[bobwehadababyitsaboy]

I have a 2005 450X I bought new. It has never liked to start and takes 5-10 seconds of starter to get going. It will die a few times and generally run like . until its hot. Then it runs fine.

At higher elevation (3500ft) it starts up in 2 seconds and never dies once.

I already have my fuel screw at 1.75 turns out. What's the range on it? I've heard if you need to exceed 2 turns you need a larger pilot.

What should I do next? Hoping to do it with a simple jet and not a $75 JD kit.

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What is your elevation ?? 500ft

What type of riding are you doing ?? trails

What is your Fuel Screw set at ?? 1.75 OUT

What jets are in it (Pilot/Main) ?? 45/155

What is the Needle Clip Position ?? (IE: 3rd from top , etc.) NCVS #3rd

Was the bike running fine then just started doing this ?? , or was it like this when you bought it , or after sitting for a extended period ?? Always been like this

Have you actually pulled the carb and cleaned it (removing all the rubber parts like Fuel Screw O-Ring , Slide , Floating Slide Plate O-Ring , gaskets , jets , and flushed everything with carb cleaner and blown out with air) ??? Yes

Do you have a Manual ??? (Yes/No) Yes

Have you lifted the subframe and airbox , and looked down the throat of the carb and twisted the throttle to see if the accelerator pump is squirting ?? , and if it just barely misses the slide and does not hit it ??? No

When/if you took the carb apart , did you note which way the floating plate is on the slide ?? , was the hole at the bottom ?? , or the Top ?? , it needs to be at the bottom .. No

Did you drain and flush the tank and put FRESH Premium in ?? Yes

[JimDirt]

Welcome to the site !!

You should be at 45/165 for jetting , so going up on the main should help ...

What is your starting procedure ?? , what you "should" be doing is ......Turn on the fuel ....... Pull the Choke ...... Twist the Throttle 5-6 times , then hit the button , it should start right up ..... if it tries but still does not , repeat the 5-6 twists and try again ....

This has been the starting procedure for my 06 since new , any other way , and its hard to start ..... , I can leave it sit for a year (with non ethanol gas in it) , and go over to it , pump the throttle as mentioned , pull the choke and it will start right up ......

1 other thing to check .... if it seems to be cranking over slowly , it won't like to start either , so pull the valve cover and check the decompressor gap , if it is off even slightly , it will be hard to start as it won't release the valve enough to lower the compression so it starts/turns over faster , which is what is needed for it to start quickly ..... so a combination of those few things , could be your entire issue ......... Hope that helped ..... if you have more questions don't hesitate to ask ....

[bobwehadababyitsaboy]

Welcome to the site !!

You should be at 45/165 for jetting , so going up on the main should help ...

What is your starting procedure ?? , what you "should" be doing is ......Turn on the fuel ....... Pull the Choke ...... Twist the Throttle 5-6 times , then hit the button , it should start right up ..... if it tries but still does not , repeat the 5-6 twists and try again ....

This has been the starting procedure for my 06 since new , any other way , and its hard to start ..... , I can leave it sit for a year (with non ethanol gas in it) , and go over to it , pump the throttle as mentioned , pull the choke and it will start right up ......

1 other thing to check .... if it seems to be cranking over slowly , it won't like to start either , so pull the valve cover and check the decompressor gap , if it is off even slightly , it will be hard to start as it won't release the valve enough to lower the compression so it starts/turns over faster , which is what is needed for it to start quickly ..... so a combination of those few things , could be your entire issue ......... Hope that helped ..... if you have more questions don't hesitate to ask ....

Yep that's my starting procedure. It will crank for a while before it starts, and won't like to stay running. Even with the choke it will usually die a few times. Then I need to let it idle with the choke on for about a minute before it'll even run.

Main jet shouldn't affect the idle at all, right? I have the stock airbox and pipe, no mods there. For a little bit I had the snorkel removed from the airbox and it REALLY wouldn't run then.

I will check my decompressor adjustment, good call! Last I was in there everything looked good and it was only about 10 hours ago.

I was thinking of going to 2 turns out on the fuel screw. Does anyone know what the maximum number of turns is before it stops making a difference?

[JimDirt]

On the Fuel Screw ..... You should notice a difference when turning it at idle , the idle should raise or lower , what you want is the middle of those extremes , so basically you will turn the screw and the idle will go up a bit , then it will stop going up and start going down , if you go the other way , it will do the same , the optimum adjustment is the middle of those 2 points basically , if ... when at that adjustment and you find you are at the extreme (over 3 turns or under 1 turn) then a larger or smaller pilot would be needed , the pilot does the work from idle to about 1/4 throttle , then the main starts having more if a effect , as soon as you move the throttle the main comes into play , then above 3/4 it is pretty much the main

Just wondering , what does your plug look like ?? , is it tan ?? , or dark/sooty ? , or is it white or have dark spots on the white porcelain ?? .... also when running and you are going along and let off the throttle completely , does it pop thru the muffler ???

