Yz's on the road

In the past I've heard some chatter about riding a YZ on the road (plated) for extended periods of times (like straight 65 mph speeds for about 1/2 hour or so) and how it's not good for it because of the smaller oil chamber it holds and the constant rpm's not being good for the engine/valves life? Can anyone elaborate on this for me? Or is there any other point of view on this issue? I understand that this bike was not designed for all road riding but I was just curious about this and how the bike would hold up?

The oil shouldnt really be a problem unless you are changing it at longer intervals than normal for an MX bike. I can imagine that holding the bike at higher RPMs will cause the engine to wear faster, but if your on the street all the time you might look into new sprockets to help that or even a WR tranny (wide ratio).

Yea, I have changed the primary out before to a 15 from a 14 and gained about at least 10 mph top end.

Try to remember the insane tempratures we get here in AZ. I've had my WR out on surface streets a few times but doub't I would run it up on a freeway. It get's too buzzy for that kind of work. P.S. it EATS up knobby tires!

I run my 07 YZ in Baja a bit. I run a 14 / 47 gearing set up. Find myself on roads going 5th gear all out for long periods of time.

I have a lot of things done to my bike to prevent heat soak and damage to the bike.

My gas tank is heat shielded as well as my fuel line and carb. I am running a better water pump impeller. Have holes in my front fender to increase air flow as well as my number plate.

Also got aftermarket radiator hoses and a higher pressure cap (stock is 1.1 and i have 1.6) with engine ice.

i have heard of people adding .2L more oil as well. i think Grayracer has a post on here about why you can do that?? sure he will correct me if i am mistaken.

There are some plastics out now that claim to increase air flow to the radiators and the engine as well but nothing you can't do yourself with a heat gun dremmel and little free time.

Also heard of people wrapping their header pipe with exhaust wrap.

As for tires they go FAST!!!

I am sure if i lost 20lbs from my 200lb fat ass it would keep the heat down as well...

I'm setting up my YZ for street/supermoto and I'm addressing the heat concerns also. Here's what I'm doing:

-oversize clutch cover from SFB Racing - holds extra 120ml oil

-Boyeson water pump cover/impellor kit

-vented front plate and front fender

-50/50 mix of Coolanol/Coolaide (per Motocross action test)

-heat shield tank with gold film

-carbon fiber carb shield

-CV4 hoses

-aftermarket rad cap

-15/44 gearing

-Graves oil seperator (returns oil from valve cover breather back to crankcase)

-possibly switching to WR trans gearing in the future

-Also plan on getting the stage 3 cooling kit from PWR when it comes out. Oversize radiators and an oil cooler built in as well

-thermal dispersant coating on radiators (see young gun coatings)

shielding gas line like Clutchless said is also a good idea. I'd run the new Cycra plastics with better cooling, but they don't make them in yellow! So, I might get the carbon fiber cooling wings from Lightspeed that direct more air to the radiators

The Yamaha valve train is probably the most bulletproof of the modern MX bikes, and is best suited imho for street conversion

Check out this company they make a 1/2" diameter tube for your gas line and it's like 15 bucks with tons of extra material.


Love your set up by the way!

Cooling is probably less of an issue on a street/supermoto than a dirt bike. My bike runs cooler when in supermoto form than when ridden off road. The speeds are much higher on a supermoto and in turn much more airflow and greater cooling. Unless you intend street use where you may be idleing for long periods I don't think heat is an issue.

I agree - when you're cruising along, there probably won't be that much of a problem, but we need all the help we can get while waiting at a light. Then again, if you're running cooler to start with, waiting at a light won't overheat you as quick. The larger the volume of water and oil you have the longer it will take to overheat also

hi i'm looking at a 2k yz 426 for sale localy and i was wondering if any one could point me in the right dertion to make it a street legal super moto thanks

i ride a yz426 on the street daily and have no problems full supermoto setup has a front fender with vents and also more stable at high speeds the mx fender flaps all over haha runs perfectly cool while cruising around some longer lights it will start to boil over im gonna add a fan off a ktm to stop the boil over when idling but the boil over is very rare only rele rele long lights or traffic i run a 14 41 sprocket have to slip clutch a little when starting but other then that its a dream on the streets and still fun as hell when we shoot off the streets and onto a trail say we do about 60/40 street to dirt riding longer street rides the vibration will get to your hands but its worth it blasting around the streets on the yz

I ride a plated 09 YZ450f.


 Your bike will commute well, but because of the short piston skirt their is a small amount of oil blow by at sustained high RPMS.  So if you do a lot of commuting, pay attention to when you change your oil. Graves makes a oil return canister you can mount that eliminates the problem, but if you change your oil frequently enough, it really isn't an issue.


My gearing is 14/40 and does well on the street, it tops out around 100 and I can ride comfortably at 60 for sustained periods.  


Up to 2010 the YZ shared the same 5 valve head configuration as the WR which is known as one of the most stable and reliable valve arrangements ever developed.  My bike has 105 hours on it and the valves are in the middle of the spec range. casper on SMJ rides a 06 YZ450 daily and just did a top end on his bike at 500 hours and the valves were still in spec. 


For lights I run a Ricky Stator 35 watt stator and a Ballistics Evo 2 - 4 cell battery.  The stator charges my battery and the battery runs my lights.  I have never run out of juice for my lights and they don't dim when my RPM's drop.  This setup can also be used to run a fan on your radiator if you encounter a lot of traffic on your commute.   I don't run a fan, but I also don't commute on my YZ, it is built for fun.

Edited by Zabrow187

I ride my YZ426 on the streets, and I love it. The YZ426 doesn't have the same coolant capacity as the WR426, because the YZ is more of a race bike vs the WR as a trail bike, and the WR has the coolant resivior that the YZ doesn't. In turn, the bike will get hot, and quick. I've had my bike at 274 degrees at a 5 minute stop light.

I'm in 5th gear at 45 mph through the city, still have plenty of gear left and have done 1+ hour trips at 60-70mph. I run 14/40 and have no problem powering up in 1-3 gear. I can sit down and slip the clutch in 4th to get it to come up, or stand on my seat and power up. I run 17's on mine with Michelin Pilot Power tires. Amazing cornering and sutible for the street.

If your gonna do it, get fans. Don't forget you will need either a WR stator (check fitment between YZ and WR stators) and remember you'll have to get the title from off road to on road.




Edited by YZ426Supermoto

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