New User FE400 02 Muffler Questions.

The intermediate pipe is different on the 03's. The mufflers are not dirrectly interchangable from 02-03.

Not sure if the intermediate pipes are interchangable. I would not think so. The header pipes are much larger on the 650 as well.

well i thought that the systems were a bit all over the show around then. some had the internal fit headers and some had the external. the tailpipes interchange. if they look similar they will fit each other. the 650 headers when used add power even on the 400.

regards

Taffy

Dan,

From your original post you say that you want more low down. The changes you are making are going to give you more up top. First, if you are fabricating stuff to begin with, concentrate your efforts on the headers. Make them slightly longer than oem, or even take the headers all the way to the silencer where you then have them go into a collector and then the muffler. You only need header pipes of approx 33mm diameter. 38 is overboard for good torque on the 400.

Simon

Hey Dan,

2-strokes are really a different kind of animal.

With the 4-stroke bergs - It kind of depends on the original muffler, but even the oem enduro muffler is good for 56 horsepower, the straight through mx one on a back to back comparison only gives and extra 1-2 horsepower. That's why on a 400, it isn't necessarily the solution. I've had really large bore silencers on the oem exhaust system without any gain whatsoever and this shows the benefits are to be had in the header and collector area. Once you get the exhaust system working properly, then you can work on the muffler, if you know what I mean. As a general rule of thumb a header pipe of approximately the same diameter as the exhaust valve will work well as will adding just a bit of length to it. Large bore headers on 4 strokes tends to lose torque with gain at the top end. If I remember correctly the 400 has tiny dia. headers to begin with so there is room for expansion, shall we say.

The other thing is that if you have the older style exhaust system with the long silencer and carbon end cap and yellowish pipes rather than chromed the collector didn't work very well.

Hope this helps,
Simon