Yamaha WR250R Mega Thread

Discussion in 'Thumpers' started by Sock Monkey, Apr 7, 2008.

  1. onetravdown

    onetravdown I can't ride where?

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    Since my house is full of females, hair spray is readily available. That's the method I use as well.
  2. duanew1

    duanew1 In my Pajama pants

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    I have used Scott's grip glue and I must have done it wrong. It was no time before they started spinning on the bars. I cleaned the bars as best as I can and used hairspray and it has lasted a long time.
  3. Rufjeep

    Rufjeep Been here awhile

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    Is that a fact? (and I am not being sarcastic). It's true I have no real indication of a lean condition, but I am utterly clueless what the FI is doing to compensate for the added air flow from the flapper mod and exhaust. I like Yamahas, but the name and praise of the products don't do much to alleviate my concern.

    Since I ordered the programmer, I will go ahead and open the airbox a bit more and see if I can extract a little more HP (I mean, hey, I like HP as much as the next guy:D). But, knowing the bike is "right" (and not just specualting) will be as or more satisfying for me.
  4. HardWorkingDog

    HardWorkingDog Super Ordinary

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    What part? And I'm not being sarcastic, either. You're not going to get much in the way of facts here, I'm offering observations based on my own unique experience...and I think what I've written is correct, until shown otherwise. :norton

    Sounds like you've got some work to do. You want peace of mind? Figure out how the FI works in this particular model, figure out if the as-designed lean fuel mapping is "harmful" or not to the longevity of the WR250R/X engine.

    That's not what I meant at all. If you took my post as some simple-minded allegiance to the name of Yamaha :eek1 I failed miserably as a writer trying to express myself. I'll try differently: The people who designed and built this particular bike have created an exceptionally hardy engine that will run on a wide variety of fuel and air conditions.

    But that's just my own observation. Feel free to ignore it.

    So, how exactly are you going to know the bike is right, beyond mere speculation?
  5. mordicai

    mordicai Adventurer

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    I would not open the airbox and put a flow through muffler on my WRR without using a programmer, unless I wanted to try and put holes in my piston.
  6. SteveO

    SteveO scratched and bruised, but not out Supporter

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    So, are you saying it would run to lean and eventually melt/blow the piston?
  7. treybrad

    treybrad Been here awhile

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    The WRR's FI system is simple, really simple. There's no O2 sensor (in the US), so it's going off a stock map, and only adjusting the A/F ratio using some kind of intake pressure sensor to compensate for altitude (feel free to correct me if I'm wrong, I may be). When you do things like open up the intake and exhaust, the bike doesn't have any way to 'see' that it's running lean, so it doesn't do anything to compensate.

    In contrast, my Bandit has an O2 sensor. It uses that, in harmony with the pressure sensor to make sure the A/F ratio is safe. Of course, you still run into the unknown area of how much the stock ECU can compensate for mods, even with the O2 sensor. It might know it's lean, but can it adjust itself back to safe...? Just like the WRR, there's lots of speculation, but not much real data...

    The point is, without spending some quality time on a dyno with a sniffer, I don't think anyone can verify that their bike is or isn't safe once they've modded the breathing, especially on a bike that runs lean from the factory and isn't clever enough to adjust itself on the fly.

    But then, I'm no expert, my Bandit and WRR are bone stock, so...

    trey
  8. thirdcoaster

    thirdcoaster Been here awhile

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    The vibration sensitivity problem is not a new one to me, but getting worse the last 10 years, so I have figured out the loose grip trick. Much of the time while street riding, the only thing my right hand is touching is the Cramp Buster, offroad requires at least a fingertip grip.

    You are also definitely correct about knobbies buzzing on the street - I just put my "X" wheels back on the bike yesterday - Oh what a relief!:lol3
  9. skian g

    skian g Adventurer

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    I'm not sure I can buy into this. If you free up the exhaust the engine isn't going to use or expel anymore or less air. It will only be doing it more efficiently (easily). This allows the engine to apply more of the power that it is making to the rear wheel instead of pushing the hot gasses through the exhaust. It can not hurt the engine by doing this alone on a stock engine.

    Now the intake part made me think a little harder. At first I thought opening the airbox on a stock engine cant make the mixture more lean. Then after a little bit I convinced myself that if the engine was for a simple example "sucking air through a larger straw" it would get more air and could cause a lean condition. However after looking at the exploded parts diagram called "intake 2" it shows number 17 in the drawing "SENSOR, PRESSURE" connected to the throttle body after (engine side) the butterfly plate. So this means that the sensor is actually reading negative pressure or vacuum in the intake plenum which makes me think it actually does a very good job of telling the ECU how much air is going into the cylinder, since the ECU knows how long the valve is open at any given RPM and also the pressure of the air, and the volume of the intake plenum the ECU can calculate a Volume Flow Rate. This allows me to reason that despite how open the airbox or free flowing the exhaust is the ECU should still be able prevent a TOO (unsafe) lean condition. Sure it might be more lean than when everything is stock but unsafe... I highly doubt.

