guzziriders.org - moto guzzi forum Homepage
Forum Home Forum Home > Technical > Big Block Tonti
  New Posts New Posts RSS Feed - Exhaust question
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Exhaust question

 Post Reply Post Reply
Author
Message
cugsy View Drop Down
Senior Member
Senior Member
Avatar

Joined: 30 Nov 2016
Location: norfolk
Status: Offline
Points: 454
Post Options Post Options   Thanks (0) Thanks(0)   Quote cugsy Quote  Post ReplyReply Direct Link To This Post Topic: Exhaust question
    Posted: 26 Dec 2017 at 17:17
Is the exhaust system on the cali sided? By that I mean are the down pipes left and right specific? I'm tightening bits up and having a looksee for what I might have missed and the exhaust seems wonky.  IF I remember rightly, one downpipe has a tighter angle than the other and maybe a tad shorter. Lining up from the back silencers mounting bolt the collector is tighter on one side than 'tother.  I think I'll take it all off again but if someone has any ideas I'd appreciate it.  Its a proper lafranconi kit.  Like that helps.   John
Honda nc750x ...hmm - a superdream for the 21st century? ZZZZZZ But the goozi is back running..yesserii jim bob. Fun time
Back to Top
Brian UK View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 13 May 2014
Location: Surrey
Status: Online
Points: 8394
Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 26 Dec 2017 at 21:46
Yes, as one pot is further forward than the other.
Brian.

Better 5 minutes late in this world than years early in the next.
Back to Top
cugsy View Drop Down
Senior Member
Senior Member
Avatar

Joined: 30 Nov 2016
Location: norfolk
Status: Offline
Points: 454
Post Options Post Options   Thanks (0) Thanks(0)   Quote cugsy Quote  Post ReplyReply Direct Link To This Post Posted: 27 Dec 2017 at 08:46
That i didn't know..
Honda nc750x ...hmm - a superdream for the 21st century? ZZZZZZ But the goozi is back running..yesserii jim bob. Fun time
Back to Top
Brian UK View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 13 May 2014
Location: Surrey
Status: Online
Points: 8394
Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 27 Dec 2017 at 10:03
Lay the two pipes on top of each other with the down bit together and you will see one is longer than the other on the top end where it fits into the head.
Brian.

Better 5 minutes late in this world than years early in the next.
Back to Top
Dukedesmo View Drop Down
Senior Member
Senior Member
Avatar

Joined: 17 Apr 2015
Location: Leics
Status: Offline
Points: 599
Post Options Post Options   Thanks (0) Thanks(0)   Quote Dukedesmo Quote  Post ReplyReply Direct Link To This Post Posted: 27 Dec 2017 at 11:18
Originally posted by cugsy cugsy wrote:

  Its a proper lafranconi kit.

As said above, yes the left is different from the right as the cylinders sit one further forward than the other, due to the conrods being side-by-side on the crank meaning one piston sits further forward than the other - if you have long legs and ride a Lemans and you'll find one knee hits the cylinder more than the other (tip; don't ride in shorts!!).

Also with regards to Lafranconi, I have the full system on my LM2 including the larger bore downpipes and the left side pipe is slightly 'under-bent'. By that I mean it doesn't quite do the full 180 degree turn from cylinder head to outlet. It's not much out but once everything is bolted up the pipe is under too much tension and the flange at the head has cracked/broken off 3 times now. First time I thought it was just down to the 'minimalist' welding so I welded both sides back on without worrying about saving a few pence on welding rod, but over time it broke the left side again due to the tension/vibration/heat moving it about.

At this point I hadn't realised exactly what was causing it and wanted to get back on the road quickly so I welded it back again, this time using even more welding rod so that it was properly strong - as the joint was now strong it proceeded to pull the end off the pipe instead of cracking the weld.

Having realised why this was happening but not wanting to try bending the pipework, I got some new flanges/rings laser cut in a thicker material to make up the shortfall and welded it on at a slight angle to compensate for the lack of bend, meaning it sits under less tension and so far (this year anyway) it's been OK but it really should have been bent around a little more by Lafranconi (I might try this if it breaks again). 

I also welded on a couple of spring loops onto the crossover (between the cylinders) joint and fitted an exhaust spring to hold it together as it tends to open up when hot, especially when the flange broke off and the joint separated, making for quite an aural experience when limping home.  

Sorry for the ramble but just pointing out that if the quality is like mine were then they may not be an ideal fit from new, even when fitted the right way round. 
Le Mans 2
Ducati 916

Ducati M900
Back to Top
Mike H View Drop Down
Senior Member
Senior Member
Avatar

Joined: 21 May 2014
Location: East Anglia
Status: Offline
Points: 5443
Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 27 Dec 2017 at 12:12
Originally posted by Brian UK Brian UK wrote:

Yes, as one pot is further forward than the other.


Originally posted by cugsy cugsy wrote:

That i didn't know..


O-ohh yes .. Big smile



"Chicken nuggets don't dance on a Tuesday."
Back to Top
cugsy View Drop Down
Senior Member
Senior Member
Avatar

Joined: 30 Nov 2016
Location: norfolk
Status: Offline
Points: 454
Post Options Post Options   Thanks (0) Thanks(0)   Quote cugsy Quote  Post ReplyReply Direct Link To This Post Posted: 27 Dec 2017 at 13:28
Grazie
Honda nc750x ...hmm - a superdream for the 21st century? ZZZZZZ But the goozi is back running..yesserii jim bob. Fun time
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.00
Copyright ©2001-2018 Web Wiz Ltd.

This page was generated in 0.125 seconds.