Hey Fellas'

Just thought I'd post something on the June 2001 ATV Sport issue. They did a shootout with 17 pipes for the 400EX.- and I got to say... I don't know who these morons are- but I would think (and hoped) that the editor would have slapped them on the side of the head and say, "what were you guys thinking"! It's a good thing these people aren't doing drug (pharmaceutical) research- because we would be in a world of trouble.

Rather than trying to compair apples to apples- they mucked everything up by compairing the pipes with the manufactures "reccomendations". For example, Curtis Sparks was the Highest producing pipe on the dyno charts with a 27.8... compaired to 2nd place winner- White Bro's 27.6. The problem?... with the curtis sparks, they followed manufacture reccomendation and took the airbox lid off. Whereas the WB airbox lid was left on.

Duh- any monkey knows that if you take an airbox lid off it's going to produce more airflow... resulting in more power!!!. Of course a manufacture will reccomend this. And to further the list of stupidity- they compaired 15 other pipes... some were full pipes, compaired to slip-on.

Lastly- there was NO JETTING done to any of the tests. There claim was that it would take too long. Well- actually- they should have said they were just too damn lazy. It doesn't take that long to rejet a bike. At the most... a few hours per bike. But think about it- Each pipe causes a different type of airflow- resulting in a different jet needed. It blows my mind that this didn't occur to them.- and of course... it's going to mess up all the results.

If a magazine wants to do a pipe compairison- they need to do all the little things- or it's not going to matter what results they produce. Jetting is EVERYTHING. You might get lucky and slap on a pipe where the air/fuel mixture is correct- but I'll guarantee you this... 90% of those pipes were not producing full power- and to compair a slip-on to a full pipe... with some with the airbox lid off is absolutely obsurd!

two thumbs down to the staff of ATV sport-

 

RotGutBottom,

I totally agree. I bought this issue of ATV Sport, and thought it was going to be a decent test of the exhausts. Boy, was I wrong.[img]i/expressions/face-icon-small-disgusted.gif[/img] They shouldn't have tested and compared full systems and slip-on silencers together. I was also upset that they used the recommendations of the manufacturer. This makes it unfair to the others. ATV Sport should have used one of those air/fuel mixture machines that tells you if the caburetor is jetted right, and then run the silencers together, and the full systems together. Maybe there will be a good, fair shootout in a magazine in the next decade.[img]i/expressions/face-icon-small-confused.gif[/img]

 

I agree that they shouldn't have compared slip-on to full system, and the part about manufactures suggestion or whatever. But the part about jetting? Over half the people that buy an aftermarket pipe aren't going to re-jet. Everyone that has a pipe around here doesn't re-jet. Everyone that I know that has an aftermarket pipe doesn't re-jet. The fact of them not re-jetting was smart. It shows what the pipes give without the help of anything else. I have the article, but all I did was read which one came in first, just like most shoot outs they do.

 

Agreed, also that Dirt Wheels beat them to the punch a few months earlier. I feel was a fair compair. If the manif has suggestions, then go with them for jetting, as this can take a while to keep swapping jets looking for the right one. Leave all the box lids off since anything beyond stock it will hinder.

 

97300exguy...

I'm not attacking you or your friends here- but why spend all that money on a pipe, especially a full pipe- and not rejet? Yes, you'll get a SMALL increase in horsepower- but the main idea to putting on a pipe is not so it sounds cool-... it's to get better airflow. Airflow won't do you much good if your fuel mixture isn't changed... and on top of that- you are going to burn your engine out much earlier because your machine will be running LEAN. It defeats the hole purpose of of increased airflow- you need to feed the engine with some fuel... you are basically starving it. Anytime airflow is changed on a bike- IT MUST BE REJETTED to get the full benifit. Without jetting- you are only getting about HALF of what the power increase should be. Rejetting is really easy- anyone can do it. I'll have to admit- I was scared to death to touch anything under my seat when I first got my 400ex- but by doing it yourself- you learn quickly how to do it... and when it comes time to changing a jet... it only takes 10 minutes. I can rejet my 400ex and hit the nail on the head after about 3 different sizes... all in about 30 minutes.

So I suggest to you- and all your buds that have changed airflow (this includes removing the airbox lid) go out and buy the K&N dynojet kit. This will give you about 10 different jets to choose from- and anytime you change airflow- you got the goods to take full advantage of the hop-up. I happen to live in Utah... elevation about 5300 feet. When I ride in the mountains (6000 feet) my machine runs like crap. When I take long weekend vacations (+3 days)- I take the 5 minutes to rejet my carb.

In summary- Jetting is everything. Give it a try- and you will absolutely FEEL a difference in how hard your quad pulls off the line. (everyone I know out here- rejets)

 

I've always thought about getting one, but never have. I'm probably going to order one soon. What should I jet mine to with a white brothers e-series slip on and a K&N Air Filter? I have a 97 300ex if you don't already know.

 

It's hard to say what jet size to reccomend. Someone can have the exact same setup as my bike and run a completely different size jet. It's specific to the bike-. Also altitude plays a BIG role.

My reccomendation is search for JETTING questions on this board. I've posted a few... Also- Post something for other 300ex users and find out what jet they are running... what altitude.. and their setup. The more airflow you increase... the bigger the jet. I would go 2 sizes bigger than what people say they put on their machine... then drop 2 sizes on the next try. Then go up one size if needed.

To test to see if you got the right size... do this test (after you "think" you got the right size)

- remove the air-filter and run it open throttle for about 200 yards.
- now, put the air-filter back on and tape 1/3 of it with duck tape. (reducing airflow).

If it runs WORSE with both of these tests- YOU GOT THE RIGHT SIZE JET.
If it runs better with the filter off- You have TOO BIG of a jet (decrease 1 size)
If it runs better with the filter taped- You have TOO SMALL of a jet (increase 1 size).

When you get the proper jetting- you will find an amazing amount of off-the line starts and wheelies should pop right up.

Dynojet kits have very easy instructions- and I know somewhere on the NET is a step-by step picture instructions.

Hope that helps..