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DPavitt

2004 WR450F Exhaust Question

8 posts in this topic

Does anyone know if the Q 4.1 slip on from a WR250F will fit a WR450F and will there be any differences? Thanks in advance.

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Probably not. Pipe diameters are usually different between 250 and 450. Some manufacturers use a reducer so that they can use the same stock # muffler for both bikes. Not sure if FMF does this, but you can measure the two and see since the FMF has a separate mid pipe design and not a welded midpipe like Pro Circuit.

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Thanks for the info. Assuming the pipe diameter is the same will the end pipe characteristics be the same or are they tuned different between bikes?

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Thanks for the info. Assuming the pipe diameter is the same will the end pipe characteristics be the same or are they tuned different between bikes?
There isn't a Q 4.1. You've mixed the model designations of two different mufflers. The Q is not listed as fitting the 450. The Q2 shows different part numbers for the 250 and 450, but it isn't a slip on, it has a welded pipe. The 4.1 has so many variations that I couldn't say. Your best bet is to give FMF a call and ask them. :thumbsup:

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Not sure if FMF does this, but you can measure the two and see since the FMF has a separate mid pipe design and not a welded midpipe like Pro Circuit.

The midpipe is held on the the muffler by two springs on the Procircuit.

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Does anyone know if the Q 4.1 slip on from a WR250F will fit a WR450F and will there be any differences? Thanks in advance.

The answer is no, the 250 has a smaller diameter header than the 450.

Yes the Q2 and 4.1 are slip on's (as cyclewriter said, two different systems), they have a slip fit that goes over the stock header as apposed to the stock clamped on one. :thumbsup:

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Thanks for the info., my mate is looking to sell the 4.1 (right model this time!) Anyways he says it will fit! Cant see how though if the header pipe is a different diameter. Thing is he will have to ship the unti to try. Does anyone know the difference in diameter?

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Thanks for the info., my mate is looking to sell the 4.1 (right model this time!) Anyways he says it will fit! Cant see how though if the header pipe is a different diameter. Thing is he will have to ship the unti to try. Does anyone know the difference in diameter?

The pipe diameter for the WR450 is about 40mm and the WR250 is about 35mm.

Why do you think that they would be the same?

The 450 is bigger engine and flows more exhaust gas. :thumbsup:

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