New '06 YZ450, jetting question?

[supermoto400]

I just picked up a new in the crate left over '06 YZ450 ? The only thing I've done to the bike is install a ProMotoBillet SA end cap. I've been doing lots of research on this forum regarding jetting and was all set to start out with a 45 pilot, 168 main, ZipTy fuel mixture screw at 2 turns out, everything else stock. But then I found this thread: https://www.thumpertalk.com/forum/showthread.php?t=316355&highlight=2006+dyno

and am now wondering if I should start with a 48 pilot, 170 main... I'd like to get this right the first time if possible. I live in the Seattle area (sea level) and temps here are between 60 - 80 in the summer. I'm most concerned with getting the pilot and air/fuel mix. screw as close as possible the first time. I know, another jetting question on the '06 but just looking for some feedback from folks with the same year bike/setup. Thanks in advance!

[hyperflow]

170

48

[grayracer513]

My below sea level (seriously) race jetting is 165/45 in the warm weather, 168/45 in the winter. Needle in #4.

[supermoto400]

Thank you Hyperflow and greyracer for your input!

I think what I might do since the bike has zero hours on it yet and that fact that were having a warm spell up here in the PNW (was in the mid 90's last week) is start with the 168/45 combo and see how that works.

Future mods include the GYTR Enduro skid plate, D.I.D. T-ring chain, 50 or 51 tooth rear sprocket, and Cycra handguards.

I've only ridden one other 450, was a barely boken in '03 YZ and it was awesome ?

[rdrata]

I have had good luck w/ the 170/48, I had a bit more backfire w/ the 168/45

[supermoto400]

Interestingly enough, when I pulled the carb apart tonight I found a #48 pilot and #172 main installed. I can only assume the dealer did this since it is a new bike. I did confirm that the needle is the standard NFPR set on the #4 clip position. The air/fuel mixture screw was set at 2.25 turns out from seated. It also looks as though there was some very old gas in the float bowl. I cleaned it all up with some carb cleaner and re-assembled with the new ZipTy extended air/fuel mixture screw set at 2.5 turns out. Also installed the #45 pilot and #168 main.

When I picked the bike up from the dealer it was popping alot. I have a feeling it could have been due to some old fuel. Twards the end of the heat cycle it sounded a little better. I've only fired it up once since I got it home and it started on the 3rd or 4th kick and seemed to idle smooth when warmed up.

I'll put the bike back together tomorrow night with some fresh fuel and try it out. Will post up the results tomorrow evening... ?

[r1usn]

grayracer why would you go with a leaner main in the winter? Colder air= more air which would imply a richer jet not leaner.

[grayracer513]

I have had good luck w/ the 170/48, I had a bit more backfire w/ the 168/45

So do I, but that doesn't change the fact that the 48 is too rich. Moderate decel backfire does not indicate that there is a problem.

grayracer why would you go with a leaner main in the winter? Colder air= more air which would imply a richer jet not leaner.

Good catch. I had it reversed, corrected now.

[hyperflow]

Thank you Hyperflow and greyracer for your input!

I think what I might do since the bike has zero hours on it yet and that fact that were having a warm spell up here in the PNW (was in the mid 90's last week) is start with the 168/45 combo and see how that works.

Future mods include the GYTR Enduro skid plate, D.I.D. T-ring chain, 50 or 51 tooth rear sprocket, and Cycra handguards.

I've only ridden one other 450, was a barely boken in '03 YZ and it was awesome ?

Go with the 51 sproket, I personaly think its the best sproket for the bike.

[rdrata]

So do I, but that doesn't change the fact that the 48 is too rich. Moderate decel backfire does not indicate that there is a problem.

Okay, I suppose I can try that combo again; will I achieve better throttle response? Initially at the stock setting I had a lot of bog when twisting the throttle. I have the Boyesen QS1 on there and an FMF MegaBomb w/ stock muffler w/ the 48/170 combo.

[rdrata]

CORRECTION: As it turns out, I did change from my 48/170 combo upon reading a similar thread and I do have the 45/168 combo. Lesson here? Keep good records when you change things, dates, reasoning, results, etc. I did this by process of deduction and remembered that I did in fact change it and it runs great (even w/ that non-problematic decel backfire:smirk:) My records are updated now:thumbsup:

[hyperflow]

My bike when reved high dosn;t backfire tell it gets into the lower rpm range, Does this mean my pilot is to lean?

[supermoto400]

I got the bike all back together tonight but it was too late to fire it up. Dumped all the left over fuel from the tank into my lawnmower and got some fresh Chevron supreme. Will test it out tomorrow night if I get home early enought.

I must say that after spending some quality time wrenching on this bike I'm very impressed with the overall high quality and fit/finish. It's very easy to work on and seems Yamaha really pulled out all the stops on there first Aluminium framed bike.

Next step is to set the race sag and raise the forks a bit.

Thanks to all for contributing to this forum, soo much good info. here ?

[grayracer513]

I must say that after spending some quality time wrenching on this bike I'm very impressed with the overall high quality and fit/finish. It's very easy to work on and seems Yamaha really pulled out all the stops on there first Aluminium framed bike.

Wait until he tries working on the carb. ?

I love my bike.

[Wiz636]

I'm in Washington and when I had my '06 I just went up one on the pilot...no other changes except for the adjustable fuel screw. Oh, and the Zipty Racing mod, but jetting-wise was just the PJ change.

[supermoto400]

I fired the bike up tonight, it started on the 3rd real kick after having no fuel in the carb. Turned the choke off after about 30 seconds, warmed it up for about a minute then jazzed the throttle several times to see if it would flame out, hesitate, hicup, etc. It responds instantly off idle with absolutely no issues. It's not broken in yet so we'll see after I get a few hours on it. I will post up again after it's properly broken in.

Just to summarize, new '06 YZ450, #45 pilot, #168 main, 2.25 turns out on the ZipTy fuel mixture screw, sea level, low 70's outside temp., and fresh Chevron Supreme pump gas.

Thanks again to all who replied with comments/experience ?

[FlashGordon]

Supermoto400,

I have the same 2006 450F bike and also live in the Seattle area. Found the 168 main with a 45 pilot works best. I also have a Dr. D. Pipe. I ride either Capitol Forest or Naches, when it's open, so a pretty drastic variation in altitude. I just need to turn the adjustable pilot jet screw a turn or two.

I found the 170 main was causing some surging when riding forest roads at a set speed. Never noticed it on trails of course. It pops alot when starting off, but after a few mins of warm up, hardly any at all. There is some hesitation if I crack the throttle, so it isn't jetted perfect, but close enough.