Most of my riding is btwn sea level and 3000 ft. As of now, my 03 z400 is bone stock running 91 pump gas and i do change tranny oil frequently.

I ordered the K&N with outwears from ALBA and about to install it. I was told that the main jet needs to be changed to accomodate for the higher air flow. Is that the real deal? and if so, what size do I need to change it to?

any help would be great, im usually on a dirtbike, but i want to get this quad dialed in.

thanks!

 

Im not an expert but I would have to say at that elev a 165 might be close. Every bike is diff, they sent me a 165 with my pipe. Finaly it seems to run the best with the 180.

 

I agree w/above post. Your quad will not run good at all without changing jets, and a 165 would be very close if not right on.

 

If you're just changing the filter without opening up the airbox (take off the snorkel noise baffle or take off the lid) the change in airflow is going to be insignificant and you shouldn't need to rejet. At the most you'll just tweak your idle fuel screw.

at 800 feet, I had to change to a ~140 or 145 when I took the noise baffle off of the snorkel (no slip on or anything else)

165 is absolutely an overkill for just a filter change, especially if you want your Z to run at 3000 feet.

BTW, the Z isn't made to run on premium (91 octane), it's meant to run on normal (87 octane) fuel. Changing your jets while running 91 is just going to make you do it improperly.

 

Corpsie, its a 11.1 compression motor. You think 87 is best for that? Did you read the manual?
Put 91 in it.
The jetting will need to be bumped about two sizes from what is in there now. I think its a 142 stock, try a 145, or 148 ish.

 

Sorry Guys I thought he was talkin pipe too!!! Their was another guy who was talkin about a slip on and no lid.KGB you might be right - might even be able to take the shooter out with those sizes you mentioned.

 

Corpsie is right. Very little (if any) jetting will be needed for just a filter.
As for the gas, I like to run 50/50 87 and 110 race gas for a nice clean burn. I've run straight 87, 89, and 91 and they all run the same, but who knows over the long run how everything will look inside with the lower octane?

<edit> Where from in Cali Viperdad?

 

It's funny that you mention reading the manual and then tell me that 87 (regular grade) octane fuel isn't appropriate.

87 IS the right fuel

Also, 11.1:1 is the geometric compression ratio, due to valve overlap that is not the effective compression ratio. Do a search about the 1999 Toyota Prius compression ratio. The geometric ratio is 13.5 to one, due to valve overlap the effective ratio is 9.5:1. They do this to get maximum expansion work from the expansion stroke.

 

The Z400 comes with a 130 main jet stock.I jumped up to a 175 main jet recomended by HMF with the (full system) and it runs like a bat out of hell.
There is no way I would run 87 octane in my quad,I'll put in my truck when I'm broke though [img]i/expressions/face-icon-small-wink.gif[/img].

 

hey LTZevil400..... im in OC.....Hunt Bch to be specific.
You close to that?

Just got back from Beaumont last night, what a killer spot to ride! Quad heaven out there!