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elevation - temp - jets

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1)2004 Honda CRF450R

2)1000ft - 40-65 degrees lately.. will be 60-90 this summer. trails/cross country/enduro

3)boyesen quick shot 2 - engine and airbox stock - pro moto spark arrestor exhaust endcap

4)NCYR (4TH)

PILOT JET - 42

MAIN JET 165

TURNER FUEL SCREW 1 1/2 TURNS OUT

5)Attached photo shows carb specs from the repair manual. I am near the cut off for a main jet change, and I'd like to know if you would recommend I do it.. Average elevation where I am is 1000ft.. when I ride, that is sure to increase by as much as 300ft. Also, the temp lately has been cool - between 40-60. the next few weeks will bring warmer average temps 50-70 and 70-90 in the summer. My instinct is to change to a 162 main..but I

d like your input.

6) throttle response much better when the bike is warm.

auxillary question: Looks like there is exhaust gas recirculation on this bike.. do I stand to gain performance by Plugging and removing it? exploded view can be found here

tubing labeled 13 comes from the cylinder head, and 15 goes to the airbox. the section that goes down is capped with a plastic plug (drain)

Thanks for your input

crf-chart.jpg

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I think the best way to evaluate your jetting is by evaluating the plug. The ceramic should look like a nicely toasted marshmallow. If it's a bit darker, that's ok, but if you get too lean, you could seize the piston. To check your main jet, run a 1/4 mile wot and hit the kill switch at the same time you chop the throttle. Pull the plug and check it. To check your needle clip setting, run 1/4 mile at 1/2 throttle. Again, hit the kill switch at the same time you chop the throttle, pull the plug and check it. Generally, you'll need more fuel when it's colder, less when it's hotter. The 300' of elevation change shouldn't bother too much.

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I think the best way to evaluate your jetting is by evaluating the plug. The ceramic should look like a nicely toasted marshmallow. If it's a bit darker, that's ok, but if you get too lean, you could seize the piston. To check your main jet, run a 1/4 mile wot and hit the kill switch at the same time you chop the throttle. Pull the plug and check it. To check your needle clip setting, run 1/4 mile at 1/2 throttle. Again, hit the kill switch at the same time you chop the throttle, pull the plug and check it. Generally, you'll need more fuel when it's colder, less when it's hotter. The 300' of elevation change shouldn't bother too much.

this is what I found::thumbsup: I suppose this is what you would call carbon fouled from running rich / clogged air filter / or prolonged idling.. I'm guilty of all three I guess. What should I do next? :ride:

IMG_0166.jpg

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