How do i know what size of jets to use on my 90 600? I am new to this, but i just installed a Vance and Hines exhaust, and have been told that i need to jet the bike
Thanks for the help

 

with just the exhaust I wouls say go with a DJ kit with a 110 main jet and see how that goes for you.

 

If you do buy a kit, use the jets provided. The stage 1 kit I believe has 2 jet selections, DJ98s or DJ102s. With a slip on I would only go for the stage 1 settings.

 

actually the stage one jets are either leaner than stock or stock jets weasel look at your conversion chart the dj98's are keihan jets 100 and the 102's are stock 105's. save yourself some money go to a hobby shop buy some .5 to 2mm small medal spacers and shim out the needle. here is the link to do some reading http://www.kawi forums.com/showthread.php?t=105901. for stage one the main reason to buy the kit is to have the needles. run stock jets and shim out the needles its an easier way to go. if you ask me runnin aftermarket needles can cause more problems as you accumulate miles on the carbs. since they have a nice taper to them the dont sit perfect in the brass seat and will egg shape them alot faster than stock needles.

 

That is another option too. But the reason why they run leaner jets is because of their needle diameters. The Dynojet needles flow more fuel at different times compared to the stock needles. If you choose to run the stock needles, I'd say 112.5 or 115 should be sufficent for your application. And also the stock jets for the non Cali 90 models were 110s not 105s.

 

Lots of good info in there!

True stock jets 87-89 are 105. In 1990 the carbs went from 32mm to 34mm, and the stock jets were bigger, 108 or 110 like camoweasel says.

Trunks I agree with camoweasel that you could just move up a jet size or two and you'll be fine. Don't even bother with your needles at this point.

 

if you want to get some **** done just sand down the stock needles a little make your own shim them out and call it a day