Haven't read about this anywhere but just wondering if im the only anal ttr owner that's cleaned up the rough weld just inside the engine end of the header pipe . After doing all the usual mods removing the restrictor a stain tune muffler ext .I removed the approx 2mm high bead of weld inside the pipe ..I've done around 5k since doing it with no issues with the pipe .now for my question has any one else done the same as I noticed a slight improvment in performance and was wondering if it's just me or has anyone else tried the same
I have done this on my WR400, mainly because the welds were splattered on, unlike the TTR250. The welds of the TTR seem quite thick but very neat. Removing some of the weld may produce a little more power but not enough to ''write home'' about.
Jarrah
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2000 TT-R250M-
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Ported & polished, 73mm bore, Wizeco piston, US header pipe, FMF Q4, #150 main jet, #52.5 pilot jet, throttle stop screw adjusted, larger snorkel, GYT-R air filter, NGK Iridium spark plug, 14/51 gearing, NOS +
Yeah, I would imagine it is usually better to fix up unintentional roughness and poor welding, BUT..
sometimes, when fluid flow (eg air-fuel or exhaust or oil) is concerned, rough can be better than smooth.
I'm not saying it is always or mostly the case, but just *sometimes* it is an engineering design factor.
just for a laugh, below is an anecdote about how one time Rolls Royce should have prefered rough over smooth.
(early last century Rolls Royce originally licensed and copied a GM transmission for their first automatic car,
but had a few teething problems)...
"A teardown of a recalcitrant Rolls Hydra-Matic revealed the problem: At the bottom of almost all automatics sits an aluminum die-cast plate, called a valve body, containing an array of channels that route hydraulic fluid this way and that as valves in the transmission open and close during shifting. The surfaces of these channels, being die-cast, aren’t especially pretty. Quite the opposite, in fact. They look dull, gray, and rough.
It was this appearance that had led Rolls astray. If the channels were to carry fluids in a Rolls, by George, they would have to be shined and made gleaming to a fare-thee-well. The worldwide reputation of Rolls-Royce could tolerate no less! This quality-driven change was what had caused the Hydra-Matic’s troubles. The rough, disreputable-looking channels in fact offered just the right resistance to hydraulic fluid, ensuring that it flowed in a stable fashion. Prettying up the channels made them too slick, speeding up fluid flow and causing shifting to happen out of sequence.
The fix? Rolls, at GM’s behest, stopped trying to improve the inner looks of the Hydra-Matics and instead just bolted them in, same as Cadillac did. Drivers in the British Empire could once more shift with confidence."
just as a matter of interest and most plumbers could confirm this, but at least with water if you increase the diameter of a pipe from 3/4 to 1" you increase the flow rate by 100%. is that correct plumbers. I don't know how this apply's to exhaust flow in an engine but what I do know about air flow at least is that the shape of a bee's honey comb is the MOST efficient at passing air, not a tube.
just as a matter of interest and most plumbers could confirm this, but at least with water if you increase the diameter of a pipe from 3/4 to 1" you increase the flow rate by 100%. is that correct plumbers. I don't know how this apply's to exhaust flow in an engine but what I do know about air flow at least is that the shape of a bee's honey comb is the MOST efficient at passing air, not a tube.
Here you go, now you can work it out
(Pi) 3.14 x R x 2
So if the pipe is 2cm radius x 3.14 = 6.28 x 2 = 12.56cm
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2004 TTR250 - Highway Dirtbike Hand Guards, 38mm Bar Risers, D606 Front & Rear, Opened up Airbox with Twin Air Filter, Re-jetted Carby, B+B Bash Plate & Frame Guards, DIY 3mm Alloy Tail Tidy, 14/47 Gearing.
just as a matter of interest and most plumbers could confirm this, but at least with water if you increase the diameter of a pipe from 3/4 to 1" you increase the flow rate by 100%. is that correct plumbers. I don't know how this apply's to exhaust flow in an engine but what I do know about air flow at least is that the shape of a bee's honey comb is the MOST efficient at passing air, not a tube.
Here you go, now you can work it out
(Pi) 3.14 x R x 2
So if the pipe is 2cm radius x 3.14 = 6.28 x 2 = 12.56cm
this is one of my first posts . i still recon removing the weld has been the easyest mods and a noticable improvment across the rev range .well worth a try .
