Mandatory Choking to Start the Bike?

New WR owner here hoping to get some advice. The bike - 06 WR450F with only 350 miles. Previous owner installed GYTR pipe, re-jetted, and all the popular performance mods.

My problem - Regardless of how long the bike has been running (10 min to 2 hours) I must always apply the choke to get the bike to start. I am using the 'hot start' after the bike is warm but to no avail. I can kick until the cows come home, but unless I apply the choke the bike is not going to start.

Side note - once the bike starts and the choke is turned off, the bike does not sit at idle reliably and will usually die unless I apply throttle and start riding it.

Thanks in advance.

Inmy opinion, the Air/fuel screw needs to me adjusted properly. I was adjusting mine last week and found this out with the same symptoms you are having. You bikes screw is probably in too much which leans out the mixture at start-up. when you pull out the choke, it richens it up. So I would suggest turning the screw out about a 1/2 turn (from where it is now) for starters, and go from there.

Lean pilot circuit. How does the bike respond to the fuel screw once warmed up?

Like JC said, try richening the fuel screw half a turn.

Do not arbitrarily adjust anything. The other two posters are probably correct, it is a fuel screw/pilot jet issue. Based on the age and low usage, I'd bet the pilot jet is gunked up. Swing by the dealer and get a new pilot jet. After it is in, do this:

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.

do what william says .. i can tell you i have that same exact bike, never touch the choke after initial start up.... ever..

Given that it's cold out right now, you may not actually need hot start. I only have to use hot start when I've railed the living shit out of my bike for an extended period of time, and that's when it hesitates a bit to start.

New WR owner here hoping to get some advice. My problem - Regardless of how long the bike has been running (10 min to 2 hours) I must always apply the choke to get the bike to start. I am using the 'hot start' after the bike is warm but to no avail. I can kick until the cows come home, but unless I apply the choke the bike is not going to start.

The hot start is not manditory, use only if needed. I find my 04 has yet to need the hot start to get it going and usually is harder to start with it. The PO said he only used it after a crash when the bike would flood out.

Mike

The hot start leans the mixture out, choke makes it richer.

So if you don't need the hot start, the bike will be too lean. Putting the choke on will make it richer.

Doing neither is probably just fine :thumbsup:

I have an 07 and use the hot start alot when the engine is up to operating temp, but never the choke. But I am pretty sure mine is a little rich to start with.

Good thing about this minor carb issue is that you'll be an expert when all is said and done, and probably have the crispest bike in your riding group!

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