2008 Wr450 Jetting


36 replies to this topic
  • jams229

Posted January 14, 2008 - 08:03 PM

#21

I've got an '07 that is jetted the same as yours. I saw a big drop in mileage when I put in the JD kit, like in half. That can't be right. Did you see that?

I'm thinking I've got something else going on and am losing gas while riding.

Any thoughts?

Thanks,


Check your fuel cap vent hose. These were faulty on a bunch of '07's - including mine - and the fuel will slosh out of the vent hose. I put an IMS tank on mine and that cap is fine, but you can check some past posts that describe what they did to theirs to fix this problem...

  • camaroman7d

Posted January 18, 2008 - 08:16 PM

#22

Got my bike back together and running today. The GYTR kit seems perfect. I installed what came in the kit but, left the AIS in place for now (California). I did do other mods at the same time but, the bike starts and runs WAY better. Haven't been offroad yet but, I didn't get any backfire on deceleration.

  • camaroman7d

Posted January 20, 2008 - 09:37 AM

#23

OK I took the bike offroad and all I can say is WOW, I could not be more happy with the way it runs. It is extremely responsive, starts easy, it's a beast. It feels like a 2 stroke that is stuck in the powerband. I don't see how it could possibly run any better. I unloaded it from the truck, fired it up (after suiting up of course), I didn't make any adjustements at all. The bike ran pefect. No problem with backfiring on decel (with the AIS in place and functioning), it would pop very slightly if I held the throttle at a constant cruising speed for an extended time and then let off. It was very minimal and not something I am concerned with. When I was on it hard or decending a hill there was no popping at all.

Once again I installed the GYTR kit per the instructions (minus the AIS removal).

  • cbrandt

Posted January 21, 2008 - 11:32 AM

#24

What altitude were you riding? What temp? I just got my AIS kit and was considering doing the same (leaving AIS on but installing everything else).

Have you done anything to the AP linkage? ie o ring mod or adjustment of the timing screw.

Thanks,
Chris

  • camaroman7d

Posted January 21, 2008 - 10:02 PM

#25

Where I rode this weekend the elevation is from 1700 feet to I don't know how high. I might have gone up to about 3000ft. I live near sea level, the bike ran great everywhere. I did do other mods, grey wire, power now, quickshot 2, air screw (set 2 turns out), Dr D pipe, on the accelerator pump I just installed an O-ring I had. Since everything was done at once I can't say which mod made the biggest difference. I will just say the bike runs absolutely perfect and I wouldn't change a thing.

  • myspeedbuggy

Posted February 06, 2008 - 03:01 PM

#26

Hey hi I had my 07 wr install the yamaha perforamce kit for air inj. remove and jet kit. wow not even the same bike. try it and check your plug for color
and operation. the if need rejet.

  • BigIron

Posted February 08, 2008 - 01:23 AM

#27

To use the spark plug method you have to kill the motor when you are in the band you "normally" ride. ie to test main jet - kill switch at 3/4 to full throttle. To test needle - kill switch at 1/4 to 3/4 throttle. Then check. If you let the motor idle, or cruise home, the plug will show a false reading. One of the problems with unleaded fuel is it runs 'black' on the spark plug.
Here are the specs for the 08 (all free mods done - stock pipe with rear baffle removed).

The details are for Australian Yamaha part numbers (not sure for US) -

Temperature: 25-28 deg celsius (77-83 deg F)
Altitude: 500-700 metres (1640-2300 feet)
Humidity: 50-60%

Accelaerator Pump: 2.75 mm gap (.108 inches)
Main Jet: 168
Pilot (slow) Jet: 48
Leak Jet: 45
Jet Needle: Yamaha 5TJ-A1 (GDDSQ) clip at 2nd Groove
Air/Fuel Screw: 1.5 Turns out (aftermarket FMSO1 - sunline)
NO AIS in Australia

Its currently our summer, come winter - needle is raised (clip 3rd position) and tune air/fuel screw (1.5-2.5 turns out).

This shows a perfect plug. Black on the base (end of thread) and clean light brown on electrode. By the way - rigged up a EGO sensor and it runs stoich - so both plug and O2 sensor methods indicate correct jetting.

Hope this helps.

  • Evad101

Posted February 19, 2008 - 03:43 PM

#28

Thought I'd add to this post:

I just installed the YEC AIS KIT along with a JD Jet Kit My settings are:

Year: 2008
Model (400 - 426 - 450): 450
Cam Timing (WR/YZ): WR
Main jet: JD 168
Pilot Jet: JD 48
PAJ: YEC AIS 110
Leak Jet: YEC AIS 45
Starter Jet:
Fuel screw (turns out): MSR 2
Needle Model/Clip position: JD red/4
Grey Wire Mod (Y/N): y
TPS Connected (Y/N): y
Airbox Snorkel/Lid (on or off): off
AIS Removed (Y/N): y
Airfilter Brand: Stock
Exhaust Brand: Stock, unplugged
Average Altitude: SEA - 2000'
Average Temperature: 45-55 (So Far)
Average Humidity: 70%

w/ Small JD KIT o-rong MOD

There are no flat spots or any bogging at all. I only have 1 ride on the bike this way so far and only got 27.3 miles until I had to switch to reserve. Everything feels good though there is a little bit of "popping" off throttle down long hills.

Think it may be a bit rich? I figured it should get better mileage than this. What do you guys think?

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  • dirtysouth

Posted February 19, 2008 - 04:21 PM

#29

Your best bet is to default to this board. I know it sounds arrogant, but we do know what we're doing, most times better than Yamaha. When in doubt, TT is the definitive source. Keep in mind, the WR and YZ board is what started TT way back when...SC


No doubt...thanks Brian

  • alburito

Posted February 19, 2008 - 07:43 PM

#30

I picked up my 08 WR450 on Sat. along with the GYTR kit and it came with a 175 main jet and a 50 pilot jet. From everthing I've read on here it looks like the 07's all came with a 170 main and a 48 pilot...