    Granted once you do these things and the engine can breathe easier then adding a programer allows you to optimize everything.
  10. Rufjeep

    Rufjeep Been here awhile

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    Hardworking Dog- I think I was the one that wasn't expressing myself well. I didn't mean anything remotely antaganistic in my response to you about the programmer. I appreciate your feedback, but as the later posts on the subject seem to attest, there is a ton of speculation on weather a programmer is needed. Some say you will burn your piston, and others have been running with a pipe and air box mod for thousands of miles with no issue.

    I was hoping there was some real data out there about the A/F ratio through the powerband with various mods (air box, slip on, full pipe, programmer, etc).

    Since I have yet to uncover that data, I am going to ere on the side of caution and install the programmer. The fact is, the life expectancy of two identical bikes can vary considerably based on the type of riding they see. You may be fine with no programmer, but my piston may fry. Since I do alot of low speed, sometimes abusive, woods riding, I just don't feel comfortable taking a chance.
  11. DougZ73

    DougZ73 Fading off.........

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    I'll throw in my backyard knowledge on the subject, and what little I have learned from shadetree working on cars, trucks and motorcycles.

    1. Most modern day vehicles come in a "lean" condition from the factory for emissions reasons.

    2. Opening up the intake and/or exhaust helps a motor to breathe(take in more air) better.

    3. Said combined air from #2, with still "normal" fuel supply, can/will make the lean condition even leaner.

    4. With 1,2 & 3 stated, programmers add fuel to compensate for extra air, now being taken in.

    5. Accurate(perfect) fuel map can not be created without running an air/fuel ratio analyzer, with bike on dyno.

    6. If a bike is lean at idle, does not necessarily mean its lean everywhere.

    7. "ideal" fuel air ratio has been found to be 14.7 : 1. This is proven with stoichiometry.

    With all the above said..I personally do not know how lean or how rich is a problem. Where will the engine burn through a piston..I do not know myself.

    Guys that tune race bikes on dynos, usually will go step by step through the RPM range and add or remove fuel, based on the torque curve, to get the optimum power curve.

    based on 1-4..I feel more comfortable myself using a programmer.

    That's all I got. :D
  12. bhd1223

    bhd1223 Been here awhile

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    http://www.wrrdualsport.com/tech-guide/dynotesting provides some dyno results showing A/F ratio with mentioned mods.

    Looking at them myself, in those specific circumstances, I don't see A/F getting higher than 15:1. Could you get by just fine forever without any programmer? Sure. Can you damage the engine by not using a programmer and running it in certain weather conditions? Sure. Really, it's a craps shoot either way you look at it. Personally, this is just my opinion, I would add the programmer if I opened it all up. Even much more sophisticated automotive fuel injection systems can't always calibrate properly for modifications. If I'm willing to shell out $500 for an exhaust you can bet I'm willing to spend $700 for that same thing with the ability to make sure it's running properly. Over the course of the life of the bike how much is $200?

    This could just be ancient history since technology has progressed so far but when I was younger I always remember between 12 and 13:1 as ideal for making power, 12 on the rich side and 13 usually around the perfect balance point. This could only be in the instance of high performance engines though. Just remember, too rich helps keep temps down, too lean causes more heat. Figure out what margin of safety you feel comfortable with and go for it. If you look at those dyno graphs you can see the green line for A/F and it appears to be about 13-13.5:1.

    *The following is more than likely an oversimplification in many ways*

    If you're not willing to purchase something to adjust for mods, why mod? Isn't some jetting needed on all carbs when mods are added? If there is no oxygen sensor in our exhaust, I haven't seen one, then all we really have is a carb that is jetted to a standard setting which has adjustments set for different atmospheric conditions. I suspect this is a closed loop system since it's only taking information from a single pressure sensor. If that's the case then there is a simple map programmed in the ecu and the sensor input just goes to the map where the output for the fuel injector is then activated. It's basically like a big spreadsheet with rpms and atmospheric conditions the determining factors. The only mods that would change anything would be intake mods. They would change the conditions the sensor sees. The map does not change, only the output for the injector. This may or may not be the same output as before. If you change the exhaust it has no bearing on the fuel map or the selection of an output.

