). He didn't show anything as the main-main (127.5 stock), he said nothing came up as that size stock, so I don't know what part number to order there. He did show a #160 air jet and a needle-jet that had a size that didn't make any sense (PJM or something... no size numbers).

Can anyone offer any advice here? If I ever get the parts, I'll share the Suzuki part numbers with everyone so we won't have to go through this again.

Or, if someone can point me to a mail-order or on-line company that knows their stuff, I'd appreciate it.

Thanks
Title: Jetting Help/Advice for '01 GS
Post by: FD3S on September 26, 2003, 11:42:49 AM
Also, are the Main and Mid-Main jets identical, other than the size of the hole in the middle (the same thread size and diamter)?
Title: Jetting Help/Advice for '01 GS
Post by: KevinC on September 26, 2003, 11:44:46 AM
Sudco is the Mikuni parts supplier for the US:

http://www.sudco.com/

Call them, because they don't answer e-mail.
Title: Jetting Help/Advice for '01 GS
Post by: Piper5177 on September 26, 2003, 05:21:19 PM
Yes the mid-main and the main are the same type of jets, just different sizes.  With the stock intake, You might want to get a UNI or K&N stock replacement filter.  A little more air is never a bad thing as long as it isn't a vacuum leak or running lean.  The jet sizes you have listed will work best with a stock airbox and replacement filter.  The orifice on the stock filter is around 30% smaller than on the K&N or the UNI.  If you want a little better fuel mixture with the stock paper filter just shim the needle with one #4 washer under each e-clip and go to a 130 or 132.5 main jet and the 20 pilot.
Title: Jetting Help/Advice for '01 GS
Post by: mp183 on September 26, 2003, 06:35:07 PM
I think we are all missing the point here.  If you are running your bike in the 2,500 rpm range you are lugging the engine.  Instead of jet kits etc. try twisting the throttle.  Let that engine wail.  It's a brave new world above 7,000 rpm.  Don't worry it won't break.  More bikes are destroyed by neglect i.e. rotting in garages than by running at high rpms.  Suzuki would not put that readline so high if the engine could not take it.
Title: Jetting Help/Advice for '01 GS
Post by: Piper5177 on September 26, 2003, 10:04:49 PM
By the way the #4 washers are the nylon type white plastic, the metal washers don't fit all the way over the needle.
Title: Jetting Help/Advice for '01 GS
Post by: TheGoodGuy on September 27, 2003, 11:07:20 AM
Quote from: Piper5177Yes the mid-main and the main are the same type of jets, just different sizes.  With the stock intake, You might want to get a UNI or K&N stock replacement filter.  A little more air is never a bad thing as long as it isn't a vacuum leak or running lean.  The jet sizes you have listed will work best with a stock airbox and replacement filter.  The orifice on the stock filter is around 30% smaller than on the K&N or the UNI.  If you want a little better fuel mixture with the stock paper filter just shim the needle with one #4 washer under each e-clip and go to a 130 or 132.5 main jet and the 20 pilot.

huh you got me confused..

the 137.5 and 62.5 and the 20's work for the stock air box with paper filter? I was going to buy the K&N Drop In.
Title: Jetting Help/Advice for '01 GS
Post by: Piper5177 on September 27, 2003, 03:55:17 PM
Your right good_guy. Look closer I told him to use smaller jets a 130 or 132.5 and keep the mid main the same for a paper filter.  The 137.7, 62.5, and 20 are for the drop in with a stock exhaust.
Title: Jetting Help/Advice for '01 GS
Post by: FD3S on September 27, 2003, 06:16:34 PM
I stopped by my local Suzuki dealership yesterday. Turns out I went to H.S. with the owner and also used to race (SCCA) with one of their salesmen. So, I had the benefit of friendly parts guys.

Anyway, according to them, Suzuki doesn't sell oversize jets... so there isn't going to be a Suzuki part number for them. I looked at the microfiche (computer, actually) and all it shows is the stock sizes for the pilot and the two mains (it doesn't differentiate between the mid-main and main... just calls 'em both mains and lists the sizes). So no dice there.

Then we pulled out a parts book and started looking. Found the proper pilot jet. They didn't have a listing for the mains in anything smaller than #80, and the jet sizes jumped in increments of 5... like #130, #135, #140. So I couldn't get the sizes I wanted. This is also the same info (increments of 5, nothing smaller than #80) I got from another dealer I called earlier.

They also recommended checking with Sudco. So I'll give them a call on Monday. I'll let you know what I find out.
Title: Jetting Help/Advice for '01 GS
Post by: FD3S on September 29, 2003, 09:22:48 AM
Called Sudco today. Very helpful people!

The main jets are definitley the Mikuni N102/221 type, they have them in any size you would want.

I thought the pilots would be the VM28/486 or VM28/213, but the parts guy I spoke to said those were usually found in older (1970's) carbs. He said he was almost positive it was the TMX36 pilots that I needed, so I ordered a couple of those.

Anyone have a good close-up shot of a '2001+ pilot so I can compare before taking my GS apart?

I got two #20 pilots, #62.5 mids, and #137.5 and #132.5 mains to experiment with. Total shipped was $26.

I'll take good close-up photos and let everyone know the part numbers and such as soon as I find out if everything works.
Title: Jetting Help/Advice for '01 GS
Post by: TheGoodGuy on September 29, 2003, 11:50:03 AM
try this...
http://www.gstwins.com/forum/viewtopic.php?t=4614

manjul