Hi,
Been reading the wealth of imfo you have on carbs,jetts and airfilters,imfo not avalable here in Australia {guess it's here some where but I cant find it}.I bought my 2002 GS 500e new 2 years ago,now has 27500 km on,really like the bike except for one thing,Low end torque,or the lack of it. Wasn't able to test ride the bike when I bought it,sat on it of coures but thats all. I have owned a Gsx 400e and a GS 450 both great bikes so figured the GS 500 should be even better.From day 1 to stationary start I've needed to slip the clutch to get it going,best likened to as if you were starting in 2nd gear,also as you back off before the corners there's a jolt as the rev's drop,then as you throtle on to get power and traction there's a power lag leaveing you coasting around the corner for I suppose less than a second but feels like ages when your leaned over coasting instead of under power with positive traction,not a nice feeling :o .Talked to the dealer several times got fobed off with"thats normal,it's only 500cc you know how could it have any low end grunt?"Well neither the 400 or 450 had this problem so is this normal for all GS 500 or even any partcular model year.To add to the mystery at the 24000 km service they accidently put in a 01D00 stock airfilter,it's used on earlier model GS 500 Im told it should have been a 01D7,careless of them but may have been a real streak of luck,instantly the bike no longer had the jolt,it had more torque low down than ever before,the power lag was gone and it rode so much smoother,there the +,the - ,top end was litterly starveing,no power over 5000 revs the more you wound on the more it died.On inspection of the plugs white too lean as I expected,compareing the 2 filters the supposed correct filter has a much smaller intake hole + a internal sleave further restricting air flow.More air helped the primarys but killed the mids and mains,ajusting the air mix doesnt help it's still either too lean up top or if its correct there too rich down low, seems the jetts are incompatable with each other,as I mention this is a stock standard bike from the factory,no one has fiddled with it so how can suzuki get it so wrong on a bike they have been produceing for over 10 years.Rejetting the mids and main and use the less restrictive airfilter seems the best solution but jet it to what. I'm left wondering is my bike some how miss jetted at the factory or are they all like this? Help Please :dunno:
I also owned a GS450 back in 1981 - and you are right, it did have more low end grunt - anyway ---the GS500 is jetted very lean. Go up one on the pilot (to a 20 on your 2002), up one on the mid-main and you should be fine with the stock filter - make that two on eht main if its an aftermarket drop in and go up to 142.5 with pods and stock exhaust - 150 with aftermarket.
An ignition advancer also helps low-end grunt a great deal - but they are no longer easy to get. There are do-it-yourself directions on the mods page.
I have a 2002. I never had the need to slip the clutch to take off unless I needed to really move. I re-jetted about 3,000 miles ago. I now have about 18,5000 miles on the bike. I left in the stock filter. I can run the bike about 500 rpm lower. The bike does not have much low end torque. No matter what you do to it, this will not change. The engine is made to rev.
I keep it at about 5,000 rpm when I am riding it. I never accelerate unless I'm over 4,000 rpm. Whem I'm in tight traffic situations where I need a quick response it's 6,000 rpm or higher.
The jet kit did not change my miles per gallon, it did give me much better warmup. I can warm it up in warm weather for about 30 seconds and go without the choke. In warm weather I can even start it without the choke.
Here's what I did with my '01 (same carbs). Replaced the air filter with a Uni foam one that fits straight into the airbox. Much less restrictive than stock. Wouldn't run worth anything, had to rejet. Tried various jet sizes and needle settings with very limited success. Replaced the pipe with a less restrictive one. Used a Factory Pro jet kit because the sizes of jets in my carbs bore little resemblence to those in the advice on this site (eg my bike had 17.5 pilots and 115 mains!!!). Now running really well. Same fuel consumption as stock but feels more powerful. Starts easily (if the temperature is >15C I don't need the choke), idles well, burbles nicely on trailing throttle.