I'm thinking about getting a silencer for my 99 400ex. I don't want to go with the whole pipe, just because of the money. My first question is, what type of horsepower difference will I feel with just a silencer? Is it worth the money? Will I need to re-jet the carb, and if so, what sizes? I'm thinking about going with the white bros. e series, or the yoshimura. Do you have any experience with either of these, or can you suggest others that I should look at? What are the prices, and where is the best place to buy them online. Sorry for all the questions. But thanks for your help.

 

Yes you will have to rejet. Pick up a DirtWheels and look through all the ads, there are tons of people selling the header pipe and silencer for your quad. A previous DW issue also did a pipe shootout for the 400EX, the White Bros E-series I believe won the shootout.

 

If you put a new silencer on your quad, you will notice a major low to mid-end power increase. In my opinion, yes it is worth the money. For a decent pipe, you are going to spend around $250. As for having to re-jet the carb, that depends. I asked the same question, when I bought my FMF pipe for my 400ex. I was told to put the pipe on and then take it out and run the crap out of it in every gear. If it backfires at high rpm's then you will need to re-jet. Mine never back-fired so I didn't re-jet it. A couple months later I invested in a K&N powerkit, and I ended up re-jetting my quad for that. I honestly don't know which is the best way to re-jet size-wise.

Both the White Bros. E-series and the Yoshimura are good pipes. To be honest with you I was planning on investing in a White Brothers E-series. Instead, the dealer that I bought my pipe from talked me into the FMF. Still today I am really pleased with the FMF. I don't really know a whole lot about the Yoshimura, but I am sure that it is a pretty decent pipe. As for prices, like I mentioned above, for a good pipe you are going to spend around $250 for a slip-on pipe.

Like what Briangi mentioned, I would go through Dirt Wheels Magazine looking for web-sites that sell 4-stroke pipes. That is an excellent idea. Some places don't charge shipping if your order is over $100 which is a pretty good deal. I hope that I helped answer some of your questions.

Fourtracker14

 

www.rockymountainatv.com does not charge for shipping on the quad exhausts, and they usually have good prices also.

 

I have the Duncan Fatboy 4. I noticed a huge difference in power. It was definately worth the money. You should replace the air filter too. Then you will need to re-jet. It's fairly simple. If you want I can E-mail you pics of the silencer mounted on my machine so you can see what it looks like. I don't know too much about the other pipes. I am VERY pleased with the results that I have achieved. Let me know!

 

I just put on the Yoshi "Race" slip-on pipe, K&N filter, and stage 1 jet kit. It made a big difference...as far as a "seat of the pants" ride test goes. I followed the jetting suggestions that came with the jet kit, and they were right on. My pipe was $270 from atvaddiction (it costs about $350 most other places, because it's titanium). There is a stainless steel "competition" version that normally sells for the price they gave me, but since they were out of that model and I'd done business before, the guy gave me a "one time only deal". I have given them alot of business, and they don't charge alot for shipping. It only cost me $7 to ship the pipe, and when I got my skidplate and bumper, they only charged $9. Great service earned them a return customer.

 

If you get just the silencer, you can also take the dremel and grind out the welds on the inside of the headpipes where they mount to the cylinder. A friend who bought a Pro Circuit silencer was told by Pro Circuit themselves to do this.