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New 2014 YZ250 Owner

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Hey everyone.  Just wanted to say hi to all the Yamaha 2 Stroke riders out there.  I just picked up my 2014 YZ250 on the weekend and had a blast riding.  The initial break-in procedures were done at the dealer (the heat cycles) so I just had to go ride for a bit and take it easy.  The only issue I had was that the bike won't idle. I stopped by the dealer to pick up some Yamalube 2-R and fill up my gas can at the Petro, and while I was there I asked the mechanic why the bike won't idle.  He said it's supposed to be like that.  I find that kinda weird.  I do admit, I probably won't be racing this bike as I bought it more for trails/fields where my parents live.  I did manage to get it idling nicely by turning in the throttle stop screw on the carb though.  It's much easier to ride when it idles.  Has anyone ever heard that the bikes apparently are set up to not idle from the factory?  What if you're in the air after hitting a jump?  I'd never want my bike to stall while I was in the air.. although I know you probably will be on the throttle the whole time, but what if you make a mistake etc..

 

Thanks everyone!

 

Neal.

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I believe this is more of a pro racer thing.  I own a YZ125, bought straight from dealer, and it idled nicely from day 1.  I recently bought a used YZ144 which idled when I bought it.  I took it to a local race shop to have it gone through and 1st ride afterwards there was no idle.  I called the mechanic and he said that 2-strokes aren't supposed to idle.  Well, I couldn't ride it like that so I turned the idle stop screw until it barely idled.

 

From my discussion with the mechanic, who was a mechanic for some pro SX and MX racers, I got the impression that this was how most of the pros used to run their 2-strokes back in the day.

 

 

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I believe this is more of a pro racer thing.  I own a YZ125, bought straight from dealer, and it idled nicely from day 1.  I recently bought a used YZ144 which idled when I bought it.  I took it to a local race shop to have it gone through and 1st ride afterwards there was no idle.  I called the mechanic and he said that 2-strokes aren't supposed to idle.  Well, I couldn't ride it like that so I turned the idle stop screw until it barely idled.

 

From my discussion with the mechanic, who was a mechanic for some pro SX and MX racers, I got the impression that this was how most of the pros used to run their 2-strokes back in the day.

Hey Pbody.  Thanks for replying.  I think you're right.  The reason my mechanic gave me was because when 2 strokes idle, they "generate a whole lot of heat".  I know they obviously do (My old bike was an '86 CR500 which idled perfectly) but if you're shifting down gears or just putting a long in 2nd and not on the gas the whole time, the bike is getting air in the rad and cooling off.  I'd not want it to stall just so it will stay cooler.  Maybe it has more to do with throttle response as reasoning for not wanting them to idle?

Edited by NealYZ250

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Part of it ,is that if a 2-stroke idles for too long it can load up and foul a plug.So just don't let it sit idling for 10 minutes.I have 2 yz125's and a yz250(now 325) and have had a few others in recent years.I set all of them up to idle nicely,and have never fouled a plug even once in 5 years.

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Lots of this will come down to how well the bike is jetted. My bike can idle for a few minutes on the stand and will not load up much at all. I've owned bikes that didn't like to idle at all and would foul plugs. Enjoy your new bike. 

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I Have new new 2014 as well had it for 3 weeks now. Mine would not idle either and that's a pain on tight trails. I messed with my idle screw but it still didn't make it idle so idk..

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Don't listen to all the nonsense about it not being able to idle! Turn your idle adjustment in just enough to make it barely idle and you will be good to go. However I don't ever let my bike idle for more than a few seconds unless I'm warming it up and then I just use the throttle to do an accelerated idle speed.

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I Have new new 2014 as well had it for 3 weeks now. Mine would not idle either and that's a pain on tight trails. I messed with my idle screw but it still didn't make it idle so idk..

 

I had to turn mine all the way in and then out 2 full turns.  The mechanic told me to start with a quarter turn which did jack sh|t.  Also, 3 more full turns in didn't do anything either.

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Don't listen to all the nonsense about it not being able to idle! Turn your idle adjustment in just enough to make it barely idle and you will be good to go. However I don't ever let my bike idle for more than a few seconds unless I'm warming it up and then I just use the throttle to do an accelerated idle speed.

Yea, riding with no idle is really tough in tight trails and/or challenging terrain.  I thought it was pretty stupid to have a bike that stalls when you let off the throttle.

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The reason that the bikes are not meant to idle has to do with throttle response. A bike that idles will be too lean. Buy no means will it harm your bike in any way.

 

I set mine to idle for about 2-3 seconds after I blip the throttle. It makes a difference.

