Welcome back - please login below. New here? It's quick & easy to register!

Register Log in
  • This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

Akrapovic S-H6R11-AFT

STOC77

2016
CB650F ABS
Messages
14
Likes
5
Thread starter #1
Hello All,
Thinking of getting one one these,
Would I come across any issues at the MOT?
 

jerzy_bondov

2017
CBR650F ABS
Messages
49
Likes
28
Location
London
#2
Conventional wisdom has it that no, you wouldn't. I've got one on my bike but it's not going to need an MOT for another year yet. One thing that you might want to consider though is a PCFC or PCV - I had a very noticeable flat spot after fitting mine before getting the power commander. Since adding a PCFC and map though, I'd say it's the single best mod I've done to the bike - feels like it's completely transformed :)
 

STOC77

2016
CB650F ABS
Messages
14
Likes
5
Thread starter #3
I think the only issue I may face is one of noise.

My first bike is due the MOT in August so I was concerned that it wouldn’t meet emissions test as it doesn’t have a cat converter on this exhaust but after a bit of research, bikes are not tested for emissions in the UK just for noise.

I think the baffle can be removed and replaced easily on these exhausts with just the removal of a small grub screw.

New to this so what is a PCFC / PCV??
 

jerzy_bondov

2017
CBR650F ABS
Messages
49
Likes
28
Location
London
#4
You won't want to be removing the baffle - it's loud enough with it in (105db at 5500rpm). The only question is whether you need to add an EXTRA baffle to get it through an MOT (which I did to get it to pass noise regs at Bedford). Think the H6R11 is louder than the 12 and 13 models which are more explicitly for normal road use (and euro3/4 certified). Having said that, I'd be surprised if it failed an MOT on noise - they're not as stringent as track day regs.

Re your question on power commanders - basically once you put a free flowing exhaust on the bike and remove the cat, you drop the back pressure the more restrictive exhaust gives to the engine. That back pressure helps with torque at low-medium revs. Without it, the bike runs lean, and you get a flat spot around the rev range you use the most in normal riding (4-6k).

So a Power Commander is a little electric box you plug in that adjusts your fuelling to take account of this. PCFC and PCV are two different models - PCFC cheaper and all you need if you don't also want to be fitting quick shifters and other gumpf.
You do not have permission to view link Log in or register now.

It is a significant extra cost (£200+), and Akrapovic say you don't need it, but I've ridden my bike with and without, and I'd say that you do. Factor it in to the cost of the exhaust system. It'll make your bike more rideable more of the time, as well as also taking advantage of the extra power at the top end.

IMG_9189.jpg
 

Johnboy82

2017
CBR650F
Messages
38
Likes
43
Location
Bedfordshire
#6
Interesting read ,
I have that exhaust on my bike (2016 model ) and I’m really interested to see if I personally would notice the difference.
Now I’m very much a bigger rider only riding for 3 years , and this is the only bike I have ever owned , I personally didn’t notice any flat spots when I had it fitted which was after 12months of riding, - but could that be because of my “amateur” riding style ?? Perhaps ??
I did read a lot about the pro’s of a PCV but decided I personally could’nt justify the cost , perhaps the PCFC is the way forward??
Either way , the exhaust sounds the dogs ———— ( fill gaps yourselves)
 

jerzy_bondov

2017
CBR650F ABS
Messages
49
Likes
28
Location
London
#7
Interesting read ,
I have that exhaust on my bike (2016 model ) and I’m really interested to see if I personally would notice the difference.
Now I’m very much a bigger rider only riding for 3 years , and this is the only bike I have ever owned , I personally didn’t notice any flat spots when I had it fitted which was after 12months of riding, - but could that be because of my “amateur” riding style ?? Perhaps ??
I'm guessing here - but the fuelling on the facelift 17+ model for euro4 may well be different on my 2017 bike than it is on your 2016 bike, producing a bigger flat spot once you swap out the exhaust. Certainly one of the things they said contributed to the extra 4hp at the time was 'exhaust changes'.

So it's not unreasonable to assume that your experience to putting this exhaust on would have been different to mine - I'm pretty sure 9/10 amateurs (in which I include myself!) would have spotted the flat spot that I did! :D
 

Johnboy82

2017
CBR650F
Messages
38
Likes
43
Location
Bedfordshire
#9
I'm guessing here - but the fuelling on the facelift 17+ model for euro4 may well be different on my 2017 bike than it is on your 2016 bike, producing a bigger flat spot once you swap out the exhaust. Certainly one of the things they said contributed to the extra 4hp at the time was 'exhaust changes'.

