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Exhaust conundrum

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Grarea
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Exhaust conundrum

Post by Grarea on Mon 15 Aug 2016, 10:57 am

Well, I have a few bits to sort on my CB.
It pops and bangs a bit and seems a bit 'vibratey'.
The point being that I reckon I can get more out of it still.

I am debating the exhaust with myself.
From a previous reply, I will lose some power if i get rid of the loud exhaust.
That would be a shame.
However, I do make a bit of a racket.
I quite like it, it is fun. 
But when I am in the under cover car park in sainsburys and going through small towns and villages here in cornwall, 
it is a bit much.

So, I am wondering how much power and torque I will lose. (Maybe I can claw it back elsewhere?)
Is there a way of finding out what exhaust I have?
It doesn't appear to have any markings other than the British standards number.



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Beresford
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Re: Exhaust conundrum

Post by Beresford on Mon 15 Aug 2016, 12:27 pm

If you can get the baffle out, a simple/cheap first step would be to block the 6 holes with nuts/bolt/washers and see if that quietened things a bit.
A great alternative which I have used in the past is to adapt a Fazer 600 can. I used one for a while and it produces great power compared with the standard one, and also has a very pleasant (but not too loud ) growl.
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jerryfudd
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Re: Exhaust conundrum

Post by jerryfudd on Tue 16 Aug 2016, 12:48 pm

Just to add my 2p, mine *feels* to run better and be quicker when I leave the baffle in on my Beowulf.

Dan
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ashcroc
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Re: Exhaust conundrum

Post by ashcroc on Tue 16 Aug 2016, 3:48 pm

I think I may have found the solution to your problems. Twisted Evil
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Grarea
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Re: Exhaust conundrum

Post by Grarea on Tue 16 Aug 2016, 5:50 pm

Very Happy
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stormbringer
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Re: Exhaust conundrum

Post by stormbringer on Tue 16 Aug 2016, 7:27 pm

@jerryfudd wrote:Just to add my 2p, mine *feels* to run better and be quicker when I leave the baffle in on my Beowulf.

Dan


Despite references to 'previous reply', I'd be tempted to agree with you. I run a Fuel can (plain medium, no race-funny-business here) and have just had it replaced temporarily (10 days, doing 3000 miles through enemy-territory where stealth was of the essence). I have the baffle in the Fuel, but still the OE can feels better in some way. A more linear power delivery - and a LOT less sound.
But oh boy does it weigh a ton! Also, the OE looks very discrete compared to the Fuel:


Are you sure you are fuelling the engine correctly? Carburettor-engines are sensitive to the varying back-pressure caused by different cans. Your setting may be incompatible with the OE can...
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liverpool_f_
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Re: Exhaust conundrum

Post by liverpool_f_ on Tue 16 Aug 2016, 9:03 pm

Back to the original post, I think you would loose almost no power with the OE can back on, especially if the bike hasn't been rejetted for your aftermarket one. Maybe someone on here looking for an aftermarket can would do you a swap for their oe if it suited you both.
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davebike500
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Re: Exhaust conundrum

Post by davebike500 on Thu 18 Aug 2016, 11:44 am

If it not be re jetted fro the pipe you will probably gain power most race pipes ( most too loud for track use !) despite what lots will say will need re jetting to gain power or even maintain what a standard unit makes sound faster just more noise
So unless re jetted you will gain power by fitting a standard or road legal one
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Grarea
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Re: Exhaust conundrum

Post by Grarea on Sun 21 Aug 2016, 10:44 am

@Beresford wrote:If you can get the baffle out, a simple/cheap first step would be to block the 6 holes with nuts/bolt/washers and see if that quietened things a bit.


Thanks for this. 
That took the edge off it for sure.
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Grarea
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Re: Exhaust conundrum

Post by Grarea on Sun 21 Aug 2016, 10:55 am

@liverpool_f_ wrote:Back to the original post, I think you would loose almost no power with the OE can back on, especially if the bike hasn't been rejetted for your aftermarket one. Maybe someone on here looking for an aftermarket can would do you a swap for their oe if it suited you both.

Hmmmm, I thought the answer to my question would be a simple one.

"oh, yes, that is a XXX can"
"They are reputed to give XXbhp over the OE silence"

So, to have some idea of the difference I might get, I would need to know the type of exhaust I have
and also whether it was rejetted.

When you say rejetted, that is changing the jets in the carbs isn't it?

