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WR 450 Gas/Air Tuning

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What's up Kids!!!

I am having some gas /air mixture issues! My bike runs quit lean I 've been told. I Have a hard time startibng when the temp goes below 12' C. Any idea how to adjust this to run at colder temp. I am sure its a jetting thing, But looking for some ideas!!\

Happy Thanksgiving!!!!!!

👍

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Hopw do you know it is lean? Rumors do not cut it.

For the hard cold starting, you probably want a larger starter jet. You need to see what starter jet is in the bike and go up in number. If you have a #68, I'd try a #72 (four number larger increments). I will assume you already did the following as it is done on a HOT bike:

Fuel Screw/Pilot Jet

Fuel screw settings in the 'book' are recommended starting points. Every bike is different, as is the temp and altitude. Set the screw according to this method. Do it with the bike fully heated up.

Gently turn the screw all the way in. Now back it out two turns. Start the bike and fully warm it up, go for a 10 minute ride. Set the idle to speed to 1,500~1,800 RPM as best you can (I know, without a tach this is tough, just set it to were it idles relatively smoothly). Once warmed, slow the idle to the lowest possible speed.

*** When turning the fuel screw, keep an accurate 'count' of the amount you are turning it and record it in case you have to reset it for some reason. Makes life easier when you can just set it from notes Vs. going through the procedure again.***

Turn the screw in until the idle becomes rough or the bike stalls.

if it stalled, open the screw about 1/4 more turn. Restart it and slowly screw it in till you can just perceive a change.

If the screw can be turned all the way in and the bike still idles perfectly and does not stall, then you need to go down a size in pilot jet.

Now very slowly, open the fuel screw till the idle is smooth. Blip the throttle, let the bike return to an idle, wait say ten seconds. Confirm it is the same smooth idle.

If the screw has to be opened more than 3 turns to get a smooth idle, you need to go up a size in pilot jet.

If you find it does not stall with the larger jet but has to be open more than three turns with the smaller pilot jet, put the larger one in and set the fuel screw at 1/2 turn.

If the idle speed increased, adjust the idle speed knob to return the bike to a real slow idle speed. You must then re-visit the fuel screw. Keep doing this till the fuel screw is opened just enough to provide a nice steady idle at the lowest possible RPM. Once this is done, increase the idle speed to the normal one for your bike, typically about 1,800 rpm, but go by the spec in your manual.

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The reason I was told it was running rich, is on a cool evening, you can see the header glow a nice cheryy glow!!!

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Glowing header is normal for a bike just sitting there idling. It is thin wall pipe.

Who ever told you it was lean because of a glowing pipe was not a person to take bike advice from. Instead, smile nod and agree and ignore.

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I just printed those directions off, I'll give them a try when I find out where the Jets and placed!!!'

Thank You!!

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