Found out why the bike dies with straight pipes!!!

[Detman101]

Check it out! Scavenging is the answer!!!
So THAT is why the bike dies when I run the straight pipes!!

"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."


YAY!!! This means I haven't killed the engine after all!!!

Dm of mD

[scotty]

All o my bikes run with muflers megaphones or straight pipes. If there is a drastic change something else is wrong,((NO IM NOT SAYING TWEAKING JETS IS NOT NECESSARY BUT THE CHANGE SHOULD NOT STOP YOUR MACHINE FROM RUNNING.)) caps lock again

[gsbill]

Usually, a good pipe is added to enhance the motors ability to breathe..Its a piece in a puzzle. Headwork, cams, big carbs, usually velocity stacks or at least hi flow air cleaners. You can put a pipe and jet kit on a stock motor and loose power or move the power band to make the bike suck for a daily driver. If you worry about fuel economy at the same time looking for more power, you re chasing your tail. More power equals the burning of more fuel and moving more air through your engine. Its a personal choice..

[Detman101]

All o my bikes run with muflers megaphones or straight pipes. If there is a drastic change something else is wrong,((NO IM NOT SAYING TWEAKING JETS IS NOT NECESSARY BUT THE CHANGE SHOULD NOT STOP YOUR MACHINE FROM RUNNING.)) caps lock again

Yes Scotty, but are they the STOCK straight pipes!?
I had the stock pipes on the bike with the mufflers chopped off.
I'm sure that Suzuki never designed those pipes to run without the mufflers. That's why they were welded on there so darn good. :P


Dm of mD

[lhanscom]

Those chopped pipes probably worked pretty well at 10,000 rpm, full throttle, but had zero power low to mid rpm. Short, straight pipes, are a horrible mix for street riding.

[Detman101]

That is just the confirmation I needed. God bless you Luke.
I think that I am going to be riding the GS again VERY soon...like TONIGHT!

The hell with the mods. I'm gonna ride!

Dm of mD

[Anonymous]

whats interesting is that i actually had this working pretty well this spring... i was putting a new 4 into 1 on my bike but i wanted to play with jetting and things with the just the old headers on to get things close. I was surprised at how well it worked.

[Detman101]

What bike you have and what settings did you use?

Cause nothing would work right for me and I wasn't about to take it to the shop to get dialed in.

Dm of mD

[Anonymous]

i have a 79 gs750....pod filters. I rejetted the carbs four sizes larger by what everyone on this site had been saying and started tuning it myself with just the stock headers on so i didnt blue my new 4 into 1 pipe. It seemed to work alright. I couldnt tell you about how much more power or anything like that but it was definately drivable.

[Detman101]

Well, I'm glad it worked out for you.

I'm running cv carbs and no one ever posts info on how to rejet with those for some reason. SoI'm dropping it off at the shop.

Dm