Yamaha WR250R Mega Thread

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

  1. Bgunn

    Bgunn Mucha distancia

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    CheapCycleParts.com $238 and $9.99 shipping, also had other parts with the order.
  2. fred flintstone

    fred flintstone Been here awhile

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    Thanks for your reply. Yes it is either on or off but it cycles to maintain pressure faster or slower depending on engine load. What I was getting at is any electric pump has a max flow rate, and at that point the electric motor inside it is cycling at its design limit to maintain fuel system pressure. This generates a certain amount of excess heat. Part of the design of an in-tank pump is that heat is dissipated by the fuel in which it is immersed.

    Performance mods + hard riding + heavily loaded will cause higher demands for peak flow rate out of the pump. Low fuel levels + high engine & ambient temps & low speeds also increase heat effects as the fuel cannot dissipate the heat from the pump as well.

    I was just guessing that many folks ride the shit out of these bikes loaded & modded (which is a good thing believe me) but maybe the fuel pump is too often at or beyond its design limits in a situation with a low fuel ( so poor heat sink) and so it fails. It would be nice to have a higher capacity aftermarket pump available or at least understand what factors are causing this so as to minimize the likelihood of occurrence. Then again I would expect Athena big bore folks to have the most failures if this is a correct thesis.

    I am purposely not modding the engine til I understand this better, much of my riding is way the hell off and gone solo in the mountains and I really don't want to have to deal with a fuel pump going out @ 12k ft 30 miles from anywhere. High elevation makes heat problems worse as the ambient air pressure is lower, so its ability to absorb radiated heat is less.

    Anyway so far the take away message seems to be, do not run out of fuel or get too low, esp while riding hard & slow, and if you do maybe ride more conservatively to minimize heat build up.
  3. Curbhopper

    Curbhopper Been here awhile

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    Rode the Meteor ride this past Saturday and crashed big time, this swift moving pine darted out just as My front tire washed out in deep sugar sand. My bike gave the tree a kiss followed by a hug with me in between. This sweet embrace took the breath out of me and offered some small mystifying stars to gaze upon. While several riders behind are pulling the love birds apart to avoid rubbernecking, I regain composure and decency only to find my Alpinestar suit saved my right forearm from becoming two and the WR unscathed. We left the love starved Pine tree alone and broken bark ed.:D

    Points I like to make:

    1) The WR is built like a tank. (weighs like one too)

    2) Alpinestar suit really works.

    3) Radiator guard works for sure.

    Protection gear for bike and rider is paramount for a great day in the woods. :ricky
  4. pfy50

    pfy50 Professional nOOb

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    Hey NeilW,

    I am thinking that the Mod is feeling the extra heat because it is in fact damaging the efficiency of the fan to pull air away from the rear of the radiator. The purpose of the shroud is to direct the air& heat coming thru the radiator to the fan for removal effectively. If you put holes in the shroud it no longer is working as designed. To move more heat away from the engine you make the radiator larger, the fan larger or the same fan faster, or some combination of those three.:huh
    Just imho.
  5. jon_l

    jon_l Long timer

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    Seems like a likely theory. I try to never let my tank get too empty for that reason, to keep the pump immersed.

    I have read this entire thread, and my impression is that fuel pump failures generally aren't catastrophic, but rather, intermittent, and parking the bike for 20 minutes usually results in it starting and running fine (until the next occurrence). So I wouldn't hesitate to go out there on the WRR, and would replace it first sign of impending failure.
  6. fred flintstone

    fred flintstone Been here awhile

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    Yep I read the whole thing too. I guess one thing would be if it does go out and you are low on fuel, see if you can't get a little more fuel in there from a buddy or aux source, whatever, for cooling, then let it sit for 20 minutes and go. Some people seem to not have the pump completely fail after a few of these episodes so I wonder if you could get away with it w/o buying a new pump if it happened once or twice.

    In my case i got a 3.1 gal IMS tank and never let it get much lower than reserve light coming on. That seems to be with 3/4 gallon left or so.
  7. what broke now

    what broke now Petroleum Brother

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    " Yes it is either on or off but it cycles to maintain pressure faster or slower depending on engine load. What I was getting at is any electric pump has a max flow rate, and at that point the electric motor inside it is cycling at its design limit to maintain fuel system pressure."

