Not enough low down power!!

[venerableChicken]

I have just recently purchased an '06 wr450 which has had the free mods done to it.

I have also added a boyesen quickshot2 to it as this bike seems to lack bottom end power. I came from a '99 ktm200 and i recon it almost pulled harder from low revs as the wr does, which is annoying and frustrating.

It was most noticeable yesterday when i entered my first race (woo hoo) and had to really ride the gearbox to keep the revs up to get some acceleration. Was riding with 2 guys on yzf450's and they said they pretty much stayed in 1 gear around the whole track.

What can i do??

Will gearing help? (running standard gearing)

What about jetting??

Aftermarket pipe??

Anyone else feel this way with theirs??

[Mutu]

Aftermarket pipes really wake the sleeping beast. That would be my first choice.

My '05 was weak as piss, untill I fed it some Procircuit Ti GP lowboy power!!!!!

The pipe is what kills power.

[venerableChicken]

Interesting.

I just picked up a White Bros MX4 pipe from ebay for the right price but was unable to fit it before my race due to it not "slipping on"! It is real loose on the header pipe. I know that this pipe was from a yzf450, do they have different headers?

And has anyone else got 1 of these pipes on a wr and does it work good?

[Mutu]

How loose is real loose? You could try a bead of RTV silicone at the slip fit. That's what I'd do. You won't need much.

The YZ and WR header pipes are the same for '06.

[venerableChicken]

I would have thought that it was too loose for silicone (from memory about a 1mm gap or so) but since you mentioned it, I had a look at the pipe and there is silicone around it where the last guy has obviously used it!!

Is a header going to make a difference with this pipe anyways? or not enough to bother with?

I see you are a fellow aussie Mutu, which end of Aus do you ride??

[erickdj]

I have just recently purchased an '06 wr450 which has had the free mods done to it.

I have also added a boyesen quickshot2 to it as this bike seems to lack bottom end power. I came from a '99 ktm200 and i recon it almost pulled harder from low revs as the wr does, which is annoying and frustrating.

It was most noticeable yesterday when i entered my first race (woo hoo) and had to really ride the gearbox to keep the revs up to get some acceleration. Was riding with 2 guys on yzf450's and they said they pretty much stayed in 1 gear around the whole track.

What can i do??

Will gearing help? (running standard gearing)

What about jetting??

Aftermarket pipe??

Anyone else feel this way with theirs??

Mutu is right, the stock pipe is very restrictive:thumbsdn: . Doing some work on the stock pipe can give you some good gains, but make surett you jet the bike properly. I have an 07 and the header on it is smaller than the one from a yz. Go for a yz header if you have the chance. I noticed a good boost of power just from the header alone. My bike has all the free mods plus the yz header and it has PLENTY of power everywhere on the powerband. Bottom end is fantastic on it. Right now I'm running the stock muffler with the baffle removed, only the spark arrestor is in place, it works much better than stock. Your bike has lots of potential, it just needs to be set up properly:prof: . If the person that had the bike before told you he did "all" the free mods it would be a good idea to check for yourself to see if in fact they were done. Don't forget to check the throttle stop length.

[Mutu]

I would have thought that it was too loose for silicone (from memory about a 1mm gap or so) but since you mentioned it, I had a look at the pipe and there is silicone around it where the last guy has obviously used it!!

Is a header going to make a difference with this pipe anyways? or not enough to bother with?

I see you are a fellow aussie Mutu, which end of Aus do you ride??

I wouldn't bother with another header anyway mate, the muffler should be more than enough. If it isn't, then you could try a FMF powerbomb or something like that. I think you will be wasting your money though.

There should be plenty of overlap (header inside the mid pipe of the muffler) so you shouldn't have any problems with the 1mm gap.

It will be fine with silicone, just make sure it is "RTV" (get from REPCO or the likes) because the pipe gets hot.

I'm located at the bottom of WA near Esperence!

[Lennie]

I would get a jet kit before a exhaust, its cheaper than an exhaust and gets good power.

[Mutu]

I would get a jet kit before a exhaust, its cheaper than an exhaust and gets good power.

He already has an aftermarket slip-on to go on his bike....

I found jetting does next to nothing with the stock muffler.

[erickdj]

He already has an aftermarket slip-on to go on his bike....

I found jetting does next to nothing with the stock muffler.

Jetting DOES give you significant gains even with the stock muffler, it just has to be done right. The WR comes way too lean from the factory even for the stock muffler.

[TooFast]

I had the same complaint - try the PMB insert, it opens the muffler outlet to the size as the end cap and makes a world of difference, mucho more bottom end. I have a home made one (same dimensions as the PMB) for sale if you're interested.

[Mutu]

Jetting DOES give you significant gains even with the stock muffler, it just has to be done right. The WR comes way too lean from the factory even for the stock muffler.

An aftermarket muffler makes 10x the power than jetting will ever do with the stock muffler.

Yes jetting has an effect with stock muffler, no it is not significant.

Once you open up the stock muffler, significant gains can be had.

Baffles and pea shooter tip are not good for power.

I take it you still have stock pipe?

[erickdj]

I take it you still have stock pipe?

I do have the stock pipe, with the whole baffle removed, not just the peashooter. Along with that, I have a yzf pipe that I use once in a while. I don't know about your bike, but mine did improve noticeably with a good re-jet. Not as much as it did with the yzf pipe, but I noticed it right away.

[bandit99]

For a little more tham $100 you can buy the YZ450 exhaust camshaft. With a pipe and jetting the bike is better but the YZ cam gives the bike the power you are looking for.

[tmckeown]

There is several ways to get more power to the lower rpm's.

1st) get jetting right

2nd) header pipe is way too big to get good flow of exhaust gases, so get GYTR one which you will notice that it is thinner than original one. Or make a cone insert to the header

3rd) programmable ignition like Vortex will give change to advance more your ignition and this you get more torque and power.

Timo McKeown

[Summit]

For sure get the GYT-R header and muffler. It's a little louder but it will give you some awesome low and mid power. My 05 is so much more fun to ride now since I put this combo on recently. I would NEVER go back to the stock pipe. I also had the PMB tip and it did make a difference.

[trailordune]

Adding an FMF sx powerbomb headpipe really changed the torque curve on my 04. It is a smaller diameter than stock and the bike really pulls down low now. The top end signs off sooner now but all in all the bike is faster and power from bottom to top is great. Bike lugs in the tight stuff much better now. I run this pipe with a ti-powercore and proper jetting is the key to making these bikes rip.

[chrispy1202]

When i bought my bike the free mods had already been done. I put the YZ450F pipe on my bike, along with the richening of the jets. This made a huge difference from stock. Then,I put the JD Jet kit in. That was another big jump in power, bottom to top end. I was surprised at the difference the JD kit made, these are a couple of must do items to bring the bike to life.

Cheers!