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Discussion Starter · #1 ·
Hi Everyone! I just got my 2008 Yamaha YZ250F and I have only ridden it two times yet.


I find it very hard to start , It was like that since i got it.

But when it's running:scooter i cannot see any problems with the bike.

Could it be something with the mixture that i need to tune or is this a major problem that cannot be fixxed :dunno ?
 

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Typically, bikes are lean from the factory. When you say it's hard to start, is it when it's cold or warmed up/hot?

Best solution is to get a jet kit from jdjetting.com for your bike, then also get a fuel mixture screw. You'll find that the bike runs much better.
 

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Discussion Starter · #3 · (Edited)
Even when it's Cold and Warmed Up it is hard to start it.

But i got some armament for the carburettor when i got the Dirtbike.

Someonetold my father that they use another armament in USA than in Sweden , but i don't think that would make it harder to start it ?
 

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I'm not sure what armament for carburetor is?

on cold start one pre blip of throttle full choke.
if bike is already warmed up you must pull in the hot start lever while kicking or the bike will not fire up or it will take a long time to start.
 

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Discussion Starter · #5 ·
Actually i don't know it either i used "Lexin" to translate a word from swedish too english that i didn't know :/
 

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Armament? Are you referring to a heat shield? :dunno

As to the hard starting, a lean bike will cause those problems in both cold and hot conditions. By replacing the main jet and needle, you will help it to start better.

I'm interested though in finding out what you're referring to. :)
 

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those look like main jets to me.
I am not sure I understand the reason for changing them in the first place. if it was because someone told your father they would need to be changed without any readings or tuning to determine correct jetting then I would go back to stock. unless the jetting changes were to correct a lean or rich situation I would go back to stock.
 

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Discussion Starter · #10 ·
I'm still using stock . :/

Btw Macattack. Did you do something to your bike (YZ250F) when you got it or has it always been easy to start.
 

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my bike always starts within four kicks.
are you using the choke on cold start and the hot start lever on hot starts?
I have noticed my 450 and now my 250 both did not want to start unless the bike was in neutral. with my two strokes you could hold the clutch in and kick while the bike was in gear and it would fire up no problem.
the 250f seems to need the hot start lever (when hot) more than the 450f I had.
the 250f needs fuel on cold starts so choke and a little throttle while kicking .
 

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If you hit up Thumper Talk, and go into the jetting or YZ250F sections, you'll find that jetting is the #1 thing people do to their bikes. It cures all kinds of problems. :fact

Ravage, have you tried opening your throttle a little when you kick it over? Not much, just enough to move the throttle a bit. That might make it easier to start. If so, turn your throttle speed up a little and it should help.

BTW, all three of my bikes were difficult to start hot or cold until I rejetted them.
 

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Discussion Starter · #14 ·
Fjorn, where in the "Da northland. Yah." do you live?

It sounds like norway ;)

Well anyway, how did you order the JDJetting Set for you YZ250F?
 

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I live in Minnesota actually. :) Would love to get to Norway and Sweden, but that's a ways out. I do have a friend that lives just outside of Stockholm that I've been trying to visit since he and his wife moved there.

As to the JDJetting kit, I ordered mine through Thumpertalk store, but you should be able to order it directly from them. I would think they'd do overseas orders, and with the way things are going, I'm sure it'd be to your advantage given our exchange rate. ;)


Here's the link for you:

2006-2008 YZ250F jetting kit
 

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Discussion Starter · #16 ·
Okay Sweet :thumbup

I was thinking of ordering a JD Jetting Kit for the Bike.

It seems like it dosen't need any kind of credit card, which is good for me because i don't have one.

So how do you pay for it ? ( With money tho )
 

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Good deal on not having a credit card, the world is better off without them. :thumbup

Good question on the ordering. Unfortunately, I don't have an answer for you. But, I know if you drop them a line, they can answer it for you. :)

Contact JDJetting

I went through the checkout process, and they do have worldwide shipping. But, they don't include shipping prices. Most likely due to needing to know where to ship it to and it's variable costs.

IMO, this was by far the best mod I ever did on all three of my dirt bikes. :fact
 

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Discussion Starter · #18 ·
Okey Nice :thumbup.

Well i hope the shipping prices are that high, but i don't think it is. Because it does only have the weight of 0.50 lbs ;)

When you did this on the YZ250F did it increase the Throttle response,Horse Powers & Starting (Easier). ? Because it says so on the box :p
 

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It might be a few dollars on shipping. Not sure as it's been a while since I shipped something to my friend over there. :dunno

As to the gains, I would give a resounding yes. It took me about an hour to hour and a half to pull the carb, replace the parts and reinstall. Two quick blips of the throttle with a closed choke and it started up almost right away. You'll also want to pick up an idle mixture screw (about $20 US) to make fuel enrichment changes easily without tools.

One thing to note, is that on my YZ250F is that I have an '05 which is the steel frame. So, removing the carbeurator was relatively easy. On my 07 YZ450F, I had to remove the subframe, and rear shock to remove it. I haven't worked on an aluminum framed 250F, so not sure what would be involved exactly.
 

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what size jet do you need? it's a standard mikuni carburettor? the jets are only worth $1.50, eh? and can be shipped in an envelope.

that said I do all my own jetting and don't trust "jet kits" as I think every motor needs to be diagnosed individually.
 
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