Finally got this stuff installed and jetted. I had the muffler and header months ago, but couldn't install it because mid pipes weren't available.

Equipment: 17" AMA legal Titanium 4 muffler with spark arrestor end cap, PowerBomb header, K&N (on Alba adapter) with Outerwears, airbox vented with 18 (1 inch) White Bros vents, and that stupid cap removed from the end of the snorkle. Ended up with a 144 main jet (but it has a little bog on the bottom that is going to require some more carefull tuning). I will eventually open up the airbox even more with an EHS airbox vent (open airbox lid with Outerwears cover), but that wasn't available yet.

I am very pleased with the results!! The setup really increases the TORQUE of this motor. The stock Z engine can really rev, but it doesn't exactly have massive torque (patricularly on the low end) to back it up. Well, the pipe fixed that!! I am now riding a lot of stuff in a higher gear, so you don't have to ride it all reved out. In particular, it now climbs hills with much more authority. In the past, I have complained about this engine for trail riding (to revey, a light dirt bike fly wheel, engine won't lug down), but now with the mods, I would recommend it!! The engine pulls hard in the middle and top, and I can see that the stock suspension (particularly the rear) just isn't going to cut it.

FMF's dyno (www.fmfracing.com/ltz400.cfm) shows an increase of 2 or 3 hp on the bottom and 5 on the top. No doubt this dyno was done with the 14" muffler and no spark arrestor, but I would say the results are in the ballpark. Notice that the engine makes its max horsepower at a much higher rpm!! I would really like to see the TORQUE CURVE that goes with this dyno, because this is where the real story is told.

 

I ordered the Blue Anodized Titanium 4, 14 inch last week. It is on back order. They said put a 160 main and move the clip 4th from the top or bottom with the lid off for a big gain. I will try it when I get it. I can't wait!!

 

Yeah, my jetting seems lean. They recommend as I recall a 155-160. I ride mostly at moderate altitude ~4,000ft.

 

I have the 14" and putting it on with jets and the K&N made this thing wake up in a bad mood. It's cranky - especially at Raptors >[img]i/expressions/face-icon-small-smile.gif[/img]

It is loud though and I would suggest getting the optional spark arrestor tip if you ride trails.

MX

 

Here in Calif, you don't dare leave your driveway without a spark arrestor!! The 17" muffler is surprisingly quiet. It only gets real loud when you are hard on the throtle at mid to high rpm. This works good, because I can cruise through my neighborhood in a high gear a little over idle, and the thing is no more noisy than a loud street bike.