Z1OwnersClub GB

Help required for the following.
My bike is a Z1B 1976 29,000 miles standard with no known mods except carbs from a later bike.
Last year I rode the bike all summer with no issues at all ,laid the bike up over winter as follows carbs drained, oil changed (castrol gtx) genuine oil filter (z power) etc. Ran the bike last week for about 30 miles no problem then again today with the following result. The bike appears to be blowing oil up into the airbox to the extent that it runs out of the drain hole down the rear of the motor onto the floor.The bike dose not smoke on start up or during running the engine is running well on all cylinders no missfires.
I dont have any mechanicl noise to be alarmed about. I hpoe I have included all relevent information but if you require any more please ask all I can add is HELP

Hi, most common cause is either rings worn/broken or headgasket leaking and pressurising the crankcases. i would think a compression test would maybe tell you whats wrong. hope its nothing serious though. could possable be a stuck ring, though as you say it ran ok first time.

Just a thought, you havn't filled it with too much oil.

I agree with Floydsz1, too much oil gave me a similar scare a couple of years ago.
I now run mine just above the min mark on the glass and have had no further problems.

Hi Alan ,
I'm sure your problem is the oil breather ,you will need to take the cap off and the plates ,underneath you will see a small hole at the rear ,i suspect that it has become clogged and it is quite a common problem ,but its easy to cure just use a good piece of wire to clear the way ,i'm sure in one of the old bulletins that were issued to dealers, there was a piece of tubing offered to cure some of the more stubborn engines ,but im sure this will cure your problem
give me a hollar if your still having trouble
ollie

I have to say that slightly over filling with oil is pretty easy to do. On my old Z1000A2 I initially had K&Ns and was a little generous with the oil on my first oil change. To start with it was fine when i was running dum de dum. One fine day I was on my way to visit a mate in Southampton and stopped to read the map. When finished I looked in the mirror and saw a great lumbering lorry. I calculated that a brisk departure would avoid the need to overtake almost immediately with all the dangers inherent in such a manoeuvre. I grabbed a big old fist full and all of a sudden the back end was swing from side to side. At first I assumed the tyre had gone - the reality was that she took that moment to evacuate all the extra oil ... all over the back tyre. Scary shit. I gently nursed her to the next garage where I jet washed the back wheel and recycled a coke can from the bin, in case any more cam out of the breather. It didn't, but it was a lesson to me!

Z1B Alan, I have seen this problem before. I have even seen the removable filter absolutely soaked in oil. Also, when the filter was removed there was a pool of oil laying in the bottom of the air filter holder. Never did find the solution, it just went away!

I am interested in the solution:
Remove oil to lower level or remove blockage from under the oil breather.
Alan, lets know what you find. I'm with Ollie on this one.

RegardZ.

Ollie as you suggested I have removed the breather and poked a wire down the drain hole I can't realy say that I moved any debris as the route the hole takes is not straight but fortune favours the brave so back went the breather and of we go for a test. After about 5 miles I stop and check the air filter and alls well so I continue for a further 20 miles back to base. A good inspection finds no oil in the air box or down the back of the motor.I wil keep a close eye on the oil level which is now just above the lower mark and will post another thread if it happens again.
For the moment thanks for the help
Alan Roscoe aka Z1B Alan

nice one alan ,just keep an eye on it ,it doesn't have to be much to block it ,just some sludge .Just change the oil on a regular basis and as said don't overfill
ollie