Missing in action (1400 that is!!)

[m2h]

Well, my intermittent miss is now full blown! Was going for an hrs ride to visit a mate and had to turn round after 15 mins. Before it happened on and off at wot, now its at all speeds.
Got home and did a few tests while it was hot.
Pulled plugs.( a bit sooty centre dark tan)
Tested coils (big gap) looked ok.
Plug in lead both sparking ok ( and before Lechy answers Yes i have shortened the plug leads 1/4" )
Pulled cap off rear cyl still ran ok
Pulled cap off front, engine stalled.
Pulled plugs again. Compression test wot Front 150psi rear 115psi Manual says 114 min 28psi max difference.
Just to check - drained rear fuel bowl for water /dirt OK
Checked de comp lever on rear and it seemed same as front for clearance.
Cleaned plugs replaced and started up again. let it idle for a few minutes and every now and then it would run a bit rough with a bit of a very slight pop from both sides. Bike uses very little oil maybe 1/2 cup mid way for change.

My conclusion at this point : maybe a valve face leak?. Maybe tomorrow will try some oil in rear and redo comp test might rule out rings.
Any other thing/s i could do guys? What's it like to pull the motor?

[Lechy]

1400's have hydraulic valve lifters, could be that one of the valves in the rear is sticking partially open. Might be worth running some flushing oil through the system, new oil and filter and a real good highway hammering.
What colour was the spark on the rear, if it was leaning towards pink or orange you have a faulty coil and the spark is failing under compression.
[emoji41]
Edit. My pet peeve is the battery earth cable, stiff or swollen at any point, replace it.
[emoji41]

[m2h]

1400's have hydraulic valve lifters, could be that one of the valves in the rear is sticking partially open. Might be worth running some flushing oil through the system, new oil and filter and a real good highway hammering.
What colour was the spark on the rear, if it was leaning towards pink or orange you have a faulty coil and the spark is failing under compression.
[emoji41]
Edit. My pet peeve is the battery earth cable, stiff or swollen at any point, replace it.
[emoji41]

Thanks Lechy thought you'd be chipping in pretty soon Yep i'll try the oil trick, its due for a filter/change soon. As for the spark it never seems to be a good one to me on either cylinder. My XL 600R had a whacking big blue spark. This bike has a very skinny insipid thing by comparison and has always been a concern, although it fires across a 7mm gap ok but is more yellow than blue. It wouldn't surprise me if it was failing under load. Could both coils be bad? I am more concerned about the compression right now. The thought of pulling the big bugger out doesn't fill me with jubilation

[Lechy]

On both of mine I had to replace the coils, 32 yo 750 and 25 yo 800 still had OEM's. I picked up a pair off Ebay for the Marauder 800, not a bad price (quite cheap really) I can get a good chunky blue spark over 1/2" gap, fails out at around 3/4". But, I would suggest you check all the connections in the firing circuit for cleanliness and tight fit first.

[emoji41]

Edit for link:
https://www.ebay.com/sch/i.html?_odkw=s ... w&_sacat=0
[emoji41]

[m2h]

On both of mine I had to replace the coils, 32 yo 750 and 25 yo 800 still had OEM's. I picked up a pair off Ebay for the Marauder 800, not a bad price (quite cheap really) I can get a good chunky blue spark over 1/2" gap, fails out at around 3/4". But, I would suggest you check all the connections in the firing circuit for cleanliness and tight fit first.

[emoji41]

Edit for link:
https://www.ebay.com/sch/i.html?_odkw=s ... w&_sacat=0
[emoji41]

Thanks mate. Bin busy today may get a chance tomorrow.

[m2h]

On both of mine I had to replace the coils, 32 yo 750 and 25 yo 800 still had OEM's. I picked up a pair off Ebay for the Marauder 800, not a bad price (quite cheap really) I can get a good chunky blue spark over 1/2" gap, fails out at around 3/4". But, I would suggest you check all the connections in the firing circuit for cleanliness and tight fit first.

[emoji41]

Edit for link:
https://www.ebay.com/sch/i.html?_odkw=s ... w&_sacat=0
[emoji41]

Thanks mate. Bin busy today may get a chance tomorrow.

Well today i warmed up the bike, pulled plugs got a tea spoon of oil into the rear cyl and redid a comp test. Pressure only up a few psi to 120. So, me thinks the rings are ok and it must be a valve sealing issue. It's not chuffing back thru the carb so must be the exhaust valve. Checked the oil and its still pretty clean after about 6500miles so i might give the flush treatment a miss. F@#k

[Lechy]

Checking the exhaust valves is easy, remove the exhaust, blow out the chambers take the piston to the bottom of the stroke and squirt some WD 40 around the valve stem, see if it pools or drains into the bore. Don't forget to remove the plugs and spin the engine when finished to blow the fluids out of the bore.
[emoji41]

[m2h]

Checking the exhaust valves is easy, remove the exhaust, blow out the chambers take the piston to the bottom of the stroke and squirt some WD 40 around the valve stem, see if it pools or drains into the bore. Don't forget to remove the plugs and spin the engine when finished to blow the fluids out of the bore.
[emoji41]

Sounds easy. You're a "mine of infomation " Lechy Will try that tomorrow. One more proof i guess Thanks mate

[Herb]

Is there any chance that the rear compression release is out of adjustment or sticking? It is supposed to hold the exhaust valve open for a short time to get the engine spinning.

[Lechy]

I was under the impression that you had checked the de-comp system. Do this first. I cannot help with this, but check in the manual.
Mine don't have this advanced technological another thing to fuck up.

[emoji41]

[m2h]

I was under the impression that you had checked the de-comp system. Do this first. I cannot help with this, but check in the manual.
Mine don't have this advanced technological another thing to fuck up.

