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WR450FGreg

YZ450F muffler on a WR450F

12 posts in this topic

.

Guys,

This topic has been quiet for a while now.

Has anyone else put a YZ450F muffler on their WR450F recently?

If so, what do you think?

I've tried it with mine and was amazed at the result!

More power everywhere!

Cheap, easy and effective!

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I've been running a complete YZ exhaust on my 07' WR for 3 years. An e-bay purchase for 100.00. Been using a Pro Moto turn down end cap with spark arrestor. A marked improvement over the stock set-up for about 200.00 total cost. A good upgrade for a modest cost. :thumbsup:

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I munched the stock head pipe on my 08 and bought a complete 09 exhaust the next day on ebay for 60 shipped and the installed the PMB spark arrestor. I liked the wr before and I like the wr now. Except it is a lot louder. Power wise it sure does seem to pull harder for longer.

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I tried the full YZ system on my 2007 WR and did not care for it either.

It saved about 2 pounds of weight, and the bike seemed to rev faster to redline.

But the YZ exhaust was crazy loud, and I lost the low end power that I was used to for single track riding.

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.

I couldn't stand the popping on decel.

You DID re-jet to suit the new pipe didn't you? Surely?

Its a waste of time if you make any sort of exhaust mod and don't re-jet!

Greg

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I tried the full YZ system on my 2007 WR and did not care for it either.

It saved about 2 pounds of weight, and the bike seemed to rev faster to redline.

But the YZ exhaust was crazy loud, and I lost the low end power that I was used to for single track riding.

What year YZ pipe did you go with? I put a 2008 YZ pipe on my 08 WR450 and it is incrediable! It has more low end, stronger mid, and revs to the top end much much faster. All that and it is no louder than my un-corked stock pipe. My son's all stock 08 YZ250f is considerably louder than my bike now.

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.

You DID re-jet to suit the new pipe didn't you? Surely?

Its a waste of time if you make any sort of exhaust mod and don't re-jet!

Greg

Yes. I think I have a different problem though. The popping was "masked" with the wr muffler and made very apparent with the YZ. It's starting to get annoying with the wr exhaust now too. I need to get a new head pipe and see if that solves the problem. I don't see any cracks, but from everything I read, the popping is generally caused by an exhaust leak. But then I also read the popping is very normal:banghead:. I also read that the YZ muffler really didn't improve anything unless you get the YZ header too. I also read that the YZ header doesn't fit properly...:thumbsup::banghead:.

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There is no issues with the YZ header; it fits just fine! I would use the YZ header along with the silencer (paired together from same year). Yamaha tunes the silencer and head pipe together for a specific result.

Do a search on the difference between the 06, 07, 08,....exhaust systems. I personally found the 08 system to offer great results, yet retained the stock's low db's.

Did you remove the AIS system? Left on it will cause popping.

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There is no issues with the YZ header; it fits just fine! I would use the YZ header along with the silencer (paired together from same year). Yamaha tunes the silencer and head pipe together for a specific result.

Do a search on the difference between the 06, 07, 08,....exhaust systems. I personally found the 08 system to offer great results, yet retained the stock's low db's.

Did you remove the AIS system? Left on it will cause popping.

Yes, I bought the GYTR kit.

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:thumbsup::banana::lol:

Ok, I think I'm finally headed in the right direction!!! I rejetted (went to JD Blue #4) and a 170 main. I also checked the GYTR AIS caps. Removed/tightened the cap on the front of the engine. I bought a tighter clamp for the little rubber cap near the carb. I put the YZ exhaust back on, bought some gasket seal and put a little on the head pipe. Set the MSR fuel screw at 1 3/4.

Bike started right up but was still backfiring/popping on decel. Turned the screw in a bit (need to go figure out where it ended up) and the pop went away except for chopping WOT.

Went for a ride around the neighborhood. First thing I noticed is the severe "engine braking " that I was encountering (almost sent me over the handlebars before) was gone:banana::ride::banana::(:banana:. Smooth excel down the street follow by smooth decel produced no pops!!!! Again, opened it up on a straight and then chopped the throttle and did have some popping. I can totally live with this. I think I may need to play around with my pilot circuit a little more, but am VERY please with the results thus far!

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Yes. I think I have a different problem though. The popping was "masked" with the wr muffler and made very apparent with the YZ. It's starting to get annoying with the wr exhaust now too. I need to get a new head pipe and see if that solves the problem. I don't see any cracks, but from everything I read, the popping is generally caused by an exhaust leak. But then I also read the popping is very normal:banghead:. I also read that the YZ muffler really didn't improve anything unless you get the YZ header too. I also read that the YZ header doesn't fit properly...:lol::banghead:.

I got an 08' YZF complete exhaust and installed it on my 07' WR about a month ago. I love it. I also like the fact that a can find them all day long on EBAY or CL for very cheap. It's nice to know that if a crush my header, I can just purchase another for about $35 on-line. I had some bad popping on decel at first. After pulling it back off and replacing the exhaust with new gaskets, and making some minor jetting changes (new aftermarket needle DTR4 @4th clip from top, 170 main, 48 pilot) it sounds and runs great. It is louder now, I might look into a quiet core insert to go with the PMB endcap/spark arrestor. Best bang for the buck in my opinion.

:thumbsup:

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