New 426 owner, anything I 'need' to know?
Guest Guest, in YZ400F/426F/450F/450FX
By Woody Oakson
I have a 2008 YZ450F with a stock header pipe and Pro Circuit T-4 Slip-On Exhaust. I'm 99% sure the slip on is shot because its loud as hell and when I take it off and shake it it rattles. I would repack it but the screws are all stripped ect.
Anyways I've gone over the carb multiple times and I've got it running pretty well. The only issue I have with the bike is that it sputters and pops around 1/2 throttle when I hold it there. When I give it full throttle from any RPM it runs great or when I give it about 3/4 throttle it spins up like a top to redline.
Initially the popping and sputtering was way worse I made the situation better by moving the pilot jet up in a few sizes from a 45 (stock) to a 62. The issue has gotten way better since then but I'm not super sure what to do from here. Should I keep moving my pilot jet up in size because that's a pretty large jump right? I tried changing my needle clip position but that didn't help much if anything it just made starting it worse and little to no impact on the ride.
Any input on this would be helpful. I don't want to buy other slip on. Also as for the rest of the carb I'm very sure everything else in it is what it needs to be at. I've replaced all the gaskets and O-rings cleaned all the jets, valve holes ect. fixed the accelerator pump timing. I just thinks its strange that my pilot jet size is going so far from the stock 45, but all symptoms point to the bike running lean.
Excel Takasago 17x3 front and 17x5 rear supermoto wheels with Metzler M3 tires in very lightly used condition. Less than 200 miles total on the setup. Warp 9 spokes. Rear has a Talon hub with 45T Sunstar steel sprocket and OEM rear disc, and front has a polished OEM Yamaha WR450F hub (for the stock speedometer), with a Motomaster 320mm disc. Included is a DID gold o-ring chain, 14T front sprocket, and front brake caliper adapter for a truly turn key setup. Everything is in excellent condition, not a single scratch on these wheels. Came off my '11 WR450F, but will fit many different Yamahas with 20mm front and 22mm rear axles. Asking $1400 plus shipping.
**Will be driving up near Atlanta, then to northern Louisiana, OKC, and down through Dallas and Houston, TX soon -- can meet or deliver if in the area (Aug 31-Sep 9)**