A complete system is $500, is it really worth all that money? Anyone know where I can veiw dynos? Thanks

 

I had a complete T4 system on my 400 before I got a 440 kit. The Sparks system was very good but loud. When the mags do a test the sparks will be the best or right at the top every time. I did and still use just a stock headpipe and a WB/E serier and it gave me almost the same perforance as the Sparks, but was not as loud. For the money go with a stock head pipe and clean up the welds inside and the WB. I have raced this with out 440's and we are dead even.

 

tprender do you know if it makes a big difference getting a full exhaust rather than a slip on

 

Just my own personal opion is that a slip on is all that is needed if just do a 440 kit. If you get a carb also, you will need a bigger headpipe. Some of the headpipes are the same size as stock on the 400's. I was told this by 2 of the big engine builders at the nationals. The welds on the stock pipe is blocking the flow by about 30% if you do the math. Remember that some riders will tell you that they got a big increase in power from doing something but the did about 2 or more changes at once to the engine or other things.

 

I had a complete x4 Sparks pipe on my 400EX. It was way too loud for my liking. I ground the welds out of my stock head pipe, and put a Yoshimura slipon on it. It was a lot quieter, and sounded great. The performance loss was hardly noticable, but well worth the sound trade.

 

$500 woah, which sparks, the x6 is $489. Get sparks x6, filter, and jet. Will make a big difference

 

..id say.Sparks..you really cant go wrong with any of his stuff..he knows what hes doing,and you pay for that..lol..but its well worth it..

 

You will not notice a big difference with any of the open pipes, especially on a stock engine.

A properly designed full system may make a small, possibly even noticible difference - but worth $500? Not in this guy's opinion.

The biggest thing with a 4 stroke exhaust is opening the system up. Most aftermarket pipes are nothing more than a glasspack setup - i.e. a straight thru pipe with packing around the outside to damp some of the noise. You are not going to find much difference between these pipes, there's nothing special going on inside. 4 strokes are far less sensitive and far less responsive to pipe changes than 2 strokes.

The wilder your 4 stroke engine is built, the more it will want a really free flowing exhaust, hence the more it will respond to an aftermarket pipe. This is why the new 4 strokes like the YFZ and 450R respond much better than the 400EX to an open pipe setup. You will only find minor difference in performance between open 450r/yfz pipes as well.

 

i have been using a slip on on my 400ex for the past year, had no problems and when i add more mods it still hols up great. i wouldnt bother getting the full system till you get it bored.