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gearhead86

yz cam with wr exhaust

10 posts in this topic

Hello fellow TT'rs

I have an 04 wr450 Canadian model. I have the stock exhaust but am considering installing a yz exhaust cam. Can I expect any performance improvement with just the cam change or would I need to de-restrict the exhaust to see any performance gains?

I really don't want to put a less restrictive exhaust on my bike. I ride it on the street and it is too loud as it is.

Thanks

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I have an '05 and a year ago I enstalled the YZ exhaust cam and an aftermarket exhaust. OMG what a difference! The power increase across the board was tremendous. Now how much is cam and how much is exhaust, I don't know for sure, but I love this bike and have no desire to buy a new one. Occasionally I put the stock exhaust back on for more sensitive races (sound check), and the performance is not as good. But overall its worth it!

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I run an '04 yz cam in a '98 wr with the stock exhaust and the GTYR exhaust tip. I was running the WR cam at yz timing before the cam change. Just going to yz timing the motor ran better and was easier to start.

Going to the '04 cam did two things for me even easier to start with out the compresison release drill (you don't have that problem) and it smoothed out the power delivery. I think the '98 WR cam at yz timing had a harder hit than the '04 yz. The "04 is more linear like a late wr450 or an exc525.

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I had YZ EX and INT cams on my 07' for a while. I was running the stock WR exhaust with the GYTR enlarged end cap as well.

The power gains were very noticeable.:p

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G'day

I have a 07 Wr450F here in Aus, so far its done 7000ks problem free. I'm looking at doing a preventative piston replacement to keep it that way.

I also brought a 06 YZ450F with a blown bottom end for spare parts. I want to use the YZ cams in the Wr, it sound like changing the exhaust cam improves power. Is there any difference in inlet cams?

Anything else that I haven't thought of?

I also have the GYTR big bore header and YZ pipe which does increase the power a bit but shifts it more towards the lower and mid range.

Thanks

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The cam is going to make a difference regardless but keep in mind you are running with a corked up exhaust so you will not get near the full benifit.

When I put the yz pipe on my 03 WR the difference was day and night, much more fun bike to ride and I like the more aggresive exhaust note.

IMO to do it right I would do the exhaust first or two of them the same time.

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Does that end cap make the bike much louder? Is it worth the money?

Not much louder, it will still pass a 98db sound check. I feel it's well worth the money.

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G'day

I have a 07 Wr450F here in Aus, so far its done 7000ks problem free. I'm looking at doing a preventative piston replacement to keep it that way.

I also brought a 06 YZ450F with a blown bottom end for spare parts. I want to use the YZ cams in the Wr, it sound like changing the exhaust cam improves power. Is there any difference in inlet cams?

Anything else that I haven't thought of?

I also have the GYTR big bore header and YZ pipe which does increase the power a bit but shifts it more towards the lower and mid range.

Thanks

Both the intake and the exh are different from the 06' YZ and 07' WR.... If you are replacing the piston I might suggest a hi-comp piston and just replacing the intake cam with the YZ cam... I don't have experience with this set up other than an engine builder told me it was supposed to be the trick set up.

I had both, YZ int and exh cams from an 06' in my 07' WR. The de-comp pin on the YZ exh cam has caused more than a few of us to have fits with the e-start afterward... just a heads up on what you might expect.

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Both the intake and the exh are different from the 06' YZ and 07' WR.... If you are replacing the piston I might suggest a hi-comp piston and just replacing the intake cam with the YZ cam... I don't have experience with this set up other than an engine builder told me it was supposed to be the trick set up.

I had both, YZ int and exh cams from an 06' in my 07' WR. The de-comp pin on the YZ exh cam has caused more than a few of us to have fits with the e-start afterward... just a heads up on what you might expect.

Thanks mate, that was the kind of info I was after.:banghead:

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