Baffle Out?

[troyleepred719]

I just took my baffle and end cap off of my stock echaust on my Predator, and was wondering if there is anything i should be aware of? I dont have anything inside it, when i started it up, it would hit rev limiter and half throttle but i let it run, and it was fine. i love it without it, it makes beautiful low end, and i love ht esound. i just broke My HMF pipe, and they wouldnt cover it, so im thinking about just keeping it this way, seeings how i will only be racing hare scrambles this year.

[krt400ex]

if it works then keep it like that....i dont see it hurting anything

[Ron89]

LOL on thumpertalk, you would be getting raped with stupid remarks right now. People over there need to chillll.

[esr250r86]

Nothing will happen it will just be louder and maybe a little more power. The worst would be a backfire or something.

[Ron89]

Correct me if I'm wrong but you can float valves with a lack of back pressure right?

[krt400ex]

Originally posted by Ron89
Correct me if I'm wrong but you can float valves with a lack of back pressure right?


not that i have heard of...exhaust gas it a totally different subject than floating the valves.

floating the valves comes from running a cam that is too aggressive for for the valve springs that your running...it is caused by high RPM running and weak valve springs...not exhaust gas. that is why so many people choose to run HD valve springs when they install a radical cam...it helps cut down on valve float

[troyleepred719]

what if i just put end cover back on, and cut a larger diameter hole and take the turn down off, a little more back pressure, with same concept.

[krt400ex]

Originally posted by troyleepred719
what if i just put end cover back on, and cut a larger diameter hole and take the turn down off, a little more back pressure, with same concept.


if you like the way it runs now...then why would you do that? it is not hurting the engine...you even said that you got more bottom end out of it. i would just leave it. odds are your already jetted right too cuz of the s/o you had on it b4

[troyleepred719]

i went back to stock jetting when i put the stock one back on. it runs great, should i go back to the other jetting, im thinking about putting a few hole vents in the airbox too, maybe it would wake it up a little, forgive me man, im a little new to quad maintenance, my dad always crew chiefed everything, but since he got sick, its all me, and i refuse to give up on the racing, cause he wouldnt want me too...

[krt400ex]

i would compare them and see what jetting makes the machine run better.

IMO if you vent the airbox lid...then you will definitely need to go richer with the jetting

[Ron89]

I don't know, I THOUGHT I remember reading how a lack of back pressure adds resonance and prevents the valves from seating properly. Maybe I'm thinking of something else.

[400eXr1d3rZ]

Originally posted by Ron89
I don't know, I THOUGHT I remember reading how a lack of back pressure adds resonance and prevents the valves from seating properly. Maybe I'm thinking of something else.

You don't need backpressure, you can run no exhaust if you wanted to, just rejet. I'm not sure about running no header though, but I know there's no problem with running no muffler, just REJET.