2008 WR450 carb removal?


22 replies to this topic
  • Wr426rdr

Posted February 12, 2008 - 09:30 AM

#1

I tried a bunch of things to get the carb off my 08 wr450, so that i could chaneg the jets. What a P.I.T.A! I was only able to get the throttle stop done in abotu an hour, sine i could barely reach the bolts. This was in part not having a long allen wrench. My question is how can i get the carb to move competely sideways so i can access the top and bottom of the car so i can change the jetting and needle. My local yamaha shop recommened going with the stock YZ450 jetting, a 168 / 45. :applause: I hope this works out for me.

So if anyone has any suggestions on how to get access to the carb, i would appreciate it. Seems like it is a tight fit behind the aluminum frame, so there is not much to work.:)


In the process, i also stipped the plastic screw top for the hot start. :cry: :banghead:

I was frustrated to say the least, and threw a wrench and put a nice size hole in my wall!:foul:

HELP~!

  • mvryder

Posted February 12, 2008 - 09:54 AM

#2

-Remove seat, side covers, and tank.
-Remove the lower bolts of the sub frame and the muffler bolts. (leave the muffler on)
-loosen air boot band clamp at the carb.
-remove the lower hose to the air box (vent hose)
-Slightly loosen upper subframe bolt and swing the rear end up.
-remove the rear shock
-remove the throttle cables
-remove the hot start cable at the lever (leave the cable attached to the carb it makes it easier i think)
-loosten the band clamp on the other side of the carb.
-remove the carb and work your magic.

I have done it a few times, it takes like and honest 15-20 min, it takes a little more disassembly but it is the least frustrating way to work on the carb.

  • beezer

Posted February 12, 2008 - 10:37 AM

#3

You can change all the carb jets and needles without removing the carb.

You can get to the needle by taking the tank and seat off.

The pilot jet and main jet you can get at by removing the 17mm access plug.

I removed the float bowl to get rid of the air screw plug and change the air screw. Put a little grease on the screw so the spring, washer and o-ring don't disappear.

The carb is a very tight fit in the frame and I used my share of filthy words too.

  • Dube2

Posted February 12, 2008 - 01:19 PM

#4

ya, what mvryder said.

beezer? NO WAY MAN...... even the yam mech. confirms the removal of all in mvryder's blog. if you did all that work without removing the carb? you are the man!:applause:

I did mine and basically coppied mvryder's instrustions and didn't even see this blog till after I was done.

dube2 OUT!

  • William1

Posted February 12, 2008 - 01:46 PM

#5

You can do everything with the varb installed... if you have the right tools.
The needle is easy with a ball end allen driver.
The main and pilot are easy with either a jetting tool or motion pro's 90 degree driver.
The leak jet.... the bane of my existence. You have to pull the bowl. I used a allen wrench shaft, cut to be slightly longer than the depth of the bowl. On one end, I use a 1/4" rachet with a 3mm socket. It still sucks. After a few times, I bit the bullet and installed an adjustable leak jet.

Pulling the carb, albeit a lot of steps, ensures you do not mess anything up as the delicate carb is safe on a bench. But then, it only is easier to pull and work on if you are doing the leak jet. The rest, do on the bike.

  • Wr426rdr

Posted February 12, 2008 - 02:32 PM

#6

I was able to get the float off the carb without removing it from the bike. It was probably more work then needed, but i pulled the exhaust header, and that along with some new long, low depth alen wrenches, i was able to get the bowl off, and replace all the jets, EXCEPT the main air #110. I could not find it in the carb, and was not sure if the carb had to be out in order to replace this one. Basically everything that came in the Yamaha AIS was installed, (except AIS itself) What will be my problem with not replacing the #110 jet? I test rode the bike down the street, and i can now pull a wheelie in 4th gear. stock, i could barely get the wheel 6 inches off the ground! What a difference! I installed the new adjustable air needle as well, and after a few adjustments, the bike its running awesome! Now, all i need to do is wait for my new hot start screw to come in, so that i can replace the one i stripped:)

I installed the stock YZ450 jets, which i guess are 170/50. Would a 168 /48 be better? difference in power / performance? The dealer said 170/50 will be perfect for my elevation, but i read different here on TT. suggestions now that i know how to chaneg the jets?

  • Kirkster

Posted February 12, 2008 - 02:45 PM

#7

I just did mine on Friday night / Saturday. What a PITA. Many bad words were yelled and the wife even came out to check on me.

After I finished with the jetting (168 / 45) and the needle I had to put the subframe down and get the fricking boot to seat all the way on the carb. This induced most of my cussing....

It runs great with the 168/45 combo...

  • beezer

Posted February 12, 2008 - 06:42 PM

#8

I did mine pretty much the same way as William did. The ball end allen wrench is a must. You can buy a couple cheap and cut them and use a vise grip on them.

I finished up the bike tonight but it's snowing out so I just staring at it.

I ran a 48 pilot and a 165 main but I have a YZ cam in mine. The 48 is lean but it's 23 degrees out.

