Aftermarket headers and cans for an XT660r, did I make a mistake?

[kjetil4455]

Dear friends

This isn't super tenere related, but I hope to get some valuable advice from you.

I have just paid 900 bucks for a set of massMoto 2-in-1 exhaust system for my XT660r 2013 mod. The doubt, however: I keep reading very mixed reviews from people about the 2in1 systems for this bike, as the bendy headers in some cases have severely attenuated performance of the bike, presumably due to pressure buildup in the exhaust pipes due to rough bends. This bike has a pretty smooth (but heavy, and double!) header and exhaust pipe system. Replacing it makes my bike drop like 20 lbs / 10kg. But I am afraid of messing up its performance. This setup that I've bought has a pretty rough 90-degree bend as it passes and ascends the swingarm laterally. Will this be enough to cause performance decline, realistically?

I ordered it just today. Was hoping to get some advice on whether or not I should cancel the purchase, or keep it -- If i cancel it, I'll stick with a set of typical Arrow exhausts and the OEM headers

MassMoto Exhaust Mid System 2in1 Titan & Carbon Silencer Yamaha XT660R 2004-2016

Exclusive Oval Titanium & Carbon cap design, handmade. Semi mid-system 2in1 setting. High-performance power and acceleration gain. Pure lightweight approximately 1.25 kg. Road legal with removable DB killer. Handmade in Italy with a full 2-year warranty. Mounting hardware included for a perfect...

www.euromotards.com

Also attached a pic of the stock headers and pipes.

Your input much appreciated

 

[cyclemike4]

Dear friends

This isn't super tenere related, but I hope to get some valuable advice from you.

I have just paid 900 bucks for a set of massMoto 2-in-1 exhaust system for my XT660r 2013 mod. The doubt, however: I keep reading very mixed reviews from people about the 2in1 systems for this bike, as the bendy headers in some cases have severely attenuated performance of the bike, presumably due to pressure buildup in the exhaust pipes due to rough bends. This bike has a pretty smooth (but heavy, and double!) header and exhaust pipe system. Replacing it makes my bike drop like 20 lbs / 10kg. But I am afraid of messing up its performance. This setup that I've bought has a pretty rough 90-degree bend as it passes and ascends the swingarm laterally. Will this be enough to cause performance decline, realistically?

I ordered it just today. Was hoping to get some advice on whether or not I should cancel the purchase, or keep it -- If i cancel it, I'll stick with a set of typical Arrow exhausts and the OEM headers

MassMoto Exhaust Mid System 2in1 Titan & Carbon Silencer Yamaha XT660R 2004-2016

Exclusive Oval Titanium & Carbon cap design, handmade. Semi mid-system 2in1 setting. High-performance power and acceleration gain. Pure lightweight approximately 1.25 kg. Road legal with removable DB killer. Handmade in Italy with a full 2-year warranty. Mounting hardware included for a perfect...

www.euromotards.com

Also attached a pic of the stock headers and pipes.

Your input much appreciated

I could not tell you the first thing about putting pipes on bikes and what it may or may not do for them but that really looks like a nice pipe. It does have that double bend under the swing arm. I don't think it would limit exhaust flow out but the sound pulses may hammer back up the pipe against the pressure waves coming out more than a straight pipe. Don't listen to me though. I am not an expert by any means. All I know is it looks good!

 

[fac191]

Check out the DNA Air Filters for the 660r. The one that opens up the airbox makes a big difference along with the air filter.

 

[kjetil4455]

Check out the DNA Air Filters for the 660r. The one that opens up the airbox makes a big difference along with the air filter.

Already bought them mate; thank you for your help. Either way, if the exhaust has backed up pressure then it won't help much (?)

 

[fac191]

Already bought them mate; thank you for your help. Either way, if the exhaust has backed up pressure then it won't help much (?)

Correct. But just doing the exhaust doesnt achieve much on that engine. My 660Z was gutless as standard. Junked the exhaust and put the DNA kit on and it was a different bike. Will run lean though so will need the fueling done.

 

[kjetil4455]

Correct. But just doing the exhaust doesnt achieve much on that engine. My 660Z was gutless as standard. Junked the exhaust and put the DNA kit on and it was a different bike. Will run lean though so will need the fueling done.

