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lemans mkv balance pipe

Printed From: guzziriders.org - moto guzzi forum
Category: Technical
Forum Name: Big Block Tonti
Forum Description: Spada, Le Mans and Cali
URL: http://www.guzziriders.org/forum_posts.asp?TID=9726
Printed Date: 28 Mar 2024 at 10:09
Software Version: Web Wiz Forums 12.03 - http://www.webwizforums.com


Topic: lemans mkv balance pipe
Posted By: chrisshrops
Subject: lemans mkv balance pipe
Date Posted: 15 Feb 2019 at 17:06
Hi Tonti chums 
 I'm almost ready to have an exhaust system made for my mk v build
my battery now lives were the balance pipes were ,what's the opinion on having a front balance pipe only ,or non at all ? .
any one used osmc ?
 regards Chris 




Replies:
Posted By: sardineone
Date Posted: 16 Feb 2019 at 15:20
I had a friend with a 1100 Bassa that tried just a H-Pipe crossover pipe in place of the boom box under the transmission.  It made more noise & less power, but was much easier to access the transmission oil drain plug.  The unspoken rule for modern exhaust design is more system volume = more power at a given sound level.  So adjustments to sound level may compensate for loss of original volume.

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George

One owner 86' Lemans 1000 (member of the family) / BMW R1200ST (current work horse)

You are what you have ridden!


Posted By: Brian UK
Date Posted: 16 Feb 2019 at 16:42
Many here have used OSMC, he does know what he's doing.

I would keep a balance pipe rather than not have one.


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Brian.

Better 5 minutes late in this world than years early in the next.


Posted By: chrisshrops
Date Posted: 16 Feb 2019 at 16:55
Hi Brian 
my battery box is right in the way now hence why I was thinking of the balance pipe in front of the engine .


Posted By: Brian UK
Date Posted: 16 Feb 2019 at 17:33
Yes, but you were considering doing away with it altogether. a front one is better than none.



-------------
Brian.

Better 5 minutes late in this world than years early in the next.


Posted By: chrisshrops
Date Posted: 16 Feb 2019 at 19:52
thanks Brian ,sounds a plan 


Posted By: dan_s
Date Posted: 17 Feb 2019 at 06:58
One cross over pipe should do the job of aiding the evacuation of gasses. AFAIK it adds eficiency.
If you opt for the cross pipe in the front, make sure it doesn't block access to the alternator cover screws.


Posted By: Mike H
Date Posted: 17 Feb 2019 at 16:37
I know I've mentioned this before, but crosspipes are used to create a deliberate break point in the downpipe and hence tune its length, when the gas pressure wave encounters the 'break' a negative pressure wave is created that goes back to the exhaust port, this literally sucks more exhaust gas out at one particular rpm; two crosspipes (typically, below the gearbox and in front of the sump) give you TWO points in the upper rpm range where you will get a power boost. This is why taking a crosspipe out often results in a power loss in the upper rpm range, and/or bike can't do what hitherto was its top speed any more, etc.




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"Chicken nuggets don't dance on a Tuesday."


Posted By: chrisshrops
Date Posted: 17 Feb 2019 at 16:57
Prefect Thanks Mike ,very helpful buddy 



Posted By: dan_s
Date Posted: 17 Feb 2019 at 17:20
I wrote to Kiehan systems a few years ago about the front cross over pipe, here's what they answered :
".. We rely mostly on customer feedback regarding our exhausts which would suggest the elimination of the front cross over pipe has no effect on performance.

Regards
Beryl Chodynicki
Keihan Systems Ltd"

So my guess is that we don't really know until someone actually tests it


Posted By: David_M
Date Posted: 20 Feb 2019 at 02:25
Some years ago I fitted a big block Guzzi engine to my Pembleton three wheeler. It should have had a balance pipe between the exhausts but I didn't fit it. Seemed fine until one day looking for some tinkering to do I decided to fit said balance pipe. Huge trandsformation! Much more low down torque and more progressive power delivery.
I suspect that if it wasn't neccessary Guzzi wouldn't have fitted it.


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David_M
LM V, V50 iii


Posted By: Mike H
Date Posted: 22 Feb 2019 at 00:51
Originally posted by dan_s dan_s wrote:

I wrote to Kiehan systems a few years ago about the front cross over pipe, here's what they answered :
".. We rely mostly on customer feedback regarding our exhausts which would suggest the elimination of the front cross over pipe has no effect on performance.


Bit strange, since I had one of their systems to put on my BMW R80, as far as I could tell an exact copy of BMW's, with 2 balance pipes, identical looking silencers etc., just made in stainless. As above, you would think BMW put 2 balance pipes on for a reason. And Keihan didn't argue.




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"Chicken nuggets don't dance on a Tuesday."



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