Conti silencers

michipons

michipons

Hero member
Location
Palma de Mallorca
Hi!

First I will share my experience with my new Conti silencers... I bought a pair of silencers in ducativintagestore.com, redirected from the Conti original website, claiming they are the "original" Conti. Price was quite ok, so I decided to buy them. After making a few trials to check the fit, (engine always off) chrome started to peel off, in the area of the holding clamp and the union with the downpipe. So I wrote them, and very kindly they exchanged them for a new pair. This new pair looks initially ok. Today when making what I hope is the last assembly before the first start up, when I start tightening the nice chromed "conti" clamps, I start to hear "crick crick", and then half of the chrome of this shiny clamps went off. But ok, no big deal, I will buy some quality SS clamps and off we go. (In addition they sent only 2 when in reality 4 are needed). The downpipes and the center balance pipe under the engine, provided from Riccardo Oro, are PERFECT, chrome is hard and shape is perfect as well.

Well, my real thread starts now. I checked the original silent blocks that holds the silencers to the frame through that plate, and they should be 25X20, but in my area I only find 20x20, 20x15 and 20x10, and I buy a pair of each. The first are bending a lot, the seconds (see video below) still flex quite a bit, the thirds are too short. So I am considering two options:

- try to find 25X20/15 silentblocks, but I don't think they will flex less, unless they are special harder rubber silentblocks.
- forget about silentblocks and just make a cylindrical spacer of aluminium.

Miguel

https://youtu.be/qAHmhtDyMno

and then the exhaust system and the chrome failures...

IMG_6316.JPG

IMG_6319.JPG

IMG_5869.jpg

IMG_5870.jpg

IMG_6320.JPG

IMG_6322.JPG

IMG_6321.JPG
 
Your silent blocks appear much too soft.
I've never had trouble with standard industrial M6 units.
I would not advise mounting your silencers rigidly. Those machines vibrate and need something flexible otherwise you risk breakage.

Paul
 
Paul Marx said:
Your silent blocks appear much too soft.
I've never had trouble with standard industrial M6 units.
I would not advise mounting your silencers rigidly. Those machines vibrate and need something flexible otherwise you risk breakage.

Paul
Click to expand...

Do you know which size are you using? 25x20?
The long ones, 20x20 are from industrial shop, the others from amazon, but they look very similar strengthwise... but I will visit a better shop, lets see
Miguel
 
You need the double silentbloc for the exhaust mounting. https://damclassicracing.com.au/21127085-silentbloc-rubber-double-m6/

Unfortunately Greg's listing shows that he is out of stock, but you can probably get them somewhere else. Wolfgang perhaps?

Anyway, I'd go with solid mountings if I were you. Forget the rubber blocks.

I have used solid mounting on Laverda exhausts, so has my brother on his 3C. The double silentbloc mounts were unobtainium for a long time so we used through-bolts with wooden blocks as spacers (paint them black and they look the same as rubber anyway). The solid mountings were there for many years with no problems. On the RGS based race bike I built, I couldn't use silentbloc mountings because they'd melt!  Most other makes of bike use solidly bolted-up exhausts with no ill effects. I don't know why Laverda used the silentblocs. Seems like a dumb idea and an un-necessary complication to me. The engine is rigidly bolted to the frame, so you don't need a flexible exhaust.  Actually, I suspect a lot of the cracking problems in the 3-1-2 collectors on Laverda triples is because of the silentbloc mountings allowing the exhaust system to flex.
 
I had genuine Ducati Contis on my SF1 for years - solidly mounted. it was a pretty smooth Sf but with lots of hard road riding and some racing they eventually cracked and the crack spiralled right around for about 270 deg. I had them welded up and gave them to a friend after i went the SFC 2/1.

The silent blocks should be pretty firm if they're like the genuine ones. The factory used the two round ones because there's a bolt head in the middle that holds a bracket to the frame. A triple monobloc wont fit. The SF with the junction box holds the headers nice and firm at least, and the rear rubbers only have to absorb a small amount of movement. When I dumped my junction box it meant the exhaust was suspended from the clamp at the head to the mount at the back - much more chance of vibes creating big movement. So maybe with the J box you can get away with rigid mount mufflers.

I have to say, I find it hard to believe they are genuine Contis - certainly NOT new-old-stock. Gowanloch sells genuine NOS Contis for Dukes and they are about A$1500 each!!
 
Looks flash chromed, no nickel or copper base layers.
As they are brand new and uncontaminated you may be able to find a chromer willing to re-plate them.
 
I bought some double silent blocks from Keith Nairn,Laverda Scozia recently,at a good price around ?18 each I think.
 
A twin is not a triple.
You do not need double silent blocks, the factory never used them. I've had single bobins on my SF2 for 30 years and 120 000 km. They're still the ones I mounted originally. Industrial material.

I had the exhaust rigidly mounted on my 3CL without any problems.
This is a twin.

Paul
 
Of course  Paul ,,but looking at those silencers it looks like a twin chrome box,.Round original rubbers I bought from Slaters.
 
On the silencer,pretty obvious,  but I think,as I"ve never had Contis they take two round blocks not a whole one on reflection? n"cest pas?
 
Since drum brake SFCs are full of them, I have custom made silent blocks that flex less, and with the waist, like the original.

Marnix
 

Attachments

  • 2020-10-25 13.05.26.jpg
    2020-10-25 13.05.26.jpg
    36.2 KB · Views: 152
I really don't see the problem.
For instance, these people are just up the road from me. Hardly time to warm the oil on a 750.

https://www.123roulement.com/gamme-plots

You'll need some for the radiator on your 3C as well Miguel.
(By the way, your english is excellent)

Paul
 
Tippie said:
The quality of that chrome is total rubbish. Send them pictures and ask if that is what is expected. They should take it up with their chromer.
Click to expand...

Well, this is what I did, and they exchanged them... but of course now.. I am just waiting for the new ones to start peeling off as soon as they start to go hot-cold-hot (hopefully not)

Anyway, I will try to mount them with silentblocks, have already a couple of sources, this is one of them:

https://gummipuffer-wagner.de/print_product_info.php?pID=1307&KeepThis=true&TB_iframe=true&height=450&width=750&MODsid=11d4aec9c3f203a808a7aab85b3265bc

looks serious and good quality. But I'll try in a local bearing/machinery shop in the area first.

I've just seen the last post from Paul, nice website as well, I'll have a look certainly.

thank you all, I'll keep you posted with new video when I find the proper solution!

Miguel

 
Piranha Brother 2 said:
The factory used the two round ones because there's a bolt head in the middle that holds a bracket to the frame. A triple monobloc wont fit.
Click to expand...

Yes, I saw the bolt head in the middle, but figured there are several ways around that little issue if you wanted to go with the double silentbloc.
 
Hi!

So finally I found 25 diameter silent blocks, however instead of 20 mm length, I chose 15mm, expecting less flexion. I think I reached an acceptable result.

Something I learned about the hardness of those materials, all silentblocks on the market now a days are around 50 sh?res, which is a meassure of a scale indicating hardness of rubber materials. Specific shocks for automotive industry, are usually around 65 sh?res. Unfortunately they have to be pre ordered and produced, with a minimum quantity of about 100 uds, but the producer said that I would get the same result reducing length by 5mm  :D Just for info.

https://youtu.be/MFqBmbU7jrQ
 
You must log in or register to reply here.
Back
Top