    My understanding was that the pumps ran constantly and either delivered fuel to the injector or bled it off through a fixed- pressure relief valve. There is a single "cycle" when the key is turn on, but I thought the pump ran 100% when underway. Is that not the case?
  8. fred flintstone

    fred flintstone Been here awhile

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    You may be right it would not be the first time I did not understand something.

    edit:

    "On most older vehicles, the fuel pump runs at a constant speed. But on many newer applications, the pump speed is varied by the PCM to more closely match the engine's fuel requirements."

    http://www.aa1car.com/library/fuel_pump.htm

    But even is the WR is variable rate I think you are right in general that the main cause is running the tank low under hot ambient conditions.
  9. Crawdaddy

    Crawdaddy Navigate 2 Adventure

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    I have a 2008 model......it has 14K miles on it.......1K with the 290 kit......I fit in category (d).......and I have had NO
    pump issues......I have to believe the failures are in the minority not majority.......oh shit, NOW I've set myself up for failure :eek1 :lol3
  10. bigdon

    bigdon Long timer

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    My bike quit in a bad place. We tested everything and put it back together. Battery was hot , would turn over but not start. Tank was full,cool morning,maybe 10 miles ridden.
    We took fuel line loose from bike and tried pump. It would send gas out in a stream but not very strong.
    We then pushed bike down hill and it fired right off. I rode it another 100 miles that day and then hauled it home.
    I started and rode the bike with no problems 4 or 5 times while waiting for my new fuel pump t arrive.
    I installed the new fuel pump and have ridden the bike probably 500 miles without indecent.

    Has anyone else tried to shoot a stream of gas with the fuel pump unhooked from bike?
    Did it dribble out maybe a foot or so like mine did or did a shoot a high powered stream like I think it should?
  11. fred flintstone

    fred flintstone Been here awhile

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    Do you frequently run the tank low or even empty? Also is yours an early production 08 model? Mine is.
  12. Crawdaddy

    Crawdaddy Navigate 2 Adventure

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    Frequently? No, not now that I have an IMS and Rotopax. But I did run it bone dry out of curiousity with both the stock tank and the IMS.....

    Ok, I guess I'm a 100% (a), 10% (b) and 100% (c) :D

    How would I know if it's early 08 vs. late 08?........do you pick that up from the VIN#?
  13. ba_

    ba_ Long timer

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    What options do I have for connecting a relay for use with a fuse block?
  14. what broke now

    what broke now Petroleum Brother

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    "Has anyone else tried to shoot a stream of gas with the fuel pump unhooked from bike?
    Did it dribble out maybe a foot or so like mine did or did a shoot a high powered stream like I think it should?"

    I have not tried that, but I am pretty sure the relief valve is set for about 32psi [+-] so it sure should go more than a foot.
  15. fred flintstone

    fred flintstone Been here awhile

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    Thanks for the info. Yeah it is the VIN # last 4 or 5 digits I can't remember. However some people w 09 models and even some with replaced pumps were also getting failures so who knows if that early VIN thing is still valid.

    Another hypothesis. Low usable fuel tank capacity + super capable & wildly popular new bike + maybe pump placement in tank leads early adopters to run out of fuel a lot.

    I was raised to never let EFI vehicle run out of fuel, so have always been careful with that but maybe the way the pump sits in the tank it is not cooled well or even at all at low levels. Who knows.
  16. Scott_PDX

    Scott_PDX Leisure Engineer

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    I tied into a rear light (blue wire IIRC) under the seat and tied directly into the battery which worked just fine. However, I just recently went with an Eastern Beaver fuse box set-up (#3CS) to make things a little cleaner down there and give me some extra ciruits for lights/heated grips. It came pretty much plug and play, took 10 days or so to recieve it...from Japan.

    http://www.easternbeaver.com/Main/Wiring_Kits/Fuseboxes/3_Circuit/3_circuit.html
  17. ba_

    ba_ Long timer

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    You still need to tie the Eastern Beaver fuse box to a wire like the rear light in order for the switched and un-switched circuits to work, correct?
  18. thumpididump

    thumpididump MacGyver

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    Been trying to find a video I saw a while ago, and wondered if someone can help me find it again.

    It was a short clip of a WR250R that was accelerating through a parking lot, and it suddenly looses power (like the fuel pump quit, or like the ignition stopped firing) for just 2 or 3 seconds, then the problem went away. Just a momentary loss of power from fuel or ignition problems.

    Anyone know which video I'm talking about?
  19. duanew1

    duanew1 In my Pajama pants

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    I believe that the fuel pumps are more of a pressure pump than a flow pump due to the low flow requirements during operation. I would think that the fuel hose is a very large orifice (in comparison to fuel jets) which would not allow pressure to increase to a long shooting stream. A smaller opening would probably shoot farther.

    On the other hand, I think that this might be a good way to kick start a stuck pump in the field if needed.
  20. Scott_PDX

    Scott_PDX Leisure Engineer

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    Yes. There is a lead ready for you to splice into the line. I think he provides one of those posi-vampire crimp things as well. But I try to solder all my connections.