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Yamaha WR450F (2012)


Owner: 51fiftey
Added on September 16, 2016



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Yamaha WR450F 2012


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2012 WR450 Starting woes

Yamaha WR450F 2012


500 replies to this topic
  • Bass Mechanic

    TT Silver Member

700 posts
Location: Colorado

Posted July 20, 2014 - 03:38 AM


I have the 14 and once I get her hott she will not at all fire with the button. I have to kick it. I just came across this thread today and Im going to call b&b cycles tomorrow to see if they can put my CO to 15 as suggested by others here. I'll post up results. Btw. My 14 has 67 hard earned hours.


There is no problem starting these bikes, my 13 was exactly the same as all these guys bikes, until I read the owners manual. Just like my dealer told me you have to crack the throttle open just slightly and it fires up every time, hot, cold, in gear ect..
The problem is if you don't remember to do this every time you'll have problems.
I posted this back several pages ago but nobody read it.
There are 2 lines on the throttle control housing.
The grip has a line on it, it's actually the line that gets made when the grip was molded in 2 halves. They install the grip at the 1st top line abs you supposed to turn the throttle just slightly to the second bottom line. It literally feels like your just putting tension on the throttle cable. ITS THAT SENSITIVE!
But in fact you are opening the throttle slightly. I know it sounds dumb, and I know it doesn't make any sence and I know the guys reading this will think I'm full of it but hopefully they will stop trying to analyze and just try it.
I read someone mentioned here turning up the idle helped. I'm not surprised. If you turn it up far enough you'll hit the sweet spot and it will start every time.
I like my idle at 1700 rpm.
But if you don't follow the instructions to the letter, wait for fuel pump to stop, slight turn, start! You'll have problems even if you do it right a second time. If you hold it open to far it won't start. If you use no throttle, it won't start initially but will eventually start. And you cannot start, then try to find the sweet spot with the throttle, it will not start that way. You have to start over by putting the grip at the bottom line and try again.
I've had my bike over a year and over 1500 miles on it and I just live it. Starts first try every time. My bike has had the cams re-degreed, custom tune and fmf exhaust, comp ecu
Hardly stock. But still fires up first try 99% of the time. This thread frustrates me because even the mechanics won't take the time to read the manual and discover how to start these bikes

Everyone wants to try to fix it by means of programming and it's really not that big of a deal.

  • mikenash

    TT Bronze Member

368 posts
Location: Nevada

Posted July 20, 2014 - 01:50 PM


There is no problem starting these bikes, my 13 was exactly the same as all these guys bikes, until I read the owners manual. Just like my dealer told me you have to crack the throttle open just slightly and it fires up every time, hot, cold, in gear ect..
The problem is if you don't remember to do this every time you'll have problems.
I posted this back several pages ago but nobody read it.
There are 2 lines on the throttle control housing.
The grip has a line on it, it's actually the line that gets made when the grip was molded in 2 halves. They install the grip at the 1st top line abs you supposed to turn the throttle just slightly to the second bottom line. It literally feels like your just putting tension on the throttle cable. ITS THAT SENSITIVE!
But in fact you are opening the throttle slightly. I know it sounds dumb, and I know it doesn't make any sence and I know the guys reading this will think I'm full of it but hopefully they will stop trying to analyze and just try it.
I read someone mentioned here turning up the idle helped. I'm not surprised. If you turn it up far enough you'll hit the sweet spot and it will start every time.
I like my idle at 1700 rpm.
But if you don't follow the instructions to the letter, wait for fuel pump to stop, slight turn, start! You'll have problems even if you do it right a second time. If you hold it open to far it won't start. If you use no throttle, it won't start initially but will eventually start. And you cannot start, then try to find the sweet spot with the throttle, it will not start that way. You have to start over by putting the grip at the bottom line and try again.
I've had my bike over a year and over 1500 miles on it and I just live it. Starts first try every time. My bike has had the cams re-degreed, custom tune and fmf exhaust, comp ecu
Hardly stock. But still fires up first try 99% of the time. This thread frustrates me because even the mechanics won't take the time to read the manual and discover how to start these bikes

Everyone wants to try to fix it by means of programming and it's really not that big of a deal.

