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kyle450rider

2007 question?

7 posts in this topic

I picked up yamaha 's offroad catalog yesterday while i was in the yammie shop.One of the new features on the new 450 was all new jetting.If yamaha rejetted the big bike how come i have seen some people with new 2007's rejetting.I know altitude makes a huge difference but you would think that they would be good right out of the box.I was seriously hoping that this was one thing that yamaha addressed especially seeing how many posts last year when the 2006 models came out.

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you have to jet to your elevation, riding conditions, temp, etc.

no company can get the jetting right for every person right outta the box

how did you come up with new jetting as a new feature for 07?

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From Yamaha :

Main Jet #160

Main Air Jet #200

Jet Needle NFLR-4

Needle Jet NA

Pilot Air Jet 1 #100

Pilot Outlet 0.9

Pilot Jet #45

Note that the pilot jet is a 45, as opposed to the 42, and the needle is the NFLR recommended for the '06 by Doug Dubach. Still has the rather lean 160 main jet.

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you have to jet to your elevation, riding conditions, temp, etc.

no company can get the jetting right for every person right outta the box

how did you come up with new jetting as a new feature for 07?

I understand that!What i meant was,how come people are still having to rejet there 2007's.MY last 2 bikes i owned i never rejetted and ran plug test on them and they were always good.I think most people never rejet they just adjust the fuel screw.

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.MY last 2 bikes i owned i never rejetted and ran plug test on them and they were always good.I think most people never rejet they just adjust the fuel screw.

Kyle the plug test is a great indicator of lean or rich conditions. I have found that even with stock jetting the bikes I have had at my altitude, run fine....but with some tinkering and tweeking with different jets and needles you can really fine tune your machine to really run much crisper, have better throttle response and in the case with JD Jetting kits, give added power :thumbsup:

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do plug chops work on thumpers?? i thought that was a 2 stroke check?! for my elevation, 5000 ft, i usually had to lean my smokers and now have to richen my thumper and the thumper is far more fussy with jetting then the smokers.

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Plug chops work for main jet selection, but not very well with unleaded fuels. They will come out white unless it's very rich.

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