New Owner

[TXSASQUATCH]

Hey guys and gals, heard about this site from several folks/I was the reciepiant of a 04 YZ450F w/less than 30 hrs!!!!! I have a lot of backfiring on deceleration..Any ideas,any help appreciated, also can anyone suggest a good stiff spring for a heavy rider?

[georgedoggy]

check the sticky section of this forum, im sure there is a section on backfiring on 450's and how to fix it. im pretty sure its because your bike

is running lean.

as for the spring, im 250 pounds and i ordered the stiffest spring i could get! ask around and find out what guys your weight are using, it might be trial and error as ifound. i have gone thru 3 rear springs to find the right one.

[BergArabia]

yeah do like George says.

I think a little backfiring on decel is pretty normal.

If it is excessive you may be a little lean on the main jet.

Oh BTW the header will glo but it is supposed to do that.

don't leave the bike idling too long.

Enjoy. You have a great bike...?

[TXSASQUATCH]

It Has A M4 Exhaust And Does It Glow, Man That Bugar Gets Hot.. Thasnks For The Input

[TXSASQUATCH]

Thanks For The Input

[capfo]

What part of TX are you in?

[Bigcr]

If it's really popping a lot, check the pipe itself and make sure there are no leaks at the head or where the head-pipe meets the silencer. As far as springs go, check www.race-tech.com or www.mx-tech.com and use their spring rate calculators. Be sure to get the matching front springs as well.

[red7]

Congrats on the new bike! Start by going up a main jet size and see how that effects things.