Wow Bass Mechanic, Your very confident or a little over confident I'll say as I have 14 with comp ECU GYTR muffler and it won't start after it gets hot with a little "Cracked" throttle stock map setting. I have owned a many bikes and this isn't normal. Yes I have gone through the manual as well. So Yes there is a lot other people out there as well as me that do have this problem and it's due to Yamaha to having to get the bikes to meet epa/carb so they can import the bikes, So Yes there come through WAY TOO LEAN!! and that needs to addressed.


Edited by mikenash, July 20, 2014 - 01:50 PM.


  • vlxjim

    TT Bronze Member

343 posts
Location: California
Garage View Garage

Posted July 21, 2014 - 11:50 AM


There is no problem starting these bikes, my 13 was exactly the same as all these guys bikes, until I read the owners manual. Just like my dealer told me you have to crack the throttle open just slightly and it fires up every time, hot, cold, in gear ect..

I'm not sure were to start on this one. 

First off YES there is a starting problem. I was one of the lucky ones that had one that started most of the time. I too use the workaround of cracking open the throttle. The problem was when too and when not too. Still this is not right. You should not have to do this. 

This is an EPA / CARB problem. If you have owned a carbureted bike in the past or a lawn mower for that fact you know that the EPA / CARB wants you to not play with the idle fuel mixture. Note that the adjustment screws are plugged or limited. For the FI WR's the power programer gives no access to this as well.

And now Yamaha is telling the dealers to bump the CO to 7  (Still to low but better).

A few of us knew how to fix this before Yamaha came up with this fix. Just as we had on FI street bikes. The hardest part was getting an IF tool to make the changes as the dealers don't know shit just like your dealer.

Look I have never worked on any performance motor that had such a lean idle as the WR. First off the fact that the head pipe glows red at idle is a sign. Or the overheating at low rpms. Or the finicky starting.

I'm here to say that a bump of 15 CO makes the bike start better in all conditions. The head pipe no longer glows. It runs cooler at lower RPM riding. And gives you more power off idle when your bike is maped right.

I also own Yamaha quads that are fuel injected. I run MSD FI controllers that start on the first press of the button. But the MSD lets me adjust the fuel at idle. Unlike the Yamahas were you are lock out (not given) that feature. 

Trust me if you could get a hold of an FI tool or have the dealer bump you to 15 your song would be different on this board. It does make a big difference.



  • woods-rider

    TT Addict

3,005 posts
Location: Oregon

Posted July 24, 2014 - 07:50 AM



I'm here to say that a bump of 15 CO makes the bike start better in all conditions. The head pipe no longer glows. It runs cooler at lower RPM riding. And gives you more power off idle when your bike is maped right.

I also own Yamaha quads that are fuel injected. I run MSD FI controllers that start on the first press of the button. But the MSD lets me adjust the fuel at idle. Unlike the Yamahas were you are lock out (not given) that feature. 

Trust me if you could get a hold of an FI tool or have the dealer bump you to 15 your song would be different on this board. It does make a big difference.

 

Bumping up the CO made starting worse for me. I used one of the FI tools and played around with the CO settings for about a week and ended up at a CO setting of 2. I should have gone back to 0, but 2 is close enough. My bike has the airbox snorkel removed, FMF Powercore 4 with competition ECU and FMF map.



  • vlxjim

    TT Bronze Member

343 posts
Location: California
Garage View Garage

Posted July 24, 2014 - 09:10 AM


Something is not right here. The tolerances of these motors is close enough that the tuning should be within plus or minis 5% between one motor and another. The air fuel mixture is way to lean for the idle set at 1900-2100 RPM's. It could be that your compression is low or your fillter has to much oil. Or your idle is not set right. Its just not adding up.

 

Also I run the airbox snorkel and use the FMF Q4. So your setup should need more fuel then I need.


Edited by vlxjim, July 24, 2014 - 09:14 AM.


