Will an '06 Yosh/FMF slip-on fit on an '09 ?

[crf450319]

I've searched but couldn't find exactly what I was looking for. Can anyone let me know if a slip on for an '06 YZ450F is a direct bolt on/fit to an '09 YZ450F ?

The info I found through the search let me know that the '06 250F silencer won't fit onto the '09 450F, but that's not what I need to know.

I'm guessing that the '03-'06's are interchangeable, and the '07-'09's are but you can't put a slip-on for an '06 onto an '09 (different pipe diameters) ? Is that correct ?

Thanks for your help !

[KJ790]

The 06 bolts on the same as the 09, but the diameter of the pipe was different. Most FMF pipes fit 06-09 because they have a large midpipe and then come with a spacer sleeve that sizes the pipe down to headpipe diameter (they send you a few different sleeves with the pipe). This then doubles as a step in the pipe. Most other brands are not like this, so they will not fit.

[crf450319]

Thanks for your help, I couldn't figure out why some manufacturers were saying their slip-ons fit from '06 to '09 but others weren't. I was looking at a Yosh. RS2 slip-on for an '06, but I'm guessing that won't work with the '09.

Has anyone had a sleeve made by a metal shop with any sort of luck/good results ? I'm wondering if I could have something made, but if other guys have tried it and it didn't work out I don't think I'd bother.

[KJ790]

Thanks for your help, I couldn't figure out why some manufacturers were saying their slip-ons fit from '06 to '09 but others weren't. I was looking at a Yosh. RS2 slip-on for an '06, but I'm guessing that won't work with the '09.

Has anyone had a sleeve made by a metal shop with any sort of luck/good results ? I'm wondering if I could have something made, but if other guys have tried it and it didn't work out I don't think I'd bother.

If you use an 06 header on your 09 then you can use the 06 Yosh silencer. You could try taking the yosh to a muffler shop and see if they can use a pipe expander to make the end midpipe large enough to fit on the 09 header.

[crf450319]

Alright, I'll figure out what I'm gonna do in the near future. If the '06 RS2 is too much of a bother I think I'd go with an FMF Powercore 4, I've searched and it seems like a lot of guys like the FMF Factory 4.1 but I can't seem to find a slip-on around the same price as the Powercore 4 on E-bay. I looked at the difference between the Factory 4.1 & Powercore on FMF's site and they don't really give a whole lot of info. as to the exact differences between the two.

I suppose it doesn't really matter which of the two I'd go with, from what I've read either of them should wake the bike up a bit.

Thumbs up to you KJ790

[KJ790]

Alright, I'll figure out what I'm gonna do in the near future. If the '06 RS2 is too much of a bother I think I'd go with an FMF Powercore 4, I've searched and it seems like a lot of guys like the FMF Factory 4.1 but I can't seem to find a slip-on around the same price as the Powercore 4 on E-bay. I looked at the difference between the Factory 4.1 & Powercore on FMF's site and they don't really give a whole lot of info. as to the exact differences between the two.

I suppose it doesn't really matter which of the two I'd go with, from what I've read either of them should wake the bike up a bit.

Thumbs up to you KJ790

The powercore 4 is about the same performance as a stock 06 or 07 silencer. The 08-09 silencer sucks something awful, so pretty much any silencer is a gain over that. The factory 4.1 is FMF's flagship exhaust, it is quite a bit lighter than the powercore, and performs much better, but it also costs quite a bit more.

[crf450319]

Thanks KJ790,

I thought there'd have to be a catch with the Powercore IV for it to be that cheap.

I know you're gonna get sick of me asking (and believe me, I've been searching like nuts) but will a full system from a YZ 250F fit the 450 ? I wonder if the header wouldn't be quite a bit smaller resulting in less power made than a comparable 450F system ?

I had found a really good post the other day on which pipes were interchangeable and what years, but I can't find it now.

? - My 4 year old likes the purple guy.

[grayracer513]

Even if it fits, the only thing a system from a 250F will do right on a 450 is point the exhaust out the right end of the bike. They're wrong for the bigger bike.

[KJ790]

The 250F system won't fit. The header is a different diameter at the head and the stud spacing is different so the flange won't bolt up. An 250F silencer will bolt up, but the midpipe is smaller diameter (actually the same diameter as the 06 YZ450 midpipe though. You can mount a 250F silencer with an 06 450 header, but like Gray said, it's not worth it since the 250F silencer is tuned for a smaller bike.

[crf450319]

I wonder if the header wouldn't be quite a bit smaller resulting in less power made than a comparable 450F system ?

Even if it fits, the only thing a system from a 250F will do right on a 450 is point the exhaust out the right end of the bike.

That was my point with my statement as quoted above. What I need is to figure out which pipe will fit/work on my new '09 and by work I mean better than the stock unit.

[crf450319]

The 250F system won't fit. The header is a different diameter at the head and the stud spacing is different so the flange won't bolt up. An 250F silencer will bolt up, but the midpipe is smaller diameter (actually the same diameter as the 06 YZ450 midpipe though. You can mount a 250F silencer with an 06 450 header, but like Gray said, it's not worth it since the 250F silencer is tuned for a smaller bike.

Thanks again KJ !! ?