[CRAIF450]

New to me 2006 CRF 450R, starts 1 or 2 kicks when warm, but you'll break your foot off when it's cold. Any cold starting tips, change the plug maybe, it has to be fouled after so many kicks. Thanks.

[JimDirt]

Welcome to the site !!

Have you done any kind of service on the bike yet ?? , like check the valve lash , FRESH gas and draining the old (if it sat for more than a month , the Ethanol in the gas could have clogged the pilot jet) , does the bike pop thru the muffler after it is running ?? , does it pop heavily on deceleration ?? , if so this could indicate tight intake valves or a clogged pilot jet

Sometimes a certain starting procedure is needed when cold , this is the case with my 450X , so try this

Turn on gas , and pull choke

Twist the throttle 4 full twists/snaps

Push down on the kick starter , and slowly go thru the stroke till you feel the compression (it will start to get harder to push) , then bring the kick start all the way up , and give a FULL FIRM kick , putting your weight behind it (don't try to start it like a 2 stroke)

It should either start or TRY to start , if it tries , then repeat the procedure , it should start within 1 to 3 attempts at this while cold

If it does not even sputter , then you need to do a check thru what i mentioned before , checking valves , and pull the pilot jet and see if its clogged , check the hot start function , make sure the lever works properly

[CRAIF450]

Welcome to the site !!

Have you done any kind of service on the bike yet ?? , like check the valve lash , FRESH gas and draining the old (if it sat for more than a month , the Ethanol in the gas could have clogged the pilot jet) , does the bike pop thru the muffler after it is running ?? , does it pop heavily on deceleration ?? , if so this could indicate tight intake valves or a clogged pilot jet

Sometimes a certain starting procedure is needed when cold , this is the case with my 450X , so try this

Turn on gas , and pull choke

Twist the throttle 4 full twists/snaps

Push down on the kick starter , and slowly go thru the stroke till you feel the compression (it will start to get harder to push) , then bring the kick start all the way up , and give a FULL FIRM kick , putting your weight behind it (don't try to start it like a 2 stroke)

It should either start or TRY to start , if it tries , then repeat the procedure , it should start within 1 to 3 attempts at this while cold

If it does not even sputter , then you need to do a check thru what i mentioned before , checking valves , and pull the pilot jet and see if its clogged , check the hot start function , make sure the lever works properly

Thanks for the warm welcome and thorough reply! The bike just had a full service and was gone through end-to-end by a pro mechanic. It runs very well when running, none of the lean indicators, popping etc. It has fresh fuel in it too. I usually have the touch getting things running, but this is a tough one.

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It's funny, I also have a 1987 230 quadrunner that has been sitting for over a month and that sucker started up immediately this morning, I've got it dialed in. So did the other 2 bikes, all have the magic button... Made me scowl even harder at the CRF.

I had an '02 CRF when they were first introduced and that would fire right up, 1 or 2 kicks. But it would flame-out easily if you didn't stay on the revs in slow corners.

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I went through the starting routine you mentioned and I'm getting good feedback, it wants to fire (a few turnovers, dub dub dub, sputter, then off again). My foot is killing me, I'll have to go after it again later.

Again, I appreciate the advice!

[Dirtclod]

All of these bike seem to have their on personally to start COLD my 04 pull the choke kick through slow twice blip the throttle once then kick it hard fires right up. My 05 choke kick it through once twist the throttle twice and kick it hard once whamo it starts.

[CRAIF450]

I may have to now check the jets then the valves. My buddy thinks a larger Pilot Jet may help before digging into the valves. I need to go get some Ethanol Free fuel as well, we have 1 station in town that sells it.

It wants to start, my kicks are effective, I'm approaching 200 lbs and have been kick-starting bikes for 25 years. So I know effort isn't the issue. - Wish me luck as we go deeper.

[JimDirt]

Keep us informed on your progress , a #45 pilot jet should be good under most circumstances , you "should" not need larger , if it has a #42 then the #45 will be fine

Here is a jetting chart to follow

Jetting Guide for Main Jet:(pilot 45) CRF450R/X

Sea level....165
2000 ft.......162
4000 ft.......160
6000 ft.......158
8000 ft.......155


Temperature/Elevation:
One main jet size (up/down) for every 2,000 feet or 25 degrees in temp.

In reference to the 02 you had , what was causing the stalling in corners was the fact that the 02 has the lightest flywheel of all the 450's , a flywheel weight would have cured the stalling issue with no other changes , i have a 13 oz weight on mine , it does not stall in corners unless i do something wrong , i run the heaviest weight , which gives me a total of 35 oz , which is the most you can run , i can also trail ride mine on tight single track with no worry of stalling , it was the best investment i did with this bike (next to re-valving the suspension , which i do myself) , , so for future reference , if you ever get another 02-04 and your constantly stalling in corners , and cant "tune" it out of it , then get a flywheel weight , and it should solve the issue....

[CRAIF450]

Keep us informed on your progress , a #45 pilot jet should be good under most circumstances , you "should" not need larger , if it has a $42 then the #45 will be fine

Here is a jetting chart to follow

Jetting Guide for Main Jet:(pilot 45) CRF450R/X

Sea level....165
2000 ft.......162
4000 ft.......160
6000 ft.......158
8000 ft.......155


Temperature/Elevation:
One main jet size (up/down) for every 2,000 feet or 25 degrees in temp.

Thanks Jim - great info, I will keep you posted for sure.

[JimDirt]

lol i was editing when you posted , so read the added info at the bottom .....

[CRAIF450]

lol i was editing when you posted , so read the added info at the bottom .....

