2005 WR performance upgrade questions

1) When you change the timing from WR to YZ is there any other MUST upgrades you have to do at the same time like jet kit or exhaust ?

2) If I’m going to upgrade exhaust should I buy a stock YZ exhaust or spend the extra cash on an aftermarket exhaust built for WR?

3) When it gomes to jet kits, how does one decide which one to get?

4) Has anyone bought and used the the “P-38 lightening” or “Power Now” upgrades found at http://www.thumperfaq.com/not_free_carb.htm

1) When you change the timing from WR to YZ is there any other MUST upgrades you have to do at the same time like jet kit or exhaust ?

2) If I’m going to upgrade exhaust should I buy a stock YZ exhaust or spend the extra cash on an aftermarket exhaust built for WR?

3) When it gomes to jet kits, how does one decide which one to get?

4) Has anyone bought and used the the “P-38 lightening” or “Power Now” upgrades found at http://www.thumperfaq.com/not_free_carb.htm

1) I'd do all the free mods and a YZ or aftermarket slip on and jetting. You will notice the cumulative effect much more.

2) If you can find a YZ muffler plus a sparky tip for less than an aftermarket, go that route. You wont feel any big difference by spending the extra on an aftermarket pipe, other than cosmetics.

3) Get the JD kit and follow the instructions along with Williams fuel screw procedures.

4) I had a PowerNow in a YZ250f and it seemed like a waste of money. I think my bike ran better without it (luckily it came with the bike).

3) Get the JD kit and follow the instructions along with Williams fuel screw procedures.

Could you help me out with some links?

You're gonna want to open the air box and cut the throttle stop. You've already done the gray wire. The stock exhaust sucks so yes if you can get a stock YZ set up that would be great. The only way to get the stock exhaust to perform is to remove the baffle and drill hole in the front baffle but then it's crazy loud. You'll need JD kit JDY003 I believe but double check. If you have a question just email James and he will reply within a few days.

Here is a link to jetting but William has better directions for just the mixture screw

http://thumperfaq.com/jetting.htm

Here are a couple more useful links

http://thumperfaq.com/

http://thumperfaq.com/free_mods.htm

You're gonna want to open the air box and cut the throttle stop. You've already done the gray wire. The stock exhaust sucks so yes if you can get a stock YZ set up that would be great. The only way to get the stock exhaust to perform is to remove the baffle and drill hole in the front baffle but then it's crazy loud. You'll need JD kit JDY003 I believe but double check. If you have a question just email James and he will reply within a few days.

Here is a link to jetting but William has better directions for just the mixture screw

http://thumperfaq.com/jetting.htm

Here are a couple more useful links

http://thumperfaq.com/

http://thumperfaq.com/free_mods.htm

Great, thanks.

Ordering these up right now ;-)

ZipTy Fuel Mixture Screw - FMS01

JD Jetting High Performance Jet Kit

Have you ever used, or know anyone who's bought and used an "Accelerator Pump Cover" Wondering if that would we worth it?

EDIT: another question if you would :-)

When you says "The only way to get the stock exhaust to perform is to remove the baffle and drill hole in the front baffle but then it's crazy loud." I've removed the baffle, but i'm not sure what you're talking about when you say "drill hole in the front baffle"? Where is this front baffle you speak of?

Edited by wdthfxup

With the rear baffle out take a flashlight and look down your muffler and you'll see a plate in there with one hole in it. Get a long drill bit and drill a bunch of holes in it. If you hold the muffler upside down so all the shavings fall out or coat the drill bit with grease so the shavings stick to the bit and not fall down into the muffler. When I did mine I drilled probably about 10 holes in and made as free flowing as possible. The bike ran perfect with no baffle but was loud. I put in the GYTR baffle and had a slight bog but it was quiet. After all that I bought a FMF Q4 and runs perfect and it's quiet

3) Get the JD kit and follow the instructions along with Williams fuel screw procedures.

Hey fourstrokin650,

Where can I find info on the " Williams fuel screw procedures"?

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