That's the plan indeed. Thanks a lot!

 

[fac191]

That's the plan indeed. Thanks a lot!

There used to be a guy on the XT660 forum who made a little device to cheat the mixture dont know if he is still on there or not.

 

[kjetil4455]

There used to be a guy on the XT660 forum who made a little device to cheat the mixture dont know if he is still on there or not.

Kev's mod, yeah. Already bought one. Waiting for it to arrive! There's also an O2 mod to eliminate the cat, but it must be used with a power commander. I'm not spending 500 bucks on a powercommander to get 5more hp out of my XT660 when I have a superten...

 

[scott123007]

The straighter the intake the better. You can twist your exhaust any way you want and it doesn't matter. Just ask John Britten.

 

[kjetil4455]

The straighter the intake the better. You can twist your exhaust any way you want and it doesn't matter. Just ask John Britten.

Thanks for your comment. Interesting. May I ask why that is? -- I was under the impression that greater bends (poor aerodynamics) would increase the susceptibility for raised pressure in the pipe and thus backup pressure from the engine. I've seen several reviews from peers that bought 2-in-1 systems for their XT660 that caused significant decline in power, despite the producer claiming that their product should raise power output

 

[scott123007]

Scavenging exhaust can be a rather complicated process, but suffice it to say, the most important aspects in exhaust pipe design, are getting the pipes diameter right, lengths all equal, and total length correct, for a multi cylinder engine. The bends are not that important, except for fitament issues.

 

[kjetil4455]

Scavenging exhaust can be a rather complicated process, but suffice it to say, the most important aspects in exhaust pipe design, are getting the pipes diameter right, lengths all equal, and total length correct, for a multi cylinder engine. The bends are not that important, except for fitament issues.

Thanks Scott!
Honestly, I chickened out after reading so many poor reviews by others; cancelled the purchase yeterday. Will buy a standard double arrow system

 

[cyclemike4]

Not sure if the XT 660 and the raptor 660 motors have anything in common but my buddies boy had a 660 raptor and it would run! In eastern KY and in Tennessee we have some hills that are probably a half mile long to get to the top. He would run that quad up those hills in 3rd and 4th gear with lots of throttle left. He would have to dab the brakes at the top to slow down enough to not get air. I don't think that motor ever quit pulling. Of course apples and oranges I suppose.

 

[kjetil4455]

Not sure if the XT 660 and the raptor 660 motors have anything in common but my buddies boy had a 660 raptor and it would run! In eastern KY and in Tennessee we have some hills that are probably a half mile long to get to the top. He would run that quad up those hills in 3rd and 4th gear with lots of throttle left. He would have to dab the brakes at the top to slow down enough to not get air. I don't think that motor ever quit pulling. Of course apples and oranges I suppose.

Some people are actually modding their XT660 by replacing its engine with a raptor 700, makes it a total beast

 

[fac191]

On the 660Z (2010 ) the cat was part of the end can i believe. What i would be mindfull of is putting a twin pipe on as it may well drop the tourque. I had an MTC Can on mine. Would pull top gear from 2000 rpm. Stock no chance.

 

[kjetil4455]

On the 660Z (2010 ) the cat was part of the end can i believe. What i would be mindfull of is putting a twin pipe on as it may well drop the tourque. I had an MTC Can on mine. Would pull top gear from 2000 rpm. Stock no chance.

The XT660r comes with twin pipes and headers from the factory. The Z is single-can? Thought it was double can as well.

 

[fac191]

The XT660r comes with twin pipes and headers from the factory. The Z is single-can? Thought it was double can as well.

Its fake. The main pipe goes into a flat square box and it exits with 2.

 

[fac191]

Its fake. The main pipe goes into a flat square box and it exits with 2.

This is the cat removal.

 

[kjetil4455]

Its fake. The main pipe goes into a flat square box and it exits with 2.

Interesting. Maybe I should change out the headers as well then!

 

[fac191]

Interesting. Maybe I should change out the headers as well then!

Off The Road do hop up bits for the 660/Raptor engine.