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

Kaos' dyno runs to test his shorty header here:
www.ttr250.activeboard.com/t64301240/shorty-header-pipe-fitted-dyno-before-and-after/

Yeah with a shorty header i saw a 1.5 HP gain, and can notice the difference. That was a seven % gain that just bolted on.   If you look at the before and after dyno runs the engine now builds revs quicker and makes power a bit longer.

The muffler IMO is worth it for the weight loss, about 2 kg lighter than the stock muffler.
Should also give a decent gain in power unless yours is already well and truly derestricted.   

Around 2 or 3 HP extra

See this test  
http://ttr250.activeboard.com/t64192586/october-1999-motocross-action-magazine-on-ebay/

So IMO is the exhaust worth it, if you have got the $$$ definitely wakes the little 250 up.

Make sure its uncorked, ie grind of the header pipe restrictor, adjust the throttle limiting stop..   If you arent worried about water crossings pull the airbox snorkel out and rejet the carby.  Totally different bike.

Kaos, I've removed the snorkel, and re-jetted already. From what I understand, my USA model stock header has lower restriction than European models already. I may be wrong on that? Anyway, thank you for your input. :)

GYT-4PX93-AU-AL (GYTR TTR250 Slip-On Muffler) $549.88
Fits:
My GYTR muffler is reasonably quiet putting around but gets a louder note at full throttle

Ps that's about £310

Nope, I can get brand new stock ones for a lot less and I still have not given up on getting another stainless one made

Jumpn wrote:

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Well, a new bike isn't in the future, so thinking about upgrading parts of the TTR.  Are exhaust mods worth the price? Do you get real performance gains, or is it just noise?  Looking at the shorty header from totallyttrs, and a new either FMF or Pro Circuit silencer.  

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 To be honest, they don‘t give you much more than a heap more noise. I have a TKP pipe on mine only because I found it cheap and I like a bit of noise.  It’s borderline too much though. It says 96db on the pipe which is clearly a lie 

A shorty header might give you some more power though.

The best power mods are opening up of the airbox and a proper jetting kit. Pipes have had more effect on other bikes I’ve owned. Sure it feels like my TTR has more power and revs better but really? I think on a dyno you’d really not notice much.

And actually, most aftermarket pipes put the power higher up in the rev range. One of the best things about the TTR is torque down low. So you might actually harm the characteristics of the bike you like.

I also ride mine on road where the power up high is a benefit. I think its a good compromise. If it was just off road though, I’d not bother. As always YMMV

If you remove the muffler the restrictor is just forward of the joint in the header pipe, looks like a washer. My dealer removed it when I bought the bike new

Thanks to both for your replies.

Speaking of the header pipe, mine has a couple dents, and I'm looking to purchase a "shorty" header pipe. Does anyone know if these are still available? Looks like Four Stroke Works is no longer in business, and I haven't heard back from Totally TTRs.

Happy riding!

Ken

I have a Staintune muffler on my TTR & while it is loud it is street legal here in Australia I think it's 94db & to me sounds like a Honda XR, I only rode it one day with the standard muffler before changing, I rode it again with the standard muffler in 2016 when I was going to sell it.

Not sure if it's in my head but with the standard muffler it felt gutless & a lot nicer to ride with the Staintune (again it might be in my head)

You can hear it in this video

Buggery creek - YouTube

-- Edited by TerryK on Thursday 21st of September 2023 01:13:31 PM

-- Edited by TerryK on Thursday 21st of September 2023 01:15:02 PM