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andrewjones11

Problems starting 08 yz 450

16 posts in this topic

I just got an 08 yz 450 a couple of weeks ago I love the way it rides but it is a pain to get started anybody have any ideas why? This morning I had such a hard time getting it started that I was trying everything I finally got it started by using the hot start when the bike was still cold? Is it just something to do with jetting?:thumbsup:

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I just got an 08 yz 450 a couple of weeks ago I love the way it rides but it is a pain to get started anybody have any ideas why? This morning I had such a hard time getting it started that I was trying everything I finally got it started by using the hot start when the bike was still cold? Is it just something to do with jetting?:thumbsup:

Where in Cali. are you? <Elevation>? How many hours do you have on it. Did you over oil the air filter? When i first got my 08 it was kinda hard to start. Once i put some hours on it < a few races> and adjusted the fuel screw to 2 1/4 turns it starts first kick all the time. when my bike is first started in the morning, I'll flip the choke on/blip the throttle twice or three times/ the give it a healthy boot. Starts every time. After that during the day, i will just kick it.....even when completely cooled off and it starts first or second kick. I have noticed that sometimes after installing a heavily oiled air filter, it needs a kick with the hot start.

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I just got an 08 yz 450 a couple of weeks ago I love the way it rides but it is a pain to get started anybody have any ideas why? This morning I had such a hard time getting it started that I was trying everything I finally got it started by using the hot start when the bike was still cold? Is it just something to do with jetting?:thumbsup:
What brand and model was your last bike?

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I live at about 3,000 feet. I have probably about 6 or 7 hours on it and I tried playing with the fuel screw a little but that didnt help. I havent even cleaned the air filter yet so it isnt ove oiled. I used to ride a 98 yz 400 that would start up so easy.

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i found mine a pain to start before it was completely broke in. it will get easier to start as you ride it more and more. just bring it up on compression and kick to the foot peg with no throttle. try the choke and if that doesn't work give the throttle 1 blip and then give it a shot, then try 2 blips. mine now takes 2 blips (but its getting cold here now around 1 degree celcius) id say one will do it for you. if it floods dont try it anymore. there will be a puddle of gas under ur bike. leave it for 10 mins or so and go back and try it again. you'll get used to it after a while. good luck.

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If my jetting is off does anybody have any suggestions on where to start or have any numbers for me. My bike is stock except for a zip ty fuel screw I live in Lancater ca which is at about 3,000 feet it is aaround 100 degrees in the summer and 40 to 50 degrees in the winter. Any help would be great.

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first clean your air filter you might be choking her up. You can mess with the jetting too but it may be a good idea just to get to know her a little before you expect to much. My '06 is a no throttle bike. My first time out I flooded the hell out of it and ended up having to push start it.

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go up a pilot size

look at jetting sticky -

for under 60 degrees - you will have to test

45 or 48pj

165/168/170mj or even a 172

1.5 -2.5 turns out on fuel screw

hot temps

leaner

45pj

165/168mj

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yes your jetting is off

How is his jetting off if its the same as mine and mines perfect? We basicly live in the same elevations and i race out in Lancaster occasionally? My 08 was kinda tricky to start when new but once it got some hours on it..........It will start first kick most of the time.

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I'm at about sea level in nor cal and I still can't get mine to fire first kick. I'm up to a 50 pilot (was at 48 and 45 before that) with a Dr.D pipe. My buddy has the same problem. I have about 5 races and many practice days on mine. What else could be off? It has been this way since day 1. The first day with all stock stuff I had to use the Hot start to get it to fire. TP sensor? Could the valves have been out since day 1? Could the idle screw have anything to do with it? After installin the pipe the bike would run on when I bliped the throttle -it would not settle down to idle again immediatly. I was able to work this out with Idle and FS adjustments but it sure seems something is not right.

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How is his jetting off if its the same as mine and mines perfect? We basicly live in the same elevations and i race out in Lancaster occasionally? My 08 was kinda tricky to start when new but once it got some hours on it..........It will start first kick most of the time.

I stated this mainly because every brand new yami is typically lean from factory. Maybe this works for you. It has not for me at all....but I am at 900-2000ft....remember just because it kicks over does not mean that it is jetting 100% correctly either.....

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I stated this mainly because every brand new yami is typically lean from factory. Maybe this works for you. It has not for me at all....but I am at 900-2000ft....remember just because it kicks over does not mean that it is jetting 100% correctly either.....

Yessir!! understood! I feel mine could use some "fine tuning" but thats only because i added a pipe. When it was completely stock, the only thing i did was bump the fuel screw to 2 1/4 turns. On my 06 i changed the needle to an NFLR, fuel screw at 2 turns, pilot to a 45 and it runs perfect. <DR D Pipe> You are very correct when you say that just because it starts right up that it doesn't nesessarily mean its jetted correctly. What jetting is working for you in your 06..................

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Just turn the idle screw CW about 1/4 turn and try again with the following: gas on, choke on, 2 blips of throttle, and kick. Don`t jack with the jetting yet. Also, idle needs to be set high when engine is hot

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I have an 08 and it takes two blips of the throttle before I try to start it, choke on and it usually fires up in two kicks. Now that the temps are between 30-45 degrees at 900ft I've gone up to a 48pj(stock 45) and a 165mj(160 stock).

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