  • mebgardner

    TT Silver Member

574 posts
Location: Arizona

Posted July 24, 2014 - 11:24 AM


Bumping up the CO made starting worse for me. I used one of the FI tools and played around with the CO settings for about a week and ended up at a CO setting of 2. I should have gone back to 0, but 2 is close enough. My bike has the airbox snorkel removed, FMF Powercore 4 with competition ECU and FMF map.

 

Woods:

 

I agree with vlxjim in this instance. You're the only one I know, so far, that has a continuing "hot start" problem after a CO adjustment.

 

I urge you to look into the matter further, starting with the things he suggests.

 

I have the same configuration as you (snorkel out, PowerCore4, Comp ECU of course), and my cycle now responds "normally" at a higher CO setting (I roll with an 8, it seems fine for the map I use, which is almost identical to the "vlxjim" base map).



  • woods-rider

    TT Addict

3,005 posts
Location: Oregon

Posted July 24, 2014 - 11:40 AM


Woods:

I agree with vlxjim in this instance. You're the only one I know, so far, that has a continuing "hot start" problem after a CO adjustment.

I urge you to look into the matter further, starting with the things he suggests.

I have the same configuration as you (snorkel out, PowerCore4, Comp ECU of course), and my cycle now responds "normally" at a higher CO setting (I roll with an 8, it seems fine for the map I use, which is almost identical to the "vlxjim" base map).


My starting wasn't that bad to begin with, I just thought it could be better. It always starts hot with the button within one or two stabs IF I am in neutral. If I'm in gear with the clutch in, forget about it.

Upping my CO made it difficult to start with the button in either scenario.

  • Corkster

    TT Bronze Member

236 posts
Location: Australia

Posted July 24, 2014 - 03:45 PM


There is no problem starting these bikes, my 13 was exactly the same as all these guys bikes, until I read the owners manual. Just like my dealer told me you have to crack the throttle open just slightly and it fires up every time, hot, cold, in gear ect..
The problem is if you don't remember to do this every time you'll have problems.
I posted this back several pages ago but nobody read it.
There are 2 lines on the throttle control housing.
The grip has a line on it, it's actually the line that gets made when the grip was molded in 2 halves. They install the grip at the 1st top line abs you supposed to turn the throttle just slightly to the second bottom line. It literally feels like your just putting tension on the throttle cable. ITS THAT SENSITIVE!
But in fact you are opening the throttle slightly. I know it sounds dumb, and I know it doesn't make any sence and I know the guys reading this will think I'm full of it but hopefully they will stop trying to analyze and just try it.
I read someone mentioned here turning up the idle helped. I'm not surprised. If you turn it up far enough you'll hit the sweet spot and it will start every time.
I like my idle at 1700 rpm.
But if you don't follow the instructions to the letter, wait for fuel pump to stop, slight turn, start! You'll have problems even if you do it right a second time. If you hold it open to far it won't start. If you use no throttle, it won't start initially but will eventually start. And you cannot start, then try to find the sweet spot with the throttle, it will not start that way. You have to start over by putting the grip at the bottom line and try again.
I've had my bike over a year and over 1500 miles on it and I just live it. Starts first try every time. My bike has had the cams re-degreed, custom tune and fmf exhaust, comp ecu
Hardly stock. But still fires up first try 99% of the time. This thread frustrates me because even the mechanics won't take the time to read the manual and discover how to start these bikes

Everyone wants to try to fix it by means of programming and it's really not that big of a deal.

Sorry mate but I totally disagree with you.  I have been starting bikes for 35 years and know how to read a manual and other peoples posts.  This method made no difference to my bike - it would not start.  Upped the CO level and now she starts first time every time, as she should.  Must be something different about yours.



  • rtheil

    TT Newbie

15 posts
Location: Colorado

Posted August 19, 2014 - 01:11 PM


Add me to the list of those with consistent hot start issues, especially at high altitude. I picked up a leftover 2012 WR450 a couple weeks ago. First day I brought it home, it took me over an hour to figure out how to get it started. I was swearing up a storm that I had just dropped 8 grand on a pile of crap that wouldn't even start. Called the service manager at the dealership and he said it's a common issue due to low compression in the cylinder because of the nikasil coating on the cylinder walls. He said to get the thing broken in, and it would start better. I had even read through the service manual and tried starting it how it says to do it. After kicking it over a few times and rubbing its private parts in the proper direction to get it hot and bothered enough to fire up, I finally got it started. I did several rides where I'd get it HOT and run it hard, varying RPMs. After the initial ride, the next few rides the bike would start cold without issue. I did not try starting the bike hot, as I was adamant about completing full heat cycles on the motor for aid in break-in.

