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Hard starting cold - Choke issues?

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So I have an 06 450R and recently it has been nearly impossible to start cold. It takes many kicks and sometimes I have to use the hot start lever lever even though it is dead cold. After it has gotten up to temperature, it starts first kick most every time. Now before you go saying it, the motor is timed correctly and the valves are shimmed dead on. The head is almost brand new and it was not a problem until recently. One variable is I run VP U4.2 in it. I drain the carb and tank after every ride, so I don't let the fuel sit in it. So yesterday when I finally got it started cold, I noticed there was no difference with the idle whether I ran it with the choke in or out. It idled low (like a normal idle when warm) in either position (in or out). So after all this, this leads me to think there is something wrong with the choke itself. Could the race gas be affecting the choke in some way and it needs to be cleaned?? Is there something else I should be looking at?? I have checked the pilot jet, it is clean, and I have tried other sizes, doesn't run nearly as good as it does with the one that is in it. Other than this cold starting issue, the bike runs crisp and strong and starts 1st kick except when it is cold. So I'm looking for some input from anyone who might have an answer. I don't want to go arbitrarily pulling stuff apart without some idea of what it could be. Thanks in advance for any input.

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Try opening the screw that releases fuel from the carb and start it with it open, a small amount of fuel should come out, but nothing in excess. It should start up within 1-3 kicks without the hot start pulled. I had the same prob with my 150r not starting cold, I just needed the screw to be open to get the right amount of fuel and air through. Try it, if it doesn't work I don't know what to tell you. :/ Or you know.. Maybe a new sparkplug? But im sure you've tryed that hahaha.

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yeah get an adjustable fuel screw. the Merge racing one it nice. Its a T handle design and it come with the spring, o-ring and washer. Most of the screws out there require you to use the old ones, but Merge includes it. And their shipping is actually WHAT IT COSTS! haha. I was looking at them and the screw will be 20 but shipping is 8.95 for a damn fuel screw? you can put that in a usps sm. flat rate box for 5.95 and thats the MAX it should be. Or you could just use a padded mailer and be ever cheaper....

None the less go with a T handle fuel screw from Scotts or Merge and adj. it 1.5 turns out to start. Warm the bike up and adjust the idle until it doesnt really idle much. Then mess with the fuel screw in and out until you find a sweet spot in between. Then adjust your idle to the correct or close to the right RPM. Thats it.

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Already have an adjustable fuel screw and am well versed in the art of using it once the bike is up to temp. I am leaning towards the choke issue, so I may just pull it out and give it a good spray with contact cleaner and see if it helps. I know this race fuel is corrosive and this will be the 3rd season I have run it. This is the first time I have had issues starting it cold. It always started 1st or 2nd kick except when the valves were out of spec.

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lol sorry bro. No pun intended... I think CamP was explaining the carb and choke circuit to me. Maybe hit him up, he might know more.

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So here is what I found today that may narrow the possibilities down for those in the know. Tried starting the bike cold, normal procedures - Two twists of the throttle, choke out, full kicks. Kicked 15 times, no start. Pushed choke in, pulled hot start lever, bike starts. I shut it off, tried with no hot start, won't start. Pull hot start lever, starts right up first kick. Now what I find even more interesting is, if I keep the hot start lever pulled in, the choke works as it should. Pull it out, bike idles high. Push it in, bike idles down. So, what is the problem?? Is there a problem with the hot start, or is it some other carb problem?? As I said in the opening post, other than cold starting, no problems with the way the bike runs.

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Hmm maybe the hot start slide ( or w/e its called ) in the carb is out of adjustment. I have heard of that causing issues... Or maybe its jets clogged?

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I posted this same question on the jetting forum. Waiting for a reply, but I think Eddie Sisneros is going to tell me I need a top end. We'll see what he says.

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My 04' seems to act a bit like this too (I need to pull the hot start to get it started even when it's dead cold), but I figured it was because it's so hot in Texas. On cool days, or if I start it in the garage (which is moderately climate controlled) I don't have that issue. Its only after it's been trailered for an hour in the Texas sun that I have the hard start.

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Well, on the jetting forum, Eddie Sisneros tells me it sounds like the piston/rings. I should have replaced them last year when I did the head but I was in a hurry. Guess I will go order that stuff now.

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So I figured I would post the final outcome of my situation in case anyone ever has the same problem. Over on the jetting forum I was being told I needed a new top end, but I wasn't convinced that was the problem. So I called a buddy of mine that has diagnosed a previous problem I had over the phone. So he tells me to take the carb apart, clean it real good and pay special attention to the jet near the main that is not the pilot. Turns out this is called the By-starter jet (hmmm?). He thinks that this jet is clogged and he said most people forget about that jet. So I pull the carb out and apart, and inspect this jet. Doesn't seem clogged but I spray it with carb/choke cleaner and then compressed air. As soon as I held it back up to the light I saw how wrong I was. The hole was way bigger now than when I first looked through it. I put it back in and for hahas checked the leak jet too. Same thing here, a little obstructed, cleaned it and put it back in. I reassembled everything, put gas in it and IT STARTED 1ST KICK!! The choke now works as it should also, in that it idles high out, push it in, it idles down. Maybe this will help someone in the future.

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Yeah I was thinking it was something in the carb... Makes sense though. Any pictures for future reference?

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