Yamaha 2005 YFZ 450 Lean condition - Adjusting the slide needle height on a Keihin CR carb

The exhaust was popping like firecrackers indicating a lean running condition. The carb was already cleaned and even the choke couldn't temporarily correct the problem. The solution was to adjust the slide needle height. Watch here to see how.

[@SpecOpsGear]

I got a yfz450 in trade as a non-running project.
Got it (barely) running and it was super lean no matter what. The intake valves were burnt and not sealing so got some new valves for it. It looks like i have that part solved based on a leakdown test, but the bike's back together and still lean.
I might just try this because i'm really running out of ideas and i still haven't turned the corner on this project.

[@HillbillyToolBox]

If you have no exhaust or after market exhaust that allows more flow, it can cause a lean condition too. Also, check the automatic decompression system. They can cause lean type issues too.

[@SpecOpsGear]

@@HillbillyToolBox thanks for the reply. The auto decompression system appears to be working; the weight on the exhaust camshaft moves with the spring so it looks like it's working.
Thanls again.

[@arnaudfabs]

Smart man!

[@HillbillyToolBox]

Sometimes...

[@CamoPajamies]

The oring mod make accelerator pump hit quicker , rich with gas - yee haw

[@HillbillyToolBox]

I read about that mod. This thing has enough snap...I'm getting old! lol