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James' 77 550f.

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luceja:

--- Quote from: minimo on April 22, 2013, 06:20:04 PM ---There's a shot of your pistons dropped into the cylinders on page 5. I may have missed it but did you end up replacing the pistons that you buffed too hard on the skirts and around the ring channels? We're those pistons in decent enough shape to reuse?

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It seems they are just fine - I was worried I scored the surface when I cleaned them up, but having had them out a couple times after running, everything is a-ok. Pretty lucky for a set of pistons/cylinders/rings I picked up off of ebay all together. I have an extra set of 600cc pistons and rings just in case :)

luceja:

--- Quote from: AgPete139 on April 22, 2013, 01:37:49 AM ---So...wow. I cannot believe you have torn/assembled your engine so many times! I'm scared to just take mine out to clean it up! This thread seriously has inspired me to just dig in and stop worrying about everything that could go wrong. If something messes up, take it apart, find the root failure, and fix your mistake.

I bought a K5 some months ago that ran, but not well. I figured it was like yours, just needed a proper rejetting or switching the mains, etc. Whatever is wrong with why the motor lacks power (I'm now guessing bad compression), I have your thread here to guide me.

I'm stealing your milk crate method, BTW.

Your bike looks great. I can't wait to see what color you actually use for the covers & tank.

Pete

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the worst part was just not knowing the cause of the first failure until I found the paper towel that caused the oil block.. and I wouldn't have found that (almost re-assembled and ran it without finding that) had I not made other dumb mistakes.

If you have a compressor you can do a leakdown test using the crappy harbor freight tester and see if the rings or intake or exhaust valves are passing air, but I'm not sure about the results I've gotten from their compression tester. Maybe I don't know how to use it.

Either way, I'm a fan of just taking top ends apart to see what's going on, check ring gaps, etc. The big risks there are trying to remove old OEM style gaskets without damaging the surfaces, and getting the cam sprocket back on, which is a nightmare until you learn the trick. The rest of it (resetting the valvetrain) is just good maintenance, and is pretty straightforward from of the shop manual.

Then again, when I take things apart they inevitably self destruct, or at a minimum leak oil afterwards, so I might not be a good guide with this stuff.

the milk crate method works great, I'm not sure where I got that from. The side covers are being gloss blacked right now, then the tank, and then I have to go back and powdercoat all the stuff that has rusted since the bike has gotten wet a few times :/

luceja:
A couple of small updates on the bike:
1) I love this thing. I did a couple hundred miles of continuous twisties around Mt. St. Helens as a final ride of the summer this weekend. I'm no fan of the tires I chose; I especially don't trust the rear. But I'm comfortable enough to take the bike over until there's no chicken strip left, at least on the right roads. I'm just careful about inputs when entering and exiting corners. Next year will be bt45's.

2) The jetting is still finicky. I started getting smoke on hard accelleration or revving, in what seemed to be mid to full throttle. It pulled just fine and was very, very responsive. I pulled the plugs: three were very sooty black, one suspiciously lean. Appearance was rich, not oil fouling, and I get very little blow by from the crankcase hose, so I don't think it's oil smoke. Appears to be black smoke/rich plugs. All idle mix screws were 2 turns out, all needles even (2nd from top, which I believe is stock for 550f 069a carbs), 100 mains, floats even at 22mm, uni oem style drop in filter, stock airbox, stock headers, mac muffler.

First I figured the floats must be uneven, like they must be saturated or have variance in bouyance, so I took an extra set of carb bowls, tapped them to add hose barbs, and measured the float height externally - all levels were about 2mm below the lip of the float bowl, which I understand is correct. Returned the mains to 98 (had 100's) - still black smoke, but now didn't pull as hard, and removing airbox made it barely run... which sounds lean??? Tried richening the needles/midrange, but that just made it dog like the choke was on. Basically just tried changing things around. I returned to where I was (stock needle position, 100 mains) and tried varying the muffler - the mac exhaust has a circuitous baffle and doesn't sound particularly good, so I took Paulages' advice and cut the existing baffle out, made a tube out of perforated steel sheet, joined the baffle caps to the perforated tube, and packed it with household insulation. It certainly sounds better, and it's not smoking rich. So... the culprit was the mac muffler? I'll be keeping an eye on the exhaust and the plugs to see where to go next.

3) I'm hoping to make time this winter to run external oil lines from the right case plug up to the head. It drives me nuts to have a light oil leak at the cylinder head, still.

4) I need to make a full separate post, but in the spring I built my own electronically controlled ignition for the 550, based on an arduino, a hall effect sensor at the crank, and a custom coil driver circuit. It allowed for custom advance curves, however you'd like, and constant dwell through the revs. It was an incredible amount of effort, and yes, it worked! (Though I'd want to refine it alot before offering it as a DIY project for anyone) I also made an automatic idle control using a stepper motor mounted to the carb rack, which adjusted idle based on engine temperature. Again, this would need refinement before putting it out there, but it also worked. There was also a computer driven tachometer that integrated with the ignition controller. I'll make a post detailing all of this sooner or later!

luceja:
Thought I'd add a couple of photos/video of the arduino ignition, though again, I'll need to find time before I can get any good information up here.

Hall effect sensor/magnet rotor instead of points:



Stepper motor based idle control:



Link to it starting/running - http://vid82.photobucket.com/albums/j242/luceja/bikerunning.mp4

I don't think there's any benefit to what I made over points or a dyna, nor is the automatic idle screw adjustment really necessary... it was just a fun project.

minimo:


--- Quote from: luceja on October 01, 2014, 10:30:51 AM ---floats even at 22mm, uni oem style drop in filter, stock airbox, stock headers, mac muffler.

--- End quote ---
Are you sure this is an accurate measure? From the photo, looks like there's at least 2mm measured below tangent of the float. Is there tolerance allowed when the float arm is barely touching the float valve per the manual?

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