Cold Starting Problem


23 replies to this topic
  • bobpara

Posted November 01, 2015 - 03:33 PM

#1

I have a problem with my 2006 WR450F that has been driving me crazy and I'm out of ideas

 

If the bike has been sitting for more than a week it is an absolute biotch  to start. If I ran it yesterday, it fires right up.

 

It has always had this problem since I bought the thing, but it seems worse as of late.

 

My first suspicion was that the fuel cock was leaking a tiny bit over time and ever so slowly flooding it.

 

I replaced the fuel cock and when I had the carb out replaced the float needle and seat.

 

I have tried starting it with fuel cock off, no choke and throttle at WOT (like starting a flooded engine)......nothing.

 

When it is difficult to start I do not smell gas, it does not seem to be flooded

 

When I spray some starting fluid at the air filter it does not seem to have any effect (every other engine I have ever put starting fluid to lights right up)

 

I suspect, but I am not 100% sure, I actually have a lean condition and not flooding

 

I just recently had the shop shim the valves

 

it is running the stock 65 starter jet and I have a dynojet kit in it that uses an O-ring to make the accel pump come on earlier and easier

 

I have al the other jetting info if that is needed or relevant (otherwise it runs beautiful)

 

.......Any ideas?



  • bobpara

Posted November 01, 2015 - 03:34 PM

#2

Poss statement of the obvious, but it has a carb and is NOT FI (although it has that TPS on the side of the carb)



  • Krannie McKranface

Posted November 01, 2015 - 04:24 PM

#3

Hard to start means pilot circuit is not adjusted properly, poor spark, or poor compression.

Probably can rule out compression....so....

 

Since you say it starts  better on a one day old cold motor than a two week old cold motor, you must need to adjust your starting procedure.

 

Your Jetting is ?

 ---you really should dump all the dyno jets; they are not flow tested, so they are crap

Last valve check ?

Leak down test?

Last plug change ?

Plug gap?

Last needle jet change ?

Last fuel screw adjust ?

TPS setting or not connected?

Fuel age?

Fuel type?


Edited by KRANNIE, November 01, 2015 - 04:26 PM.


  • rah7777777

Posted November 01, 2015 - 06:22 PM

#4

I too have an 06 that greatly changes how she starts after sitting a week versus a day. But it's not a big pain.

Sitting overnight I just twist the throttle real quick and usually fires right up with no choke (anything over 70 degrees.

Sitting a week, 2 quick throttle twists and choke on, she cranks up. but took me forever to learn this. Still fine tuning it.

I pulled the hose off the carb with valve in off state and didn't have any leaks.


Have you tried using the choke after it's been sitting a week? Even in 100 degree weather, if she's been sitting a week, the choke is needed to start mine unless I just crank and crank and crank first, but within 1/2 a second I push it in and idle drops and she stays running.

Rest of the day she fires right up, no choke no throttle twists, no hassles.

  • bobpara

Posted November 02, 2015 - 05:31 AM

#5

Correction, Jetting is by JD Jetting, recommended by many on this site

 

MAIN:  170  (165 is stock)

NEEDLE: JD Blue Needle, 3rd from top position

Pilot Jet 48 (45 is stock)

Pilot Air Jet (stock 80)

Starter Jet: (stock 65)

Leak Jet (stock 50)

Air screw 2 1/2 turns

 

All pretty much stock, but I 'fattened' it up a bit to make it run cooler in hot weather and works well

 

Valves adjusted less than 5 hrs ago by shop

No leak down test but runs fine so why?

 

New plug & gap by shop 5 hrs ago

Beautiful fuel n 93 octane

 

......Now how about the TPS? Can that effect starting? Again, it runs fine

I have never touched it or removed it but it has a whole sect in the manual how to adjust it

Why F with something that's not broken though

I did add an electronic ign module per Karannies suggestion to get rid of the throttle surge, but I leave the dip switches in the stock position anyway

 

I AM TOTALLY CONFUSED AS TO WHY THIS IS HAPPENING AND I AM ABOUT TO TAKE IT TO THE STEALER AND ID LIKE TO AVOID THIS

 

It has an accel pump, I will try the two twists thing....does twicting the throttle squirt gas in the throat?



