Sign in to follow this  
Followers 0
mx250_rider

Need more power for a 2005 WR450F

20 posts in this topic

Just got a 2005 WR450F doesn't have as much power as i thought it would and i wanted to know what i could do to it to get a lot more power out of it other than a pipe and major engine work.

Share this post


Link to post
Share on other sites
is it uncorked?

Ya the past owner had a dealer uncork it and had them put on one of those Performance WR muffler inserts but last night i took it off it sounded louder, but didn't get to ride it to see if it was faster.

He also had the dealer take some sort of eco friendly attachment to make it better for that sort of stuff.

Share this post


Link to post
Share on other sites

You could add a couple of teeth to the back sprocket. Obviously you'll lose some top speed but since the gear spacing on the WR is really wide you could afford to lose some speed on the top.

However the only way to make these things run like they should is to add an aftermarket exhaust (correct jetting and uncorked airbox, but that goes without saying). The stock pipes that came on the '05-'09 models were pure garbage from a performance standpoint.

Share this post


Link to post
Share on other sites
train harder and ride more, you will go faster. More power is rarely the answer....

+1. even the pros rarely need all the power a 450 can offer. A pipe will keep you happy and jet to suit. Then id be looking at spending your cash on suspension, tyres and fuel. :banana:

Share this post


Link to post
Share on other sites
You could add a couple of teeth to the back sprocket. Obviously you'll lose some top speed but since the gear spacing on the WR is really wide you could afford to lose some speed on the top.

However the only way to make these things run like they should is to add an aftermarket exhaust (correct jetting and uncorked airbox, but that goes without saying). The stock pipes that came on the '05-'09 models were pure garbage from a performance standpoint.

Would a stock yz450f pipe work and give me more power.

Share this post


Link to post
Share on other sites

A new can will only net you 2 or 3 horsepower and raise the db level. Make sure the stock pipe is uncorked. Remove the airbox snorkel and open the right side if you're feeling adventurous. Get a JD jet kit and install the YZ setup. Cut the grey wire. Drop a tooth on the countershaft. The bike will has plenty of power once the factory stops are removed.

Share this post


Link to post
Share on other sites
Would a stock yz450f pipe work and give me more power.

I put a YZ header on my WR and it helped the bike rev a bit quciker. I have put FMF pipes on my race bikes and have had great luck with them. The Factory 4.1 is a great silencer and showed to give more HP gain than the others in a dirt bike review a year ago or so.

Share this post


Link to post
Share on other sites
I put a YZ header on my WR and it helped the bike rev a bit quciker. I have put FMF pipes on my race bikes and have had great luck with them. The Factory 4.1 is a great silencer and showed to give more HP gain than the others in a dirt bike review a year ago or so.

Your 08 WR header is greatly changed compared to the 05's. In the 05's, the headers on the WR and YZ's are nearly identical (as far as I can tell)....the midpipe, however, is greatly reduced in diameter on the WR, creating restriction. I've got an '05 WR and put my leftover '05 YZ pipe (I knew I held onto that for some reason) on it and it's a LOT closer to my YZ power I remember now. HUGE difference. Yeah, it's louder, but I'll deal with that for the added power. It's a wheelie machine......:banana:

Share this post


Link to post
Share on other sites
Your 08 WR header is greatly changed compared to the 05's. In the 05's, the headers on the WR and YZ's are nearly identical (as far as I can tell)....the midpipe, however, is greatly reduced in diameter on the WR, creating restriction. I've got an '05 WR and put my leftover '05 YZ pipe (I knew I held onto that for some reason) on it and it's a LOT closer to my YZ power I remember now. HUGE difference. Yeah, it's louder, but I'll deal with that for the added power. It's a wheelie machine......:lol:

Thanks for clarifying. :banana:

Share this post


Link to post
Share on other sites
A new can will only net you 2 or 3 horsepower and raise the db level. Make sure the stock pipe is uncorked. Remove the airbox snorkel and open the right side if you're feeling adventurous. Get a JD jet kit and install the YZ setup. Cut the grey wire. Drop a tooth on the countershaft. The bike will has plenty of power once the factory stops are removed.

2-3 hp at peak. However the power is greatly improved below peak and there is a bunch more overrev (that I've only used once or twice :banana: ). Even though I'll never come close to using everything a 450 has to offer, the added grunt down low has made the power more adaptable to my riding style.

Unless you get a full race pipe, the sound increase over stock is not unreasonable. The stock pipe with PMB insert on my bike tested 92 db and the pipe I have on there now is right at the legal limit (96db).

Share this post


Link to post
Share on other sites
Would a stock yz450f pipe work and give me more power.

Yes. IIRC the stock '03-'05 YZ 450f pipes performed good but were loud as F:foul:

Pro moto billet offers spark arrestors and quiet inserts so you'll have options when it comes to legality and sound compliance.

Share this post


Link to post
Share on other sites

How much do you need. My 06 WR has the free mods, opened airbox, JD jetting , FMF Ti Q, and a Boyeson Quickshot. It's a beast. It may be lacking in some areas including rider skill, but power ain't one of them.

Share this post


Link to post
Share on other sites
How much do you need. My 06 WR has the free mods, opened airbox, JD jetting , FMF Ti Q, and a Boyeson Quickshot. It's a beast. It may be lacking in some areas including rider skill, but power ain't one of them.

Ditto....less the Boyeson QS....I can get the front up in almost evry gear just on trottle!....stock sprock's to boot!

Share this post


Link to post
Share on other sites
2-3 hp at peak. However the power is greatly improved below peak and there is a bunch more overrev (that I've only used once or twice :lol: ). Even though I'll never come close to using everything a 450 has to offer, the added grunt down low has made the power more adaptable to my riding style.

Unless you get a full race pipe, the sound increase over stock is not unreasonable. The stock pipe with PMB insert on my bike tested 92 db and the pipe I have on there now is right at the legal limit (96db).

my 06 (used)came with a m4 exhaust on it... it was way loud. just put a oe silencer and pmb insert, left factory arrestor in it, and it is way quiet and still runs great.. (insert old rider here) you can actually stand to be around it now...:banana: i need to put my db meter on it, but it is quiet....

Share this post


Link to post
Share on other sites

YZ pipe

Thats all you need

I was going to sell my bike until I installed one

Made it feel like a new bike

Share this post


Link to post
Share on other sites

Guys, I have an 05 WR450 thats runs really strong. The stock exhaust works fine with the restricter insert removed. A long with the free mods, the best thing I did was buy the AIS removeal kit from Yamaha , it came with jetting and is spot on for Michigan weather. I,ve had 5 KTM'S, 2 YAMS 1 Honda , and a Drz400. I like the Yamahas the best, they seem the most durable. I hope this helps. good luck!!!

Share this post


Link to post
Share on other sites

Make sure you have:

Complete open pipe, yz or after market

yz cam

Opened up airbox with the side cut outs. (There is also a vent for the other side you can buy. Between all of those it should flow as well as a YZ airbox).

Jetted correct.

If you need more power still then buy a big bore kit.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0