Yamaha WR250R Mega Thread

[AKASY]

10cup--hope you figure the key thing out, could be a real PITA.
Looking forward to your RR hope the weather holds for you like it did for me.
Ride safe.

Originally Posted by 10Cup

Guys, searched this forum but came up dry so will ask. Has anyone found a key blank that works with the Yamaha ignition hey? Tried all the Walmart blanks with no luck. As it is I'm on an extended trip and lost my key, do have a spare but would like to get another made while I can.

Any help appreciated

[bhd1223]

Originally Posted by debaisley

don't bolt the shroud on , just use thin zip ties. That way if you fall hard on the right side , the zip ties will break , and will save your radiator. If you use the bolts , the radiator can get squished. I have always used the zip ties , the shroud is perfectly secure.

Originally Posted by Crawdaddy

+1

Thanks for the tip guys. I do this for the plastics on my road race EX to help keep them from cracking but didn’t even think about their uses in other applications. Do you recommend the small ones or the normal size? The small ones are the ones that are like 4 or 5 inches long and maybe 1/16 or 1/8” wide. I think the normal size are about 8” long and 1/4” wide.

[debaisley]

i use the smallest ones i can get , i think they are about 1/16" wide , they hold real well.

[bhd1223]

Originally Posted by debaisley

i use the smallest ones i can get , i think they are about 1/16" wide , they hold real well.

Just one per hole? Does that stand up well to highway speeds?

[debaisley]

yep, pull em down nice and tight, will give the shroud a little flex when you fall on it , but it wont feel loose at all.

[bhd1223]

Well I removed the bolts and installed the small zip ties. There is some play which worries me about the ties wearing down over time but they'll get a nice long high speed test shortly. I'm sure they'll do fine.

[Krabill]

Just be sure to carry extras with you.

[SchizzMan]

Originally Posted by bhd1223

Well I removed the bolts and installed the small zip ties. There is some play which worries me about the ties wearing down over time but they'll get a nice long high speed test shortly. I'm sure they'll do fine.

Try fitting two thin ones in each hole. That way when they start cracking and shedding off you have redundancy and an easy visual check. Should still break off to save it in a hard fall.

[Crawdaddy]

Shameless plug....

We're only about a month away from the next ride at Primm/Bar 10 Ranch/Toroweap, etc......I'm about half booked right now and I need to get the numbers finalized for motels/Bar 10/T-Shirts/etc.....join us if you can......the trails/views are incredibly scenic....

http://crawdadoffroadevents.com/core-calendar/view/15

[R_Lefebvre]

Originally Posted by HardWorkingDog

I don't know if that's just a weird coincidence, or maybe if I took the time to figure out all the unit conversions it would turn out that we're really saying the same thing. Or not.

Anyway, the stoichiometric ratio of 14.7 parts air to 1 part fuel is what would be needed to just exactly burn every bit of fuel, completely. In a perfect world.

Modern fuel management systems try to get the air-fuel ratio as close to that as possible to minimize exhaust pollution, while still providing enough power to satisfy the need for speed. And sacrifice performance in the process. Racers, as an example, don't aim for 14.7 to 1.

Not entirely correct.

First of all, the 14.7 number is just pure coincidence. It's actually based on a mass ratio, atmospheric pressure has nothing to do with it, and 14.7:1 is still the number if you're on top of Everest where the air pressure is lower than 14.7psi.

Secondly, even in a perfect world, 14.7:1 will not burn every bit of fuel, or every bit of air, completely. Due to randomness of nature, there will always be some molecules that do not combine properly. This is why even the cleanest engine will still emit CO, NOx and O2 before it gets to the catalytic converter.

The amount of unburnt O2 in the exhaust stream is measured, and this is how we determine the AFR. When you run richer than 14.7:1, NOx and O2 falls off, and CO and unburnt hydrocarbons skyrocket. When you run leaner than 14.7:1, O2 goes up, NOx skyrockets, and CO and HC falls. 14.7:1 is the point at which NOx, CO and HC are the lowest in combination, and also provides the correct balance of chemicals to the catalytic converter to clean up all three.

Modern fuel injection systems only shoot for 14.7:1 at light and moderate loads. At full load, they ALL go richer than that. In this regard, racers and street engines are the same. At light loads where you can run full timing advance, 14.7:1 actually makes more power than running rich. But above a certain load, you have to start either pulling timing, or richening the mixture to ward off detonation. 13.0:1 is a pretty safe target for a naturally aspirated engine. 13.5:1 will yield even more power, but at the risk of detonation. This is where racers differ, as they will push the limits to get more power and sacrifice engine life.

[HardWorkingDog]

Originally Posted by R_Lefebvre

Not entirely correct.

First of all, the 14.7 number is just pure coincidence...

Secondly, even in a perfect world, 14.7:1 will not burn every bit of fuel, or every bit of air, completely. Due to randomness of nature, there will always be some molecules that do not combine properly...

Alright, let's get into metaphysics! I love it

So, in a perfect world is coincidence possible?

Is there such a thing as randomness, in a perfect world?



Anyway, thanks for carrying on the afr search. I'd love to get a Power Commander and an afr meter. In the meantime, I just want to ride even more...

[jtmajors]

I have an x and putting pirelli mt 21's on it. Sizes are 120/90x17 for the front and 130/90x17 for the rear. Having a hard time finding a tube in those exact sizes and wondering if a msr heavy duty tube that is 70x100x17 will work?

[bhd1223]

Originally Posted by HardWorkingDog

Alright, let's get into metaphysics! I love it

So, in a perfect world is coincidence possible?

Is there such a thing as randomness, in a perfect world?



Anyway, thanks for carrying on the afr search. I'd love to get a Power Commander and an afr meter. In the meantime, I just want to ride even more...

I believe in the perfect word everything is a random pattern. So anyways, the zip ties held fine. I doubled up upon return anyways though.

[cug]

Originally Posted by HardWorkingDog

Is there such a thing as randomness, in a perfect world?

In a perfect world, randomness would be truly random and not based on physical or algorithmic pseudo randomness, or other reasons.

[Reposado1800]

Originally Posted by jtmajors

I have an x and putting pirelli mt 21's on it. Sizes are 120/90x17 for the front and 130/90x17 for the rear. Having a hard time finding a tube in those exact sizes and wondering if a msr heavy duty tube that is 70x100x17 will work?

It should work. I got the WRX tube sizes at SWMoto tire. Have you checked there yet?