So heres what happened......

[helitrooper]

Symptoms Sound like a typical coil breakdown, or loss of fuel to that side, but that would leave you with either a clean, dry plug, or a clean wet plug...

Was it smoking at all before it got really bad? the plug should be wet if fuel's getting through and dry if its not, but should never be "gungey" , or sticky unless oil's getting into the cylinder?.... If that's the case, you may have blown a head gasket, allowing oil to slowly gunk it up and kill the spark on that side?

Here's one

Working on that one - got to get hold of a compression tester

 

[Ugly Cow]

Plug gungy = oil. If the plug is as you say and poor running has suddenly started I would suspect broken oil control / piston rings.

 

[Comfy Old Boots]

expensive self service?

 

[helitrooper]

Do a compression check - it sounds like you've burnt out an exhaust valve.

Finally managed to get my hands on a compression tester, almost 12bar on the right nothing on the left cylinder.

Today I spent the afternoon in the garage and this is what I found

I have had a good look at the head & the top of the piston and there are no marks or scratches. Is it safe to assume that the missing piece went out through the exhaust? What is involved in fitting the new valve? Do they still need to be ground in with the wooden dowel thingy or am I out of date?

 

[JohnnyBoxer]

Steptoe was correct

 

[Steptoe]

I have had a good look at the head & the top of the piston and there are no marks or scratches. Is it safe to assume that the missing piece went out through the exhaust? What is involved in fitting the new valve? Do they still need to be ground in with the wooden dowel thingy or am I out of date?

The missing piece has been teleported out of the exhaust - I've found a new valve on these engines needs very very little lapping in, so don't over do it.

Steptoe was correct

With the symptoms posted it could only be a burnt valve.

Happens suddenly on one side, lack of power, banging and popping, bad idle, and then refusing to start and a wet and fouled spark plug .

 

[warmshed]

Could the valve head get trapped in the cat? If so would it be prudent to shake it out?

 

[Steptoe]

Could the valve head get trapped in the cat? If so would it be prudent to shake it out?

It's a piece (if it's still in one piece) half the size of your finger nail . Don't worry about it.

 

[helitrooper]

Yes top marks to Steptoe he is bang on again.

Could the valve head get trapped in the cat? If so would it be prudent to shake it out?

The cat is long gone in favour of a y-piece, I used to have a Remus pipe which was straight through so it could have been stuck in someones windscreen, luckily I put the oem can back on so no worry there.

 

[Ugly Cow]

Out for a ride yesterday,(gs1150 66k on clock) on my way home, going for it on the dual carriageway 80ies+, bike seems to loose power and was very rough, got off the main and bike is very rough open throttle no go, popping & banging. I limp home and it wont idle stalls, pull the plugs and right is ok but left is wet & gungy so would appear that the left is not firing and therefore running on 1, where should i start looking ???? what are my possible problems? recently changed the oil, all the filters and gave the valves a going over but I dont think that has caused any problems, Electrical
helitrooper is offline Report Post Reply With Quote

steppers you musy be a clairevoyant, there was no oil (carbon) on the valve heads so plug just wet not gungy.


Must be better than lucky

 

[Steptoe]

steppers you musy be a clairevoyant,

Not really, just simple experiance - i see one bike approx every six weeks with the same symptoms -

Burnt valves. I can now identify all the different exhaust valves just by sight.

 

[Uncle Rob]

Not really, - i see one bike approx every six weeks with the same symptoms ,Burnt valves.

is there a common cause to this fault then,if your seeing this many

 

[warmshed]

" The cat is long gone in favour of a y-piece, I used to have a Remus pipe which was straight through so it could have been stuck in someones windscreen, luckily I put the oem can back on so no worry there"


Y piece and sports silencer?? may turn a lean burn to too weak. damage might have been on the way before the change back to OEM

 

[Steptoe]

is there a common cause to this fault then,if your seeing this many

Happens to RT's and GS's. Standard exhausts systems or remus etc.
Most have highish mileages.

 

[helitrooper]

Continuing on with my problem, I have only had the bike for a year and I believe that it did not go far in the years just before I got it.

Twice now it has blown the oil filler right out of the head, do you suppose that the stem seals may have hardened a bit and could have been letting a bit of excess pressure & oil through? it has always smoked badly if left on the sidestand and then restarted - big clouds of smoke, a bit embarressing in town!

I intend to replace all 4 on this side when I put the new valve in, or should I examine the rings & bore too?

 

[littleredrooster]

Hardened stem seals do not cause excess crankcase pressure, only piston group wear can be the problem. Worn rings are the usual suspect, but more likely is that the O-ring or plastic housing for the oil-filler have hardened and need replacing.

 

[CPL]

Steptoe's immediate, correct diagnosis just goes to reinforce my long held belief that no matter how good an all-round mechanic you are, there's no substitute for specialist experience.

As for pressurising the crankcase, the breather should be easilly capable of venting any pressure getting past leaky valve stem seals, so it sounds like either large gobs of compression getting past the rings, which would contaminate the oil very quickly turning it black with carbon, or a blocked crankcase breather not allowing the pressure out.... That would also mean that a little oil could be pushed past the rings and stem seals, when you stop the engine, making it smoke like a chimney on startup