With my bike , (I am at 2,100 ele.) I run a 45/162 with the fuel screw at 1-3/4 , it runs excellent and starts right up with the procedure I mentioned , after it is warmed up , it just starts right up as well , up to about 8,000 , then I have to adjust the fuel screw a bit ..... however , at lower elevations , like 400 or so ft. , I have to go up on both the Pilot and Main ... The last time I had my bike in Washington , I had to run a 48/180 and 2-1/2 turns out , I don't know why , but it as well as my 02 450R would not run with any lesser jetting , I had asked Leardriver ( out resident carb guru) and he did not have a answer as to why it needed such rich jetting , his only thought was some kind of internal blockage ..... I completely disassembled both carbs , including the mid body , and found nothing wrong , but once back where I lived , and with the jetting (45/162) I had been using , both bikes ran great ....... What your description is sounding like , is something is causing a rich condition if it is starting fine at higher elevations , which should make everything leaner , what it is , I can say for positive .... but what I would suggest is if you have the stock(42) pilot to test with , see if it starts better using the same starting procedure , if it does , then you can conclude that there is a rich condition , then it will have to be traced out , but at least by doing that , you will confirm if the starting issue is because of being rich , but at least then you have something confirmed to work with as far as lean or rich .... , it could be the the choke plunger is hanging slightly , I don't know , but it sounds like something in the system is causing it to be rich

You could also try (with the current jetting) doing the starting procedure , but do not set the choke , just pump the throttle and try , if it starts that will also confirm rich ....

I would also suggest giving a PM (Private Message) to Leardriver , if anyone here can figure out what is going on , it is him ....

https://www.crfsonly.com/forum/memberli ... le&u=14707

[bobwehadababyitsaboy]

On the Fuel Screw ..... You should notice a difference when turning it at idle , the idle should raise or lower , what you want is the middle of those extremes , so basically you will turn the screw and the idle will go up a bit , then it will stop going up and start going down , if you go the other way , it will do the same , the optimum adjustment is the middle of those 2 points basically , if ... when at that adjustment and you find you are at the extreme (over 3 turns or under 1 turn) then a larger or smaller pilot would be needed , the pilot does the work from idle to about 1/4 throttle , then the main starts having more if a effect , as soon as you move the throttle the main comes into play , then above 3/4 it is pretty much the main

Just wondering , what does your plug look like ?? , is it tan ?? , or dark/sooty ? , or is it white or have dark spots on the white porcelain ?? .... also when running and you are going along and let off the throttle completely , does it pop thru the muffler ???

With my bike , (I am at 2,100 ele.) I run a 45/162 with the fuel screw at 1-3/4 , it runs excellent and starts right up with the procedure I mentioned , after it is warmed up , it just starts right up as well , up to about 8,000 , then I have to adjust the fuel screw a bit ..... however , at lower elevations , like 400 or so ft. , I have to go up on both the Pilot and Main ... The last time I had my bike in Washington , I had to run a 48/180 and 2-1/2 turns out , I don't know why , but it as well as my 02 450R would not run with any lesser jetting , I had asked Leardriver ( out resident carb guru) and he did not have a answer as to why it needed such rich jetting , his only thought was some kind of internal blockage ..... I completely disassembled both carbs , including the mid body , and found nothing wrong , but once back where I lived , and with the jetting (45/162) I had been using , both bikes ran great ....... What your description is sounding like , is something is causing a rich condition if it is starting fine at higher elevations , which should make everything leaner , what it is , I can say for positive .... but what I would suggest is if you have the stock(42) pilot to test with , see if it starts better using the same starting procedure , if it does , then you can conclude that there is a rich condition , then it will have to be traced out , but at least by doing that , you will confirm if the starting issue is because of being rich , but at least then you have something confirmed to work with as far as lean or rich .... , it could be the the choke plunger is hanging slightly , I don't know , but it sounds like something in the system is causing it to be rich

You could also try (with the current jetting) doing the starting procedure , but do not set the choke , just pump the throttle and try , if it starts that will also confirm rich ....

I would also suggest giving a PM (Private Message) to Leardriver , if anyone here can figure out what is going on , it is him ....

https://www.crfsonly.com/forum/memberli ... le&u=14707

Thanks Jim, appreciate it!

I'm not sure how I can adjust the fuel screw with the engine running cause it's tucked up in there. I see some guys saying to get this RD flex jet but half the people say it falls apart and you need to lube it and stuff - seems like more hassle than its worth for something you pretty much set and never touch again.

Stock pilot on my 05 is a 45. I do notice a little bit of popping on decel but it's not terrible. To be honest once the bike is warmed up it's fine, I don't get any stumbling or hesitation. I just sort of dread starting it up because it's so finicky.

I can't say I've looked at my spark plug in a long time but last I checked it was just a brownish color, nothing out of the ordinary.

It's definitely a lean condition because without the choke it would never start no matter how many times I pumped it haha.

[Back2-2]

Pretty simple. You need to go one size larger on the pilot jet. You asked the range of the fuel screw. No more than 3 turns CCW from lightly seated. You can try to go to the 3 turns out and see if there is any improvement in starting but one size larger will correct your starting. Yes, the MJ is not in the equation what so ever for your starting.

Put a 48 PJ it that bad boy & go.
As for the adjustable fuel screw - My opinion they are next to mandatory if you want your bike running at it's peak performance. I suggest a brass screw over aluminum and one. If you do go with an aluminum type get one that has numbers on it so you can see how much of an adjustment turn you made since you are using the tip of your finger to make the adjustment. Your not getting your hand in there to get on the knob.
As for the type that has the flexible cable to the side of the carb body. That is what I plan to install when I have the need to remove the one I have presently.