 

So, that leads me to Sunday when I got the bike up into the woods for the first time. Bike would not start cold at 9k in elevation. I had to screw with it to get it to start. Great start to the day. After a little bit of a ride, I shut the bike off to listen for my wife who was behind me. After that, could not get the bike started. Once again, I felt like I was performing religious rituals, or like I was trying to sleep with a woman who needed extra foreplay. Took me about 5 minutes before I could get the bike running again. Never have I been so regretful of any vehicle purchase. NEVER. I have numerous other off-road fuel-injected vehicles that start on the first crank, every time, without having to fiddle with anything. Needless to say, this bike is a damn lemon. I'm about ready to retain an attorney and have a little battle with Yamaha, up to repurchase if necessary. I shouldn't have to do anything to make this bike run. I should push the button, and it should start, EVERY SINGLE TIME. Well, as the day went on, I finally figured out how to get it to start most times, but it was still a huge PITA, and not consistent. A little throttle crack would often cause a backfire, and sometimes pulling the starter knob would work, even though the manual clearly says that's for cold starts. The manual also says to use the kick start for "high altitude", but I'm not sure that what I consider high altitude, is the same as what someone else would consider high altitude. To me, high altitude is above 12k, which I pretty much never cross. Most everything I rode this weekend was just under 10k. Once, after the bike sitting for about 15 minutes, I started it back up and the damn thing was bogging down like a carbureted bike running too rich. Took several minutes of easing the throttle up, then taking off, before the bike ran normal again.

 

The bike had the throttle stop screw removed, as well as the air box snorkel, by the dealer. Aside from that, it's all stock. I refuse to replace the ECU, the muffler, and numerous other parts to fix a problem that is clearly a manufacturer issue. I want to replace them when I want to replace them. It's really sad that my old hunk of junk 2002 WR250 is an easier bike to start, runs better, but just has a little less power. Starts on the first kick ALWAYS, and when hot one or two kicks with the hot start pulled. Talk about additional reason to have extreme regret for my purchase.

 

Just called the local dealer (not the one I bought it from) and the guy said he'd have to charge me shop time for adjusting with the FI tool. That's complete BS. I am NOT paying a damn penny to anyone to fix a problem that should be covered under warranty. The guy said he had never heard of this hard starting issue, and that Yamaha has never put out a bulletin about it. He did say he'd be happy to contact them about it and see if it's something they are aware of, but that he'd have to charge me to do the work if Yamaha won't pay them under warranty. So, I guess we'll see what Yamaha says. I'll be giving them specific instructions about what has been said in this thread on adjusting the CO setting, but I'm not holding my breath.

 

As pissed as I am about the starting issues, I really love how the bike rides and feels. Even though it's like 70 pounds heavier than my 2002 WR250, it feels just as light and nimble. I bought this bike because I weigh like 140 pounds, soaking wet. A heavy bike would rule me. I knew this would be LOTS of power and be nimble like the 250, and that's exactly what it is once it's being ridden. Couldn't be happier in that regard.

 

HUGE thanks to everyone in this thread, and all the great info. I'm hopeful Yamaha will do the right thing and fix the bike without charge. 


Edited by rtheil, August 19, 2014 - 01:14 PM.