 

If you like it to idle, then keep it. It will not hurt the bike at all.

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Remember you air screw also affects idle

This is true and in my experience an overly rich pilot jet will not idle. If you are having trouble getting it to idle correctly the problem may be that your pilot jet is one size too big.

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Remember you air screw also affects idle

Yeh I figure there will be a bunch of variables in play, especially with a brand new bike with only break-in time on it.  I remember the carb in my '86 CR500 wasn't quite right and I actually ended up making it worse by playing with the air screw and being a moron and not recording my turn ins/turn outs/original position.  So far so good with the black, plastic throttle stop screw turned out 2.5 turns or so.  According to the shop manual, that is the screw to turn to turn idle up or down.  As far as richness/lean-ness goes, I'm still not sure where she is because I have only had her out for about 45 mins or so with easy riding.

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The reason that the bikes are not meant to idle has to do with throttle response. A bike that idles will be too lean. Buy no means will it harm your bike in any way.

 

I set mine to idle for about 2-3 seconds after I blip the throttle. It makes a difference.

 

If you like it to idle, then keep it. It will not hurt the bike at all.

souliog is correct. The throttle response is usually stronger off the bottom when the bike doesn't idle well. That doesn't mean you can't get it adjusted to your liking with a decent idle, but that's not how Yamaha prefers them to be set-up. You won't harm a thing if you take the time to get your bike adjusted to the way you like, with an idle.

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Turn that black idle screw in until your bike is idling steadily.Everything is beautiful.The air screw is just below and to the right of the idle screw.It's a little slot screw,and it's almost hidden.I think 1 1/2 turns out from all the way in should be in the ballpark.But YES,record where it is now as a reference.If you want to make sure it's set properly,warm up your bike real good and set your idle so it is idling steadily.Turn your air screw in(clockwise),and as it closes ,your bike will want to die....start backing it out,noting how many turns,until your bike reaches it's highest idling point,and then don't go any further.You  want to stop right exactly at it's highest RPM.Exactly where it reaches it.Then reset your idle screw if you need to.

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Turn that black idle screw in until your bike is idling steadily.Everything is beautiful.The air screw is just below and to the right of the idle screw.It's a little slot screw,and it's almost hidden.I think 1 1/2 turns out from all the way in should be in the ballpark.But YES,record where it is now as a reference.If you want to make sure it's set properly,warm up your bike real good and set your idle so it is idling steadily.Turn your air screw in(clockwise),and as it closes ,your bike will want to die....start backing it out,noting how many turns,until your bike reaches it's highest idling point,and then don't go any further.You  want to stop right exactly at it's highest RPM.Exactly where it reaches it.Then reset your idle screw if you need to.

thanks Flapwick.  So far so good by just turning the black screw in all the way and then out 2.5 turns or so and she idles perfectly.  I might actually turn it down a bit to get it like Souldog has where it dies about 3 seconds after you blip the throttle..  The mechanic didn't say anything about messing with the air screw.

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Most of all, Yamaha wants every YZ to be reliable & meet the expectations of the original purchaser, presuming basic maintainence proceedures are performed.  They do an exceptional job by providing an extensive shop manual along with every bike.  (This is very different than all other products they sell!)

This means every single YZ 2-stroke sold throughout the world is jetted rich enough for the most dense air any owner will experience. It will never overheat or blow up, no matter where you ride it, if you follow the basic instructions.

The service manual is provided, because most YZ's will not be run in cold, dry, sea-level conditions.  If you want the best performance your YZ is engineered for, you need to tune (jet) it according to your ambient conditions.  This is a machine designed for competition, & all the information to make the changes you need to make it run optimally are in the manual, & readily available on sites like this on the web.

A precisely & accurately jetted YZ can idle an entire tank of fuel dry, & never foul a spark plug.  It will also out perform a stock YZ in every aspect of performance.

Take time to learn to jet & tune your YZ, & you'll reap rewards that most owners who spend much $$ on aftermarket products never enjoy.  Consistant fuel, ignition timing, & minor cylinder head modifications are other low-cost keys for optimal performance.

 

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You can make them idle. They tend to load up with fuel during idle though, and best way to jet is a touch on the rich side...so many only idle for short periods.

 

Theres a brass mixture screw used for tuning to the bottom right of the idle screw...give it a gentle quarter turn in either direction and see what you get. Welcome to tuning!

 

Btw i just picked up a '13 a few months ago. Ive had 4 different years of these. Ive ridden lots of others. Great bikes. Great choice.

Edited by jeffdanger

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