Is it true?

I was told that running my pipe cut way short and open will burn the valves around 4000 miles or so,is this true?

theres a reason why we used to shove a towel in the end of an open header after racing,ive since learned to run atleast an endcap

Having an exhaust like that allows cool air to go up to the hot valves and possibly warp them.

Bluemeanie wrote:

Having an exhaust like that allows cool air to go up to the hot valves and possibly warp them.

Yep, that's what I was taught as well.

When the bike is off is that what you mean?

kzmarvo wrote:

When the bike is off is that what you mean?

When a hot motor is first shut off, am guessing the towel stuffed into exhaust is to help keep the hot air inside the pipe and prevent cooler outside air from entering the pipe and traveling up to the hot exhaust valves and cooling them too quickly.

Was taught not to run the engine without headers attached (exhausting from head ports directly into open air), as that exposes hot exhaust valves to open air whereby the valves may be warped.

Am thinking that running headers alone isn't so risky as running without headers. But don't know how short the headers could be without genuine risk.

Am thinking that running just headers likely results in poorer overall performance, even if it doesn't risk exhaust valve damage.

And that racing performance will be better with a good 4>1 exhaust system, and poorer if just running open headers.

Good Luck!

lemmee get a pic on here...1 sec

My work in progress,she is painted now though,about a week from the streets..

Very nice looking, what kinda swing arm ya got back there? Would highly recommened running some kind of muffler as the PoPo wouldn't like you!

the only guy's that you will ever see running open shorty pipes like that are guys that are running injected nitro in there big inch drag motors and hillclimbers that are running huge amounts of alcohol through their 1400cc+motors and the do it mostly because of ease of maintenence easier to remove and replace one pipe than 4 after it has been crushed it isn't for a performance advantage that's for sure. i can tell you from personal experiance after running straight wide open pipes for awhile on ridgid framed xs650 they are a total nightmare when it comes to the gestapo you might as well put a sign around your neck saying kick-me. the cops were on me all the time until i put mufflers on it. and lo and behold the bike ran better as well. so two benifits came out and slapped my hard core biker ass the bike ran better and the coppers were gone so good news on both fronts. and what the hell is that sign over your door way it had better be leading to the bathroom!!!!!!!!!!