So it's not unreasonable to assume that your experience to putting this exhaust on would have been different to mine - I'm pretty sure 9/10 amateurs (in which I include myself!) would have spotted the flat spot that I did! :D
That sounds like good reasoning, however it appears I’m a idiot and don’t know my own bike - it’s a 2017 model CBR650f - ( UK 67 plate ) 🤦‍♂️
 

Johnboy82

2017
CBR650F
Messages
38
Likes
43
Location
Bedfordshire
#10
You won't want to be removing the baffle - it's loud enough with it in (105db at 5500rpm). The only question is whether you need to add an EXTRA baffle to get it through an MOT (which I did to get it to pass noise regs at Bedford). Think the H6R11 is louder than the 12 and 13 models which are more explicitly for normal road use (and euro3/4 certified). Having said that, I'd be surprised if it failed an MOT on noise - they're not as stringent as track day regs.

Re your question on power commanders - basically once you put a free flowing exhaust on the bike and remove the cat, you drop the back pressure the more restrictive exhaust gives to the engine. That back pressure helps with torque at low-medium revs. Without it, the bike runs lean, and you get a flat spot around the rev range you use the most in normal riding (4-6k).

So a Power Commander is a little electric box you plug in that adjusts your fuelling to take account of this. PCFC and PCV are two different models - PCFC cheaper and all you need if you don't also want to be fitting quick shifters and other gumpf.
You do not have permission to view link Log in or register now.

It is a significant extra cost (£200+), and Akrapovic say you don't need it, but I've ridden my bike with and without, and I'd say that you do. Factor it in to the cost of the exhaust system. It'll make your bike more rideable more of the time, as well as also taking advantage of the extra power at the top end.

View attachment 2794
if I go for the cheaper PCFC option , will that take care of all the fuel & air mixture that I need ? I have no intention of adding a quick shifter so is it fair to say that I'm better of going with a PCFC over the PCV ? - after trolling through loads of you tube and web pages it seems the PCV is the more popular choice ? - the more I read the more confused I get !!!
 

jerzy_bondov

2017
CBR650F ABS
Messages
49
Likes
28
Location
London
#11
if I go for the cheaper PCFC option , will that take care of all the fuel & air mixture that I need ? I have no intention of adding a quick shifter so is it fair to say that I'm better of going with a PCFC over the PCV ? - after trolling through loads of you tube and web pages it seems the PCV is the more popular choice ? - the more I read the more confused I get !!!
Yes, if you don’t want autotune, to add a quick shifter later or whatever the other functions are the PCV has then a PCFC is just fine. It’s what I went for :)
For managing the fuelling via a Power Commander map available on the website or getting a dyno to tune it for you, it’s just as good as the PCV.
 

STOC77

2016
CB650F ABS
Messages
14
Likes
5
Thread starter #12
UPDATE -

Its arrived,,,,, purchased second hand at a reasonable price from a chap who sold his cb650f and stuck the original exhaust back on and sold the Ak separately to make a few more quid,,, Good idea,,, he had it for 9 months and was a fair weather rider so very low miles with it on the bike which was very clear as there was hardly any dirt residue that came off the pipes when cleaned in a tub of water.

No dents dings or otherwise,,, Its in excellent condition!!

the pipes were slightly grubby as was the connector but i've sorted all of that by spending about 2-3 hours with some fairy liquid, window cleaner and then some very good American metal polish (autosol) so everything is nice and shiny. Titanium is an easy metal to work with.

I found the grub screw that allows the removal of the baffle but i was gutted to find that Akrapovic place a tiny the spot weld so that the screw cannot be easily removed. Im sure that it will sound great with the baffle but i want the option to at least hear it without.
Its a very small opening to get access to the grub screw with no real room to get any sort of tool, nothing i own anyway, in to be able to tackle the weld.

Im thinking that a Dremel may well be the answer with a bit that will allow me to carefully file detach the weld from the screw.

Anyway, Just a quick update, i will put a few more posts on and maybe a vid or two of the installation and of the difference between sounds (Stock, Baffled Ak, Non baffled Ak)
 
Last edited:

STOC77

2016
CB650F ABS
Messages
14
Likes
5
Thread starter #16
Im going to install and see how it is before I make a decision on PCFC.

Need to advise the insurers about the Akra,, it’s not on the “standard mod” list.

Probably going to cost an arm and a leg. 👎🏻
 

Brammers

2014
CBR650F ABS
Mod
Messages
2,313
Likes
926
Location
Hampshire, England
#17
You'd be surprised.

If it doesn't "affect performance" (which without the PCV it won't much) you can declare it as cosmetic and be fine. So long as the exhaust value is <£1500

EDIT: Most of the performance you'll notice will be in weight savings, rather than BHP.

J
 

jerzy_bondov

2017
CBR650F ABS
Messages
49
Likes
28
Location
London
#19
My experience was that the bike had a little more at the top end with just the straight exhaust swap (I did two track days on the same track a week apart, with the two different configs) , at the expense of mid range torque. PCFC subsequently fixed the mid range torque issue and probably liberated an extra hp or two at the top too.
 

cma90

2014
CBR650F
Messages
1
Likes
0
#20
been using it nearly a year, really love it, its sound quite slow during idle but when you open up throttle, especially after 7k RPM, you will get a very great sound