Near Disaster!

[pilgrim]

Last Monday, 30th April, I had a big worry. I'd spent some time simply cleaning out the air box, oiling the clutch cable, removing the moisture and mould off the parts hidden by the petrol tank when I thought the spark plugs were overdue a visit......well yes but I didn't envisage one that would cross-thread when I put it back! My mistake I know. Just a couple of new attempts and........the plug sheared off at the cylinder head!

"Oh my goodness", I said. What can I do? Big expense in view.

First impulse was to see if the engine held compression on the 'dumb' cylinder, I might get it to the garage on three plugs I thought. Err..no, but it blew out the centre of the plug which was left inside the thread. Hmmmmm....ahh! I can get that out with an 'easy-out'. And I did. ;D

So how much damage has been done?

Today I've carefully eased another spark plug in and out at the right angle continuously until all the thread debris had been removed from the cylinder head and the plug now screws in by hand, like the other three, and it seals firmly like the others.

I think I lost the first two turns of the thread before it seized the plug in it's descent. It's like new now, and the other three after this little episode......

[bobh]

Phew!!!

[bigbuck]

Pilgrim , you jammy burger, hope none of the ceramic centre aint fell in the pot mate, If it did its probably been blown out by now and sounds like a very lucky escape.

Nice one Buck

[pilgrim]

Yes, bigbuck, the engine turns over OK although it was a very 'shy' initial press on the starter button.

Off to get new plugs today if I can find a bike shop open..........

;D

[CD]

Well done Pilgrim. Trying to start it & blowing out the plug centre was a master stroke. ;D

Unless you take off the fuel tank, the D9 is a burger to get the middle plugs in straight. I got one crossed but thankfully only turned it one flat. But that was enough to make it really hard to get the plug in straight. I now use some straight rubber hose on the plug to thread it in by hand. I also use a good anti seize paste on the threads. The old plugs are always rusty so cant trust them to not seize.

[alan292]

nice recovery ......remember to put a lottery ticket on...

[teejayexc]

May 7, 2012 9:55:28 GMT CD said:

Well done Pilgrim. Trying to start it & blowing out the plug centre was a master stroke. ;D

Unless you take off the fuel tank, the D9 is a burger to get the middle plugs in straight. I got one crossed but thankfully only turned it one flat. But that was enough to make it really hard to get the plug in straight. I now use some straight rubber hose on the plug to thread it in by hand. I also use a good anti seize paste on the threads. The old plugs are always rusty so cant trust them to not seize.

If you get rid of all that AIS carp they're more accessible

[CD]

True but still a bit fiddly.

[samfan]

A South African plug thread cleaning up tool is made by hacksawing down thru the threads of an old plug and then carefully screwing it down into the cylinder head .the edge of the narrow slot that you have cut cleans the threads up a treat .

[CD]

The threads on mine were great. I just (nearly) duffed it up getting the new plug crossed-up.

I'm not a fan of chasing threads unless they are clearly in need as it weakens the existing threads.

[samfan]

The thread cleaning tool that i mentioned above .Is purely a thread cleaning tool it is not a thread chaser tap or cutter . A clean thread is far less likely to get crossed or damaged , most crossed theads are caused by crud stopping the thread from starting squarely.Sorry for not explaining myself more clearly

[CD]

Me too I wasnt meaning to be picky. Some folks always run threads through with a tap. I dont believe its a good idea unless the threads are really clogged.