Simple question, I know its probably been talked about before, but I did a search and find what I was looking for. My buddy wants to remove his airbox and pull the pea-shooter on his YFZ..We are at about 1000 feet and need a good place to start on jetting. Anyone with this same set up, let me know..

 

to the TOP!

 

Come on all you YFZ boys..where's the love...and advice!

 

Tell him to:

1) remove the airbox cover (after making sure the filter foam is oiled and has grease between it and the airbox)

2) pull the spark arrestor

3) drill four 1/4 inch holes in the stock silencer (using a foot long bit down through the outlet

4) change out the stock needle for that of a yz 450 bike and put it in the 4th position

5) change out the stock pilot for a 45

6) change out the stock main for a 168

7) feel the power!

I am at an elevation slightly above yours and this set-up is spot-on. The power increase seems substantial over showroom-stock. I still have my Quadzilla but have less ambition to ride it after making these simple changes to my YFZ.

 

[quote]
Originally posted by: dissimilar
Tell him to:

1) remove the airbox cover (I run the GYTR filter)

2) pull the spark arrestor

3) drill 5 1/2 inch holes in the stock silencer (using a foot long bit down through the outlet

4) change out the stock needle for that of a yz 450 bike and put it in the 4th position

5) change out the stock pilot for a 45

5.5) 2.5 turns out on the air screw

6) change out the stock main for a 170

7) feel the power!

This is my setup, just slightly differnt.

 

just wanted to add if you have a 04 you don't have to fiddle with the needle because it's been updated to the 4th notch from the 3rd

 

Thanks..thats the kind of input I was looking for. One question though..I hope its not a dumb one..explain more about what you guys mean when you say to drill holes in your silencer?

 

Cdalepaul, the dirt bike needle is different than that of the atv (unless the '05's got the bike needle as an update too). If a person was to keep the stock needle then they would want to go to the 5th or 6th position. In other words, the bike's needle is richer.

Dingo2, once you pull the spark arrestor, shine a flashlight down the hole. You will notice a dead-end wall about 11 inches in. Drill your holes through that wall.

TRLYFZ450, there must not be anything left to that wall after drilling 5, 1/2 inch holes in it! Are you sure the bit you used was that big? It seems as though 5, 1/2 inch holes would take-up more surface area than the entire wall! Also, did you try using smaller holes first? I would think that removing that much back pressure would greatly reduce low-end.

BTW, my air screw is out 2-1/4 turns.

 

Yep 5 1/2 inch holes 1 in the middle and 4 around the outside. The inside diameter on the exhaust is 1.900, plenty of room. Not overly loud either, sounds good.