The adjustable leak jet sounds like a good idea.

  • tweav

Posted February 12, 2008 - 07:07 PM

#9

I did mine pretty much the same way as William did. The ball end allen wrench is a must. You can buy a couple cheap and cut them and use a vise grip on them.

I finished up the bike tonight but it's snowing out so I just staring at it.

I ran a 48 pilot and a 165 main but I have a YZ cam in mine. The 48 is lean but it's 23 degrees out.

The adjustable leak jet sounds like a good idea.


I got tired of taking my bike apart all the time so I got a rd powerbowl It works great the only thing that could be better is if the bike weas fuel injected so there was none of this nonsense in the first place

  • beezer

Posted February 12, 2008 - 07:47 PM

#10

What does the power bowl do?

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  • tweav

Posted February 13, 2008 - 02:42 AM

#11

It's a true bolt on adjustable leakjet . all the other's I've seen you had to drill this or that . it also address the pump linkage issue . by replacing a very weak spring. also the adjustment screw sits a bit higher then the others so it is easier to get to over the pipe. I think It may be the best bolt on mod I've done to my wr . It is much easier to fine tune now.

  • beezer

Posted February 13, 2008 - 06:10 AM

#12

240 bucks.

Sigghhh!

  • C-P

Posted February 15, 2008 - 06:30 PM

#13

I was able to get the float off the carb without removing it from the bike. It was probably more work then needed, but i pulled the exhaust header, and that along with some new long, low depth alen wrenches, i was able to get the bowl off, and replace all the jets, EXCEPT the main air #110. I could not find it in the carb, and was not sure if the carb had to be out in order to replace this one. Basically everything that came in the Yamaha AIS was installed, (except AIS itself) What will be my problem with not replacing the #110 jet? I test rode the bike down the street, and i can now pull a wheelie in 4th gear. stock, i could barely get the wheel 6 inches off the ground! What a difference! I installed the new adjustable air needle as well, and after a few adjustments, the bike its running awesome! Now, all i need to do is wait for my new hot start screw to come in, so that i can replace the one i stripped:)

I installed the stock YZ450 jets, which i guess are 170/50. Would a 168 /48 be better? difference in power / performance? The dealer said 170/50 will be perfect for my elevation, but i read different here on TT. suggestions now that i know how to chaneg the jets?



If i recall the main air is on the intake side of the carb. There's two jets at the bottom of the carb intake that you can access once you remove the airbox boot. The one on the left is already in, and you're installing the one from the AIS kit in the pre-tapped hole on the right. Should be in the GTYR kit instructions.

  • Wr426rdr

Posted February 16, 2008 - 08:26 PM

#14

I figured it was in the intake boot. What a PITA to get that book off. It seems to run really well right now. I'm taking it out on Monday, so we'll see how the re-jet does. This will be my 2nd ride on it. The 1st was purely STOCK. I already notice a HUGE difference just riding it down the street to test. Idle is perfect, so we'll see if i need to add the new air jet after.

Thanks!

  • William1

Posted February 17, 2008 - 04:52 AM

#15

240 bucks.

Sigghhh!


RD PowerBowl adjustable leak jet is like $100. Contact James Dean, he will send one out post haste.

For those bikes where pulling the float bowl to swap leak jets is a PIA, it is money well spent.

  • Gary Murray

Posted March 14, 2008 - 08:58 AM

#16

how do you get the shock out? Do you remove the airbox also?

  • 2lcf

Posted March 14, 2008 - 09:55 AM

#17

When I did mine, I followed the GYTR instructions...........the instructions said it sould take around 1.8 hours.......more like 3.5 cause I was going slow and have never done it before.........I removed:

----Seat
----Side panels
----Unbolted rear frame and swung it off to the side and held it up with a bungee cord so it would not stress the resevoir lines
----Removed rear shock, both top and bottom mounting bolts

Once those are out of the way it is alot easier getting the carb off.......

Good luck............I also used all the jets that came in the GYTR kit and love the power......even at high elevations, it runs like a branded pig..........:thumbsup:

  • JSanfilippo

Posted March 14, 2008 - 12:42 PM

#18

Like beezer said, you can get to the main and pilot by the big plug at the bottom of the bowl.

The needle requires removing the tank, seat, and top engine mounts.

Its not air screw, its fuel screw!

  • henrics

Posted March 14, 2008 - 01:48 PM

#19

What is the main airjet doing, leaning out the main jet??
And by the way does anyone removed/plugged the venthose that comes from the startermotor. There are no one on the -06 and it is really in the way of adjusting the fuelscrew.
The engine is "open" from the starter to the top of the engine, right?

  • JSanfilippo

Posted March 14, 2008 - 04:08 PM

#20

And by the way does anyone removed/plugged the venthose that comes from the startermotor.


There is a hose venting the starter motor on the '07-'08. I move it out of the way to adj the fuel screw but then I put it back.




 
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