  • Jonesy11

    TT Titanium Member

2,624 posts
Location: California

Posted August 19, 2014 - 01:21 PM


There is no problem starting these bikes, my 13 was exactly the same as all these guys bikes, until I read the owners manual. Just like my dealer told me you have to crack the throttle open just slightly and it fires up every time, hot, cold, in gear ect..
The problem is if you don't remember to do this every time you'll have problems.
I posted this back several pages ago but nobody read it.
There are 2 lines on the throttle control housing.
The grip has a line on it, it's actually the line that gets made when the grip was molded in 2 halves. They install the grip at the 1st top line abs you supposed to turn the throttle just slightly to the second bottom line. It literally feels like your just putting tension on the throttle cable. ITS THAT SENSITIVE!
But in fact you are opening the throttle slightly. I know it sounds dumb, and I know it doesn't make any sence and I know the guys reading this will think I'm full of it but hopefully they will stop trying to analyze and just try it.
I read someone mentioned here turning up the idle helped. I'm not surprised. If you turn it up far enough you'll hit the sweet spot and it will start every time.
I like my idle at 1700 rpm.
But if you don't follow the instructions to the letter, wait for fuel pump to stop, slight turn, start! You'll have problems even if you do it right a second time. If you hold it open to far it won't start. If you use no throttle, it won't start initially but will eventually start. And you cannot start, then try to find the sweet spot with the throttle, it will not start that way. You have to start over by putting the grip at the bottom line and try again.
I've had my bike over a year and over 1500 miles on it and I just live it. Starts first try every time. My bike has had the cams re-degreed, custom tune and fmf exhaust, comp ecu
Hardly stock. But still fires up first try 99% of the time. This thread frustrates me because even the mechanics won't take the time to read the manual and discover how to start these bikes

Everyone wants to try to fix it by means of programming and it's really not that big of a deal.


You are correct on that I read it in my owners Manuel as well. But when I do it sometimes it starts better and sometimes it just POPS but won't start.

  • GP1K

    TT Gold Member

1,346 posts
Location: Washington

Posted August 19, 2014 - 02:54 PM


The bike had the throttle stop screw removed, as well as the air box snorkel, by the dealer. Aside from that, it's all stock. I refuse to replace the ECU, the muffler, and numerous other parts to fix a problem that is clearly a manufacturer issue. I want to replace them when I want to replace them. It's really sad that my old hunk of junk 2002 WR250 is an easier bike to start, runs better, but just has a little less power. Starts on the first kick ALWAYS, and when hot one or two kicks with the hot start pulled. Talk about additional reason to have extreme regret for my purchase.

 

Just called the local dealer (not the one I bought it from) and the guy said he'd have to charge me shop time for adjusting with the FI tool. That's complete BS. I am NOT paying a damn penny to anyone to fix a problem that should be covered under warranty. The guy said he had never heard of this hard starting issue, and that Yamaha has never put out a bulletin about it. He did say he'd be happy to contact them about it and see if it's something they are aware of, but that he'd have to charge me to do the work if Yamaha won't pay them under warranty. So, I guess we'll see what Yamaha says. I'll be giving them specific instructions about what has been said in this thread on adjusting the CO setting, but I'm not holding my breath.

 

Well you're going to need to either A) put that snorkel back in B) replace the ECU and muffler. The bikes are VERY lean from the factory, and removing the snorkel (more air) without adjusting for that will simply make it worse.

 

The reality is this is the way Yamaha has chosen to get their bikes to pass EPA etc regulations. They cork them up, lean them out, and put a throttle stop on them. They pass and are rideable in stock form, but are leaving a LOT of performance on the table. To get the most out of the WR, you need the snorkel out, competition ECU in, and a free flowing muffler like FMF.  

 

All that said, that is not the root cause of the hot starting issue, the idle CO level is. While I agree with you that it is kind of a design flaw, good luck getting a dealer to cover it under your virtually non-existent 30 day limited warranty. I just paid my dealer to do it, and it was money well spent, IMO. Before, my bike was also a huge PITA to start hot, and no way no how would it ever start in gear. Well after getting my CO adjusted (I already had the snorkel removed, comp ECU and FMF pipe) the problems went away. Now it starts hot or cold no problem, and will even start when hot in gear. Worst case scenario I have to pull the 'choke' and it fires right up.

 

One last thing... have you checked your idle? The manual calls for 1900-2100 RPM and going below that will multiply your starting woes for sure. I keep mine on the high end of that (2100) and it helps.



