Cold Blodded Son of a @#$%^&*!!!!!

[nevadanotch]

All right you guys what do you do to get these @#$%^&* cold blooded buggers to start easily?
Mine has always been cold blooded and it doesn't seem to make a difference if it is 40 degrees or 90!
It didn't even make a difference when I put in a one size larger than stock pilot and main because of the open air box and Pro Aluminum pipe either!
Of course, once she's warm she cranks up first time every time!

[racenaked_400ex]

i dont get it, 3 of my friends have 400ex's and all of them are hard to start. neither of them have any internal mods. i have 11:1 piston and stage 2 cam, when doing the cam you remove the compression release valve, and they say it becomes harder to start. i have no problems with starting mine, cold or warm. i dont get. sorry couldnt help you out man but to me it just seems normal for most 400ex's.

[Ace Sixx]

Set the choke then pump the throttle quickly once before you crank it. It should fire right up.

[400exrider707]

With a pipe and open air box, bump it up to a 42 pilot. Also you should have changed other jetting than just the main and pilot... where is your needle set? Whens the last time a valve adjustment was done? that will effect starting. Start with the 42 pilot, no need for the choke, pump the gas a couple times, then hit the starter button.;)

[REDRIDDER]

This might sound stupid to you but how good is your battery?cause a weaker battery will produce a weak spark their fore harder starting.This is just something i thought i would add because my friend had about the same problem and he got a new battery and it fired up easily afterwards.Just my 2 cents$

[nevadanotch]

In reply to suggestions here is the status to the maintenance condition of my quad.

1.) Battery is in great shape with a full charge.
2.) Valve adjustment was done less than 50 miles ago.

Now a couple of questions:
1.) As far as carb adjustments, what other jets are there other than the pilot and the main? It's been a while since I've had the carb apart and don't recall seeing another jet.
2.) What is the size of the pilot for a 2005? The dealer gave me a jets that are one size up from stock for both the main and pilot. I thought this was appropriate due to the 5000 ft altitude I ride at. (Carson City Nevada)
3.) I have not touched the needle setting so it is still stock. What notch should I move it to? I didn't move it cause I didn't think it would have anything to do with starting and the plug looks great.
4.) What about air/fuel adjustment? I haven't touched it yet since it runs great once it is warm and like I said the plug looks fine.

In a nut shell the damn thing fires right up but won't stay running until it builds up some heat. I have to play with the throttle continuously until I can get it to even rev up. Basically I crack the throttle slightly and it usually dies! It will idle for a couple of seconds and then it dies! The problem is so bad I could probably start calculating the run time on my starter I use it so much!

[300exOH]

Originally posted by nevadanotch
In reply to suggestions here is the status to the maintenance condition of my quad.

1.) Battery is in great shape with a full charge.
2.) Valve adjustment was done less than 50 miles ago.

Now a couple of questions:
1.) As far as carb adjustments, what other jets are there other than the pilot and the main? It's been a while since I've had the carb apart and don't recall seeing another jet.
2.) What is the size of the pilot for a 2005? The dealer gave me a jets that are one size up from stock for both the main and pilot. I thought this was appropriate due to the 5000 ft altitude I ride at. (Carson City Nevada)
3.) I have not touched the needle setting so it is still stock. What notch should I move it to? I didn't move it cause I didn't think it would have anything to do with starting and the plug looks great.
4.) What about air/fuel adjustment? I haven't touched it yet since it runs great once it is warm and like I said the plug looks fine.

In a nut shell the damn thing fires right up but won't stay running until it builds up some heat. I have to play with the throttle continuously until I can get it to even rev up. Basically I crack the throttle slightly and it usually dies! It will idle for a couple of seconds and then it dies! The problem is so bad I could probably start calculating the run time on my starter I use it so much!

Stock pilot is a 38. I would go with a 42. You'll want to adjust your air/fuel screw when the engine is warm. Turn it out until you achieve the highest idle possible and then back it off slightly. You may have your idle set too low as well. I had the same problem with my quad and I turned the idle up a couple hundred rpm's and it starts great now.

[Nates400ex]

With the mods I have in my SIG all I do is hit the throttle 2 times then start. Fires first time every time. As well once she is started I sit and warm it up by little blips of the throttle.

[fastredrider44]

I had a friend with a 400 that actually had to heat the block with a propane torch before he could crank it under 50 degrees. I had another friend that put a rev box on his, and he had to take it off in the winter, crank it, and warm up the motor before he could kill it and put the rev box back on. That was on a 440 stroker motor. Mine has always been better starting than most, and I choke it to start it in the summer, but in the winter, I have to leave it choked for a long while.

[AbnMP13]

Maybe these will help, this is a popular topic on here.

Jetting (http://www.exriders.com/vbb/showthread.php?s=&threadid=274536&perpage=15&pagenumber=2)

Pilot Screw (http://www.exriders.com/vbb/showthread.php?s=&threadid=229923)

[Brehmmotorsport]

i second the last one. I have a 400 that starts very quick and my race partners old 400 was like you say. We delt with it for years and then sold it to another friend who had the same problems. Then just messing around he put in another cdi since then the thing fires on the first crank even cold.

[400exrider707]

Originally posted by fastredrider44
I had a friend with a 400 that actually had to heat the block with a propane torch before he could crank it under 50 degrees. I had another friend that put a rev box on his, and he had to take it off in the winter, crank it, and warm up the motor before he could kill it and put the rev box back on. That was on a 440 stroker motor. Mine has always been better starting than most, and I choke it to start it in the summer, but in the winter, I have to leave it choked for a long while.


