Hardest Mod. yet!

[michaelj]

I finally got my 450r carb. jetted right! It only took me three weekend saturdays, it was very frustrating, I tried about 15 different setups(170 main all the way through to a 225 main). I am running a 170 main needle on the 4th position air screw at 2 turns out with a 50 pilot. It is alot snappy on the bottom end and mid range than the stocker...

I dont understand how other dudes are running over 200 mains on the board? It seems way to rich?

465 stroker kit
WB r4/powerbomb header
KN airbox cover
prodesign air filter
WB CDI box

[zrpilot]

There are a lot of reasons for jetting differences.
First, engines are ALL different.

Second things like environmental changes are different. Mine will be jetted at 30F and 800ft vs. someone at 70F and 1500ft.

Third engine mods make a HUGE difference. For example, cams, exhausts, compression ratios, ETC.

I believe jetting recommendations are just that, recommendations. You need to figure out what works best in your engine.

To answer your question, do you have a ported/polished head? If you do, then your engine may have a better demand signal and need a smaller jet to be at the correct mixture.

[drew416ex]

Like zrpilot said, every engine is different. I have a 440 stroker with a 39mm fcr running a 205 main. My buddy has the same settup except his isnt ported and is running a 450 carb with a 180 main.