That seems to be a fairly substantial jump in jetting from one year to the next with no reall changes to the bike other than BNG's.

A little help?

Hello, I bought an 08, and used the gytr kit, did all except the grey wire, I have rode it at altitude and sea level, and it workd great! Not sure about 07 or 08 jetting.

  • BigIron

Posted February 20, 2008 - 12:50 PM

#31

Thought I'd add to this post:

I just installed the YEC AIS KIT along with a JD Jet Kit My settings are:

Year: 2008
Model (400 - 426 - 450): 450
Cam Timing (WR/YZ): WR
Main jet: JD 168
Pilot Jet: JD 48
PAJ: YEC AIS 110
Leak Jet: YEC AIS 45
Starter Jet:
Fuel screw (turns out): MSR 2
Needle Model/Clip position: JD red/4
Grey Wire Mod (Y/N): y
TPS Connected (Y/N): y
Airbox Snorkel/Lid (on or off): off
AIS Removed (Y/N): y
Airfilter Brand: Stock
Exhaust Brand: Stock, unplugged
Average Altitude: SEA - 2000'
Average Temperature: 45-55 (So Far)
Average Humidity: 70%

w/ Small JD KIT o-rong MOD

There are no flat spots or any bogging at all. I only have 1 ride on the bike this way so far and only got 27.3 miles until I had to switch to reserve. Everything feels good though there is a little bit of "popping" off throttle down long hills.

Think it may be a bit rich? I figured it should get better mileage than this. What do you guys think?

Depends how hard your terrain is. Most times the WR will max out at about 70 kms (40 or so miles) when you hit reserve. This is not cruising open roads in 5th, this is riding on the main jet. If it starts to get tight and technical - lots of boulders, bogs or tight terrain don't expect much more than 50km's (30 miles) when you switch. Similar, if your racing single wheel forest country - 30 miles max. This is seems to be the standard (CRF 450's identical) - if the free mods and jetting are done.

  • WR_Dave

Posted February 20, 2008 - 01:03 PM

#32

Your mileage seems a bit low ,but the popping you are getting is likely due to the ACV valve that opens when you are decellerating and allows fresh air to bypass the carb and go into the intake boot. Lean mixture at that point will cause the popping. You can simply flip the diaphram and spring over and eliminate that as a problem. WR Dave.

  • Evad101

Posted February 20, 2008 - 02:01 PM

#33

Depends how hard your terrain is. Most times the WR will max out at about 70 kms (40 or so miles) when you hit reserve. This is not cruising open roads in 5th, this is riding on the main jet. If it starts to get tight and technical - lots of boulders, bogs or tight terrain don't expect much more than 50km's (30 miles) when you switch. Similar, if your racing single wheel forest country - 30 miles max. This is seems to be the standard (CRF 450's identical) - if the free mods and jetting are done.


This was in mostly single track and first second gear tight stuff. On the gas off the gas, clutching it, some wide open fire road action. Maybe this was accurate and I just need a bigger tank

Your mileage seems a bit low ,but the popping you are getting is likely due to the ACV valve that opens when you are decellerating and allows fresh air to bypass the carb and go into the intake boot. Lean mixture at that point will cause the popping. You can simply flip the diaphram and spring over and eliminate that as a problem. WR Dave.


Might have to give that a try as well.

  • BigIron

Posted February 21, 2008 - 01:02 AM

#34

This was in mostly single track and first second gear tight stuff. On the gas off the gas, clutching it, some wide open fire road action. Maybe this was accurate and I just need a bigger tank



Might have to give that a try as well.

One thing I forgot to mention - if it is hard, tight "hell country", or ridiculously slippery and your off the bike as much as on - or stopped sideways on extreme hills - turn the fuel "off" while your both on the ground or stopped. You'll be suprised when the bikes on top of you watching fuel flow out of the bowl. The more spills the less mileage. As soon as you start fanning the clutch, mileage drops off 'cause your perfectly on the thirsty jet and needle. We sacrifice fuel for weight (why DRZs etc run the endurance), and our bikes are modded to be a YZ (35 minutes of flat out motocross-but with a litre more fuel). Interesting note, if you have the DRZ and WR doing the same riding (same tracks and pace) they both use about the same amount of fuel - only the DRZ has an extra 2 litres of confidence!
Your jetting sounds about spot on, but I would drop the clip on the needle one - (richen it up), and go to a 170 main - at 1.5 turns out on the fuel screw; this will reduce popping.
Hope this helps.

  • WR_Dave

Posted February 21, 2008 - 10:01 AM

#35

Another thing I forgot to mention is to make sure the float level is correct on the carb. If it's too high then the fuel bowl will constantly slosh fuel out the overflow and you will be losing mileage due to lost fuel not burnt fuel. I know that you will drain the fuel bowl every time the bike is layed over as well and that can use up alot of fuel if your dumping the bike quite often. WR Dave.

  • brebro

Posted February 29, 2008 - 08:09 PM

#36

So BoBr what did you find worked the best for your 08 450?

  • dowdy6

Posted July 28, 2008 - 02:59 PM

#37

I have an 08 with the stock pipe, no restrictor and the block off kit. I run a 162 main, 48 pilot and an 03 yz needle 2nd position. I generally ride at 3500 to 7500 feet. We are going to colorado and will be riding up to 10000 feet. I was going to go down one on the pilot and two on the main. any suggestions? by the way, my current jetting I read in an ariticle in one of the dirt bike magazines and it works well.




 
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