  • bobpara

Posted November 02, 2015 - 05:35 AM

#6

To Karannie's first point: Pilot circuit is now 48 (vs stock 45) and air crew is 2.5 turns out.....I don't think this is a radical departure from stock

Is the 48 jet RICHER or LEANER?

My suspicion is that I have a LEAN condition when I leave it for a long time



  • Krannie McKranface

Posted November 02, 2015 - 05:52 AM

#7

To Karannie's first point: Pilot circuit is now 48 (vs stock 45) and air crew is 2.5 turns out.....I don't think this is a radical departure from stock

Is the 48 jet RICHER or LEANER?

My suspicion is that I have a LEAN condition when I leave it for a long time

 

That is way too rich, first off.

You need a 45 with proper fuel screw adjustment

...and you don't have an air screw, you have a fuel screw.

Adjusting the fuel screw is the most important thing you will learn.

You do it starting at 1.0 turns out, hot motor, lowest possible idle.

Then turn the fuel screw out to RAISE the idle.

Re-adjust the idle, if too high, with the idle screw, and try adjusting the fuel screw again.

 

There is no way you can get peak idle with a 48 at 2.5 turns unless you have a massive air leak...........

 

 

 

Secondly, a bike will start differently with minor changes in temp or air density.

It's up to you to figure out what starting procedure works best for what.

 

Typically, choke on, no throttle, and start, is all you need to do.

 

More than likely, your excess fuel in the cylinder and crank is becoming stale, and hard to fire. That is why you are not starting up exactly the same.



  • bobpara

Posted November 03, 2015 - 02:18 PM

#8

Thanks Krannie !

Let me give that a try

Unfortunately I have to go in there and pull that SOB carb out to change back to a 45 and its a MoFo compared to most bikes

So I want to do this once if I can

 

I remember the fuel screw being a bit of a problem though

I think at 1 turn it wouldn't even stay running.....but I have to double check my notes

 

BTW: I am in New England roughly sea level and ride in 40 - 95 deg F weather 

With a carb altitude info is important



  • Krannie McKranface

Posted November 03, 2015 - 02:39 PM

#9

Thanks Krannie !

Let me give that a try

Unfortunately I have to go in there and pull that SOB carb out to change back to a 45 and its a MoFo compared to most bikes

So I want to do this once if I can

 

I remember the fuel screw being a bit of a problem though

I think at 1 turn it wouldn't even stay running.....but I have to double check my notes

 

BTW: I am in New England roughly sea level and ride in 40 - 95 deg F weather 

With a carb altitude info is important

 

No reason to pull the carb!

You can change the pilot via the bowl cover plug.

You just need a motion pro carb tool or similar.

You just rotate the carb a bit.

 

08-0023.jpg



  • SilvFx

Posted November 03, 2015 - 03:32 PM

#10

Bob,

 

I may be wrong but it sounds like starting technique issue to me.

 

I start my WR just like the old carbureted cars  (you had to pump the gas a couple times to set the choke and to have the accelerator pump squirt fuel in the carb throat...sometimes you would have to crank it for awhile while pumping the accelerator as the mechanical fuel pump would fill up the fuel bowl in the carburetor because the gas has evaporated). 

 

If my WR has sat for a week or two or it was cold overnight (below about 50-55 degrees), I turn on the gas and give it a bit of time to fill float bowl, pull out choke, twist throttle 3-4 times....to give it a couple squirts of gas in the carb throat.  Fires every time when cold.  Run it about 15-20 seconds with choke on and then turn off choke.

 

If it is warmer out (engine cold), I may turn on the choke but not twist the throttle and start cranking.  If it doesn't immediately fire, I stop cranking and give it one or two twists of the throttle and it usually fires up.  Now if it is warm out (engine cold) or you give it too many twists (e.g. too many shots of fuel), you can flood it...so you need to use some technique and common sense.