If you have to heat the bock to get it running its more than likely something isn't right with that motor, and probably had carb issues.

The one with the 440 had problems because of the CDI, about 95% of aftermarket cdi's for these quads are only rebadged xr250 boxes and they will cause starting problems.

[billyboy]

:confused: I dont get it. All of my EX's have mods of some sort. They all start on the first roll? The one with the bad valve guides is giving me fits.

Timing usually plays a pretty good factor in some of the hard starts, Or at least that would be my thinking.

[steve #7]

I had yhe same problem with one of My 400's. First off It is not the battery . ours are now kick and they starts up with one slow kick . The coil does not get any spark from the battery. I don't have one on the system. also why buy a CDI when all you have to do is cut the rev limiter wire. Take the auto decompresison off or adjust it. get rid of the dyna jet. and your problem will be solved they do not work. Check out [400ex kick conversion] thread. and all other theads relating to kick. You will be impressed . I am 51 and have been helping my son build 460's to race nationally. We've tried it all Every CC every cam ,pipe and carb. There is no comparison to Curtis sparks x-6 full exhaust

[nevadanotch]

I don't have a CDI unit installed nor do I have a Dyno Jet kit in the carb. I have raised the idle and it seems to have helped some what. I guess I will have to live with a high idle until I can tweak the carb a little closer.

Couple of questions.
1.) Does anyone know if the needle position will affect starting?
2.) Will the air/fuel screw from an earlier model carb work so I don't have to buy a "D tool to adjust air /fuel?
3.) Where do I buy a "D" tool to adjust air/fuel if I can't swap the screw?

[AbnMP13]

3.) Where do I buy a "D" tool to adjust air/fuel if I can't swap the screw?

I got mine from the local shop, it comes with jet kits and they keep them so I got mine for free.

[krt400ex]

there are 2 "clicks" when you pull the choke. pull it to the first click, and then hit the button at about 1/4 throttle. it will fire up without a problem. they always say you dont need the throttle with a 4 stroke, but i use it anyway and it always starts first time everytime

[Sparky_20]

all i do is pump the gas twice with the choke off and it starts easy every time. thats with a 42 pilot

[nevadanotch]

Question for You guys that are running a 42 pilot.
What altitude do you guys ride at?

[Sparky_20]

i ride anywhere from 200-1500ft.

[GPracer2500]

A couple of fast jabs of the throttle prior to hitting the starter button usually helps a lot with cold starts. Doing that causes the accelerator pump to squirt a stream of fuel straight into the engine. It's the same thing as having a primer/enrichener.

[nevadanotch]

I've tried the "couple of fast jabs prior to hitting the starter button" and it fires every time. The deal is she will start but she won't continue to idle. She dies and I have to do this probably 5 to ten times to keep it running!

[CarGuy7a]

Originally posted by nevadanotch
Couple of questions.
1.) Does anyone know if the needle position will affect starting?
2.) Will the air/fuel screw from an earlier model carb work so I don't have to buy a "D tool to adjust air /fuel?
3.) Where do I buy a "D" tool to adjust air/fuel if I can't swap the screw?

the needle position will not affect starting. the needle meters fuel from the main jet at 1/2 throttle to full throttle.
i believe the 2005 needles are not adjustable. if you don't have an adjustable needle in your carb you can get one for a 2004 model and it will fit in your carb.

i would say either play with the fuel screw adjustment or install a larger pilot.

i have a #40 pilot at 1 3/4 turns out in mine and i can start it on the first choke notch at one push of the starter button and then immediately turn the choke off and it will sit there and run fine without messing with the throttle. or i can leave the choke on and it will idle fine.

[krt400ex]

Originally posted by nevadanotch
I've tried the "couple of fast jabs prior to hitting the starter button" and it fires every time. The deal is she will start but she won't continue to idle. She dies and I have to do this probably 5 to ten times to keep it running!


you have to hold the throttle at about 1/4 throttle for a couple minutes. they all are like that. i think it is just a honda thing cuz my 300ex is like that and my dad shadow 750 is like that too

[Sparky_20]

you dont need to hold the throttle if its adjusted correctly. You either need to bump up the pilot or adjust your idle speed

[krt400ex]

Originally posted by Sparky_20
you dont need to hold the throttle if its adjusted correctly. You either need to bump up the pilot or adjust your idle speed


idle speed is set at 1400 rpms from the factory. im running a 42 pilot, 2 1/4 turns out on the screw and the factory setting for the idle speed. if i turn the screw richer the bike bobbles off the bottom. that means too rich, so since my bike it jetted correctly and idle is set correctly...the only thing to do it hold the throttle open a little for a few minutes

[CarGuy7a]

Originally posted by Sparky_20
you dont need to hold the throttle if its adjusted correctly. You either need to bump up the pilot or adjust your idle speed

X2. of course every carb will run different it's just a matter of finding that sweet spot.

my theory is if you have to hold the throttle open some on starting, the pilot is not adjusted correctly. because mine did run kind of wierd when i left the stock pilot in the carb at 3 turns out after doing the dynojet kit. it would idle up then back down till it died until it got warm. i put the 40 in and it runs great now.

[jarrod]

I have had 2 2000 400 ex's and they were both great.
You say the valve job was done. Did you check them or just trusted a shop to do it right.
I had a shop do my first ones and the F)(&)_*& it up. It is wise to check the clearances for yourself.