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cb450

popping at steady throttle

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I have just started setting up my new '07 wr450. I have installed the entire gytr kit, unhooked the grey wire, and I put the rear part of an exhaust from an 'o6 yz 450 on it that I had. The clip is up one from center. I live a 9800' and ride up from this elevation. Right now it pops on steady throttle at any throttle position. It runs great on acceleration. As long as I give it more and more throttle no popping. any input would be appreciated. thanks

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I have just started setting up my new '07 wr450. I have installed the entire gytr kit, unhooked the grey wire, and I put the rear part of an exhaust from an 'o6 yz 450 on it that I had. The clip is up one from center. I live a 9800' and ride up from this elevation. Right now it pops on steady throttle at any throttle position. It runs great on acceleration. As long as I give it more and more throttle no popping. any input would be appreciated. thanks

I thought the GYTR jetting would be OK for sea level. :thumbsup: it is richer then what I run for sea level to 4K'

have you looked at the jetting data base?

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Yeah I checked the jetting database. There is very little for my altitude. I figured it the gytr jetting was a good place to start. I'm just not sure where to go next.

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Yeah I checked the jetting database. There is very little for my altitude. I figured it the gytr jetting was a good place to start. I'm just not sure where to go next.

did you install a fuel screw??? I got a zip ty. and I've been real happy adding or subtracting a quarter turn to get good throttle response. It seems easy to dial in for me... but I got buddies that just don't have a feel for it.:thumbsup:

I also got the jd kit, in regards to actual parts you get, it is kinda a rip off. but you can email JD for help or general FAQ and the recommended settings work real good. so... for a jetting newbie like me, it gave me confidence.... and my bike runs real good.:bonk:

for example the GYTR main jet is a 175. I run a 168 for sea level to 4K. and the stock main jet is a 162. the needle is probably more important then the main jet... but I don't know anything about the gytr needle.:ride: I installed one on a buddies 08wr450. but he replaced it with a jd kit after about 4 rides.

this is from the third post on the jetting page.

Elevation 8,000 to 11,000 feet: ( Note you will loose a lot of power due to altitude but your bike will idle and not foul plugs!)

45 to 60 degrees: 165 main, JD Red #5, 48 Pilot, 1.25 turns, 70 starter jet, #40 leak jet

60 to 75 degrees: 160 main, JD Red #4 , 45 Pilot, 1.75 turns, 68 starter jet, #50 leak jet

75 to 90 degrees: 158 main, JD Red #3, 45 Pilot, 1.5 turns, 65 starter jet, #60 leak jet

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I saw that post in the jetting thread. I am hopeing that this bike doesn't have to be that finicky. in a Typical ride here in Crested Butte I could go from 9500' to 12,000' and the temp could change from 75 to 40. My last bike (a husaberg 450fe) ran flawlessly from during these changes and all with the stock jetting. It would have been way lean at sea level but, I guess that is the way thing are these days. I don't mind messing with my WR to get it right but, I can't be having to make adjustments during a ride.

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I saw that post in the jetting thread. I am hopeing that this bike doesn't have to be that finicky. in a Typical ride here in Crested Butte I could go from 9500' to 12,000' and the temp could change from 75 to 40. My last bike (a husaberg 450fe) ran flawlessly from during these changes and all with the stock jetting. It would have been way lean at sea level but, I guess that is the way thing are these days. I don't mind messing with my WR to get it right but, I can't be having to make adjustments during a ride.

its not that finicky. and the stock WR jetting probably would have been fine for your altitude.

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its not that finicky. and the stock WR jetting probably would have been fine for your altitude.

good thats what I like to hear. I think that my bike my be a little lean so i am going to raise the needle a notch and see if that fixes the popping. I am open to any other suggestions.

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good thats what I like to hear. I think that my bike my be a little lean so i am going to raise the needle a notch and see if that fixes the popping. I am open to any other suggestions.

so you'll be moving the clip to the center slot?

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Exhaust leak ?

Popping sounds lean but with GYTR jetting you should be way rich at your altitude. I ride between 2000-6000ft and had to lean the GYTR jetting out across the board even with a full 08 YZ exhaust system.

Also did you remove the AIS ?

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yeah I took the ais out at the same time. I think that the pipe leaned it out a bunch. no exhaust leaks. I took out all the airbox junk

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with GYTR jetting you should be way rich at your altitude.

the orginal post says that he installed the GYTR, but that he used The 3rd clip on the needle. I believe the 4th clip is what you are supposed to use per the GYTR instruction. thus he set the needle leaner. Which is exactly what I would have done given his altitude.

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the orginal post says that he installed the GYTR, but that he used The 3rd clip on the needle. I believe the 4th clip is what you are supposed to use per the GYTR instruction. thus he set the needle leaner. Which is exactly what I would have done given his altitude.

Thats right I thought it would be rich, but it sure runs like it's lean. I pulled the air filter and the cover and rode it down the road that. It did the same thing that it was doing only worse. This reinforced the thought that it is lean, to me. Hopefully I will get some time this evening to move the clip and try that.

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I have just started setting up my new '07 wr450. I have installed the entire gytr kit, unhooked the grey wire, and I put the rear part of an exhaust from an 'o6 yz 450 on it that I had. The clip is up one from center. I live a 9800' and ride up from this elevation. Right now it pops on steady throttle at any throttle position. It runs great on acceleration. As long as I give it more and more throttle no popping. any input would be appreciated. thanks

---Did you remove the carburetor slide at any point during the installation??

The thin plate on that sits next to the carb slide must be installed with the square end downwards or you will get excessive popping and backfiring at low and mid-throttle. The jetting becomes extremely lean at low throttle if the plate is upside-down.

Otherwise, look for any air leaks from the installation.

James

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What about TPS? I know a lot of guys complain about the popping at constant speeds on their converted SM. Everyone says it isn't designed to be at constant RPM and if you remove the TPS is stops, but is best if used off road.

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Well I moved the clip to center. Made it worse. Checked again for any intake or exhaust leaks, none to be found. I know that I should be rich but, it just isn't acting that way.

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Well I moved the clip to center. Made it worse. Checked again for any intake or exhaust leaks, none to be found. I know that I should be rich but, it just isn't acting that way.

have you thought about putting the stock muffler back on?? should only take 3 min. I was kinda surprised to hear that an 06 YZ muffler fit on the 07WR header.

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have you thought about putting the stock muffler back on?? should only take 3 min. I was kinda surprised to hear that an 06 YZ muffler fit on the 07WR header.

I haven't tried that. It fit easy I just had to switch the lead bushing. The wr one is thicker for a smaller diameter head pipe. It sounds so good with the yz pipe I'd be sad to see it go, but I may have to give it a try.

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yeah I took the ais out at the same time. I think that the pipe leaned it out a bunch. no exhaust leaks. I took out all the airbox junk

When I first changed to the YZ exhaust from the uncorked stock I thought I needed richer jetting as well. This was early season though, when the temps where cool.

Now that the temps have warmed my optimum jetting is leaner than in the same temps with the stock exhaust :thumbsup:

I definately find the jetting more finicky with the YZ exhaust.

That being said go lean and see what happens.

Are you running the GYTR 50 pilot ? I have a 48 and am on the verge of a 45 at alot lower elevation than you. I find the pilot circuit has a big effect on lower steady throttle positions on this bike.

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