HoughMade

One idea would be to get a good charge in the battery, then see if it runs. These don't charge well at idle and they need the battery with a decent charge to make spark. You don't say, but were you riding it for that hour you had it running after getting the oil in? Air cooled engines don't like sitting still and running for too long.

OK- here is the surest way (I know of) to find TDC on the power stroke. Since you are adjusting valves anyway, take the cover off the intake valve on the cylinder you are working on (works on any cylinder, just make sure you are looking at the right valve). Rotate the engine until the intake valve goes down, then back up (opens, then closes) and the next time the piston reaches the top, you are at TDC compression/power stroke. I'm no expert on 4 cyls., so I'll leave that for someone else...2 is enough for me.

Agreed.

I suppose anything can be debated, but physics are physics. If you have 2 bulbs that put out the same amount of light, one in white and one in red, then you put them behind a red lens- the red one will transmit more light through. The only way the white one can be brighter is that if actually puts out more light than the red one to begin with. The red lens does not convert light to red, it filters out all wavelengths other than red. If there is more red to begin with, more will make it out the lens.

Well, I don't want you to think that there's no one out here...just apparently no one who knows the 750 and jetting. Sorry I can't help.

When's the last time you balanced the carbs? How about cleaned them out? I would do the latter, then do the former and see where you're at. While you're at it, clean and gap the sparkplugs, and if they are more than a couple of years old, just replace them.

You measure from the surface where the bowl seat, not the rim, but where the surface of the bowl actually sits- so just inside the yellow.

Agreed. You have to take the carbs off and give them a thorough cleaning.

Well, if it's not fuel and you don't have the only XS400 with a radiator, I'd guess it's oil. The question is from where, and only you can tell us that. Common culprits are the neutral switch, the clutch actuator rod or the gasket on the screen cover of the sump.

I use the first notch only almost all the time. I use the second notch only when the bike is cold and it's below about 55 or 60 degrees out. My routine is to pull the enrichener out to the first notch (it adds fuel, does not restrict air as a true choke), then start it. The idle is up around 2000 rpm usually. I sit still and let idle until the revs start to rise on their own. Then I push the plunger in and ride. The first mile or so, there is a small bit of stumbling at lower rpm (very slight), but when it warms up (shortly) everything is smooth.

Were it me, I would take the idle mixture screws to about 3.5 turns out, adjust the throttle stop to 1200 rpm after it has idled for a couple of minutes and see what it's like when thoroughly warm.

My flasher was broken and a used unit was over $70, new about $120. I plugged in a $5 unit from the auto parts store I had laying around and everything works perfectly except the self cancelling...now i cancel it myself. No problem at all.

Go to 3-3.5 turns out and try it. Popping is more often lean than rich. In these old bikes, there is always some fuel in the exhaust. It will not ignite in the exhaust unless the exhaust is way too hot- and that's caused by lean.

I do, but I have a manual petcock. Looks like you have the original vacuum petcock. If it is working correctly, no need for you to do that.

Did you get the tail light from Superbright LEDs, or somewhere else? I'm interested.

The main thing is that I took the bracket that the horizontal adjusting screw attaches to off the original sealed beam and used hi-temp epoxy to attach it to the new reflector unit. It can probably be used without that bracket, though.

Those boots need to be replaced, but it seems odd to me that gas would seep from the inside out. Usually the concern is air leaking through the cracks because there is vacuum inside the boot. If there is vacuum inside when the engine is running, gas should not seep out. The only exception I could think of is if raw gas is leaking in when the engine is off due to a leaking float needle or bad petcock. There's probably something I am missing here.

I installed the Candlepower-H4 conversion for the 162mm/6 3/8" headlight. It took a little "customizing", but works well. I have taken rides over 50 miles with the light on the whole time and the higher wattage has not created a problem yet.

Excellent!

If there is power to the light...and check that, then replace it and see what happens.

I find it almost impossible to move the rod by hand with the sprocket cover off, but it seems to work fine with the clutch lever.

I agree. Make sure there are no sharp bends and get get a proper cable lube device and lube the cable. Also, consider taking the sprocket cover off and lubing the clutch actuator parts with some grease. Should be pretty light. I wouldn't spend the money on a hydraulic clutch kit even if I could find one.

If the direction matters, I did it wrong. In my case, they friction fit so I did not need anything to hold them in. Good luck!

The answer to your previous question is: because mine was doing something similar. I can't tell from the vid, are the air boxes in place? if not, put them on and see how it runs. Is it now running on both cylinders?

That's a good question. Also, are the lights essentially working right other than the fuse blowing?