So I have a 2006 YFZ450 and was hoping one of you oh wise and knowledgable YFZ450 experts out there might be able to give me some jetting tips.
She will start right up for me and idles great. Tons of power and seems fine if I accelerate relatively fast and keep the RPMs up but if I really romp the gas it will either stall and backfire or stall, sputter, and then die completely.
I have been scouring through hundreds of these jetting threads trying to find someone with my same basic setup but not sure I have found one so here is a list of the relatively minor mods I am using
- Removed stock airbox lid
- Removed stock screen/plug out of my stock exhaust
- Installed zip tie on throttle assemble
- Installed Phoenix screen type spark arrestor
- Installed 168 main jet
- Installed 45 pilot
- Installed Tusk fuel mixture screw and set at 2 turns out
- Stock leak jet (unsure of size)
- Stock needle (non-adjustable type)
On order (and arriving tomorrow):
+ Keihin FCR Jet Kit (comes with NCVQ needle, 45 48 50 52 pilots, and 160 162 165 168 170 172 175 mains)
+ #35 Leak Jet (4TJ-1494F-01-00)
Any suggestion on which way to go with the pilot, main, and which notch to put the new needle on? Any other suggestions in general?
My current plan is to install the 35 leak jet and go with the 3rd notch from the top on the needle, upsize to a 48 pilot jet, and stay with the 165 main jet for now.
My reasoning for this is that I feel like it is not getting enough gas on the low to mid end and once it catches up does fine in the upper end when the RPMs are high. I understand this to be a problem with the needle and/or pilot jet as opposed to the main.
On the other hand, I wonder if it could also be from too much gas causing a flooding situation when I romp on the gas too hard?
Thanks for reading - your time is appreciated.