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Daruu

Bought a 04 wr450 - have a few questions

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Hi, just bought a 04 wr450, which is also my first road legal bike.

1: A friend of mine has a set of ktm 640 sm wheels, has anyone tried fitting these to the wr? If so, what needs to be done to make them fit?

2: Does the rear fender from a yz450 around the same year fit?

3: I have fmf factory 4 exhaust , and the thing is LOUD! Even tried repacking the muffler and add the quiet core insert, but it didn't seem to help alot... Any suggestions for a quiet replacement muffler?

I hope you understand my poor english writing :)

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KTM wheels will not fit

YZ fender will fit, from 2002

FMF pipes are boomy sounding. If you want quiet, you will have to go to a modified stock pipe

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You will have to cut a few small holes to fit the fender to the overflow tank

The 03 to 05 yz450 rear fender will fit. Im sure of that

A stock yz450 silencer works fine and isn't obnoxious as long as its packed.

A quite WR is a slow WR.

No idea about the wheels

Edited by MaxPower

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Thanks for the replies!

New question, the clutch doesn't seem to engage properly... Sometimes the bike will continue to move forward with the lever fully pulled. The arm with the spring on moves as it should, so I'm thinking the problem must be inside the clutch. Is there any adjustment on the clutch pack behind the clutch cover?

The strange thing is that sometimes it works as it should, and other times it's as described above...

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Thanks for the replies!

New question, the clutch doesn't seem to engage properly... Sometimes the bike will continue to move forward with the lever fully pulled. The arm with the spring on moves as it should, so I'm thinking the problem must be inside the clutch. Is there any adjustment on the clutch pack behind the clutch cover?

The strange thing is that sometimes it works as it should, and other times it's as described above...

 

This is a typical WR issue

There is nothing 'wrong' with the clutch, it just doesn't work all that great for disengagement.

You will notice some days it works great cold, others hot.

A new set of fiber and metal plates will help, and usually cure the problem

Adding less pre-load to the clutch springs (washers) or using (3) WR250 springs also can help

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A quite WR is a slow WR.

 

Not true. My WR has FMF QF. It is most assuredly not slow, and is still fairly quiet.

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Been riding for a while, and loving it! The clutch problem seemed to have cured itself (more or less)
But having a new issue now....

Went for a 40-50km ride earlier today, and when i got home i checked the oil - It wasn't showing on the stick.

Filled up 1dl at the time and started it and let it idle according to the manual a few times until it was almost at the top of the stick.

At that point i had added almost 3dl of oil.

 

It isn't smoking, so I think its probably a leak somewhere.

Any tips to places where it "usually" leaks? Clutch cover and crankcase cover will be checked off course

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Been riding for a while, and loving it! The clutch problem seemed to have cured itself (more or less)

But having a new issue now....

Went for a 40-50km ride earlier today, and when i got home i checked the oil - It wasn't showing on the stick.

Filled up 1dl at the time and started it and let it idle according to the manual a few times until it was almost at the top of the stick.

At that point i had added almost 3dl of oil.

It isn't smoking, so I think its probably a leak somewhere.

Any tips to places where it "usually" leaks? Clutch cover and crankcase cover will be checked off course

If it's leaking that fast it will be really noticeable.. Try riding up and down the street for a minute or two after making sure the oil is right and look for leak marks. Although, you could be checking the oil incorrectly and be way overloaded.

Be sure to clean the bike so a oil leak is easy to see.

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If it's leaking that fast it will be really noticeable.. Try riding up and down the street for a minute or two after making sure the oil is right and look for leak marks. Although, you could be checking the oil incorrectly and be way overloaded.

Be sure to clean the bike so a oil leak is easy to see.

 

Having it on a race stand so it stands straight --> idle for atleast 3 mins ---> check oil.

Thats what it says in the manual, so thats what i've been doing.

I'm not sure that i checked the oil after the last time i rode either tho, so it might have been about 100km since i checked last

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Having it on a race stand so it stands straight --> idle for atleast 3 mins ---> check oil.

Thats what it says in the manual, so thats what i've been doing.

I'm not sure that i checked the oil after the last time i rode either tho, so it might have been about 100km since i checked last

Huh. No noticeable leaks on the bottom of the engine?

I see you are/were looking for a quieter pipe. I am looking for a fmf pipe for my 04 and getting rid of my stocker with a gytr power tip, if you decide to get rid of that fmf let me know, I would be interested in it.. I love a loud pipe :)

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Oh and check the crankcase vent, could be blowing it out of that but it should be VERY noticeable.

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Back with a little update here.

Went to a Yamaha specialist to get the oil issue checked, his "well trained nose" thought that the piston might have a bit of wear and/or that the head seals were slightly leaking. He recomended a teardown and check,including the crankrod (he also said he heard a knocking noise that shouldn't be there). The timing chain was also quite worn, so a service is probably much needed.

 

 

Is this doable for someone that hasn't done this sort of thing on a bike before? Will be following guides/videoes and it doesn't look THAT hard but..

I've rebuilt a few car engines, so a tiny mc engine shouldn't be to much of a challenge?

 

And where do you guys buy parts? They need to be able to ship to Norway :)

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Pulling the top end off the motor is pretty easy to change rings/piston.  Measuring the bottom end crank, cylinder walls, piston, plaining the head etc is a little more challenging.. but there's not much for special tools that you'd need.  There's lots of great video's on youtube how to pull the top end.. and the manual does a pretty good job explaining it as well.

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Haven't had time to look at this, so i got a mechanic to tear it down.

I need a new crank, new cylinder + piston and timing chain.

Was so worn that he was surprised that it did run at all...

 

So I was thinking of getting a big bore kit. Is there any downside to thoose at all? Been looking at a JE kit on ebay, looks decent enough.

 

That kit, combined with a YZ exhaust cam and proper jetting = it should be a bit faster?

 

Edit: Or is there a similar cam available that works together with the electric starter?

Edited by Daruu

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Haven't had time to look at this, so i got a mechanic to tear it down.

I need a new crank, new cylinder + piston and timing chain.

Was so worn that he was surprised that it did run at all...

 

So I was thinking of getting a big bore kit. Is there any downside to thoose at all? Been looking at a JE kit on ebay, looks decent enough.

 

That kit, combined with a YZ exhaust cam and proper jetting = it should be a bit faster?

 

Edit: Or is there a similar cam available that works together with the electric starter?

 

Yes

More vibration

Non-oem parts

Less top end

 

Unless you just want to stay in 3rd gear all day, there is no reason to get a big bore

Proper jetting and tuning will make it plenty torquey

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So you wouldn't recomend getting it, even tho its about the same price as a OEM cylinder + piston kit?

I thought that "bigger is better" was also the general rule on theese thumpers, but it might not be the case then :)

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So you wouldn't recomend getting it, even tho its about the same price as a OEM cylinder + piston kit?

I thought that "bigger is better" was also the general rule on theese thumpers, but it might not be the case then :)

 

Absolutely not 'better', just different.

 

The stock bore and stroke have been worked out over decades of trial and error.

Best compromise of torque, smoothness and top end, combined.

 

Now, if all you do is climb sand hills, yes there is an advantage.....but a porting and YZ ex cam is still a better upgrade.

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OK, thanks for the replies.

Is there a cam equal to the yz exhaust cam that works with the decompression thingy?

Hot Cams makes one. Don't recommend it. I had (2) defectives and a friend had one.

The 2006/7 YZ stock ex cam can have the decompression pin ground down to work flawlessly

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