Exhaust graphite collar
Preserving the graphite collar when removing exhaust:

Loosen the clamp around the collar first, then remove the rest of the exhaust mounting bolts while supporting the exhaust as steadily as possible in its original position. The best support is provided when the top/center bolt is removed last. To slide the exhaust off, gently turn it back and forth a few degrees, it will soon slide off directly backwards. Do not let the exhaust exert any sideways force on the downpipe, especially when the exhaust is part-way off.

The graphite collar should remain inside the exhaust itself, and if it looks reasonably intact can be left there. Only ever take it out if you intend to replace it! The downpipe should be clean where the collar covered it, any collar residue on there will also mean replacement.

When replacing the exhaust be careful not to nick the collar with the end of the downpipe, and do not over-tighten the clamp, the collar is designed to slide on the downpipe as the pipe expands due to heat. The GTS' clamp needs just 9-10 lbs/ft of torque (12-13 Nm). For the GTS Yamaha replacement collars are reported to work and may be both cheaper and easier to find. The Yamaha Part number is 3YF-14714-00. There is also the Caltric collar - even cheaper: https://www.amazon.com/gp/product/B01DR2251Y

Between 4-6 exhaust removals should be possible for each collar, the normal lifetime is about 12,000 miles.

When replacing the collar, make sure both the inside of the exhaust and the outside of the downpipe are scrupulously cleaned before inserting the collar all the way into the exhaust. This should need no force, the end of the exhaust will need to be splayed open a bit.

On the 400 and 500 engines at least, there is a new design of collar, and there are no instructions with it as to which way round to insert it.

Note:

When I wrote the original Wiki article, I had only considered the 500 Master engines, as at that time the OEM 250/300 collars were still graphite all the way through - though they changed a few months afterwards. On the 500 it's easy to insert the collar with the mesh facing outwards - not so on the 250/300s for some reason. On these I insert the mesh into the silencer, with the graphite end facing out. This ensures that the end of the downpipe doesn't cut a ridge into the graphite, making full insertion difficult - it just squishes the mesh instead. Also it means that the collar can be 'hammered' into the silencer easily.


This fully graphited end goes into the silencer on the 500 only:

External inline image provided by member with no explanatory text

This mesh end can be left just poking out towards the engine on the 500, but goes into the silencer on the 125 to 300cc scooters:

External inline image provided by member with no explanatory text

Another photo of the same graphite collar, with Part# 874946:

External inline image provided by member with no explanatory text

Installed (with the "fully graphited end goes into the silencer"):

External inline image provided by member with no explanatory text

However, starting with the model year 2009, Piaggio upgraded the exhaust clamps (for MP3 400's and 500's), and now they have these two tabs (which may help keep the graphite collar from sliding out), so I ordered one for my '08 MP3 500, Part# 874957:

External inline image provided by member with no explanatory text

External inline image provided by member with no explanatory text

External inline image provided by member with no explanatory text

Installed, looks like this:

External inline image provided by member with no explanatory text
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