I think I've blown a head gasket

I got my '82 GPz750 running about a month ago and it's been doing pretty good until the past few days. In the afternoons on the way home it's been loosing power at highway+ speeds. I'll down shift to get back up to speed and it will pick back up. It might repeat this once, twice at the most then i wont have a problem the rest of the way home. It's stalled a few times as well but it was at the bottom end of the tank so I figured it was just starting to starve of fuel and about to hit reserve. Perhaps the petcock was going bad so i would switch it to prime. That seemed to help until today. i couldn't get it to maintain speed on the highway at all and exited ASAP. I took the surface streets home and it seamed to do better but would stumble from time to time but run strongly at other times.

I was also thinking I might just need to readjust my valves, resync carbs and all which I was planning on doing this weekend and maybe do some ignition diagnostics for good measure. I was also going to replace my oil pan due to a leak at my drain plug and replace my headers at the same time.

Now as I was in the garage a few minutes ago to spray Kroil on my exhaust flange bolts so I could remove them tomorrow I noticed that there is some black soot on the right front of the fuel tank. It's black and dry to the touch so it doesn't appear to be a leak from my oil cooler and I can't really see anywhere else it might be coming from since the GPz engine is black as well. Would i be correct in assuming that this indicates a head gasket leak? If it is this is curtains for my abbreviated riding season and I'll just start to tear it down for my long term referb and improvements I'd like to make and look forward to next spring.

It's a bit of a long shot, but check to make sure the petcock screen inside the fuel tank isn't clogged up; also, if you have an inline fuel filter make sure it is not clogged. Ed

650ed wrote: It's a bit of a long shot, but check to make sure the petcock screen inside the fuel tank isn't clogged up; also, if you have an inline fuel filter make sure it is not clogged. Ed

I'll check that, thanks!

Realize that valve clearance decreases with mileage and eventually the valves don't close anymore and then they burn. Once the engine starts to misbehave it's too late to avoid damage. Hopefully this didn't happen on your bike though.

Nessism wrote: Realize that valve clearance decreases with mileage and eventually the valves don't close anymore and then they burn. Once the engine starts to misbehave it's too late to avoid damage. Hopefully this didn't happen on your bike though.

Any damage would have already been there. When I go the bike it only had clearance on 2 exhaust vales and no compression at all on one cylinder. I set the clearances about 1 month and less than 1k miles ago.I was going to go back and reset everything this weekend anyway.

Set your valve clearances and check for a exhaust leak.
Steve

Oh, and greetings from Grants Pass Oregon. Horrible corrupt little town. Can't wait to leave.
Steve

swest wrote: Set your valve clearances and check for a exhaust leak.
Steve

That will be handled regardless I guess since I'm putting on a stainless header off a '01 ZR7.

Your crush gaskets may be shot. You should be hearing a chirping if it is a head gasket. I doubt it. If it's the exhaust, it's more like a ticking noise.
Steve
I hate this place. Scenery is beautiful, the people suck. :sick:

swest wrote: Your crush gaskets may be shot. You should be hearing a chirping if it is a head gasket. I doubt it. If it's the exhaust, it's more like a ticking noise.
Steve
I hate this place. Scenery is beautiful, the people suck. :sick:

I'm not hearing any loud ticking besides maybe valves. I've been hearing a squeak that I thought was something rattling in my head light bucket. Not sure, my hearing is shot from an ear infection when I was in middle school and working around guns and loud machinery all my life. I'll fire it up and give a good listen before I start taking things apart.

Oregon is nice. My wife wants to move up somewhere in the Pac NW very bad. Funny thing is the ear infection I mentioned was one I got while visiting my sister when she was going to school in Eugene.

You may not hear it at first. A loose clamp could be the culprit. It have the tendency to shoot forward and up thus the soot on your tank. I thought I was developing a head gasket leak but one of the flanges was loose and misaligned. I must have been in a hurry last time I put them on. I'm going to use the masking tape trick this time.

Oregon is beautiful but this town is like Desperate Hot Springs. Homeless everywhere, old money, angry people, not all of them, 10' alligators in the river, sewage plant spill in the river, corrupt officials and so on. Reminds me of the old west and judge Roy Bean. My daughter was telling me of a connection to CHICAGO. Well, isn't that special? :blink: This is my fifth trip up here. I've been told on more than one occasion they need Officers by the staff at the court. I have to check in wherever I go and this would be a good place to retire in as long as you have the income. Too bad, I love the trees and I'd like to take a ride up here and further north. It's that damn San Joaquin valley is the problem. 500+ miles of nothing. Like the mob guy on Rockford said, "10 hours of brown, nothing to look at, hot, THIS IS HELL."
I've got to get out of California for a while. :whistle:
Steve

swest wrote: You may not hear it at first. A loose clamp could be the culprit. It have the tendency to shoot forward and up thus the soot on your tank. I thought I was developing a head gasket leak but one of the flanges was loose and misaligned. I must have been in a hurry last time I put them on. I'm going to use the masking tape trick this time...

Would that account for the drastic loss in power?