 

Anyhow, you may have other issues going on, but my first impression is your starting technique is not giving it some initial fuel to get it to fire with the engine cold and it has been sitting.

 

Now...if it is mid summer and it is 75+ degrees....I just crank the bike without the choke and it fires.

 

Frankly this is the same technique I use on my '70 Buick GSX 455 that I keep at my in-laws and start maybe once or twice a year.  Works every time.



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  • bobpara

Posted November 03, 2015 - 04:51 PM

#11

It seems to run absolutely beautiful otherwise

Perhaps I should check my starting procedure

How long do y wait for the float bowl to fill?.....I assume 30 seconds or less

 

The design of this thing is such a royal pain in the boules

Its a major undertaking just to pop the plug

That way, I would know for sure if I had too much gas or too little

 

Your solution is simplest and Karannies I will do after that

I have never cranked the throttle 3 or 4 times....I just assumed that would flood it

Maybe 2  times at the most



  • Krannie McKranface

Posted November 03, 2015 - 05:13 PM

#12

I NEVER crank the throttle if I use the choke, and I usually use only the choke, under 70 degrees.

 

I turn on the gas, pull the choke, and press the button.

 

10 min ago....

 



  • RiderDeAzul

Posted November 04, 2015 - 06:20 AM

#13

No reason to pull the carb!

You can change the pilot via the bowl cover plug.

You just need a motion pro carb tool or similar.

You just rotate the carb a bit.

 

08-0023.jpg

Can you also do this on the Aluminum framed bikes?



  • Krannie McKranface

Posted November 04, 2015 - 06:26 AM

#14

Can you also do this on the Aluminum framed bikes?

 

Yes.

 

You just have to be careful about rotating the carb, so you don't crack the plastic hot start nut.

 

I turn off the gas, plug the tank vent with a screwdriver, and lay the bike on it's side with the carb rotated up towards me.

 

 

You can also use a right angle driver with an extentsion, the small kind, to get in the tight confines.

right-angle-screw-driver.jpg


Edited by KRANNIE, November 04, 2015 - 06:28 AM.


  • RiderDeAzul

Posted November 04, 2015 - 07:06 AM

#15

Yes.

 

You just have to be careful about rotating the carb, so you don't crack the plastic hot start nut.

 

I turn off the gas, plug the tank vent with a screwdriver, and lay the bike on it's side with the carb rotated up towards me.

 

 

You can also use a right angle driver with an extentsion, the small kind, to get in the tight confines.

 

You don't have to unscrew the throttle cable? Wish I knew this before, last time I changed jetting I took the rear shock out and everything.



  • bobpara

Posted November 04, 2015 - 07:21 AM

#16

Krannie: Let me get the Fuel Screw Adjustment thing 100% correct.

 

1) I place the 45 jet back in there

2) I set the fuel screw on bottom of bowl at 1 turn out and try to start it.....If it starts I suppose we have one route, what if it will not fire at 1 turn out?

3).....Can you describe the rest of the procedure?

 

I agree every other properly running engine I have ever had is choke on no throttle, just poke the button



  • SilvFx

Posted November 04, 2015 - 10:39 AM

#17

It seems to run absolutely beautiful otherwise

Perhaps I should check my starting procedure

How long do y wait for the float bowl to fill?.....I assume 30 seconds or less

 

The design of this thing is such a royal pain in the boules

Its a major undertaking just to pop the plug

That way, I would know for sure if I had too much gas or too little

 

Your solution is simplest and Karannies I will do after that

I have never cranked the throttle 3 or 4 times....I just assumed that would flood it

Maybe 2  times at the most

 

Bob....Krannie runs circles around me with his knowledge and experience on the WR450F and CRF450X, but one difference that I am thinking about with his technique is that he lives in Southern California where it is generally quite a bit warmer than Colorado (me) or Connecticut (you)...hence why I think the need to twist the throttle to squirt some fuel into carb throat when it is stone cold and hasn't been started for awhile.  Try it.  If it works...great....if not....move on to other variations

 

As far as how long to wait to fill up float bowl....not long maybe 5-30 secs. and that is assuming that it is empty or some fuel has evaporated since you last ran it  You just want to make sure there is fuel in the float bowl so that the accelerator pump is actually squirting fuel into the carb throat when you twist the throttle.

