I have two near-stock F2's completely apart at the moment, and I can't find the wire you pictured on either harness. (one's a hack-job, the other is extra clean and fantastically stock) The only on-engine sensors present on our bikes, if I'm correct, are the oil pressure idiot switch, the neutral switch, and the coolant temperature sender for the dash display. (unless you count the pulser.) There are other doodads on the radiator responsible for radiator fans, but I think that's it.

Problems are much easier when something's obviously broken. The fuel delivery issue should be easy enough to deal with. That's a good thing in a way, I guess.

You might be on to something with the head gasket coolant leak. If there's A LOT, you might be able to give your header a dump and see if anything's in there. If it's green... well... there you are. Otherwise, you're on the ball with the plug check. If you have a camera handy I'll offer an opinion.

 

Hey guys,

I took some pictures for you all to examine. I also snapped a picture of the exhaust ports with the exhaust removed, but there really wasn't anything to see there. No funny color, no liquid even. Just gray soot. The spark plugs look gray and dull. From a few sites I've been on, I would diagnose them as "dry fouling."

So tonight the goal was to possibly determine what liquid had been burned this afternoon. It was either primarily coolant or primarily oil -- there was a lot of smoke. Because of all the factors I mentioned earlier, I believed it to be coolant. But the smell wasn't especially sweet like you might expect. It didn't smell like oil though, either.

I stuck my finger into the exhaust pipe (see pic) and swirled it around -- it came out very wet and very black. The question becomes -- is the liquid oil or coolant? To test this, I wiped the mystery liquid onto a piece of aluminum foil. Then, I heated it slowly over my gas stove. In about two minutes of relatively low heat, all the liquid had evaporated leaving a dry sooty dust behind. (see pic) Because of the ease with which the liquid evaporated, my guess is that it's coolant. But I want it to be coolant so I'm biased!

Also while I have your attention -- two more unrelated questions. I think my neutral sensor is broken. The light doesn't come on and the bike shuts off when I put the side stand down (when in neutral).

My bike came with the rad fan permanently connected. How does the radiator thermo switch work? When it gets hot enough, does it connect to ground? Basically my bike has two wires leading out of the fan, connected to nothing. Does anyone have suggestions how I can wire the thing to run properly? Assume the original connector has been chopped off.

Thanks everyone, for you input so far! -Andrew

 

Just a fun observation for you to ponder. The three Autolites are all pretty normal looking, and the NGK looks like you may have been experiencing a lean condition. If they are ordered cyl. #1 left to cyl. #4 right, then maybe this pattern is also tied to why backfiring didn't happen in cyl #1. Also, if the vacuum line wasn't hooked up, like you said, then the extra air pulled in would cause the lean condition that I suspect exists.

On to other matters. I'd see if you could find a clever way to take a peeky inside the cylinders. I had good luck shoving a mini flashlight in the intake port and looking beside it to see the top of the piston when the intake valves opened (rotating motor by hand) or look down the spark plug hole with the flashlight in the intake port and the valves open. See if you can spy any coolant chillin' (pardon the pun) out on your piston crown. Just for the record, I'm definitely pulling for some random other cause for your smoke because I really really don't want to buy a head gasket and I was secretly considering re-using mine and not telling anyone. This could change my mind...

I also have a rad-fan hack job on my hands. When I figure out how to make mine go I'll post up. (That was business/managerial speak for "when I get my EE housemate to figure out how the heck to make this thing rotate and then personally take credit for it, I'll tell you")

See if you can 'trick' your neutral switch. All the switch does is ground the wire to the case when you click into neutral, so just make a jumper and jump it to the case and see if the neutral light comes on. If the light flickers when you contact the wire to the engine cases, then you're golden. Just the switch then.

 

Well I placed the order for the new head gasket over the weekend. But I the parts are undoubtedly being drop shipped from all over the country and different times, so at this rate I'll be lucky to have the new stuff by next weekend. So anyway, I'm probably stalled on that work for the next week and a half or so.

I figure in the mean time I can work on other issues, like the neutral light I mentioned. Today I went out and tried to form a diagnosis using Jimmy's suggestions. Surprisingly, I couldn't get any useful information. I unplugged the whitish-clear plastic connector with three wires. On the "sensor side" of the connector, all three wires had continuity with each other, and they did not have continuity with ground. They were not grounded in either neutral, or first gear. Tentatively, this would suggest a faulty switch.

But I also couldn't get the blue neutral light to flicker. I tied a test wire to ground and touched it to the wires in the white clip on the wire harness. I tried touching each of the wires individually, then in pairs, and then all together -- no blue light.

I haven't looked through the Clymer's manual yet to help diagnose, but for now I'm mildly confused with those results. I was touching the right connector... right?

 

skibbideywabbledoozey? something's mixed up here. My neutral light is green, and my high beam light is blue.

 

In neutral, is the neutral switch's brass plug nipple a common ground with the case? It should be in neutral, but shouldn't be in any other gear. That will rule out faulty switch.
There is nothing else that controls the light, as far as I know. Touch the neutral switch wire to ground, and the light pops on. I just fixed my housemate's XL600r with a similar problem.

 

Hey Jimmy,

This afternoon I probed around the bike a bit more -- I was going to investigate the neutral switch more. After taking the stator cover off, I realized that the black, 3-wire cluster of wires going into a white connector was actually the generator power.

Then, in about 30 seconds, I solved two mysteries at once: "the mystery of the spare wire" and the "mystery of the non-functioning neutral switch." lol. That cable I showed a picture of earlier was actually the neutral switch wire. Once I shined a flash light into the crevasse behind the chain, I finally noticed the brass nipple you mentioned! So now that's taken care of -- my head gasket comes Tuesday, and I just have to work out the electric fan. Will take care of that this weekend.

 

....oil temp. Right. I guess the PO thought there was a reliable way to take oil condition readings from the rear of the cases by the sprocket. I should have put that together from your other post. I'm dumb. Thermodynamics has taken a toll on my quick-wittedness.


I'll assume the order of events was:

1.) I spy with my little eye a brass bullet connector nipple!
2.) pop! (on goes the connector)
3.) click... clickclick... (gears changing)
4.) light comes on.

Nothing else was broken and it just worked when you plugged it in?

 

How about that -- nothing broken, the light just came on! The PO did describe the little green light so I had a feeling that it was working.

 

Nice. Lemme know if you need anything else!

I got my crank yesterday, rods a few days before, a new piston, and Service Honda just shipped my lower end bearings. I should be doing business soon enough...