  • MidlifeCrisisGuy

    TT Platinum Member

1,869 posts
Location: Other

Posted August 19, 2014 - 03:08 PM


I hate to say it, but my WR isn't even starting well with kicking.  And its getting worse.  And I've adjusted C1 to 8.  It definitely helped with low end power and flameout, but starting is getting inconsistent.

 

I agree that there shouldn't be this much variation from bike to bike.  I'm wondering if its something like fuel filters being clogged.  Or if our valves are all tight.

 

My bike would barely start with the eStart before I took it off.   That was one of the reasons I did.

 

Is all the fuel for starting delivered by the fuel injector or is there a starting or idle fuel bleed in the injector assembly ?

 

I wonder if all the fuel pumps are delivering the same fuel pressure.  Has anyone put a gauge on their bike ?

 

Has anyone checked their spark plug ?  I haven't...

 

I'll investigate these things and post back.

 

Edit: my bike starts on the 2nd kick every time when its cold.  Every time, without fail.  I've never had a cold start issue when kick starting it.

 

Could someone put a voltmeter on their battery and watch its voltage while cranking ?


Edited by MidlifeCrisisGuy, August 19, 2014 - 03:14 PM.


  • rtheil

    TT Newbie

15 posts
Location: Colorado

Posted August 20, 2014 - 08:12 AM


Well you're going to need to either A) put that snorkel back in B) replace the ECU and muffler. The bikes are VERY lean from the factory, and removing the snorkel (more air) without adjusting for that will simply make it worse.

 

The reality is this is the way Yamaha has chosen to get their bikes to pass EPA etc regulations. They cork them up, lean them out, and put a throttle stop on them. They pass and are rideable in stock form, but are leaving a LOT of performance on the table. To get the most out of the WR, you need the snorkel out, competition ECU in, and a free flowing muffler like FMF.  

 

All that said, that is not the root cause of the hot starting issue, the idle CO level is. While I agree with you that it is kind of a design flaw, good luck getting a dealer to cover it under your virtually non-existent 30 day limited warranty. I just paid my dealer to do it, and it was money well spent, IMO. Before, my bike was also a huge PITA to start hot, and no way no how would it ever start in gear. Well after getting my CO adjusted (I already had the snorkel removed, comp ECU and FMF pipe) the problems went away. Now it starts hot or cold no problem, and will even start when hot in gear. Worst case scenario I have to pull the 'choke' and it fires right up.

 

One last thing... have you checked your idle? The manual calls for 1900-2100 RPM and going below that will multiply your starting woes for sure. I keep mine on the high end of that (2100) and it helps.

So really, the removal of the snorkel by the dealer, is part of the issue. I should contact the dealer and ask for that part, since I didn't get that at the time of sale. Seems like the dealer also misinformed me of the warranty period. I get that they are all corked up, but the bike should start and run without issues when it's that corked up. Again, I have plenty of other off-road vehicles which do that just fine and are in 100% stock form. I will de-restrict the moment I know the bike starts properly.

 

You say they are tuned lean, but when I start it hot and give it gas, the bog screams that it's running rich. Maybe I'm wrong. I'll do my best to make the dealer do the work. I'm sure that having an attorney breathe down Yamaha's throat it going to cause them to pay the dealer the half hour of time that has been stated, rather than thousands in legal fees by their attorney and mine. Lemon law cases are often fought by attorneys working on contingency, for good reason. Manufacturers want to avoid litigation.

 

I've turned the idle all the way up. I don't have anything to measure what it's actually running at, but it's as high as it will go by turning the knob. I read about that when I couldn't get my bike started the first time.

 

 

I hate to say it, but my WR isn't even starting well with kicking.  And its getting worse.  And I've adjusted C1 to 8.  It definitely helped with low end power and flameout, but starting is getting inconsistent.

 

I agree that there shouldn't be this much variation from bike to bike.  I'm wondering if its something like fuel filters being clogged.  Or if our valves are all tight.

 

My bike would barely start with the eStart before I took it off.   That was one of the reasons I did.

 

Is all the fuel for starting delivered by the fuel injector or is there a starting or idle fuel bleed in the injector assembly ?