 

I will say that every carbed bike or car sometimes has their idiosyncrasies and you might have to fine tune your starting technique. For example, most people say when hot don't twist the throttle at all when starting, but I found on my WR that if I just slightly open throttle (not enough to create a squirt from accel pump) it usually fires right away.  If I open it 1/8th or more, it will not fire and can tend to flood.  But, this technique does not work on my buddies '09 WR450F.

 

One thing I loved about my '10 Husaberg FE450 with fuel injection, is that no matter whether engine was cold, hot, or hadn't started in 2 weeks, 2 days, or 2 months, or I just dropped the bike, etc. it would start right away with no issues and no extended cranking.  Never even had to charge the battery.   At some point, I will pick up a used 2012+ WR450F and hopefully enjoy that same type of starting performance as my Husaberg with FI.

 

Lastly, if you are playing around with the fuel screw and changing out the pilot to a 45, make damn sure that you have the o-ring in there properly (and you don't have pieces and parts of a busted up old o-ring stuck up there or have a missing o-ring altogether).  The order of the parts on the fuel screw from the tip down (e.g the part you are inserting into the fuel screw cavity is o-ring, washer, spring.

 

I also found that in winter time with the JD Jetting kit installed/adjusted per instructions in the kit (for high altitude) with the 45 pilot jet that my exhaust pipe was getting so hot that it was softening/melting the underside of the airbox because it was running so lean.  I put in a 48 pilot jet (with JD needle at recommended setting) and it didn't run nearly as hot and runs great even at high altitude.  And, of course everything I read says that I should be running the 45 pilot.  And, my buddy runs the 45 pilot jet in his WR450 and works great for him.  So, my only point is to play with it and find what works for you.  And I also agree that instead of running the 48 pilot at 2.5 turns out, it would probably be better going down a size on the pilot and turning the fuel screw in (e.g. starting at 1 turn out and adjusting from there - at least on paper and based on everything I have read).

 

Good luck finding/resolving your issue.



  • bobpara

Posted November 04, 2015 - 11:17 AM

#18

Note: I must have gotten this confused with another machine I have. My Fuel Screw at bottom of Bowl is 1.25 Turns out from seated (with the 48 jet) not 2.5 turns as I claimed earlier

I guess I still have 3 questions:

 

1) I dont think this is too far off from stock (I could be wrong however)

2) It has Always done this from the day I got the bike even before the jetting changes (I has the 45 jet at 1.5-ish turns at that time)

3) The starting problem is only after the bike sits for a while....I started it two days ago. I'm 99% confident if I went out to the shed to start it it would fire right up.

    If I leave it for 2 weeks I will have a problem. Seems like the variable is TIME and not the JETTING



  • Krannie McKranface

Posted November 04, 2015 - 12:56 PM

#19

1.25 turn with 48 is fine, as long as you started with the lowest possible idle before turning the fuel screw out.

 

Typcially, in a cold or wet climate, you are rich, so having a 48 in MA is not typcialy.

 

Do you have the ACV ( the coast enrichener on the left side of the carb) and pilot air jet stock (70) ?

 

You use a 70 pilot air jet when the carb's ACV valve is intact and working

You use a 100 or 110 when it is blocked off (like on a YZ, which has the ACV valve cast shut)

 

If you are using a 100 or 110 pilot air jet, you would NEED a 48 or 52 pilot.......



  • bobpara

Posted November 04, 2015 - 02:07 PM

#20

I dont even know what the ACV is, I will have to look in shop manual and see.

Pilot jet is stock

What about the TPS?.....could that be fouling things up?






 
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