Spada Woes

Hi,
On Thursday I pulled into the office car park and there was a load 'pop'. It thought I'd run over a bag or blown a tyre and I parked the bike. There was oil running down the engine and splattered over the front mud guard and radiator.
I got the bike home on a trailer and started to investigate.

The valve cover gasket has been 'blown' out of the front cylinder so I'm figure there is pressure build up in the crank case. I've taken the crank case breather off cleaned the oil/vapour separator and the pipe that goes back to the air box. however they were not blocked. I've checked the valves, the clearance is spot on and they open and close when they should, and the timing is perfect.

Next it to do a compression test, which I hope to do tomorrow.

If anyone has any other ideas of what could cause this, let me know.

Glenn.

 

Hi,
I'm beginning to wonder that myself. I will do a compression test and if that checks out OK put it back together and wait and see.

Wombat.

 

HI,
I could not get a compression tester locally that will fit a 10mm plug so I've ordered one. I was talking to a bike mechanic and he reckoned blocked crank case breather. Yesterday I put the bike back together after cleaning the crank case oil breather, separator and pipe that goes back to the air box. Checked the timing and it's spot on and the valve clearances are in spec. I torqued the valve cover to 10Nm as per the manual and took it up the freeway last night for an hour or so and it's running fine. I'll test the compression at the weekend but I'm leaning away from a broken ring as the oil is so clean.
I'll see how the commute goes today.

Wombat.

 

Hi,
it blew again when I was up at Mt White today. The good news is that a couple of riders stopped to help and one gave me lift to my front door on the back of his Triumph. I have not ridden pillion for 30+ years and it was scary at first. Thank you Greg for your kindness.

Trailer is hitched and I'm going to pick it up.

Wombat.

 

Hi,
The compression test was fine , no problems as far as I can tell. I was discussing this with mechanic friend of mine and he had watched the bike as I rode off and he had not noticed any smoke and he concluded there is nothing wrong with the rings/valves. He phone a friend of his who is carb specialist who said that he had seen this problem before and it is most likely due to the carb flooding due to incorrect float height or the petcock leaks. The carb theory is something like this - when the engine is hot and you switch off the engine the excess fuel evaporates and makes its way into the intake. It will eventually condense and seep past valves and rings so over time you get contamination of the oil. I put my nose in the filler spout and is smells of petrol. I've changed the oil and filter, stripped the carb , cleaned the jets ,(some were partially blocked) and more importantly set the float height 6.8mm. One was only 4mm, which is a huge difference. The carb upside down when you set the float height, so the right way up that float would have to rise almost 3mm extra to to close the valve. It's back together now and running.

He's hoping!!

wombat

 

Stu,
yes I checked the petcock..seems OK, but I'll make sure I switch to off and not rely on the diaphragm.

Wombat.

 

Hi,
I've done about 30 kms and so far so good. I had to tickle the carbs a little to adjust the idle but it runs OK and no apparent flat spots. The throttle free play needs adjusting but I can fiddle with that this week.
And If the Gods of motorcycling smile on me , I might pass my MOST next week on this bike.

Cheers,
Wombat.

 

Hi,
damage report! The bike died again and came home on trailer ( 3rd time in three weeks). The battery is not charging, so I've tested the alternator as per the manual and I get erratic readings on the three output wires. I took the alternator cover off to take a look and a lot of oil ran out! I figure my mini explosion has damaged the crank shaft oil seal and the oil sloshing about must be shorting out the alternator. I'll pull it apart on Thursday and take a look. Now I am wondering what other unseen damage there is

Wombat.

 

Hi,
update on this: The Honda common service manual suggests that there is supposed to be oil in the housing so there goes another theory. I have a lot to learn about bikes.

Wombat.

 

hi,
I pulled the alternator flywheel off and this is what I found. The stator bolts have sheered of and are stuck to the flywheel magnets.



All the bolts have come loose ( they are supposed to be thread locked but I can't see any thread lock) and the stator is just hanging on by a few threads. You can't see in this pic but the sheered bolt has taken the coating of some of the coils, there is continuity between one of the wires and the coil which there should not be. I'll try to get a second hand one or have this rewound.



Wombat.