Wow! You guys are super helpful May I trouble you again?

The expansion chamber/downpipe/exhaust/whatever - the first, big bit - is fine on my bike (surface rust, nothing that a good clean couldn't sort out) but the silencer/muffler bit is in a much worse state:



Note the circled parts :( Question is: should I try and restore this, e.g. weld some threads on, drill and tap, etc. given that this is just a cylinder full of rust & dust - one that is not particularly good at lowering the decibels.

I'm considering making something to allow the use of a generic silencer. If I do that I could either:

1. Make an entirely new "link" pipe
2. Recycle the old pipe by cutting off the chamber

For the first option the question would be how to seal the pipe. Recreate the indent for the O-ring? Seal with exhaust cement? For the second option it feels like sacrilege but for the fact the existing part is in a poor state.

I would welcome any comments

Afternoon!

Is what Yamaha call the "Pipe, Outlet" present? Part number 438-14752. If not, that might explain the lack of silencing.

If it's not and you're prepared to fork out 60 or 70 quid for a new one (CMSNL have them in stock), then I'd probably try and drill some new holes and tap new threads. Saying that, knowing how limited my competence is in that sphere, I might get a mate to do it!

No "Pipe Outlet" on this one, it's European. The only way inside to renew any baffle material (if, in fact, there was any to start with!) would be to cut it open and then re-weld :(

Soo... that looks like the muffler/spark arrestor from maybe a DT250/360/400 to me. On the units similar (in appearance anyway) to the ones this side of the pond, the rear has a removable end (held on by 6mm fastener), which I don't see from the angle of your photo. Are you condemning the unit because 1.) you feel the "guts" inside are deteriorated so badly as to render the unit unusable, or 2.) the 6mm studs are broken off from the standoffs?

If the first is correct, then a replacement may be what you are faced with, but in that case certainly do not toss the old one just yet, as that inlet end with the groove for the O-ring and the bend, may prove to be very valuable at that point.

If it is the second case, then anyone with a TIG welder should be able to quick weld a bit of 6mm thread onto the end of those. (cut the head off a bolt maybe, to get the threaded portion) Alternately, how steady is your drilling hand, or do you have a drill press? Maybe drill (carefully) into the standoff sections, and thread the remaining standoff for a 6mm bolt. 2 hex head 6mm bolts with washers should hold the muffler in place as well as the original acorn headed nuts.

Worth a thought?

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