Pam works for Powroll. She is probably one of the smartest people on the planet when it comes to Quads and she has an Italian last name. What more could anyone want? She helped me with my 99 Warrior. It screamed when it was done. Thanks again Pam. By the way, I bought a 2000 400ex. You might get a call from me again.

 

Pam maybe you can answer this question for me. Why do quad exhaust have so much larger diameter pipes than dirtbikes do. I've see things like the LRD and Sparks are like 2.5 or 3 diameter at the spark aresster and dirtbikes like the YZ400 are like 2 or 2.5? And the dirtbikes always sound so much better.

 

On the yushimaura (something like that) i found out that it is cheaper on the 300EX to buy the slip on at $269 (standerd series) and then buy the head pie for $110 (standerd series) that equals $379 instead of paying $469 complete. I know it sounds a little funny but thats what i did. On the 300Ex it makes pretty close to the highest power out put (4-5 horse power) with one of the lowest decibal ratings (anywhere form 93-96) for the 300EX!! Try to find places to buy it the factory is almost alway more expencive and the set might be more expencive then buying then sepret

lbz300EX

 

hi guys!

Thanks for all the kind words Hakmazter! Good to hear you got a little speedier scoot! ;-)

Yea, I do work for Powroll -- but I've been riding lots longer than I've worked here, so don't expect me to plug Powroll stuff over other companies! I just go with what I think works best (which is sometimes our stuff, and sometimes other peoples).

Okay, in answer to the question about where to drill.... basically, you can unbolt the end cap on the '99 models and you'll see the restrictor there -- just remove about 1/4 to 1/2" more material and re-install it. It only increases noise by about 1 dB, and gives you about a 5-8% increase over stock hp.

One problem -- they changed the design on the 2000, so you acutally have to replace that whole tip. I believe the one that Thumper Racing makes for the XR400 will work for the EX. They're out of Texas, 903-938-0570. I think they're under $20, and they work well.

Okay, next question!
Eeveslage: Why do quad exhausts have so much larger diameter pipes than dirtbikes do?

Probably because there's more room for 'em on a quad! Seriously, probably the main reason is that most of the aftermarket Bike mufflers are set up for closed-course racing primarily, and the quad stuff is set up for enduro or trail riding. The race-only setups for the quads are also small reverse-cone megaphones. And conversely, the spark-arrested versions of bike mufflers are bigger (look at the Supertrapp).

The size of the muffler isn't as important (unless it's too small!) as the header diameter, which can greatly affect engine performance. Those systems you're talking about may have exactly the same size head pipe (the area that matters), but different mufflers.

As far as headpipe diameter goes, here's a rule of thumb: smaller diameter = more torque, less top end. Shorter header = Lots of top end, no torque. So the "perfect" system for a 4x4 quad would be small-diameter and relatively long. A 400EX likes larger headers with a little shorter length.
All this also has to be designed to work with the cam and porting too!

Hope this answered the question!

Pam