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silencer

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Harold 400/4:
Think I may have the thread issue with my recently bought DSS silencer as well. Can you confirm the tap size Mattsz?. Also is the conclusion the issue with the gasket is due to the silencer dimensions or the the gasket size? TIA.

mattsz:

--- Quote from: Harold 400/4 on August 30, 2020, 07:51:01 AM ---Think I may have the thread issue with my recently bought DSS silencer as well. Can you confirm the tap size Mattsz?. Also is the conclusion the issue with the gasket is due to the silencer dimensions or the the gasket size? TIA.

--- End quote ---

8mm, 1.25mm pitch for the tap.  My original mounting bolts had some rusty threads, so I cleaned them up with a die as well.  Smooth results!

I plan to reassemble the exhaust later today (still early morning here!).  I'll let you know what happens, but I don't expect to be able to answer your question, since I don't have an original gasket to compare with, and I had to destroy my original Honda silencer's end to remove it from the header, so I can't compare silencers, either...

mattsz:
So I believe the issue is with the silencer - the opening is too small.  I compared the new gasket to a well-used on still mounted on my "spare" collector, and they seem to be virtually the same inner and outer diameter - however the new gasket is about 2mm longer (measuring the cylinder length).  The new silencer opening is too tight to fit the new gasket, and too tight to fit on the old one.

I decided to try opening the silencer tabs just enough to work the new gasket in and then try to use the tabs to turn the gasket down to size.  It sort of worked, it might need some fine tuning with some sort of blade or scraper...

EDIT: damn upside down thumbnails!  I give up...

AndyD:
Matt,
Glad you got the gasket to 'work' OK.
Finally had a chance to finish off fitting mine today - tidied up the threads and had to lengthen the fixing hole in the frame a small amount but now all fits properly and tight to the bracket etc.
On to the next challenge...
Cheers,
Andy

Skoti:
It's possible to reduce the outer diameter of the new gasket so that it fits in the silencer better.

I done it on my F1 because I didn't want to wait for the proper gasket coming in the post all the way to CZ.

Here's my botch method,

Find a socket that's a good tight fit into the gasket.
Fit the socket onto an extension piece and clamp it in a vice with the socket base flush to the vice jaws.
Fit the gasket over the socket.
Line the inside of a piston ring clamp (or whatever you have suitable) with 40 grit paper and gently turn the outside of your gasket down to the correct fit.

Hope this helps

Skoti.
   

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