WB exhaust, s-bend or pro-meg.

What is the difference between the s-bend and pro-meg WB exhaust system?. The two have the same performance?. Physically, the two are same?. What is better?.

Thank from Tilisarao, Argentina, WR400F´99.


A megaphone exhaust (pro-meg) has a tapered pipe from where it enters the muffler to somwhere near where it meets the headpipe. The megaphone boosts mostly top-end horsepower.

The s-bend is for sombody that wants more power in low-end and mid-range. It's pipe diameter is constant from the muffler to the headpipe.


2000 Yamaha WR400F

1988 Honda NT650 Hawk

1977 Suzuki RM250B

1974 Honda XR75K1

Like Moto-Mike said the S-Bend is a pipe for down low performance, but there are 2 S-Bends. One has a 2" diameter (the shorty) and the other which is about 4" longer and has an internal diameter of 1-3/4, this is the "Hawkins Replica" or sometimes known as the WR E-Series, and the other sometimes the YZ E-Series.

Anyway my point being, the Hawkins S-Bend is even better for bottom end and midrange than the short S-Bend. Actually they say that all Randy Hawkins need to beat the opposition is an E-Series on a WR400, and no other mods, how true ? Don't know. If it is then he is another Shane Watts who has won on 5 different KTM EXC's in the GNCC, some 2 stroke, some 4 stroke, and he doesn't even modify them, he is truly a freak !!


RodH Canberra, Australia<A HREF="http://www.400thumpers.oz-au.com" TARGET=_blank>

400 Thumpers Australia</A>

2000 WR400F See Photo's and Modifications

What happen if I put WB e-serie SHORTY on may WR400.

Elian I have a couple of different pipes I run on my 00'WR. I have a MegaMax and it make good bottom end and has strong mid range pull. The e-series s-bend shorty has awesome low end and mid range. It rips on the top end. It is kinda on the loud side though. I might want to sell it because I have to keep it quieter in the woods where I've been going. Let me know


00'WR400 75'Yamaha 250 enduro

White e-Series S-bend 12 discs, Yz timed, rejetted to Clark specs, throttle stop cut, lid removed, Topar Racing top clamp, Tag Metals T2 bars, Scotts damper, Devol disc guard and frame guards, lights removed, Cr routed Fastline brakeline, Acerbis Rally pro hand guards fastened to the top clamp, Gel grips Live in Southwest Ohio

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