Been doing some more tinkering on the YZ250.
First, been playing with oil weights/heights on the forks as well as clickers front and rear. Bike was perfect for my slow race pace standing up and attacking...... but as soon as I would slow down to chill and relax going slow seated... a bucking bronco. Think I've finally accomplished a good compromise for me and really stoked. Will have to add a few clicks of compression when I do the next hare scramble, but I am ok with that. Ended up taking 2.5 wt fork oil and a big airgap (low oil height) to get them plush enough for slow stuff. Very happy!
Next up was installing my head that RB Designs modified. I wanted as close to the 250X spec as we could get by slightly lowering compression, tightening the squish, and anything else that will allow me to run Pump Premium reliably. Got about 10 hrs on it now, and feel confident it was worth the $90.
Performance wise, its not massively noticeable. I'm already running the G2, retarded ignition, oem pipe, and 11oz flywheel weight. Those were very noticeable in smoothing out the motor for trail riding. Biggest gains I have experienced is the bike runs cooler and less apt to get the heat related lean condition knock/preignition on really really steep long hills.
Only experienced a minor one on a hill I had to abuse the clutch all the way. Big improvement.
Biggest gain... my spooge is now under control!
arty No matter how lean (even dangerously lean) on my pilot/needle I would run, I would get a significant spooge affect running single track. Wide open like Moab or SoCal, no spooge. I had read it has a lot to do with the design of the turbine type spark arrestors such as the FMF Turbinecore II I run. Screen types dont slow the air as much, where as the turbine slows it enough to allow the oil particals to fall out and collect in the silencer. So I have read and experienced.
10 hrs of slow trail riding and as you can see, clean tip.
Per RB Designs claim, the head does burn more efficiently, thoroughly, and cleanly. On my 1.45 hr loop today from Middlecreek up around past Penny Pines and back today, I only burned a gallon of gas. I am sold and will do the other head when I finish building the second motor with the wide ratio transmission too. I LOVE this YZ!
Nice CJ! Gotta get out on my smoker soon!
