Your the only one who will know. How is your Z running? Does it backfire? Does it seam sluggish on acceleration?

If you backfire, that means you are too lean, and should go to a larger jet, If you are sluggish on acceleration, it could mean you are too rich. Also you can ride for a bit and check your spark plug for color, which will indicate if you are running rich or lean.


P.S. the Z450R is the "new and improved EFI Z400".

-ThaChad

 

You are absolutely right. The bike runs great now, no backfiring, good acceleration. It was just that one of our riding buddies had questioned the jetting.

My concern is that the new 450 will not want to putt if we are doing that - too race ready, in other words. We do have some friends that don't like to fly so on the 400s we are able to go either way. Guess we will have to wait and hear what the new owners say about the 450s. We do have a friend that rides a YFZ450 and I would say that he rides with his younger daughter and doesn't push the throttle so it goes slow or fast, I guess.

 

You had mentioned that you had increased your stock jet with a slightly larger jet, which probably was enough to compensate for the filter/lid change... no matter how much you increase the air flow in, the engine will only suck soo much air. If/When you change your exhaust and the engine is able to flow more, than you will definitly need to rejet. The increased intake flow, and increased exhaust flow kind of go hand and hand. Replacing only one or the other will give slight differences, but to get the biggest gain, you would need to increase both the intake and the exhaust flow. If your Z is running good, thats all that matters, If it ain't broke don't fix it.

I have not gotten to see, or ride the new 450R, but I would think being fuel injected, it should be able to putt all day with out problems, but as you said, we will all see when people start getting them and posting results.

-ThaChad

 

My perpensity to provide extra information stems from the belief that most people are looking for that extra horse power that lurks within their stock engine. It happens when you hang out in the Bombardier forum for a while. If you're happy with your set-up thats all that counts.

 

Thanks for all the info. Actually I enjoy reading about all you guys' modifications. Think someday I will probably get a 450 with EFI. This will solve the jetting problems and then all you need to do is add power if you can't make it fast enough to the top of the dune!
Merry Christmas and happy riding. We are headed for Glamis in Feb. Whoopee[img]i/expressions/face-icon-small-smile.gif[/img]

 

I was eyeballing the 450 as well. Can't wait to see if they live up to the hype.
Merry Christmas and have fun in Glamis.