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kyle450rider

2007 starting issues?with only 3 hours!

18 posts in this topic

My bike was very easy to fire when new and with stock jetting.However i put in the 170 main and the 48 pilot and since then takes a few more kicks.Today i started up and got a loud backfire on the first kick and then on the second it started right up.The jetting completely eliminated my bogging issue and seems to run like a raped ape on the track.It also idles and runs great on the stand with no hesitation when i open the throttle.Do you guys think that this is a give a little to get a little issue with the bike?I'm not real concerned about it but it backfired last weekend to while i was starting it.I'm going to mess with the fuel screw tomorrow and check valve clearance.Currently i'm 2 1/4 turns out on the screw.Also wanted to ask if this could be a pilot jet issue.Some peeps on this board think the 48 is too much and that a 45 is the magic number.Even with the backfire this bike kicks AZZ!

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you gotta remember it's starting warm up so u might have to go to 45 pilot for summer and 48 for winter. i was running 165 main for winter and just when't to 160 but is'nt backfiring an air leak issue?

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My bike was very easy to fire when new and with stock jetting.However i put in the 170 main and the 48 pilot and since then takes a few more kicks.Today i started up and got a loud backfire on the first kick and then on the second it started right up.The jetting completely eliminated my bogging issue and seems to run like a raped ape on the track.It also idles and runs great on the stand with no hesitation when i open the throttle.Do you guys think that this is a give a little to get a little issue with the bike?I'm not real concerned about it but it backfired last weekend to while i was starting it.I'm going to mess with the fuel screw tomorrow and check valve clearance.Currently i'm 2 1/4 turns out on the screw.Also wanted to ask if this could be a pilot jet issue.Some peeps on this board think the 48 is too much and that a 45 is the magic number.Even with the backfire this bike kicks AZZ!

Yamaha has to push the pilot circut so lean so as to allow easier starting. I also have a brand spankin' new '07 450 also, and have been putting my new engine through some heat cycles. It's been like 40F for temps here in NH, and my bike starts awesome, but overall low speed running is horribly lean. I bumped my jetting up to a 162 main, and 2-3/4 turns out on the screw. My bike now starts and runs better (but not perfect). As the weather warms, our 450's will run way better.

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My bike was very easy to fire when new and with stock jetting.However i put in the 170 main and the 48 pilot and since then takes a few more kicks.Today i started up and got a loud backfire on the first kick and then on the second it started right up.The jetting completely eliminated my bogging issue and seems to run like a raped ape on the track.It also idles and runs great on the stand with no hesitation when i open the throttle.Do you guys think that this is a give a little to get a little issue with the bike?I'm not real concerned about it but it backfired last weekend to while i was starting it.I'm going to mess with the fuel screw tomorrow and check valve clearance.Currently i'm 2 1/4 turns out on the screw.Also wanted to ask if this could be a pilot jet issue.Some peeps on this board think the 48 is too much and that a 45 is the magic number.Even with the backfire this bike kicks AZZ!

I don't know the temps out in kansas, but I can tell you that your bike is too rich; even for the conditions here in socal. That is why your getting a backfire, and it's hard to start. Have you tryed starting the bike with out the choke, that should make it easier. You should rejet.

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I agree with Ranger18, might be rich. I tried the 48 - 165 combo in my 07...too rich. Mine prefers 45 - 162 and about 2 turns on fuel screw. Another thing to keep in mind is the air filter. While it seems obvious, a friend of mine was having a problem getting his 07 started and running one morning. He said it ran perfectly the week before but now it won't run. After fiddling with it awhile we took off his seat and his air filter was dripping with air filter oil. I took the filter off mine, put it on his and his bike ran fine again.

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I agree with Ranger18, might be rich. I tried the 48 - 165 combo in my 07...too rich. Mine prefers 45 - 162 and about 2 turns on fuel screw. Another thing to keep in mind is the air filter. While it seems obvious, a friend of mine was having a problem getting his 07 started and running one morning. He said it ran perfectly the week before but now it won't run. After fiddling with it awhile we took off his seat and his air filter was dripping with air filter oil. I took the filter off mine, put it on his and his bike ran fine again.

