Fast Taker Secaha - a blog

Yayy, glad to hear you're sorted. I have to admit the multiple faults did kinda sound like a bad earth but wow, would never have thought the level sensor earth could cause it... 8O

So you now have everything working except the flashing for indicators (could be bad connections/old or incorrect bulbs causing low current draw, or bad flasher)

And headlamp, what's going on with that, thought it was working?

 

Yeah... no... no.. yeah... no...

Headlamp never worked for some reason. And the flashers were also good before I took the bike apart.
I've ordered new plugs and connectors to replace the ones that may be too exposed to wear. We'll just have to see.

 

Found another weird bit of info looking at Len's ultimate guide for sensors, diodes, relays, and switches.

It states that my 11M Euro model Seca should have a headlight relay, which I can honestly say never existed when I bought the bike. Can't find it on the wiring diagram, and I cannot find wiring for it either.

 

If you have a headlamp off/side/on switch, you won't have a relay by my understanding.

AFAIK the only headlamp relay fitted to these bikes was the latching relay on the models that had Volvo style running lights and no switch (kept lights off for starting & then switched them on once the generator begins charging, keeping them on if the motor stalled).

 

Well...
I have some rather disappointing results after checking compression.

Cylinder 1 dry, 125
Cylinder 1 oil, 140

Cylinder 2 dry, 82
Cylinder 2 oil, 100

Cylinder 3 dry, 90
Cylinder 3 oil, 104

Cylinder 4 dry, 105
Cylinder 4 oil, 150

New valve shims were installed where needed during engine assembly. Check them again?
Any other sources I should look to?

 

Are you sure your compression gauge is accurate?

 

Pretty sure. I used it before I took the bike apart with great success.

I'm puzzled by the fact that the compression gets better when I put oil in the cylinders. This means that the piston rings may be failing to seal.

 

How much oil are you using?

I'd lean towards possible head gasket between 2 and 3 from those numbers, provided the gauge is accurate (always worth double checking with another )

How does the bike run? If it's running well I'd suspect the gauge since numbers that low on the middle 2 would make for very rough running...

 

I put just a tiny amount of oil into the cylinders, equal to a teaspoon.

Haven't actually tried running the bike on petrol yet. Thought I'd make sure everything were up to spec before I did that. Might as well try starting her up this weekend.

Thanks for the brainstorming support!

 

I was told more than one time on this forum that it is possible to free up stuck piston rings with Kroil or Marvel Mystery Oil. So there is a cure, if it appears to be your problem.

 

You mean if they're stuck inside the cylinder, or if they're stuck onto the piston?
The engine was completely redone last winter. What I suspected initially, was that the piston rings might not compress enough to seal inside the cylinder, but then I realised they were never altered from their original state.

I want to check the valve shims again before going as deep as the head gasket...

 

Stuck into piston.
Good idea to check the valve shims again and to do the compression test one more time.

 

Agreed, check the shims & try to use a different comp gauge for the next test.

1tsp of oil is fine for wet test so there was a fair improvement shown that might suggest rings. But, if you're saying it's been opened up and rebuilt with a hone & new rings, it may take a short run of the engine for them to start to bed in and seal, so maybe worth trying a test run to see where you're at, once the valves are known good.

Another thing you could do is a "hiss" test (using air line set to about 70psi, fixed into plug hole with the cylinder at BDC on firing stroke so the valves are closed) and listen to see where the air leaks from. If you hear hissing at the breather it's going past rings, if you get hissing from either inlet or exhaust it's passing valves, and if (especially on 2 and 3) you get hissing from the adjacent spark plug hole, it's head gasket.

 

That's a great idea! Thanks for the info. Need to get a stethoscope :lol:

 

I had a very heart-warming chat with a fellow at work, where I told him about changing head gaskets and about the compression problems.
Short story, gears in our heads began to turn, and we came to the conclusion that the metal rings on the gasket surrounding the cylinders need to heat up and expand for the gasket to seal properly, and that this might explain why I get bad readings on compression.
Time to take the bike out!

 

Wow... I've not updated things in a while, I see.
I've been struggling with minor electrical issues for a while, and found that my headlight and blinker problems were due to the coils not being grounded. YIKES!
Now, the blinkers work, but the RH lights switch sends only 5V to the headlight and aux light, and the brake/plate light does not work. When in park mode, it sends full 12V to the aux light.
Hopefully, after some more fiddling, I'll have it sorted out.

Can anybody tell me what this pigtail is for? Black wire, single connector coming out of the loom at the same place as the coil wires do.

 

Finally fixed the lighting problem. The aftermarket RH switch I bought, was not wired properly. Now rewired to replicate the original lighting conditions.

Tried turning her over, but ended up with fuel dump into (and then out of) the airbox plenum chamber. Will need to check the floats and try again tonight.