Haha, it was stalling in slow tight stuff when it was new to me. I learned to manage the clutch better. Started riding more open motocross tracks and it was no longer an issue, but flywheel weight would have helped for technical sections. Glad you worked yours out.

[CRAIF450]

Okay, proud moment; (It has been between 20 and 30 degrees over night here)... Went up from a 48 to a 50 pilot put heaters on the trans and got it lit after much tinkering with the fuel screw and dialing in a firm but fluid kicking style. It turns out I must have been kicking it too hard as well. My bro-in law had put 15w50 Shell Syth in the trans, must have been too thick, dragging, not allowing enough 'run-on' for it to catch fire.

Thanks for all of the great advice, I hope my experience helps someone else!

[JimDirt]

That is WAAAAY to big of a Pilot jet no matter the temperature or elevation , what is the setting on the fuel screw ??? , it should be between 1-1/4 turns out , to 2-3/4 turns out , no less , no more , a pilot jet that large would indicate a major vacuum leak , or a major clog or air leak in the carb

a 50 , is just not the correct "fix" for your issue , there is something else you are missing

When its 20 here , i can fire my bike up within 3 kicks with a 45 pilot jet and a 160 main jet , i use the same jetting in the summer when its 100+ , and just lean out the fuel screw (in) , i also use Shell Rotella , but its full synthetic , and 5w-40 , and i have ran a 48 pilot jet , but i was at 500 ft elevation

You compensating for something else your missing , its either a fuel delivery issue (not enough) , within the carb , or its a massive air leak , (within the carb or exhaust system) , , or you have a issue with the timing being off , or your valves , you need to check the valve lash and see where its at , check the spark plug , as it could be going bad , or have too large of gap , but no matter what , your overlooking something here , and a 50 pilot jet , is not the answer ..... if you can turn the fuel screw all the way in , or more than 3 turns out to get it to run , then your jetting is not correct and/or you have a air leak , or blockage in the carb (or a timing or valve issue)

I understand your happy its running , but its not correct and needs to be addressed , you need to find the issue that is causing the need to over jet dramatically , 50 is just waaay to big , period....sorry

PM leardriver ,, he hangs out in the Jetting part of the forum , he is the resident carb expert here , and does carbs for a living , he will confirm what i am saying , but , he should be able to direct you closer to the issue than i can at this point

[CRAIF450]

That is WAAAAY to big of a Pilot jet no matter the temperature or elevation , what is the setting on the fuel screw ??? , it should be between 1-1/4 turns out , to 2-3/4 turns out , no less , no more , a pilot jet that large would indicate a major vacuum leak , or a major clog or air leak in the carb

a 50 , is just not the correct "fix" for your issue , there is something else you are missing

When its 20 here , i can fire my bike up within 3 kicks with a 45 pilot jet and a 160 main jet , i use the same jetting in the summer when its 100+ , and just lean out the fuel screw (in) , i also use Shell Rotella , but its full synthetic , and 5w-40 , and i have ran a 48 pilot jet , but i was at 500 ft elevation

You compensating for something else your missing , its either a fuel delivery issue (not enough) , within the carb , or its a massive air leak , (within the carb or exhaust system) , , or you have a issue with the timing being off , or your valves , you need to check the valve lash and see where its at , check the spark plug , as it could be going bad , or have too large of gap , but no matter what , your overlooking something here , and a 50 pilot jet , is not the answer ..... if you can turn the fuel screw all the way in , or more than 3 turns out to get it to run , then your jetting is not correct and/or you have a air leak , or blockage in the carb (or a timing or valve issue)

I understand your happy its running , but its not correct and needs to be addressed , you need to find the issue that is causing the need to over jet dramatically , 50 is just waaay to big , period....sorry

PM leardriver ,, he hangs out in the Jetting part of the forum , he is the resident carb expert here , and does carbs for a living , he will confirm what i am saying , but , he should be able to direct you closer to the issue than i can at this point

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Hey Jim,

Thanks for the advice, Jim! Thought I had something good . I will PM leardriver. The thing is, I don't know the history of this bike, it's a worked full-on race bike with a megabomb header and FMF Factory 4.1 system on it. It has things done to the engine that I don't even know about. Has the Boyesen Quickstart system on the carb. It runs crisply, valves are quiet, response is snappy. What is the detriment to a larger pilot jet? I have rebuilt carbs to stock spec in the past, but I am mostly ignorant regarding modification.

Best, Craig

[JimDirt]

The detriment is heat , a richer engine will run hotter than a properly jetted or lean engine (less fuel , less heat) , this is why you lean a engine in the summer and richen it in the winter , though not to the extreme you have , just a fuel screw adjustment and maybe a main jet change by 1 (up or down depending on temp) is all that is needed for most

Talk to leardriver , if anyone can pinpoint your issue he can(if its fuel related) , i would still check the valves and such , and just do a good go over of the bike/engine to rule out and narrow down everything

[CRAIF450]

The detriment is heat , a richer engine will run hotter than a properly jetted or lean engine (less fuel , less heat) , this is why you lean a engine in the summer and richen it in the winter , though not to the extreme you have , just a fuel screw adjustment and maybe a main jet change by 1 (up or down depending on temp) is all that is needed for most

Talk to leardriver , if anyone can pinpoint your issue he can(if its fuel related) , i would still check the valves and such , and just do a good go over of the bike/engine to rule out and narrow down everything

Thanks, Jim. Will do, the header pipe was glowing at night before (with the original #48 jet). Hmm - I thought only a lean condition would cause too much heat? I do have oversized radiators on it almost +50% over stock so have additional coverage there. Appreciate the assist.

[JimDirt]

Keep everyone posted on your findings ...