What size are stock mains?

[Stime187]

Just curious, I'm in the middle of rejetting my GS and was just curious what the stock ones are so I can know if mine has already been done or not... I can tell someone has atleast been in the carbs...

Thanks guys,
Scott

[JLKasper]

My stock mains are 122.5s.   Usually on a stock bike, the mains are the last things to replace, after doing the #40 pilots first and shimming up the needles  

[Stime187]

K, thats what was in it... so good.   There were already #40 pilots though... but does the performance lie in the mains? It would seem so.

Scott

[JLKasper]

The pilots help in correcting the low-end only, and the mains help with top end, and to a lesser degree midrange.  Have your needles been shimmed with little metal washers under the amber nylon one?  You'll want to check that as well.

A stocker will benefit from 125 mains.  A stock airbox with K&N air filter and an aftermarket pipe will need 127.5 at least.  If you switch to pod filters, most riders use 140s.  More extensive engine mods will require 150s or so.

[Stime187]

Thanks for the reply, yes... I checked and shimmed the needles adding 2 #4s on each. They hadn't been touched. I'm running a pipe and k&n pod filter (not the drop in) so I went with 150 mains...

Scott