Can I ride without my exhaust cans?

[silverbullet132]

I can't put the cans back on myself, my riveter won't work with the rivets needed. So, would it be ok to ride with the pipes + baffles on but no cans?

Also, should I weld it back together or would riveting be a better idea? I do not plan to open them ever again.

 

[jay-d]

I can't put the cans back on myself, my riveter won't work with the rivets needed. So, would it be ok to ride with the pipes + baffles on but no cans?

Also, should I weld it back together or would riveting be a better idea? I do not plan to open them ever again.

Sometimes the things we plan not to do, we end up doing down the road.

You can ride without the cans, but it will be loud as hell. You might lose power because depending on your bike, your engine might require back pressure to work optimally. If this is temporary, sure.. but all the time? Hmm... shift before 3k every time? :lmao:

 

[silverbullet132]

I do that anyways haha
Its a 1982 Honda Sabre V45

 

[frekeyguy]

On the way to Dover this weekend, a chick on her R6 rode with no midpipe/exhaust can.....DAM! it gave me a headach!

 

[El Zilcho]

You might lose power because depending on your bike, your engine might require back pressure to work optimally.

I doubt that there will be any difference. An engine can gain a bit of power with a lower back pressure if the fuel injection is adjusted, but a mere decrease of back pressure without any other changes shouldn't really have any significant effects.

 

[frekeyguy]

I doubt that there will be any difference. An engine can gain a bit of power with a lower back pressure if the fuel injection is adjusted, but a mere decrease of back pressure without any other changes shouldn't really have any significant effects.

backpressure + valves.....

 

[El Zilcho]

backpressure + valves.....

You've mentioned that to me before, but however I look at it I can't come up with any hypothesis about why that would have any effect.

Lower backpressure would simply cause the exhaust gases to escape more quickly. The "wind" could push the exhaust valves back in (as in "closing" them), but since the valve position are controlled by the camshaft and the return springs (hopefully without any floating), the valve movement wouldn't be affected.
In the intake phase, the initial pressure in the cylinder would be lower, causing more air to enter (but with final pressure unchanged). If the amount of fuel injected does not change, the amount of generated power shouldn't change either, if the engine was tuned optimally to begin with. (This is assuming that the additional amount of air wouldn't affect the burning process.)

 

[silverbullet132]

Thanks for the advice.

My bike is carb'd, and even though there would be no can on the exhaust, the baffle would still be there so when I take it out later today hopefully it is not too bad.

 

[El Zilcho]

Thanks for the advice.

My bike is carb'd, and even though there would be no can on the exhaust, the baffle would still be there so when I take it out later today hopefully it is not too bad.

You could put those leather strips that you can sometimes see on cruisers' handlebars on your pipes. That would look badass (or funny)... lol

 

[socially distorted]

ok... go easy on me but I'm serious: what the hell are "cans" [and i'm not talking about female anatomy]! I always thought "cans" were simply the muffler part of the exhaust system, with the baffles inside.

 

[bear22099]

You've mentioned that to me before, but however I look at it I can't come up with any hypothesis about why that would have any effect.

Lower backpressure would simply cause the exhaust gases to escape more quickly. The "wind" could push the exhaust valves back in (as in "closing" them), but since the valve position are controlled by the camshaft and the return springs (hopefully without any floating), the valve movement wouldn't be affected.
In the intake phase, the initial pressure in the cylinder would be lower, causing more air to enter (but with final pressure unchanged). If the amount of fuel injected does not change, the amount of generated power shouldn't change either, if the engine was tuned optimally to begin with. (This is assuming that the additional amount of air wouldn't affect the burning process.)

I have never really understood why people say low back pressure will hurt valves (along with not having manifolds or headers on, exh port wide open will cause valves to be hurt by the "cold" air hitting them) and then offer no reasoning. Only reason I can come up with is it may be a bit leaner with lower back pressure, causing a higher temp of exhaust, thus burning a valve, but have never seen it happen.

 

[JohnnyP636]

I have never really understood why people say low back pressure will hurt valves (along with not having manifolds or headers on, exh port wide open will cause valves to be hurt by the "cold" air hitting them) and then offer no reasoning. Only reason I can come up with is it may be a bit leaner with lower back pressure, causing a higher temp of exhaust, thus burning a valve, but have never seen it happen.

Correct running lean because you removed the exhaust can cause burnt valves........Simply put its not good because the motor is not tuned to run without the exhaust...It can run fine without one if it was tuned to do so, but just taking it off is asking for problems
http://mechdb.com/index.php/Exhaust_back_pressure_myth

 

[matt123]

I was told by a mechanic that running the bike with lower back pressure will move the power band higher because of reduced savaging effect at low rpm .He explained that an properly engineered exhaust will actually clear the gases from the cylinder in pulses.The speed of the leading gas pulse leaving the exhaust will pull the next exhaust pulse out behind it(scavenging).If it's too restricted or open it messes with this effect and poor drivability will result .I was chastised for using the term back pressure because it's leads one to miss the point.
Also if the exhaust is too open the valves will hit the seat harder than designed(valve springs)and will harm the valves over time

 

[El Zilcho]

Correct running lean because you removed the exhaust can cause burnt valves

What exactly would be the temperature difference? 20C more? 100C more? With the temperatures that are already in the exhaust I'm feeling somewhat skeptical about this. Have you seen burnt valves due to simply removing an exhaust (i.e. no other modifications)?

 

[JohnnyP636]

What exactly would be the temperature difference? 20C more? 100C more? With the temperatures that are already in the exhaust I'm feeling somewhat skeptical about this. Have you seen burnt valves due to simply removing an exhaust (i.e. no other modifications)?

I have seen burnt valves in engines that weren't tuned properly, removing an exhaust without retuning will cause an engine to not be tuned properly...There are millions of engine and exhaust combos, you cant pick a magic number for all of them...Point is removing an exhaust effects the A/F ratio, most commonly making the engine run too lean, engine running too lean burn valves...So removing an exhaust completely (without re tuning) can and will cause premature valve wear, among other problems...How much or how soon is too broad of a question with the millions of possible engine/exhaust combos out there....

 

[Stewart]

if you increase the exhasut, you must increase the intake. and vise/versa. plain and simple rule of tunning.

 

[bear22099]

Also if the exhaust is too open the valves will hit the seat harder than designed(valve springs)and will harm the valves over time

Can't possibly close harder. Think about it, the valve is being held open buy the camshaft, and is closed by the spring pressing the valve stem against either a cam follower, or a rocker. It is physically impossible for the valve to close harder.

 

[silverbullet132]

Update:
Got a video of it after the packing was removed, here it is:
[video=youtube;45GuSImGEAk]http://www.youtube.com/watch?v=45GuSImGEAk[/video]

 

[toysareforboys]

Update: Got a video of it after the packing was removed, here it is:

Keep the camera much farther away when recording the video to stop the mic from clipping =)

-Jamie M.

 

[TheDirty]

I was told by a mechanic that running the bike with lower back pressure will move the power band higher because of reduced savaging effect at low rpm .He explained that an properly engineered exhaust will actually clear the gases from the cylinder in pulses.The speed of the leading gas pulse leaving the exhaust will pull the next exhaust pulse out behind it(scavenging).If it's too restricted or open it messes with this effect and poor drivability will result .I was chastised for using the term back pressure because it's leads one to miss the point.

Your mechanic is correct. Pressure waves give the main scavenging effect. Pipe (header and main exhaust) lengths and widths effect timing and duration of the pressure waves and on properly engineered systems are tuned for specific effect.