 

I wonder if all the fuel pumps are delivering the same fuel pressure.  Has anyone put a gauge on their bike ?

 

Has anyone checked their spark plug ?  I haven't...

 

I'll investigate these things and post back.

 

Edit: my bike starts on the 2nd kick every time when its cold.  Every time, without fail.  I've never had a cold start issue when kick starting it.

 

Could someone put a voltmeter on their battery and watch its voltage while cranking ?

 

That's not a bad idea to check voltage while cranking. I have wondered if some of the issues I have with my bike are because I bought a 2 year old '12 that's been sitting in a box or on a showroom floor somewhere. Never know what the history of that battery has been.



  • MidlifeCrisisGuy

    TT Platinum Member

1,869 posts
Location: Other

Posted August 20, 2014 - 08:53 AM


That's not a bad idea to check voltage while cranking. I have wondered if some of the issues I have with my bike are because I bought a 2 year old '12 that's been sitting in a box or on a showroom floor somewhere. Never know what the history of that battery has been.

 

FI or no FI, all engines need fuel, compression and spark to start.  Its great to complain about the starting issue, but if we as a group want to improve things our first step is to start investigating what is actually causing the issue.  Until now most everyone has assumed the problem is the fuel mixture during the (hot) start, but that may or may not be the case.  For sure its not the case, or shouldn't be, in a cold start situation.

 

For those with bikes not hot starting, what happens if you activate the cold start knob (while turning the engine over with the starter )?   It starts right up ?

 

 

 

The KTM 350 uses the same injector and throttle body setup as the WR450F.


Edited by MidlifeCrisisGuy, August 20, 2014 - 09:01 AM.


  • Jonesy11

    TT Titanium Member

2,624 posts
Location: California

Posted August 20, 2014 - 08:56 AM


FI or no FI, all engines need fuel, compression and spark to start. Its great to complain about the starting issue, but if we as a group want to improve things our first step is to start investigating what is actually causing the issue. Until now most everyone has assumed the problem is the fuel mixture during the (hot) start, but that may or may not be the case. For sure its not the case, or shouldn't be, in a cold start situation.

For those with bikes not hot starting, what happens if you activate the cold start knob (while turning the engine over with the starter )? It starts right up ?



nothing still hates to start.

Even if it did help when I'm barely hanging on to the side of a mountain I want it to start in gear,hott. Without pulling knobs or doing anything. Just pull clutch and push magic button.

Edited by Jonesy11, August 20, 2014 - 08:59 AM.


  • MidlifeCrisisGuy

    TT Platinum Member

1,869 posts
Location: Other

Posted August 20, 2014 - 09:07 AM


nothing still hates to start.

Even if it did help when I'm barely hanging on to the side of a mountain I want it to start in gear,hott. Without pulling knobs or doing anything. Just pull clutch and push magic button.

 

If it won't start with the cold start knob pulled then it probably isn't a fuel mixture issue.  If it was really lean and you pulled the knob, it would richen and fire right up.  Or flood, but that doesn't seem to be the case.

 

I wasn't recommending the cold start knob as an operational fix, only as a troubleshooting step.

 

Has anyone checked their injector, fuel filter or fuel pressure ?

 

Page 10-1 in the WR450F manual has a list of troubleshooting items for "Starting Failures".  I suggest the group go through them one by one until the issues is found.  It doesn't appear that Yamaha or a dealer is going to come to our rescue, so its time to dig in and figure things out for ourselves.


Edited by MidlifeCrisisGuy, August 20, 2014 - 09:11 AM.

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  • rtheil

    TT Newbie

15 posts
Location: Colorado

Posted August 20, 2014 - 09:27 AM


In my case, I had a lot of luck pulling the cold start knob when hot starting. I never pulled the knob in the middle of it cranking though. I would try to start without it, then when I couldn't get it to start by cracking throttle, I'd pull the start knob and it would usually start pretty easily after that. In some cases I also had to add that throttle crack to get it to start with the knob out.

