Wr450 pos


32 replies to this topic
  • DezertXR400

Posted December 24, 2011 - 12:10 PM

#1

So long story short my buddy has an 05 WR450 that hasnt ran right since he bought it. He bought the bike used with all the free mods done and an FMF pipe.First trip out it had battery issues, popped and backfired a fair amount and about 10 miles into the ride the fuel drain screw fell out of the carb. not a good start to owning a bike. since then it has gone through several more batteries (not the bikes fault) and been in the shop twice for it just running like shit and both times it came back running better but still not right and went back down hill after a ride or two. One shop said the cam timing was off and reset and the other rejetted the carb and sealed an exhaust leak.

Now to the current issue. Bike has been sitting for about 2 months in doors since its last ride. Buddy has been busy with work and asked me to get it ready for our annual Glamis new years trip. Got the bike out and it was a BITCH to start and once it did it would not idle with the choke off. it never really has liked to idle with the choke off but it is worse now. i drained the gas and put fresh 91 in and it made no difference at all. pulled the carb (spotless inside) and went form a 52 pilot to a 55, again no difference at all. the fuel screw also make 0 difference, all the way in to 5 turns out does nothing at all. It will idle for maybe a minute once its warm but usually dies and while ride the throttle is very touchy with flat spots when under 25% throttle. it back fires and blows flames out the exhast occasionally and just all around runs like shit lol. carb seems clean, has what seems to be a huge pilot jet in it (55) and it still seems to be running supper lean especially when under 25% throttle.

Buddy is now getting very tired of the bike, its been nothing but problems since day one and has left him sitting the desert. Im trying to get it running right for him before he sells it but im at a loss. We have never once had to touch my XR and the carb has never been off since we both bought our bikes used at about the same time.


so cliff notes:

55 pilot jet
Wont idle
backfires/pops a ton
occasional flame out the pipe
very rough power when under 25% thorttle
no carb adjustments seem to effect how it runs at all.

Im 100% new the the WRs and appreciate any help i can get. we are running out of time before our trip and i dont have time to sit and read for hours like i normally do to solve a problem.

Thank you!

  • 2grimjim

Posted December 24, 2011 - 12:30 PM

#2

Do you know what the jetting has been changed to?

  • DezertXR400

Posted December 24, 2011 - 12:42 PM

#3

i have no idea what was in it when he got the bike. the second shop he took it to put a 52 pilot jet in it and i put a 55 in it last week. i cant remember what the main is at the moment.

  • mikewrf18

Posted December 24, 2011 - 12:43 PM

#4

A 55 seems too high to me. I run a 45 in the warmer months, and a 48 in the colder months. I own an 07' though, so I may be wrong. What other jetting changes have been made by the PO? Sounds like the PO may not have known what he was doing when uncorking that poor WR.

  • mikewrf18

Posted December 24, 2011 - 12:46 PM

#5

Just checked. The stock Pilot for the 05 WR450F is a 45.

With all the free mods on my 07'wr450f, I was running this:
MJ 168
PJ45
SJ65
PJ70
LJ50
NEEDLE-NEW DTR-4, 4TH CLIP FROM TOP
FUEL SCREW-2 TURNS OUT
I never messed with my jetting throughout the year, and I was happy with the way my bike performed. I ride the NW, and my elevation ranged from about 0 to 4,000 feet.
When I replaced my stock exhaust for a complete YZF exhaust I moved to a:
MJ170
PJ48 (winter)

  • dgcars

Posted December 24, 2011 - 12:47 PM

#6

I would check the hotstart mechanism (assuming there is one fitted). That would be a good place to start.

  • 2grimjim

Posted December 24, 2011 - 12:49 PM

#7

i have no idea what was in it when he got the bike. the second shop he took it to put a 52 pilot jet in it and i put a 55 in it last week. i cant remember what the main is at the moment.


Wow! The pilot jet is WAY off. No wonder it runs like poo!

  • DezertXR400

Posted December 24, 2011 - 12:50 PM

#8

i agree the 55 and even the 52 the shop installed seemed to large but is has all the signs of being very lean. the second shop also said there was an issue with the hot start and replaced the plastic piece with a metal one. anything else i should look at related to the hot start? also, should the entire stroke of the hot start handle have tension? the first half of the lever doesnt seem to have any resistance and the second half has a little bit of resistance.

  • 2grimjim

Posted December 24, 2011 - 12:53 PM

#9

Could be a couple of things. Float level way off, plugged vent hoses, or, if someone has the slide apart, they put the the front piece in upside-down.

  • DezertXR400

Posted December 24, 2011 - 12:56 PM

#10

hmm ive never had the slide out. any pics of how it should in installed? i can check it tomorrow. i also forgot to add the stock exhaust has been reinstalled so its basically an uncorked stock WR.

