how to get better flow from stock exhaust

[djwilliams0822]

I was wondering how you can get better flow from the 400exnew exhaust. I looked inside the pipe and I was wondering what happenes if you drill all of it out so if flows better. I wanted an aftermarket pipe but I didn't want to spend all that money because I am just a weekend warrior

[JOHNDOE83]

Theres a thread in here about grinding down the welds for more flow, theres also another thread a few down from this one that stats the fact that the stock headers are fine even without grinding the welds and this is true.

Grinding them down is a way to pick up a lil more flow but its only flow into the header and doesnt effect the mass air flow that the header is capable of, it mainly just allows a smoother transition, like a clean up port job.

In all honesty, a full exhaust is a GREAT idea but if your a weekend warrior and not worried about squeezing every ounce of power the EX can push, a slipon is the best bang for the buck.

Slipons all look different and some are said to be the best, in reality they ARE all the same, pick a nice looking in your budget slipon and it will be just as good as a high dollar slipon.

Some people will disagree, I have all the info I need to prove my point and Im open to discussing it. The only one I wouldnt buy is the DG sipon with the spacer plate design, its just not right IMO.

[kt1148]

http://www.exriders.com/vbb/showthread.php?s=&threadid=445008&highlight=grind+header+welds...This shows where to grind the welds down inside the headers(I recommend using a die grinder, not a dremel, unless you have a lot of time:p ). Right now Motoworks has there slip-on for only $209.95, well worth the money it's a great pipe...http://www.motoworks.com/

[whyzee]

Leave stock exhaust alone. Remove air box lid, leave off. Install kn air filter and Outerwears. Rejet to around a 175 - 180 main.
you will not believe the difference! !!

[Drfat400ex]

Originally posted by whyzee
Leave stock exhaust alone. Remove air box lid, leave off. Install kn air filter and Outerwears. Rejet to around a 175 - 180 main.
you will not believe the difference! !!
Holy 175-180 for no lid and k&n, that's pretty rich man if that's what yours is jetted at and it's running good then you might wanna get that checked out!

[djwilliams0822]

I've got the lid off and a uni filter. I've actually got a 440 kit in it. With stock exhaust. I was going to either get a slip on or a full system if the price is right. I was either going to get exhaust or a 450r carb

[JOHNDOE83]

My 440 uses a 220 main jet

[Rohr397]

I wouldn't mess with the stock silencer. They don't really work like an aftermarket pipe and hollowing it out would be like taking the silencer off and attaching a tin can to the end (exaggeration but you get the point). The flow isn't going to give you any power gains because there'd be very little back pressure. The inside of those pipes are ridiculous, If I remember correctly there are two chambers with a wall separating the two and a small inlet. That's what I remember on my 450r pipe anyways.

Motoworks makes a great exhaust, you can also find some nice used systems on eBay but I didn't tell you that ;) (Sponsorships...)