Somethings gone bang!

[melbxs]

Great work getting the head off.

Those badges are going in the post Monday, couldnt find them after the shed move, but wife reminded me today that there was a box of stuff in the kids cubby house.

[XSNT999]

Hi Brett

Sorry to hear about this problem of yours, especially so close to Bourke.  I hope it all works out ok and you still get to ride it next month.

Cheers

[Christian Raith]

Call me for gaskets if needed

[BrettS]

With some help on the phone from Jonesy I have the head off. Looks like he was spot on and the head gasket has blown between 3 and 4. Is this enough to have no compression in 3 ?  Valves and everything looks ok at a glance. I turned the head upside down to view and all the shim holders fell out so i will have some fun getting them all back in order. Hope I put the mud map for that in a safe place last time I had it out 
I will put some petrol in the ignition chamber tonight and see if they are still sealed up, any other checks I should do while I have the head off?

[BrettS]

Apparently,  "blown gaskets make these old girls pigs to start cold" from Steptoe.

Just starting to take it apart and we will see, fingers crossed.

[Jonesy]

Just to cover all the bases..........while the head is off you can pour some petrol into the inlet  and exhaust ports to check for valve leak/bent. (not starting at all has me concerned about valves) although I cant see how they would just bend while cruising along. A cam chain sprocket coming adrift would do it but you wouldn't have limped home, that'd be terminal on the spot.


for a quicky job all you need is a head gasket, other gaskets like cam chain tensioner and valve cover can be done later in a jiffy
Just let me know and I can get a head gasket in the post Monday arvo

[BrettS]

Hope not Jeff, Just reading up a bit and chatting with Jonesy and everything is pointing towards a blown head gasket, I haven't mentioned it won't start cold this morning. I just hope I haven't done further damage.
There has been a slight sqeak in the engine for a while now. It went away when the engine warmed up. Talking with Christian I think we were guessing it was the thrust bearing but now I think it had something to do with this.

I am starting to wonder how far I go with this repair. The engine has to come out at some stage and if it was not for the rally I would probably do that now 
Just checking to see what a head gasket is worth, anyone want to do a shopping list of all I would need at the moment?

[excess.11]

Brett..........i hope your right that it s just the head gasket...........but no compression at all on 3 sounds like a bent valve..there would be some minor compression if the head gasket was just leaking i would think.

With a bent valve the crankcase becomes pressurised and oil leaks become more apparent.
Remove the oil cap and run the motor with the palm of your hand over the opening and see if you can feel positive pressure .........turn the engine off before removing your hand so you don t spray oil over the engine.

Which ever way it is....looks like the head has to come off........good luck

[BrettS]

Thanks for the kind offer as always Jonesy 
Just checked and number 4 is a half compression and number 3 has no compression. it seems obvious now that oil is leaking from all around the head gasket on the front half of the motor so hopefully it is "just" a head gasket.
I am a bloody idiot, I just checked the oil to see if any water had leaked in 
Just waiting for Jonesy to wake up and I will have a chat 

[Jonesy]

hey Brett if you check all the bolts that Jeff mentioned are tight give it a start and get a pump spray bottle full of soapy water and see if you can find the leak with that. also get a rubber mallet and give the header pipes a tap to see if ones come loose.....you'll know the difference in noise.
hate to be a profit of doom but it does sound like head gasket has blown....check the security of the head/cylinder hold down nuts.    Better it happened now instead of on the way to Bourke.
I've got a head gasket if you need it. if it is head gasket and you can trailer it to my place we can get it sorted if you don't want to take it on by yourself

[excess.11]

If the tensioner is not set and held where it should be.........your timing will be all over the place as you rev the motor......make sure the pinch bolt is holding the adjuster ok.
Oil leak will be from the bung .......hopefully...... not from loose mounting bolts and gasket.
If the adjuster has gone loose.......there s a chance you may have bent a valve......when you gunned the bike.

[BrettS]

Thanks Jeff I will check the compression tomorrow. I have checked for air leaks as I said I can't feel any. The noise is suspiciously near the chain tensioner. One thought is it blew a head gasket but can't find any indication.
The oil leak that was around the chain tensioner does seem to have spread around the whole front half of the motor. last I checked the oil looked good but will check again tomorrow.

[excess.11]

Brett.....if you don t have a compression tester................remove all the plugs and place your finger over the hole while cranking to check compression.
Replace the plugs and with the motor running rev it  try and feel for air leaks .
Thats where i d start..unless you have any other info on what you ve already done or tend to think it may be.
Check the cam chain tensioner is set right and the 2 mounting screw are firm. if you think the problem is at the front of the motor

[BrettS]

I was cruising the streets getting my NRL tips in. On the way home I saw an early model Yamaha that I wanted to get a better look at. Gave the bike a bit of stick to catch up and something went pop 
At first I thought it was an exhaust type noise. Home was not far away so I limped there and tried to find where air was escaping from the engine. Couldn't find anything.
Now I have no idea what is going on. The noise is some where between exhaust noise and a loud squeak. Increases with the revs. Seems to be coming from the centre front of the motor but of course unsure.
I have removed all the plugs and they seem fine no oil or anything obvious. All cylinders seem to still be firing but there is a loss of power.