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  • DezertXR400

Posted December 24, 2011 - 12:58 PM

#11

and the electrically issues have been sorted. it was a combo of cheap batteries, using the elec start alot due to it running poorly and HID lighting that the stator couldnt really keep up with. all of which have been taken care of and it has been running the same battery for a year now.

  • dgcars

Posted December 24, 2011 - 12:59 PM

#12

i agree the 55 and even the 52 the shop installed seemed to large but is has all the signs of being very lean. the second shop also said there was an issue with the hot start and replaced the plastic piece with a metal one. anything else i should look at related to the hot start? also, should the entire stroke of the hot start handle have tension? the first half of the lever doesnt seem to have any resistance and the second half has a little bit of resistance.


Pull the lever...when you release you should hear a distinctive clink when it closes. If the plunger is not completely seated, the carb will have all the symptoms of being lean and no amount of jetting changes will have effect.

  • mikewrf18

Posted December 24, 2011 - 01:01 PM

#13

hmm ive never had the slide out. any pics of how it should in installed? i can check it tomorrow. i also forgot to add the stock exhaust has been reinstalled so its basically an uncorked stock WR.

I think it would help to get exactly what jets your friend is running in there and what mods were completed. The 52 and 55 pilot has me scratching my head, and if I were you, I'd definately be curious as to what other jetting changes have been made. At least then you can rule that out. If it was jetted for the aftermarket pipe that was on it, then you put the stocker back on, it could cause some issues with your jetting as well. When was the stocker put back on? Before or after your current symptoms.
I think DGcars is right on the money with ruling out the hotstart as well.

  • 2grimjim

Posted December 24, 2011 - 01:06 PM

#14

hmm ive never had the slide out. any pics of how it should in installed? i can check it tomorrow. i also forgot to add the stock exhaust has been reinstalled so its basically an uncorked stock WR.


The flat piece of the slide (with the round rubber seal) has a small hole in it. The hole should be at the bottom.

  • DezertXR400

Posted December 24, 2011 - 01:47 PM

#15

I just talked to the owner of the bike and he said he can hear a noise in the carb when he lets off the hot start so we are guessing it is closing properly. he also said he had the slide out a few months ago and looked a diagram to make sure it went back in right because he had heard about it being installed wrong. We are thinking about putting all stock jetting back in the carb, but that kind of freaks us out because EVERYTHING points to it being lean and we are going to put a smaller pilot and maybe a smaller main (neither of use can remember whats in it) in.

  • 2grimjim

Posted December 24, 2011 - 02:14 PM

#16

he also said he had the slide out a few months ago and looked a diagram to make sure it went back in right because he had heard about it being installed wrong.


Yeah, I would check the slide again.

The first time I encounterd this problem is when I worked at the Yammie shop and a customer brought in a DRZ with the same problem.

I beat myself senseless trying to figure it out untill I completely disassembled the carb.

  • DezertXR400

Posted December 24, 2011 - 02:28 PM

#17

thanks for the help everyone. we have a few hours to get it sorted out tomorrow before it goes on the trailer. hope we get it figured out or we will be taking turns on the trusty XR lmao.

  • 2grimjim

Posted December 24, 2011 - 08:32 PM

#18

Here's a pic of the carb exploded view. The slide plate is item 10.

Posted Image

  • miweber929

Posted December 25, 2011 - 05:46 AM

#19

Not sure how well you cleaned the carb, but the days of cleaning the jets only are long gone (like your do on your XR) and you need to clean ALL the holes, passageways and nooks or you're going to be forever chasing your tail.

Get new jets (stock), and clean that bad boy out. It still sounds to me, and I'm just guessing here, that the slow jet passageway is partially blocked or that slide is wrong as well. These FCR carbs are very finicky if everything isn't 100% perfect. and the tiny orifaces get clogged very easily.

I had an XR250 for 12 years that I absolutely loved. I think I cleaned the carbs (yup, it had 2) maybe twice in all the years I owned it. This WR will feel like a hyper XR once it's all sorted out. And about as reliable.

Mike

  • dustdogg

Posted December 25, 2011 - 12:23 PM

#20

If you want the fastest and easiest way to get the bike running like a champ go with the JD jet kit http://www.jdjetting.com/ and replace the fuel screw with an R&D flex srew http://www.r1dean.com/ or any other brass fuel screw. The JD kit has very good instructions for different temps and elevations and it will give you an assortment of jets, needles and a pilot jet. The carb should be thoroughly cleaned but watch the slide as the rubber will expand and cause it to bind up. This should help solve the carb problems.
I really don't think these issues are really the fault of the bike. All of the newer 4 strokes that are carbed run the FCR and it has proven to work very well when tuned properly. I do know that they do not do well when left with gas in them for long periods of time. Most of my problems with old gas has been a clogged pilot. These issues are not just Yamaha, they will affect Honda's, Kawis, Suzuki's etc... if treated the same. Start over with new jets a clean carb and make sure to drain the carb when it will be sitting for a month or more and you will be one happy rider that will forget about the ol' XR!!!




 
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