A forum for owners of Yamaha TTR250 trail and enduro bikes!

DRZRIDER · Member

What "WAS" inside the exhaust?

PlumasDude · Senior Member

You definitely need the spark arrester, which is just a metal screen tube that slides in the muffler before you put the chrome cap back on, regardless of laws its a fire hazard without the arrester (I assume you're in the western US). Where you get one I don't know, I could send you a picture of what came stock with my 2003 if that would help. I haven't really looked for an arrestor but the ones I've seen at the local shop look more restrictive than the stock version (tighter mesh and smaller arrestor).

As for the interior baffling, etc., all I know is that you're subject to the 96dB noise level (I think that's right for newer bikes, it used to be 99 but I've been told its now 96 in Calif, which is a problem for some aftermarket pipes), but so long as you aren't making it street legal I don't think any Calif emission controls apply. Presumably the lack of back pressure will affect performance but I'll leave that to the gurus to figure out.

TTRfan · Super Guru

If you follow the two links in this thread you will get an idea as to what might have been inside your zorst wink

Brian

DRZRIDER · Member

Thanks guys!

TT-R250M · Super Guru

TTRfan wrote:
If you follow the two links in this thread you will get an idea as to what might have been inside your zorst
Brian

That was the UK version. The US exhaust has a different end cap (and maybe internals?) as seen here- http://www.partzilla.com/parts/search/Yamaha/Motorcycle/2000/TTR250+-+TTR250MC/EXHAUST/parts.html.

Better picture...

$_57.jpg

The US OEM spark arrestor is not listed separately and AFAIK cannot be bought separately. Other than getting one made up I am not sure what you can do.

The only other thing that I can think of is using the WR end cap and spark arrestor but you would have to measure the bolt holes and the diameter of the end cap. If you are interested I can let you know the dimensions.

Jarrah

TTRfan · Super Guru

I realise the US exhaust is different Jarrah - got one on my latest refurb but I am not chopping it open to see what's inside wink

US exhaust 1.jpg

Apart from the end section, the rest of it looks very much the same shape and size as the UK zorst so thought the internals might be similar.

Nothing in the end of mine and it doesn't sound too loud.

US exhaust 2.jpg

Brian

TT-R250M · Super Guru

TTRfan wrote:
I realise the US exhaust is different Jarrah - got one on my latest refurb but I am not chopping it open to see what's inside

Oh okay Brian, just thought I would mention it. By the looks you can just take the end cap off to see what is inside (that is if it's like the WR exhaust anyway).

They do look nice! Wonder how they perform. aww confuse

Jarrah

PlumasDude · Senior Member

Here's the stock 2003 US arrestor, 1 piece with the cap stock TTR arrestor 2003.jpg was 1 piece with the cap.

DRZRIDER · Member

Thanks PlumasDude,

It seems that the US can may be differant than the EU or AU. Does/did your exhaust can have the same series of tubes as shown in the thread links above? With your spark arrestor shown here, it seems that it couldn't. Thanks for your photo!!

Markvan · Guru

Be interesting to find out the weight of a US TAILPIPE. Aussy model is just over 4 kg.

PlumasDude · Senior Member

DRZRIDER wrote:
Thanks PlumasDude,

It seems that the US can may be differant than the EU or AU. Does/did your exhaust can have the same series of tubes as shown in the thread links above? With your spark arrestor shown here, it seems that it couldn't. Thanks for your photo!!

I'm not sure what's inside the can (cause its inside the can!), but the last foot or so of the muffler is empty, the baffling, etc. ends in the middle of the fat section (where the pipe exits a solid baffle and just blows through the last foot or so). I'm not sure about the UK/AU versions but I gather they have a restrictor at the back end of the tail pipe that doesn't exist on the US version, and it sounds as though they may have more baffling inside (its all baffling to me) -- the gurus could probably fill you in.

If the prior owner managed to cut the baffling out of the front half of your muffler I don't see how you could repair it, probably need a new one. But why not just leave both airbox and muffler hacked, check your jets/needle position, and keep it "uncorked?" Uncorked mo bettah no?

DRZRIDER · Member

You described mine just the way I see it, empty the last foot or so past the solid baffle, thats good for me! looks as if the PO has just hacked off the spark arrestor. Think Ive already found a possiable replacement screen. Thanks again!!