Starting w/o Exhaust system on

I just bought a 1974 Z1-900. It has the original exhaust w/ it but it's currently off the bike. Is it safe for the bike to try to start it with out the exhaust on it? Is it possible to damage the motor that way?

Jason

DUDE!!!!
I have no idea. As long as you don't run it for hours without exhaust pipes, I kinda think it won't harm anything. But, I could be wrong.
HOWEVER, DUDE That will sound LOUD!!!!! Oh Man I'd love to hear that!!!!!

Rock On!!!

I once started, and rode around a little, a CB750 without the exhaust. Really really loud, and flames came out of the exhaust holes. It was pretty cool.

It would not be advisable, it is too easy for the cold outside air to get in there and bend a valve.

DO NOT RUN THE BIKE WITHOUT IT!!!, it will bend / burn valves!!

i think if you just want to know if it will start, fine, run it for a few seconds and then shut it down.
and how is cold air going to bend a valve?

This is not a great idea. Cold air pulled into the combustion chamber (COLD AIR WILL BE PULLED IN) will hole a piston in very short order. Like I said, not a great idea to start the bike without the exhaust.

flht1997 wrote:

i think if you just want to know if it will start, fine, run it for a few seconds and then shut it down.
and how is cold air going to bend a valve?

Because it will not cool the valve equally.

A long time ago when I was 18 years old I worked for a metal fabrication shop, and my job there was to straighten rather large I-beams. This was accomplished by heating one side with a torch and throwing water on the other side. Since heat and room temp water can bend rather large I-beams (as in 36" across the web), I have no problem believing it can do the same thing on little valves (heat and room temp air).

I don't think running it for just a few seconds will get the valve hot enough to cause a problem though.

Yes, I'm just looking to start it for 5-10 seconds.

Jason

ok i agree cool air will be pulled in. but what temp exactly is the temp of the air coming in the intake side? i know the exhaust side is closed and the stem will not receive any cool air blast, but i feel that the mixture, while it will be affected, will not be signicatly leaned to cause engine damage when run for a short time.

5-10 seconds will be ok. Just don't get crazy and rev it up. You will tweek a valve or four. Then you will have to crate it up and give it to me. Or better yet, send it to me before you abuse it. I have a shelter for abused kz's.

donthekawguy wrote:

5-10 seconds will be ok. Just don't get crazy and rev it up. You will tweek a valve or four. Then you will have to crate it up and give it to me. Or better yet, send it to me before you abuse it. I have a shelter for abused kz's.

thats touching don:blush: you are a humanitarian!i nominate don for one of those nobel/kawasaki peace price things!