    I've never truly understood how exhaust changes lean an engine out but they do. My simple theory for explaining this proven fact is that a free flowing exhaust allows the cylinder to fully clear during the exhaust stroke. This allows a full injection of fresh air during the intake stroke when before some residual combusted material was taking up space not allowing a complete fill of fresh air. Less air, same fuel, richer mixture. Add exhaust, more air, same fuel, leaner mixture. In the case of our WR250R/X it had been proven with dyno runs that opening the airbox on a stock exhaust shows no/little change, therefore the max amount of air is already being taken on the intake stroke. Adding available air does nothing, it's already taking in the most it can before you create additional air. Provide a more flowing exhaust, then open the airbox, big difference. The exhaust is allowing more to clear out of the cylinder, this in turn allows more air to be taken in. Opening the airbox shows that it was limited by what was available and now the additional air is usable. Hopefully that was as simple as it sounded in my head.
  13. ramz

    ramz Professional Trail Rider Supporter

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    Actually, you can only create a fuel map for a limited number of throttle openings (usually full throttle) and engine RPM, and only one gear by using a dyno. If you want a close-to-perfect fuel map, you need something like the DynoJet Power Commander V and the partner Auto Tune unit. With these and an O2 sensor in the exhaust, you can get AFR values for every 10% of throttle opening, every 250 RPM, and for all 6 gears. This includes whatever mods you've done to the intake/exhaust or any other engine related system on the bike, now or in the future. Further, the AFR values are used to correct the actual fuel injected pulse WHILE you are riding at whatever elevation and temperature you happen to be riding at and whatever speed you select. And it calculates these changes every time you ride your moto. And YOU select the target AFR values you want: performance vs economy. You can also lock in a map at any time as well.

    Dyno generated maps and the FMF Power Programmer (and related units) are a good first step to getting better performance (and possible reliability), but the PC V and AT are far more powerful tools. The cost, from $500 - $700, may put some people off, but I can tell you that as far as I am concerned, the cost is more than acceptable.

    Theory is great, but the actual values you want are found to be different. I was advised by Eddie Sisneros, the ThumperTalk tuning moderator, the following:

    Eddie Sisneros 11/12/09

    You will find that above 14.0 the bike will run bad; I would not go leaner than 14.0.
    12.8 is also rich for max power production; you will want 13.0-13.2.

    I would set the 100% throttle column at 13.0 and the rest of the columns except 0% to 14.0.
    This will give you good economy at any partial throttle openings and best power when you open the throttle fully.

    If you decide you want better driveability than what 14.0 offers at partial throttle, you can test 13.5 to 13.8.
    -------------------------------------------------------------------------

    Check it out:
    http://rickramsey.net/WR250Rtuning.htm
    :thumb :thumb
  14. kawagumby

    kawagumby Long timer

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    Just opening up the airbox did not seem to lean my bike out at all. It starts and runs very well when cold - just as it always has, and the plug is the right color...
  15. DougZ73

    DougZ73 Fading off.........

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    I did say shadetree. :evil
  16. HardWorkingDog

    HardWorkingDog Super Ordinary

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    :thumb
  17. big-t

    big-t Been here awhile

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    How do I get out of the diagnostic mode ??

    I was adjusting the EXUP cables and did the "hold 2 buttons down,switch on,toggle to Diag and hold the 2 buttons down to confirm diag mode.Then went to test 53 and worked the EXUP. After I finished, my understanding is when the switch is turned off the pcm exits the diag mode.Not happening..

    Now when I do the "two buttons down,turn switch on " it goes to the Diag mode and I can't get it back to the Co mode.

    Probably got the sequence wrong or something like that...any one else have this problem??

    Anybody know what I'm doing wrong ??:ear
  18. GSBS

    GSBS FunHog

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    Added FMF PC4 pipe - no programmer - at 8K miles. Simultaneously removed EXUP and AIS stuff, opened up airbox, added K&N air filter. Went into CO mode and rode the bike, set CO, rode some more, tried another setting, etc. etc. Ended up running best at +4 (factory setting was at -3 or -4). Checked spark plug 100 miles later and it looked just right (not too light or too dark).

    The bike absolutely rips. I can't think of a place in the powerband I'd change. So I see no need for a programmer.

    FWIW, the bike is now at nearly 15K and it's been run hard (often up against the rev limiter). Not a hiccup. YRMV, but that's my experience for almost 7K miles without a programmer.
  19. Rufjeep

    Rufjeep Been here awhile

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    How much di dyou open your airbox? Flapper mod or even more than that?
  20. GSBS

    GSBS FunHog

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    It now has no top. Removed flapper completely.

    BTW, the bike actually runs cooler since doing the mods. The radiator fan seldom comes on unless it's really hot and I'm barely moving. Before removing the EXUP, AIS and opening airbox, adding pipe, it would come on much sooner.