No Mo Muffs and now No Mo Crossover

[Anonymous]

All I have now is the header pipes. While I have them off the bike I am going to paint them with high heat resistant flat black.

It looks like the OD is 1 1/2 inches.

I rad somewhere that the Yama XS650's prefer someking of muffs but another guy said long sytraight pipes work well too.

Any opinions on what I should try first with my gs450?

[Anonymous]

at least a good crossover pipe at the torque burns in your paint will let your engine maintain max torque efficiency, you should be fine with the straight pipes but watch your plugs for a lean burn. then jet accordingly. (don't forget to resync the carbs after a rejet.)

[Anonymous]

[quote="Don Watson"]at least a good crossover pipe at the torque burns in your paint will let your engine maintain max torque efficiency,

What??????

[Detman101]

So, straight pipes don't require jetting changes, right? Actually, they usually do. See it's a trick
question. By not providing good cylinder scavenging, at least as good as the stock system, a
couple of things happen. First, more exhaust mixture may remain in the cylinder, diluting the
fresh charge for the next intake cycle. This may also mean that less fresh charge will enter the
engine because we've effectively cut down on its ability to flow air. So now we open the throttle
further in an effort to get some of our power back. But we're not providing as much signal to the
main jet. What this all means is we often end up having to rejet the carburetor(s), usually richer,
to get some of our power and driveability back. Gas mileage usually suffers as well. The
motorcycle may sound like it's fast, but put it on a dynamometer and there may be little to no
gain in power over a good stock system. This is in spite of the stock system's more restrictive
mufflers.

[Anonymous]

by having a crossover in your exhaust system it helps tremendously in the exhaust scavenging process. if you spray some paint on your exhaust pipes and run the engine around the block a couple of times the paint will have burned in several locations, these are called torque burns. also the discoloration of the cromed pipes are the same as the paint burns. so with no crossover then detman is correct in stating that you need to rejet. however with a properly placed crossover tube between the longer headpipes, there is a much less need for a rejet change.