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

Ok 50 views and no replies so I might as well ramble . My thoughts are that the shorty header effectively shortens the route for expelled gas. From my (limited) knowledge of exhaust tuning, the shorter the pipe,  the greater the hp further up the Rev range and a rediction in torque low down. Longer pipes give better torque at the expense of high rpm hp. Any aftermarket exhaust also shortens the route for exhaust gasses to exit. Therfore they'll also reduce the low down torque.  Unless of course you re jet to suit the application. 

I'm thinking about the Chinese pipe on alieexpress that I can pick up delivered for $210 ish AUD. I'll rejet to suit and open the airbox and see how I go. It's the cheapest pipe by a mile that I know of .I like the tractable low down torque you get on the ttr from the combination of pumper carb and single cylinder - I think the shorty header might affect that. I'll report back when I've saved up  

Perhaps the biggest contributor to low down torque was the restrictor Mr Yamaha put in the header pipe from new. When I removed mine on my (then) new TTR the difference was very noticeable but the bike was still better off without the restrictor as the TTR became a bit breathless at higher revs.

The Totally TTRs design was based upon the shorty pipe made by CRD following their research and that of the Australians tuning a TTR250 for the MX nationals where the TTR won its class.

Sadly I was never able to find any dyno readings or other power readings from CRD or anyone else and never had the chance to do a back to back test on a dyno myself so it would be wrong to make any more definite claims about the shorty pipe's performance advantage.

Brian

 

 

Awesome work Steve! It's good to hear that you rejetted with the standard pipe. My snorkel is long gone so I'll try opening the airbox top and rejetting first. 

Just an update - managed (as of recent tax return!) to score a TK Pipe off gumtree for the TTR for $200 .  It's winging its way to me at present.  Hopefully Australia Post will have the horse fed and watered so it can deliver the mail in under two weeks (from Melbourne).  That's normal for us here in Australia - you poms have it so lucky to have a great postal service.  Rant over

So have ordered some other parts from the TTR store as well including the float bowl gasket as mine was leaking. Used my new multi-cutter tool thingy to cut a nice new hole in the top of the airbox similar to Steves.  Have the jets in the shed and when the pipe gets here I'll put it all together.

Have also had to redo the fork seals.  Can't remember if I said that on here yet but I managed to put them in upside down.  Not entirely my fault as I was following the way they were installed by the previous owner.  Turns out he didn't know squat either.... So I can now do fork seals in under two hours go to whoa. They started leaking on the first ride.  Bum.

Brians short header pipe didn't give any more power but I did
make the motor rev out slightly faster..
I have a GYTR tail pipe on it.. top cut out of the air box...



..

So pipe arrived late in the week. Got it on the bike and jetted the carby to suit. Took it for a good 2hr ride today. Stoked. Pipe's a little loud but I ride with ear plugs so all good

Carb air/fuel screw set at 2 turns. Runs like a dime. More power everywhere. Going to swap to 14/48 sprockets soon. Will see how it pulls then. I'm currently running aussie std 14/44 and it's a bit breathless at 100kph. 

 

 

 

 

Very nice Noise can be a bit of a problem with aftermarket exhausts