goose exhaust

i have some 4-2 straight pipes i want to put on. They are stock exhaust pipes fom a kz1000 with no baffles. I want to know if it would hurt the motor to have them on. The carbs are jetted for a 4-1 header. I didnt know if a 4-2 open exhaust would need rejetting.

Nick

Any time you change the amount of air getting into the engine (ie = pods, stacks or airbox) or air getting out (ie = stock exhaust, 4 into 1, 4 into 2, baffles or unrestricted) you change the ratio and are subjected to variations of how the engine will run. This is seen also where people who have switched to pods will frequently experience throttle fluctuation's when passing vehicles or when being buffeted by cross winds. These things like a constant air flow ratio. Disrupt it and you might not like it. Change it and you may have to re-jet to find the optimal. Another thing to keep in mind is there a crossover equalization tube between the exhausts? This is frequently overlooked. My 900 breathes out through 2 and 2 with no crossover to equalize the back pressure between them. It adds a slight difficulty in dialing it in but nothing big. A 4 into 1 should be equalized if it is any good and a bit easier.

the exhaust has an equalizer tube, if that makes a difference.

I kind of take it you are resistant to re-jetting. How much do you want to switch exhausts? If you are serious about switching go ahead you may get lucky. You may have to re-jet or you may be able to switch back. Nothing is irreversible or unfixable in this. Stock exhaust with stock airbox and filter should take stock jets. This is your control. Change 1 factor and you MAY get away with it but change two and you'll certain need to adjust. Do you know if she has been re-jetted already?

The carbs have been totally rebuild and rejetted for pods and 4-1 header.

Why don't you just try it then see if it needs rejetted? It could be spot on or maybe just the clips need raised or lowered but no jetting changes. Trying to guess ahead of the mod is pretty hard to do. As far as hurting the engine, probably not as long as you see how it runs first then check the plugs for too rich or too lean. Personally I never liked the sound of stock 4 into 2's with the baffles out, tends to cut the top end too. Not knocking it if you like the sound so just do it and see if you think it needs jetting.

KZ_Rage wrote:

Why don't you just try it then see if it needs rejetted? It could be spot on or maybe just the clips need raised or lowered but no jetting changes. Trying to guess ahead of the mod is pretty hard to do. As far as hurting the engine, probably not as long as you see how it runs first then check the plugs for too rich or too lean. Personally I never liked the sound of stock 4 into 2's with the baffles out, tends to cut the top end too. Not knocking it if you like the sound so just do it and see if you think it needs jetting.

I agree with you Jim

just tried it, its loud but its nice!!! Im gonna wait till the motor cools to check the plugs.

NickW900LTD wrote:

i have some 4-2 straight pipes i want to put on. They are stock exhaust pipes fom a kz1000 with no baffles. I want to know if it would hurt the motor to have them on.

I would guess straight pipes would run very lean.

They will also destroy your hearing in short order.

Post edited by: bountyhunter, at: 2008/02/08 13:23

[qoute]They will also destroy your hearing in short order.<br><br>Post edited by: bountyhunter, at: 2008/02/08 13:23[/quote]

Fo sho. I ran my 1100 with 2 and 2 straight pipe for a while. It was loud and could give a headache. It was even louder than my 370 dirtbike with no baffles on the end of the expansion pipe.:evil: