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Post Info TOPIC: Silencer packing


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Silencer packing
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Hi All,

My question is does the silencer packing material in a muffler in any way affect the tuning and power output?

I was hoping to be able to sort out this question with some thorough searching but the Forum search function seems to be out of order at the moment - or maybe it is being maintenanced.  Anyway, I recently bought a 1999 TT250R from a friend who had to replace the silencer packing material before he could get it registered as it was too loud.  The muffler is a White Brothers E Series.  Rather   than use a genuine silencer cartridge he used a generic product requiring him to drill the rivets around the outer the skin and then put it all back together after repacking with the silencer material.  Yeah I know.............I asked the same question............why do people do such things??

The reason I have raised the question is that I do not think the bike is running quite as well as it should in that it very bogs slightly at 3/4 revs or thereabouts. I am not looking at the carby for the moment as it was recently professionally removed and cleaned up (was badly gummed up as had been left standing) without any changes to jets etc.  I note the muffler has 8 disc plates at the end.  Once I can dismiss the silencer packing as the potential cause of the problem then I will look at the carby.

Appreciate your help on this.  Incidentally,  I note from the White Brothers instructions that cartridge is supposed to be inspected every 2 months. The one on my bike was probably never checked and if the bike was originally tuned (years ago) when the cartridge was badly deteriorated would tuning be affected with new silencing material?

Noel

 



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Super Guru

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IF ITS RUNNING OK LEAVE IT PACKING SILENCERS REALLY ONLY APPLY ON 2 STROKES

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I COULD BE WRONG BUT I THOUGHT THOSE PLATE STYLE MUFFLERS U ADD OR REMOVE PLATES TO CHANGE THE DB LEVEL?

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I bought a second hand silencer recently and it was very loud, drilled out rivets, wrapped the baffle in a felt like wadding from one of the local bike spares places. Wrapped in sellotape to help fit back together, on startup still a bit loud, then the lovely smell of burning sellotape and the bike becomes quieter....

Felt very similar in terms of power before and after re-packing...

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I wouldn't have thought fresh packing would make a huge difference unless there was virtually none left in there before (when originally tuned) If the baffle is having some effect I would assume it's causing a rich mixture - you could try running without the airbox lid to attempt to lean it off a bit and see if there's any improvement. Still suspect the carb, even with "professional" cleaning - the TK carb on the ttr works really well when it's clean, but they are quite susceptible to dirt/gummy fuel deposits in the jets, which take some effort to clean properly. Use some copper wire to ream them out rather than trusting carb cleaner spray and compressed air.
At 3/4 throttle the needle might still be having some effect so you could try dropping it a notch to lean the mixture a bit.
Good luck! I need to be in just the right mood, with just the right amount of time available, before I start fiddling with carbs, but sometimes you just have to bite the bullet and get on with it!
Ride safe,
Simon.

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Thanks Guys, for all the input. Everything said is consistent with my own gut feeling.  I haven't worked much on a bike carby before and know little about them (but have begun some research), although I have worked on Yammy  and Suzuki outboard carbies!  As Simon says, you got to be in the mood to tinker with a carby: AND I need to have some idea where the source of the problem lies within that little bit of metal! 

Re gummed carbies it seems to me if people just ran the carby dry after they finished with it each time then they would avoid so many problems and heartache, not to mention expense. It astounds me that the previous owner of this bike could have left it standing for nearly 2 years with fuel in the carby - and yet he took great pride in changing the engine oil every 1000 Kms!  no

That's my bleat - I feel better already!

Thank god for this Forum

Noel



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