The bike in question is a Suzuki DRZ400S
Mikuni CV Carb (Cant afford the Keihin FCR)
DEP End can.
I have done an airbox mod commonly refered to as the 3x3.
Which basically entails removing the snorkel (which is roughly 1" by 2") from the airbox and then cutting the hole to 3" x 3"...
I have done that, and have lifted the needle to the 4th clip and its running brilliantly...
Apart from the top end...
It used to get to around 85mph (private road) and then run out of puff (big rider plus low gearing
![Razz :P](./images/smilies/icon_razz.gif)
Since doing to mod it wont get past 75 and anything past 70 is slow.
So I know its running lean....
Across the rest of the range its brilliant as I said, so its only when the main jet is in play...
Now, I know that every engine is a little different and that you should tune to your engine...
BUT, I dont really feel like constantly having to fiddle with the jets (its a fiddle time consuming job)
So, if the main jet is 142.5 what size would you reckon to get the power back?
I was thinking a 150~152.5
If its already a 150, a 160?
Thanks...