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MRD Exhaust is fantastic on my 2009 KX450F

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I just rode my bike with the MRD exhaust installed this weekend. I have a 2009 KX450F. I tried a Yoshimura pipe and a friend has the FMF power bomb system. They were lacking upper rpm pull. the bottom to mid power did not seems that different. I have a 51 tooth rear sprocket. MRD header is high & tight, so it is less prone to rock damage with better top end performance. The bike feels like it wants to pull forever. Super strong top end were you can late shift to clear a jump. Kind of takes away the inbetween gear feeling you get sometimes. Fit and finish is better then the Yosh. Dave A++ great job

Edited by MUSTANGCOBRA1353

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MRD is a great product. I ordered mine to help with lower mid. Mind you, running a 51 tooth rear/gearing. The pipe did help there. Both changes together were just what I needed to wake the 08 back up for my style.

I do wonder what we will need to do when all the DB testing changes next year though, and what Dave REALLY plans for that. It will be alot tougher, and it looks like the BS is out the window this time.

I would really like if he would put DB ratings on his page. I may have to go PC for next year, which pisses me off. I barely pass with the 2008 MRD I have now. I check packing every other time I race +40... Just to be sure.

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Mine is the Pro Comp 96db. It does not need an insert. I would never use an insert pipe for closed course MX racing...

Besides, it will not cut down enough for next year. The pro comp will barely make it now.

Performance will be hurting for everyone who will need to quiet up. So, worrying about that too much is a joke.

PC seems to have a way around. Or, resonance chamber seems to be a way... I dont care to know how or why, more like WHO CAN, so I can keep racing.

It is going to get tougher next year. Period.

The details of how SX/MX/AX will be tested next year are very good this time around, and will be done at a greater range at operation RPM. Manufacturers claiming the AMA does not test properly and this pipe will pass mumbo jumbo wont pass this time around. Testing and reading ALOT will help us get the best balance of DB vs performance, hence real DB numbers (utilizing USED testing procedures) for MRD exhaust's would be needed for those racing and getting tested. I dont know about the other disciplines, ie: worcs/enduro/whatever.

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Maybe with the FI bikes we can download a program to run for testing DB (new fuel/timing map). I know the factory teams do it, but the carb bikes would still have a issue. Also a insert like FMF uses in the muffler on the end cap would work.

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Mine is the Pro Comp 96db. It does not need an insert. I would never use an insert pipe for closed course MX racing...

Besides, it will not cut down enough for next year. The pro comp will barely make it now.

Performance will be hurting for everyone who will need to quiet up. So, worrying about that too much is a joke.

PC seems to have a way around. Or, resonance chamber seems to be a way... I dont care to know how or why, more like WHO CAN, so I can keep racing.

It is going to get tougher next year. Period.

The details of how SX/MX/AX will be tested next year are very good this time around, and will be done at a greater range at operation RPM. Manufacturers claiming the AMA does not test properly and this pipe will pass mumbo jumbo wont pass this time around. Testing and reading ALOT will help us get the best balance of DB vs performance, hence real DB numbers (utilizing USED testing procedures) for MRD exhaust's would be needed for those racing and getting tested. I dont know about the other disciplines, ie: worcs/enduro/whatever.

HALILUYAAAAAAA, the full throttle test is way overdue , it is the only way to tell how loud a bike is on the track , where it matters , I cant believe it took them this long to figure it out :thumbsup:

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Maybe with the FI bikes we can download a program to run for testing DB (new fuel/timing map). I know the factory teams do it, but the carb bikes would still have a issue. Also a insert like FMF uses in the muffler on the end cap would work.

I have been dyno testing the different setups for quieting these bikes down and have found that my quiet insert that is a baffle type insert installed into a large core with a normal size tip has the same effect on power as the smaller core/ small tip open type mufflers they are running now at AMA PRO races , the catch is that the baffle type muffler is alot quieter at full throttle than the open choked down ( AMA ) mufflers, ( 4 to 5 db quieter at full throttle ) , both loose a little lowend compared to a typical high flow muffler but niether one gives up peak HP,the loss on bottom could be regained with variable cam timing so I expect these bikes to be coming stock with baffled mufflers and variable cam timing in the future

Edited by DH367

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I just took delivery of a 2010. The MRD is sweet. Had one on a CRF. Ordered one yesterday. I will be running that with 48T and a rekluse. I am gitty like a schoolgirl.:thumbsup:

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You might rethink the 48, I put on the 49 that was money on my 06 on my new 09 before riding it, and I dont care for it at all when its a tight track. The gaps between 1-2 and 2-3 just seem off, either screaming or lugging badly, and with our less then stellar clutches, the 48 might be a bit tall for all but desert, just a fyi.

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I hear you. I had one ride on this Vortex 48 on the 08 and then yanked it for the new scoot. Wondering how it will ne. I absolutely loved it on the 08:smirk:

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I ride a 250f but is there any company out there selling aftermarket headers with resonance chambers like the ktms and akrapovic exhausts have?

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It's awesome on my '10 as well. Can't beat the price, craftsmanship and customer service.

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