My 2015 YZ 250 Build

Now that the 2016 Yamaha YZ 250 has been released I can breathe a sigh of relief that I didn’t buy a YZ the year before Yamaha spent some R&D money on making an antiquated design newer.

I had a nice, low-hour Suzuki RM-Z 450 but after getting sucked into Vital MX’s forums and reading about the many and varied horrors of four-stroke-dom I sold it and bought a new YZ 250. This is the third YZ 250 I’ve had (first was a 1999 and second was a 2006) so I knew what I wanted to do to the bike. I also spent endless hours on Vital MX, ThumperTalk (which is ironic of course) and other websites researching the best mods for a YZ 250. I don’t want a YZ 300 (295) and my goal was to spend less than $2,000 on it but ended up spending about $2,500.

Here’s my 2015 Yamaha YZ 250 build… some highlights of the parts:

MOTOR:
Pro Circuit Platinum Pipe (I’m going to try the DEP pipe when I bash this one up. I’d only used FMF pipes on my other YZs and wanted to try the top-end of the PC pipe I’ve heard about.)
Pro Circuit Ti/Carbon Fiber Shorty Silencer (it’s more than two pounds lighter than the stocker and super awesome looking)
Steahly Offroad 7 oz. fly wheel weight (the lightest flywheel Steahly makes for the YZ 250)
Boyesen SuperCooler Kit
RB Designs head mod (after doing a squish-band clearance test; http://rb-designs.com/rb_designs_llc_017.htm) – Ron got my head on Monday and it was in the mail back to me on Wednesday. That’s fast turnaround! This is probably the best “bang for your buck” mod ($92.00 plus shipping to Oregon) and wasn’t very hard to do either.
2009 Yamaha YZ 450F clutch springs (3) – I did this in my ’06 and think it helps with hook up

CONTROLS:
Renthal TwinWall handlebars (998)
RollOn Lightning Quick Turn throttle tube (I love quick turn throttles)
Yamaha GYTR Factory Perch (GYT-5TA38-30-AL; required an older-style lever, some other parts and some grinding to remove the thumb-operated hot start bracket)
Raptor Titanium Xtreme foot pegs (I had those on my Suzuki too – they’re the best)

DRIVE & BRAKE:
Braking W-OPEN over-sized 270 mm brake kit
Ride Engineering Rear Brake Clevis (which I polished)
LightSpeed Carbon Fiber Chain Guide
All Balls black upper chain roller (because the stocker is yellow-orange and ugly)

OTHER STUFF:
Works Connection Radiator Braces
Acerbis Blue Front Number Plate (I bought a UFO front number plate and thought it was poor quality. The Acerbis still doesn’t match the Yamaha blue color quite right but it’s better quality at least.)
Factory Effex Custom Number Plate Graphics

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Some observations about the bike:
- The front number plate bolt was cross threaded and I had to re-tap it
- The air filter was only partially oiled
- The bearings weren’t dry but they all needed to be greased
- There was some carbon build up next to most of the welds on the frame and subframe that I sanded off with a fine sanding foam pad
- The shock spring isn’t titanium anymore – magnets stick to it and it says so on www.yamaha-motor.com – this is a bit of a bummer… “Rear, fully adjustable KYB® shock features a STEEL shock spring and reduced-friction Kashima coating of internals. 12.4 inches of travel, separate adjusters for high- and low-speed compression damping, and a full lock oil rebound system for increased comfort all add up to fantastic rear wheel control and a sweet ride.”
- Yamaha-Motor.com lists the “wet weight*** as 227 lbs for both the 2014 and 2015 models… I’d guess the weight gained by switching back to a steel spring was lost on the lighter plastic…
- Lubing the clutch cable really helped improve the clutch pull and feel (you have to make sure not to over lube the cable though since the cable routes through the side case).
- The Pro Circuit silencer is riveted together top and bottom
- It is amazing how much lighter this bike feels compared to 450s.
- The bike sounds much, much better now than stock

Next steps:
- Core Moto braided front brake line once the stocker goes squishy
- I want a non-aluminum glide plate
- Maybe a VForce reed valve. I call MotoTassinari and they said they have no plans to make a VForce 4 for the YZ 250…

Maybe down the road:
- YZ-F swingarm and the needed parts
- Different offset triple clamps. MXA has said the 25 mm stockers are best but in the latest issue they are using Ride Engineering’s 22 mm offset clamps with the Showa steering dampener… Applied makes a 24 mm offset verison and I rode a YZ with 22.5 clamps once…

PHOTOS:

This is what it looked like stock – Let’s Ride in Idaho is a great dealership:



Here’s some of the black marks next to the welds:





Stock cylinder head:



Doing the squish band test:





Modified cylinder head – Ron at RB Designs said most of the 2015 YZ 250s he’s seen have somewhat lower compression than previous models so he bumped the compression a bit. Still runs on premium pump gas:



Picture of the clutch GYTR clutch perch:



And finished:







Vital MX rules!