We were also trying to jet a buddies bike and could not figure out what was wrong. It's amazing what a stock air filter that has not been cleaned in 4 rides will do to a bike:thumbsdn:

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My bike was very easy to fire when new and with stock jetting.However i put in the 170 main and the 48 pilot and since then takes a few more kicks.Today i started up and got a loud backfire on the first kick and then on the second it started right up.The jetting completely eliminated my bogging issue and seems to run like a raped ape on the track.It also idles and runs great on the stand with no hesitation when i open the throttle.Do you guys think that this is a give a little to get a little issue with the bike?I'm not real concerned about it but it backfired last weekend to while i was starting it.I'm going to mess with the fuel screw tomorrow and check valve clearance.Currently i'm 2 1/4 turns out on the screw.Also wanted to ask if this could be a pilot jet issue.Some peeps on this board think the 48 is too much and that a 45 is the magic number.Even with the backfire this bike kicks AZZ!

Is a backfire a bad thing? Does it backfire when warm? Could be too rich for start up.

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mabye thats it.ITs too rich for startup.It runs great no bogging or hesitation anywhere on the track.I'm just getting a backfire somtimes when i go to start it.

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mabye thats it.ITs too rich for startup.It runs great no bogging or hesitation anywhere on the track.I'm just getting a backfire somtimes when i go to start it.

If it's too rich for start up, then it's too rich.

Just because your bike doesn't bogg or hesitate, doesn't meen it's not rich.

Your bike is not overly rich to the point were you are getting other symptoms of poor jetting, but you are showing one, and that's you hard starting.

If you lean your bike out more, you will be able to start you bike easier, and you will proabably notice it being a lot faster, and more responsive.

With engines you can be:

1.too lean

2.perfect on the lean side

3.perfect on the rich side

4.and too rich

You are probably a little above the (perfect on the rich side.)

You want to be perfect on the lean side.... that is were the most power is made.

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170mj is too fat for temps above 65........go down to 165/168

45/48 pj should be fine

2turns out on fuel screw

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170mj is too fat for temps above 65........go down to 165/168

45/48 pj should be fine

2turns out on fuel screw

thanks for the tip.I'm going try the 165 main this weekend.I'll let you guys know how it went.:thumbsup:

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I don't know the temps out in kansas, but I can tell you that your bike is too rich; even for the conditions here in socal. That is why your getting a backfire, and it's hard to start. Have you tryed starting the bike with out the choke, that should make it easier. You should rejet.

Dude, exhaust backfiring is a result from a LEAN condition, not rich. Sometimes it's also a bad exhaust pipe gasket sucking air.

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Dude, exhaust backfiring is a result from a LEAN condition, not rich.
Dude, he's talking about a backfire out of the pipe while starting, not on decel. That's from unignited fuel in the pipe.

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My o6 450 has a 165 main and 48 pilot and stock jet needle in the #4 clip position and Iam at 5200ft elevation and mine runs fine>no backfire! until the temp drops below 40 and then I get some backfire on decel and maybe a backfire on the second kick when tring to start.

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170mj is too fat for temps above 65........go down to 165/168

45/48 pj should be fine

2turns out on fuel screw

165 and the 48 is what im running now.I will give a ride report tomorrow.i'm gonna take the 160 main with me just in case.Thanks for the tips fellas!

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Changing the main jet will have NO effect on starting. If I were you I would try the 45 pilot, that is what I am running now. Also, go to the jetting forum and there is a sticky about setting you fuel screw and choosing the correct pilot jet.

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Changing the main jet will have NO effect on starting.
True, but that doesn't change the fact that the 170 is too big.

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True, but that doesn't change the fact that the 170 is too big.

Agreed. I am running 45 p 165 m with the Zip-Ty mod, can't imagine a motor running any cleaner or crisper.

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