[emoji41]

Herb, Lechy
Yep i did check it. It was free moving and seemed to have the same clearance as the front. I even moved it into contact with valve
while the engine was running and could feel it tapping on the valve. Just had a thought that i might try putting a screwdriver to my ear and on the exhaust pipe and compare to the front while running see if they sound majorly different. Not looking too good eh!
Cheers for the input
ps: sorry to hear about the big blow you got going in Texas. Wish you guys down there all the best.

[m2h]

Checking the exhaust valves is easy, remove the exhaust, blow out the chambers take the piston to the bottom of the stroke and squirt some WD 40 around the valve stem, see if it pools or drains into the bore. Don't forget to remove the plugs and spin the engine when finished to blow the fluids out of the bore.
[emoji41]

Well Mate i squirted some CRC in the exhaust port and it sat there happily for ages i gave up checking it. So where to now? Possibly a broken ring? Not getting any oil drips from anywhere so it doesn't appear to be pressurising the crankcase much or at all. Will check the breather pipe. Maybe i will try the flushing oil as a last resort. If that fails i guess its motor out

[Lechy]

Slow down cowboy. you are loosing focus. Let's get back to your original problem. You need to get your spark sorted out and the bike running again before thinking about pulling the motor because the compression is a bit low.
Stick your finger in the exhaust pipe, is the residue sooty or is it oily? Sooty, don't worry about anything, slightly oily the rings or valve stem seals are passing a bit, still not too much to worry about, very oily, engine out for surgery.

[emoji41]

[m2h]

Slow down cowboy. you are loosing focus. Let's get back to your original problem. You need to get your spark sorted out and the bike running again before thinking about pulling the motor because the compression is a bit low.
Stick your finger in the exhaust pipe, is the residue sooty or is it oily? Sooty, don't worry about anything, slightly oily the rings or valve stem seals are passing a bit, still not too much to worry about, very oily, engine out for surgery.

[emoji41]

Well buddy the residue is dry sooty which it all ways has been on the rear. Running rich until recently when i adjusted the A/F and got the plugs looking dark tan. The bike starts easy ,idles pretty good mostly. Ran it again today to check both decomps were working they were ok, and CRC in the port. The plug was firing a blue spark but not big and fat. Is this normal with this bike? If the compression is low on one cylinder will it not effect running to the point of bad combustion = posible miss? I could see the near inlet valve when the piston was down,the face looked clean so maybe that one was ok. Still think if an inlet v/v was bad it would chuff back thru the carb, yes?

[Lechy]

The way to check with a compression tester is to watch the needle. If it goes straight to pressure after 2/3 revolutions and the reading is low put a couple of squirts of oil in the cylinder and check again, if it goes to a higher reading then you have usually a ring problem. If the needle flutters around before getting to pressure then you would be looking at leaking valves. I made up an adapter by knocking the porcelain out of an old plug, welding a 2" 1/4" nipple to it and screwing an air quick connect to the nipple so I could pressure up the bore with the valves closed and see what came out of the manifolds, I got pressure in the radiator but that's a different story.
[emoji41]

[m2h]

The way to check with a compression tester is to watch the needle. If it goes straight to pressure after 2/3 revolutions and the reading is low put a couple of squirts of oil in the cylinder and check again, if it goes to a higher reading then you have usually a ring problem. If the needle flutters around before getting to pressure then you would be looking at leaking valves. I made up an adapter by knocking the porcelain out of an old plug, welding a 2" 1/4" nipple to it and screwing an air quick connect to the nipple so I could pressure up the bore with the valves closed and see what came out of the manifolds, I got pressure in the radiator but that's a different story.
[emoji41]

Thanks mate my tester is hand held and couldn't see bugger all in there. Might make up one of those plug ins and try that. I am really reluctant to start pulling things apart yet. Keep up the good ideas and we might worry it back to health

[Lechy]

Just humour me on this one please.
Remove the battery to frame earth, make up a new one and change it out.

[emoji41]

[m2h]

Just humour me on this one please.
Remove the battery to frame earth, make up a new one and change it out.

[emoji41]

Spent part of the morning making up the adapter to pressurise the cylinder. That was fun Cracked most of ceramic off in the vice and tried to punch the middle out. uh uh it just peened the centre rod over so i stuck it in the lathe and drilled it fron both sides. Long /short screwed it in, used torch to see the ex v/v was shut (pulled header) connected to the air and hear it in the airbox
looked in plug hole and can see the inlet open. F@#ked about trying to get bottom of inlet stroke with the starter. Gave up. will put it on the lift and in gear see if i can be a bit more precise. Tomorrow. Gonna worry about the spark issue later.

[Lechy]

In the middle of the alternator cover is a plug, maybe slotted may have an allen fitment, remove this, you will then see a 17 mm head use this to turn the engine over CCW otherwise you will engage the starter sprag and think that the bottom is falling out of the engine. On the front of the cover is another small plug, this is the view port for the timing marks you will see 2 indications, FFT & RFT when you see these marks the piston is at TDC either on fire or exhaust. These marks are used for valve lash checks.
Don't forget to put the plugs back before firing the machine up, you will be astounded as to how much oil will fly out and how far it travels. (experience talking).

[emoji41]

[Herb]

In the middle of the alternator cover is a plug, maybe slotted may have an allen fitment, remove this, you will then see a 17 mm head use this to turn the engine over CCW otherwise you will engage the starter sprag and think that the bottom is falling out of the engine. On the front of the cover is another small plug, this is the view port for the timing marks you will see 2 indications, FFT & RFT when you see these marks the piston is at TDC either on fire or exhaust. These marks are used for valve lash checks.
Don't forget to put the plugs back before firing the machine up, you will be astounded as to how much oil will fly out and how far it travels. (experience talking).

[emoji41]

Not on the 1400.