Pablo's gs500 page
Why re-jet a stock US bike
R1 taillight install on 89-00 gs500
Clear Taillight Lens for 01-03 Models
My Local Canyons
What's it worth?
Progressive fork spring install-the lazy way
Rear shock swap information
More rear shock info-SV650 install
Suspension tuning 101
Installing Suburban-Machinery SV650 handlebars
Install an SV650 headlight
Converting standard 1/4 throttle to 1/5 throttle
Installing LED's in stock taillight
Uber Fender Eliminator
R1 Taillight on 89-00 GS500
Speedo/Tach light replacement
Better handlebar grips
Installing Buell turn signals - Rear
Installing Buell turn signals - Front
Flush mount rear (stock) turn signals
Installing a 2001 Ducati Monster fairing
Fix a broken oil filter cap bolt
General battery info
A Wal-Mart sealed battery?
Chain Maintenance
Installing SV650 Chainguard
Spark plug information
Installing a GSXR front end
Installing a GSXR swingarm
Installing GSXR rear passenger peg brackets
Installing an OEM Bandit 400 rear hugger
Installing a Bandit 400 rear wheel
Installing a GSXR rear wheel-simple swap
Polishing your wheels
"The Mystical Art of Tire Reading" and other tire info
General tire info for the GS #1
General tire info for the GS #2
General tire info for the GS #3 - mixing brands/types
gsJack's opinion on tires for the GS
Gearing and sprockets
Slip-on mufflers
Slip-on exhaust : using stock SV650 muffler
Installing an R6 tail
Installing GSX-R600 stock rearsets
Installing CBR600 stock rearsets
Replacing stock front pegs with CBR pegs
Replacing stock front pegs with Katana pegs
Why re-jet a stock US bike
More on re-jetting your carbs
Jetting for 2001 models

Jetting a bike means changing the size of the apertures the gas flows through. Doing this changes the ratio of fuel-to-air mixture. Generally, 15 to 1 is a start for gasoline engines. From there, a LOT of variables creep in. The art of "jetting" means to adjust this ratio so your engine pulls well from idle through full throttle. Simple way is move the taper up, or down, making the mixture slightly richer, or leaner, using washers under the carb needle. If the jet (hole) stays the same, moving the taper up or down will either restrict the hole(leaner), or open up the hole(richer) for a given slider(air) setting. Thus, the ratio changes. Pulling the plugs proves this. A light brown color is best. If plugs are whitish, or gray, the mixture is lean. If plugs are dark brown, or blackish, rich.

Here are few reasons to rejet your bike even if it is stock. Stock bikes come jetted lean because of emission standards. By correcting the stock jetting of your bike, the combustion should be more efficient. The increase in power, although slight, means your bike does not have to work as hard. More importantly, a richer mixture causes your engine to burn cooler, extending engine life. It should also crank easier because the initial coolness of the cylinders displaces some of the fuel in the combustion chamber. This is reason choke is needed until the bike warms up. Rejetting a stock bike requires minimal increase in jet sizes so do not expect noticeable power unless you change your filter and or exhaust. You will then, of course, require more jetting.

US bikes are bad at warming up. They had 37.5 size pilot jets while the rest of the world got 40, hence the leanness and awful warm up/start up situation. The remedy is to put 40's in place of the 37.5's.  You can order the pilot from a Suzuki dealer near you. You should also install 127.5 large round Mikuni mains, go 2 1/2 turns out on the idle mixture (adjust to taste).

Part Name - JET, pilot (40)
Part Number - 09420-40014