loose head?

I noticed this morning after I started my 77 kz650 that oil was bubbling out of where I believe the head gasket is.(not a lot but enough that after a few rides it drops a little oil) do the head bolts usually come loose on these bikes? does anyone know what to torque them to? Hopefully this fixes it. My bike did come with a head gasket but it's at least a year old so I dont know if it is still good to use or not, it does look ok.

They will weep oil after a while, only a new head gasket will fix it but you could check the torque if you want. Id be amazed if it stopped it

Torque spec on mine is about 30 ft-lbs (360 in-lbs).

Head gaskets do seep oil sometimes, even new ones.

If it was rebuilt, the head probably needs retorqueing. Mine definitely did.

BTW: on mine, there are several small bolts that go up from under through the cylinder into the head. Those are there to help stop the seepage. Don't know if yours have these, look for them. Mine torque to about 100 inch-lbs.

Im not at all familiar with the 650s, just the 900/1000 motors so it could be. I didnt realise the head had been off recently either, I thought it was an original motor. Worth a try anyway, go for it.

As Bounty says the head should be torqued around 30 ft.lbs (27-31ft.lbs/36-41 Nm). No bolts coming up from underneath, but there are two bolts (front and rear) right under the cam sprockets, these should be torqued to 16-20 ft.lbs/22-27 Nm.

If the oil is coming out at the front just above no. 3 exhaust it might be your tach drive leaking.

Another possible source of leak could be a loose exhaust header clamp, or an exhaust gasket failing to completely seal.

Good Luck!

If not already done, could also do a compression test (hold throttle wide open during testing). Then if compression is low, would also assure correct valve clearances and re-do compression test, and also perform a leakdown test, before blaming the head gasket for low compression.

Im going to try to re torque it soon, the leak is on the inside (not exhaust) like I said the leak is minimal so I think it will fix it. just a side question, has anyone heard of using leak stop that you use in cars in a motorcycle? just wondering.

Even if there WAS such a product,I wouldn't even think of using it in the KZ.I think you would end up with clutch problems(slipping,or even sticking) because the clutch uses the same oil as the engine.

good point, I did not know that.

I feel your pain. I started getting discolored pipes down the middle of the headers about a year back. I figured it was a weird bluing pattern caused by it being out of tune. Then, as I gunned her one day (79 kz650b3), I felt something wet on my knee. When I got her home, I saw I had a head leak. Oil had been pushing out of the head sometimes and was shooting onto my headers in the middle causing the weird bluing/browning. I bought the top end gasket kit, but I need to screw my courage together in order to take everything apart and put it all back together again properly. I will get in it soon and post a topic with pictures to show my progress. Let's do it together!

dude now your scaring me! my pipes are bluish also! but I havent had any oil squirt on my legs when I gun it. If torquing it doesnt work we will have to do it together.