So, to know for sure, I guess i need to get a stock can, see what happens and then maybe some new standard jets  and fiddle with it and see where I am at.
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trevor machine
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Re: Exhaust conundrum

Post by trevor machine on Sun 21 Aug 2016, 11:14 am

As mentioned elsewhere, I run two cb500s - both with the same kind of Fuel end can on (both with no baffles). One bike is drum, the other disc. As a consequence of the same somewhat freer exhaust gas flow they actually both run slightly differently. The older one is fluffier at slow speeds, the more recent one seems to have a very slight flat spot at 65-70mph. The former pops and bangs on the overrun quite a lot, the latter hardly ever does. The plugs on both look the same - very light brown, i.e. healthy, colour. And, afaik, they're both jetted standard.

So one moral of the story is that each bike is potentially, albeit subtly, different. Secondly, any loss in power as a result of a failure to re-jet and take account of a more straight through system is afaict pretty negligible. But then I don't ride to the bike's limits very often, where such things would presumably be easier to tell. For me the main reasons to fit a non-standard exhaust were firstly because I very much like the sound of the bike's engine when it's actually audible and secondly because the OEM exhaust is very heavy and it's good to be able to have a slightly lighter bike to wheel around.
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stormbringer
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Re: Exhaust conundrum

Post by stormbringer on Sun 21 Aug 2016, 12:48 pm

@trevor machine wrote:So one moral of the story is that each bike is potentially, albeit subtly, different. Secondly, any loss in power as a result of a failure to re-jet and take account of a more straight through system is afaict pretty negligible. But then I don't ride to the bike's limits very often, where such things would presumably be easier to tell. For me the main reasons to fit a non-standard exhaust were firstly because I very much like the sound of the bike's engine when it's actually audible and secondly because the OEM exhaust is very heavy and it's good to be able to have a slightly lighter bike to wheel around.
Nice read.

I haven't had my bike rejetted when switching to the Fuel can - and I ride with the baffle in. Little if any change. Like you, it's the sound that is my main reason - and the weight is a nice bonus.

Bikes being different: Hehe, could that be 'personality'?
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Beresford
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Re: Exhaust conundrum

Post by Beresford on Sun 21 Aug 2016, 12:58 pm

@stormbringer wrote:it's the sound that is my main reason - and the weight is a nice bonus.


I must admit that my reason for changing was that I wanted a nice shiny stainless steel non-rusty can.
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eternally_troubled
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Re: Exhaust conundrum

Post by eternally_troubled on Wed 24 Aug 2016, 10:38 am

@Beresford wrote:
@stormbringer wrote:it's the sound that is my main reason - and the weight is a nice bonus.



I must admit that my reason for changing was that I wanted a nice shiny stainless steel non-rusty can.

Both my down-pipes and my can had bits that rotted off - I probably had the loudest CB500 with the standard exhaust out there. It's actually quieter with the stainless down pipes and fuel exhaust!

Is it possible that your 'loud' can just needs re-packing? There is often glass-wool type lagging material around the outside-of-the-inside of the can which can degrade over time which won't help the noise.

Unfortunately it isn't often possible to re-pack most cans without drilling out the rivets, pulling it all apart and riveting them up again.
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goulton
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Re: Exhaust conundrum

Post by goulton on Wed 31 Aug 2016, 10:04 pm

Re-jetting clearly depends on what system is fitted as replacement.  Eight years ago when the OEM silencer had just about rotted away I fitted a Predator stainless system.  Predator state in their literature that re-jetting is not necessary but I nevertheless had the bike on a rolling road just to be certain and Predator were correct - it did not need and changes to the carburettors.

The only small disadvantage with the system is some popping on the over-run but on the plus side it has been a case of fit and forget and everything is still as shiny as the day it was fitted.  I don't count the blueing on the downpipes!
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trevor machine
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Re: Exhaust conundrum

Post by trevor machine on Thu 01 Sep 2016, 9:12 am

@stormbringer wrote:Bikes being different: Hehe, could that be 'personality'?

Yeah - but seriously, it does make me wonder what it actually is? Some of it will probably be wear and tear - one bike's more knackered than the other. That can't be the whole story though.
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Jameshambleton
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Re: Exhaust conundrum

Post by Jameshambleton on Thu 01 Sep 2016, 11:15 am

My restricted engine only did 55mpg at best ever since I got it. This new engine I have has been doing 67mpg with the exact same style riding only it has a +2 rear sprocket and it doesn't have the restrictor washers. This one pops and bangs a little more but that was one of the main reasons why I got the cb500.
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liverpool_f_
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Re: Exhaust conundrum

Post by liverpool_f_ on Thu 08 Sep 2016, 9:36 am

If you are interested, i have just removed the stock Honda downpipes and can from my bike and i will sell for a very reasonable price to a forum member before sticking it on ebay. PM me for details if it is something you would be interested in.

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Re: Exhaust conundrum

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