2013 Yamaha YZF270cc Cylinder Works, FMF and Rocky Mountain ATV/MC
The 2013 YZF250 is a great 250! However, there are four other 250’s that come with fuel injection and they seem to garner all of the attention. One of the best things about the YZF is that the motor last for ever. It has a carburetor and has not had a major motor change since it came out it just keeps plugging away. It gets a little better each year.
Stock the bike can us some more giddie up and that is why went to the 269cc kit from Cylinder Works and some Hot Cams.
At the same time we added a few mods for better durability and a few for looks. Our hope is that all of these mods would give us a big increase in power and handling while not loosing durability and so far we seem to be well on track. We have used this kit in a YZF250 the last four years and it has proven to be bullet proof.
The motor now is 269cc with a Cylinder Works big bore kit. This kit is a complete drop in kit that looks completely stock from the outside of the bike. Yes, no one but you will know. The Hot Cams Stage-2 cams were the next mod and they really help increase mid-top end power. The Hot Cams are designed to work well with the stock valve train and stock valve springs. This keeps the cost down and does not require as often valve maintenance as a full race team cam.
We also added a new FMF 4.1 full Ti system.
The stock jetting is really good (for a carb J). We ended up using the grey (richer) coupler after testing in all three. When the motor was stock we ran the white leaner coupler. It was great that after all of the mods that no serious re-mapping was needed. The bike did not have any popping or bogging and that is saying something with a carburetor.
We did add a bit of VP U4.4 to help even a bit more and since we don’t have to worry about being legal we are ok with this as a fuel choice.To finish off the motor we went to the one of the weaker spots for durability, the clutch. A full Hinson set up is exactly what we needed as we know they last for a long time.
To get this power all to the ground we are running two smaller on the rear sprocket for gearing which works great with the added power and Renthal chain and sprockets are the choice here.
Of course Dunlop MX51’s work good everywhere and the new MX51 FA front is our new top choice.Works connection clutch perch and bling pieces really set off the machine. The radiator braces provide a real benefit in crash situations and could help save a radiator. WC Ti Footpegs are great and their Holeshot device is great for our Dirt Starts.
Decal Works custom graphics are just cool and allow you to do what ever you want. MX plastics was able to help with some all white plastic for our Yamaha. We have a very custom looking YZF250 (well 270cc).
Jetting Specs- Courtesy of Chris Johnson
172 Main Jet
55 Leak Jet
42 Pilot Jet
2 turns on the Fuel screw
2nd from top on the stock needle 3rd from top with Yamaha optional needle 5TA-14916-PS-00
About every major product for this project can be obtained directly Rocky Mountain ATV-MC: www.rockymountainatvmc.com
Cylinder Works www.cylinder-works.com 515-251-4070
3mm Big bore Cylinder Kit 269cc
Includes Forged Vertex Piston and Cometic Top-End gasket kit
Hot Cams www.hotcamsinc.com 515-402-8200
Stage two cams
FMF Racing www.fmfracing.com 310-631-4363
Factory 4.1 RCT Ti Muffler
Ti Megabomb header
MotoTassinari www.mototassinari.com 603.298.6646
Air4orce air boot $298.00
VP Racing Fuels www.vpracingfuels.com 210-635-7744
U 4.4
Uni Filter www.unifilter.com 714-535-6933
Air Filter
CV4 www.cv4.net 800-874-1223
Formed Silicone Coolant hoses in yellow
High pressure radiator cap
Renthal www.renthal.com 877-736-8425
Stock front and rear sprocket
R1 Works Chain
997 Twin Walls
Dual compound grips
Dunlop Tire www.dunlopmotorcycle.com 800-845-8378
MX51 FA front 80/100-21
MX 51 rear 110/80-19
DeCal Works ww.decalmx.com 815-784-4000
Semi-Custom Graphics kit
Pre printed number plates backgrounds
Moto Seat www.motoseat.com 951-258-5229
Custom Cool seat cover
Works Connection www.worksconnection.com 800-895-8292
Titanium foot pegs
Holeshot device either one of these (wherever more room and better)--
Elite Perch
Factory II Stand
Front brake cap
Rear Brake cap
Radiator Braces
Chain blocks
Engine plugs
Oil filler plugs
Rotating font brake mount
Hour meter and mount
Fuel screw
ARC front brake lever
Skid Plate
Hinson Clutch Components www.hinsonracing.com 909-946-2942
Inner Hub/Pressure Plate Kit
Billet Clutch Basket
Fibers, steels and springs
Outer Cover
Tusk Off road www.tuskoffroad.com 800-336-5437
270mm Oversized Rotor/Adaptor Bracket 270mm OS Rotor -
270mm Adaptor Bracket -
Rear Disc -
MB1 www.mb1suspension.com 951-371-5045
Suspension re-valve
