TT500 exhaust length

[cloggy]

 I'm trying to put My Mann mark 4 framed TT500 back to something close to it's original spec [free Simons forks anyone?]. The front pipe looks original and I have a supertrapp to be grafted on. I have a 1and 5/8" pipe . Does anyone know the length?

[Graeme M]

Not sure of OEM spec but tuned length is right around 36" (about 90cm) from memory. Anything over 38 really knocks the power around.

Hope I'm remembering that right...

[cloggy]

 Thanks very much!
I had a memory of a Dick Mann quote of 37".
 I've got another problem now  I had an old 1983ish single bolt Supertrapp with 4" discs. It rusted away and Daz copied it. I had planned to swap it from my DR to the Mann. However Daz noticed that it was longer in the body and wondered if the shorter possibly earlier 4" disc bodies also had internal baffles, or were they just a cone with  discs. He also wondered if the baffles robbed power. I've searched the Supertrapp website but not gleaned anything.
 Anyone enlighten us?
 

[smed]

  [free Simons forks anyone?].

Yes please

[Graeme M]

Hmmm... I had a Supertrapp on my HL500 and it was a fairly short one. No internal baffles in that one, just the centre bolt and the discs. Whether though it's the shorter one is uncertain but I think the muffler was sourced when the bike was built around 1978 or so.

[TT5 Matt]

isn't there something better around then the "fall apart traps" back in the day those thing broke the centre bolts off time after time and on full song you didn't notice it till you got home and youd have to buy another set of disc/bolt and end cap,the yam dealer made a mint from those things

[cloggy]

 I want the bike original, thus supertrapp Anyway I've never had bolts fall off. We have a special substance in the UK , it's called "rust". It's unsurpassed as a fixing agent.

[Marc.com]

I want the bike original, thus supertrapp Anyway I've never had bolts fall off. We have a special substance in the UK , it's called "rust". It's unsurpassed as a fixing agent.

Rust, you mean the old Maori Loctite  ......

What carb are you running, that will make a difference to how much exhaust resistance you need.

[MX?]

Hey Cloggy, I have a couple of Supertrapp info sheets that came with mine. They talk about tuned lengths and correct disc use. I'll see if I can email them to you.

[cloggy]

 Thanks MX It's a 36 or 38. Dick Mann favoured the 38

[Marc.com]

Thanks MX It's a 36 or 38. Dick Mann favoured the 38

Yeah I am just toying with my 38mm at the moment, its fine after you get past the first 8th throttle. just contemplating bleed down jetting arrangement

 

[cloggy]

MX
I've put the call out for an old Supertrapp, but given that I live in a far away land, all be it one now without the Witch; I expect I'll have to get one made. Daz reckons that he can happily build one with the info you emailed, so thanks again for that.

[MX?]

Glad it was useful! I was just looking at the cost of new 3" disc universal mufflers. 
Geez they seem to have gone up in price, $259 here in Oz. I'm sure I didn't pay anything like that a couple of years ago when I got mine?

[cloggy]

 Turns out the Mann's used a 3" unit, at least some did. MX kindly sent me a Trapp spec sheet. It was for a 4" unit to go on an XT.  It gave pipe lengths for various models to be used with Trapps. It also stated that Trapps needed a shorter pipe than other "silencers". 32" was the XT length for peak revs. My pipe is 52"! Pulls well out of slow corners.....
 

[g465b]

hi,the following info is from the paperwork that comes with a supertrapp purchased in 1978,for XT/TT500 - 1.625"  or 1.750"  ( OD of tailpipe)
clamp on type with 32 inch pipe for max. power.   1 3/4 inch core with 18 discs 'racing'   8 discs 'trail'
my TT500H runs the std header   35mmOD approx 650 mm long into 39mm OD pipe approx 380mm long into supertrapp muffler,280mm long
body -89mm expanding to 102mm OD running 10 discs and 38mm long end cap.
my XT500H runs a period after market full system approx 990mm long 41.5 mm OD pipe into a 300mm long X 80mm OD repackable muffler
and another runs a stainless system 44.5 mm OD 950mm long , cheers Grant