Product Reviews

Product/Service: M4 Stainless Steel Full Exhaust System
Manufacturer/Provider: M4 Exhaust
Reviewed by: Jeff Kufalk

When it comes to buying an exhaust there are many factors that people consider. Some of which (but certainly not an exhaustive (no pun intended) list), would be:

For my purposes, I care about performance #1, price #2 and quality #3. All of the other factors do play in, but they're just not as important as performance and getting the best bang for my buck. I'll address all points through this review, but wanted the reader to know my biases.

After trying several exhausts, seeing their results and then seeing the results that my fellow racers were getting out of their M4 systems, I called up M4 to work out a deal.

I explained to them my needs and budget and we agreed that the H06472, Stainless Steel full race system with Aluminum can (MSRP $852) would be the best option. 3 minutes later my order was complete, and about 4 days following that, the box was in my garage.

Packing of the box was perfect. Each piece was individually wrapped with bubble wrap, and the can had an additional cardboard sheath around it for protection (complete with a 'do not cut with knife' warning).

What's in the box:

The installation was a snap for me, mainly because I had the bike apart to begin with, and I have all the tools necessary. However, if you are still in street trim, the installation still isn't all that difficult.

Remove the old exhaust system, Can first, followed by headers. If you are in street trim, you will have to remove the side & lower fairings. I believe it can be done without removing the tail fairing. You will also have to remove the bolt at the bottom of the radiator and swing the radiator forward a bit for access to the headers.

Once you've got the can and headers off, it's the PERFECT time to change the oil! Everything is wide open and you won't make a mess. Don't worry about heating the motor up, just drain the oil, replace the filter & oil, clean it all up and then continue the install!

The install is pretty straight forward. Each down-tube is marked for which cylinder it goes to, and the collector pipe has a corresponding number. The down-tubes also have a line on them for how far they should be inserted into the collector. The down-tubes and collector are assembled before you put the headers on. This helps ensure things are together tight and correct before they go on.

The rest of the install is blatantly obvious. Slip on the mid-pipe and the can. The big thing to remember is to leave the install 'finger tight' until you have everything on and lined up. From there, you can start at the headers and work your way back, tightening everything up. Again, just follow the instructions and you'll be fine.

A few differences with the M4 system over the stock system which people may have questions about:
Q - Does it have a bracket to hang the side heat shield?
A - No, it doesn't have the bracket on the mid-pipe like the stock system does. However, you can STILL use the OEM heat shield! Just attach it at the top as it was, and you're good to go. Or you can leave it off, but you might feel the heat on your leg.

Q - Does it have the same heat shield over the can, or should I worry about heat?
A - No, it does not have the massive heat guard of the OEM exhaust. It will get a little hotter than the OEM exhaust, but it's not hot enough to melt anything or require you to install any heat shielding.

Q - What is the weight difference?
A - The stock system weighs about 23lbs. The M4 is around 12lbs

Now, back to address the points listed in common decision making at the top.

Sound - Obviously it has much more growl than the OEM pipe. It's deeper and louder, but not super annoying. You can easily run it through your neighborhood in the middle of the night, provided you keep the RPMs LOW. But if you hammer it, plan on lights coming on and people sending the po-po to your door.

Looks - The whole system looks great. The Aluminum can is nothing special, but it looks far better than the stock can.

Price - I haven't found a full system yet that is less than the $852 MSRP of the M4

Ease of installation - I don't know that there is much difference in the install of this exhaust over any other, but it was all pretty straight forward. Basically, if you have general metric tools (sockets, allen keys, wrenches), and understand "righty-tighty / lefty-loosey", you can install the thing.

Naturally, if your tool-chest is comprised of a crescent wrench, a hammer and two screwdrivers, you might want to have a dealer install this for you.

Performance - Here's where the rubber meets the road so to speak. I did not run the pipe without a custom power commander map, but the results I've been provided for those who ran it just plug-n-play (no remap) showed a stock peak HP of 104.2 and an M4 peak HP of 110.1. An increase of 5.9HP is pretty impressive for no remapping.

With the custom map, running pump gas, we ended up with 106.1. I had really hoped for higher, but talking to Matt Drucker of MD Racing, he was very pleased and impressed with the results. Thinking about it, the results from Matt's dyno really can't compare to the 103.9 which I started with originally since they were on 2 different dyno's about a year apart. In any event, the gain is NOTICEABLE.

Fit & Finish - The fit and finish to the M4 exhaust is perfect. It leaves nothing to be desired. They obviously had an RR for a good long while to do the R&D on, versus doing R&D based on someone else's exhaust or by side-by-side comparison of an OEM exhaust without the bike. The mounting point for the mid-pipe to the subframe is another added strong point that some others do not have. This keeps the system rock solid mounted through the abuse of a racing environment (so it'll SURELY stay put on the street).

At this time, I've been racing on this pipe for a couple of weekends. I have to say that I really like it. I did notice another decent power increase by using VP U4 fuel from MD Racing but even on pump gas, the M4 runs strong. Another neat design feature I'd like to point out is the INDIVIDUAL tube sections which M4 uses. I note this because I've seen 2 other riders so far have to replace ENTIRE exhaust systems because their can had an integrated "down-pipe" and in a crash, this folds up. With M4, you can replace any INDIVIDUAL section of pipe much cheaper than any other system.

Also, a note on noise. If you're looking for a wail, the M4 is not going to provide it. Don't get me wrong, it will scream at 15k, but it is not as loud as the Micron, Hindle or Erion exhausts.

So, where can you get yours?

M4 Of course!
Lake Country Powersports
Hi-Side Racing
MD Racing

Did you find this review helpful? Think it sucked? Tell us about it in the forum!

Copyright © 2005 Kufalk Media LLC - All rights reserved