 

Also, when I had the engine bogging down after a somewhat hot start (sitting off about 15 minutes), pulling the knob would make it run normally. My understanding based on the description from the tech at the dealer where I bought the bike, is that the start knob is like a choke in that it adds air to the mixture, therefore causing the computer to respond with more fuel. The bogging engine seems like a too much fuel issue. I remember from my R/C nitro engine days that when the engine would bog from a stop, too much fuel.



  • MidlifeCrisisGuy

    TT Platinum Member

1,869 posts
Location: Other

Posted August 20, 2014 - 09:51 AM


I believe the hot start button closes off an air bleed.   I suspect that the ECM fires the injector a set amount at idle and adjusting the hot start button adjusts the mixture (and idle RPM) by tailoring how much air is getting through the air bleed.  Disclaimer: I've never looked closely at this system. 

 

I wonder what cracking the throttle does ?  Move the butterfly a bit ?  But that would lean the mixture ?

 

2 things to investigate in this regard.

 

1) The throttle body has a throttle position sensor (TPS) on it.  I know a guy that could not get his YZ250F (carbureted) to start properly.  The issue was the TPS adjustment.  You need an FI tool for this.  (I have one.)  Diagnostic code number d:01.  Value is to be 9-16 with the throttle body closed.  Page 9-37.

 

2) Intake air pressure sensor.  Diagnostic code d:03. Value is to change when the engine is turned over with the starter.   Page 9-36.   ECM probably won't fire the injector if it doesn't sense some vacuum downstream of the butterfly.

 

Another thing to investigate.   Pull the fuel injector from the throttle body.  Plug the hole.  Turn over the engine.  Does fuel come out of the injector ?  How much ?

 

Unfortunately my bike no longer has eStart, so I can't investigate some of this stuff like the rest of you can.  I'll do what I can with kicking.


Edited by MidlifeCrisisGuy, August 20, 2014 - 09:52 AM.


  • GP1K

    TT Gold Member

1,346 posts
Location: Washington

Posted August 20, 2014 - 10:15 AM


The hot start/cold start/choke/whatever simply raises the idle speed a bit, that's it. No FI bike has a true choke that changes the mixture. Having your idle too low is a sure fire recipe for hard starting with these bikes, hot or cold.

 

The problems all revolve around the fact that these bikes are super lean from the factory to pass emissions etc. Personally I think Yamaha is kind of lazy in how they went about it, with stupid shit like throttle stop screws. Even more amazing cheap tricks like that fool the EPA at all. Honda & KTM have managed to make their trail bikes EPA legal AND 100% rideable showroom stock, while Yamaha makes bike that it is an unwritten rule that the owner will ditch all that stuff the second the bike is sold, and thus rendering it close-course use only.

 

So in order for the bike to start and run properly, that super lean condition MUST be addressed. You can remove the snorkel, replace the exhaust & tune the FI and you will get all the performance out of the motor, but none of that effects the idle, which is where the starting problems are. That is where the CO level adjustment comes in. The idle circuit is also way too lean, and richening it up is what solves the issue for almost everyone.

 

My bike always starts easily cold, and always has. But hot it was total PITA. No way no how would it ever start in gear hot, and often took several minutes to get it started in neutral. Getting the bike uncorked and FI tuned helped, but did not solve it. Getting my CO level set did. Now it starts hot or cold, no problem. It even starts in gear when hot. Occasionally I still have to pull the knob when hot, but then it will fire right up, and again in gear as well.

 

I can't claim it's 100% fixed and will start 100% of the time hot/cold in gear or not (like my KTM does) but I now consider it a non-issue. The WORST case scenario now is I have to pull the knob when hot sometimes, but it will definitely start right away.



  • MidlifeCrisisGuy

    TT Platinum Member

1,869 posts
Location: Other

Posted August 20, 2014 - 10:18 AM


FWIW, IMHO, the idle enrichment change is worth doing even if you don't have a starting problem.  

 

On my bike it really improved off idle throttle response and decreased engine flameouts.   I specifically love this change when I get off line climbing some mudder farking big hill and I have to snap the throttle closed and then get back on it and I need engine response NOW and I'm done.   My WR now always seems to pull through in these situations and save my sorry butt.







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