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General Category => General Discussion => Topic started by: Simon_London on October 12, 2015, 05:01:04 AM

Title: Removing Baffles Le Mans I / II Silencers - anyone done it?
Post by: Simon_London on October 12, 2015, 05:01:04 AM

I would like a less restrictive exhaust silencer on my G5 Cafe racer. (36mm carbs, ported, fast cam and lightened flywheel, Keihan Le Mans I/II silencers).

I have a spare pair of Keihan stainless Le Mans I /II silencers. Keihan will remove the end cap, and take out the baffle and replace the end cap with a one that has a larger exit hole for £100. They will be unable to remove the proximal baffle which they estimate conributes 30% of the flow restiction.

I have large bore stainless down pipes (42mm) with a cossover and a 38mm stainless H Pipe.

Replacing with a Lafranconi sytem will be expensive and will rot in time (not sure how long they last), so a cheaper compromise would be removing the rear baffles of the Keihan silencers.

Any thoughts on performance and sound?

Cheers

Simon

Title: Re: Removing Baffles Le Mans I / II Silencers - anyone done it?
Post by: PeteS on October 12, 2015, 05:42:31 AM

Are these copies of the original 850 LeMans mufflers? If so back in the day we drilled 1/4" holes in a circular pattern  centered halfway between the exit hole and the outside edge. The stock exhaust is very restrictive.
This did help a bit but I don't think you want to completely remove the baffle. Any bike I did that to lost power. You need a certain amount of back pressure.
What made a significant difference is the Rennsport 2-1-2 exhaust. POS workmanship but great performance.

Pete

Title: Re: Removing Baffles Le Mans I / II Silencers - anyone done it?
Post by: Simon_London on October 12, 2015, 12:18:57 PM

Yes they are Le Mans replicas in stainless.

Think I will bite the bullet and buy some Lafranconis and sell the spare silencers.

Title: Re: Removing Baffles Le Mans I / II Silencers - anyone done it?
Post by: canuck750 on October 12, 2015, 01:06:32 PM

This is how the exhaust on the 77 Le Mans I bought last spring looks like. I take it the holes are not stock?

It sounds real nice though and I noticed the increased low end grunt that my V7 Sport is lacking.

(http://i249.photobucket.com/albums/gg217/canuck750/1977%20Moto%20Guzzi%20le%20Mans/P6290097_zpsngxoe3vp.jpg) (http://s249.photobucket.com/user/canuck750/media/1977%20Moto%20Guzzi%20le%20Mans/P6290097_zpsngxoe3vp.jpg.html)

Title: Re: Removing Baffles Le Mans I / II Silencers - anyone done it?
Post by: Simon_London on October 12, 2015, 02:11:34 PM

Yes non standard holes! Anyon else running his mod?

Title: Re: Removing Baffles Le Mans I / II Silencers - anyone done it?
Post by: Stevex on October 12, 2015, 04:39:27 PM

I bought some original Lafranconis which were rotted and dented at the back end. I cut out the damage and had the backs rewelded on. The process removed the main baffle. Sounded nice at idle but after running them for a couple of weeks I refitted my set of Keihans. The modded 'conis sounded like a Lancaster on its take off run. I may try them again next spring.

(http://i845.photobucket.com/albums/ab18/Stevex998/IMG_0975_zpsnxyoykzz.jpg) (http://s845.photobucket.com/user/Stevex998/media/IMG_0975_zpsnxyoykzz.jpg.html)

(http://i845.photobucket.com/albums/ab18/Stevex998/IMG_1002_zpsc2alkgqk.jpg) (http://s845.photobucket.com/user/Stevex998/media/IMG_1002_zpsc2alkgqk.jpg.html)