Well, I finally got the garage cleaned out and got my title and plates from the DMV.  Premature I know, but I wanted to make sure I could register the little beast under "my-brother-in-law-won-a-dirtbike-in-a-drunken-card-game-and-gave-it-to-me-twenty-years-later-title-what-title" conditions before putting hundreds of hours into working on it.  It's go time.  As background, I have 100K+ miles on big bikes and am the proud custodian of a vintage truck as my daily driver.  I'm an engineer and am handy but slow.  An outside observer would think I know exactly what I'm doing, but I've never had the time to dive super-deep and in general have let other people do the tricky bits on my vehicles.  I don't know what the hell I'm doing, especially with an old two-stroke so it's going to be a fun ride for y'all to chuckle at.  Ha!  My ultimate goal is to have a fun, stinky-in-all-the-right-ways city bike that I can occasionally take to the dirt or the campsite and teach my daughters to ride.

So!  Started from the top a couple of days ago.  First goal is to make sure it runs - for some value of "runs" - and determine whether I need to do any work in the cylinders.  It turns over with the kickstart so nothing is seized.  But am waiting for carb rebuild parts to arrive, so I wanted to pull some non-essentials and get started on long-lead stuff.  Pulled the fuel tank and catalogued the funky rubber bits that I'll need to find replacements for.  Wanted to bring it down to metal as much as possible (considering electrolysis with a power supply to de-rust) so pulled off the petcock and the top of the "regular-not-reserve" tube was so jammed in schmutz and a mix of deteriorated gasoline and Temecula Valley dust that it broke off in the tank.  Dumped a bunch of PB Blaster in there to soften up the schmutz and was able to push the tube into the tank and eventually shake it out along with a cupful of other crap.

Remembered that there are two tanks - the LT2 has an oil tank as well as the gas tank - so I might as well refurb the oil tank at the same time.  Started to pull the oil tank and my daughter came down to the garage when she heard me smacking the mounting screws with my treasured JIS impact driver.  Got them loose and let her unscrew them the rest of the way, and after some origami that had me loosening up the battery box the oil tank finally came free.  It was full of oil so I had my oil catcher there, but it was downhill in the wrong direction so a bunch of oil drooled out onto my garage floor which amused my kid.  Good times.  The oil tank cap was way too small, entirely not identical to stock, and was delicately placed on top of the oil tank with no actual sealing ability, so that goes on the new-stuff list.

Pulled the seat and decided what to do with the seat pan.  I've heard of people fiberglassing an existing seat pan and that sounds like the only practical way to deal with a pan that is rusted and structurally unsound but still retains a faint ghost of its original shape.  Gonna blast off that rust with some combo of 15VDC/sodium carb and my wire brush then seal it and glass it up.  Stay tuned as this is likely to be a shitshow.

Ordered battery, carb rebuild stuff, carb cleaner, a couple of extra jets, a compression tester, and some extra O-rings.  Too cheap to buy an ultrasonic cleaner so it's nitrile gloves and baths of really sketchy chemicals.  Next step - rebuild the carb, dangle a transfusion bag of premix, and see if I can get this 50-year-old engine to fire at least.  In parallel, strip the ancient gasoline / SoCal dust / varnish + electrolyze + coat the inside of the tanks.

Pictures shown are of the whole bike pre-resto and then me trying to keep track of parts for the gas cap.  Note small spiders and general amount of crud!  I'll get more specific pics of the stuff I'm talking about the next time I post.

Oh, and resto == getting the thing running safely, functionally, and non-embarrassingly.  I guarantee the finished product will not be pretty.  Feel free to give me shit if you see the meaning of "restoration" differently. 

Onward!

Greetings from Tennessee  
 I have it’s older cousin a Ht1 

 

Smart man.  I've heard more than one "horror story" of someone spending thousands of dollars and countless hours of time on a restoration only to have the CHP confiscate the bike because it was reported stolen even decades ago. 

Loved the whole story, looking forward to following...  (LT2 was my first "real" motorcycle...  I have a "parts bike" if you need something)

hello from OC CA
I love your bike and Temecula

Glad to see that bike being restored or refurbished. So often they end being parted out when they lose their shine.

Off topic.
I was involved in the design and build of the machine that embossed the lettering around the top collar on that MicroStar beer keg in the background of your first photo. It was an interesting job. 

Making what goes in them beer kegs is another hobby of mine.. and that can be a rabbit hole as well!
Sneezles61
Whoops, off the topic too.

My interest is in the contents within. Specifically how I can make it come back out and pour down my throat.

Motorcycles are just a diversion while my main interest as detailed is not being engaged in due to societal rules and regulations regarding time, place and quantity.

And both hobbies rely on a gas of some sort… there, all tied together!
Sneezles61

Hello from a wintery Blackpool in the UK.
Bill Bekker whom frequents the pages of this site has or had a very nice LT3. I see more of the 2 and that same colour alot . I like them and will be keeping tabs on your progress.
Welcome along.
Dave.

 
Update on my LT2 project!

First - thanks for all the replies, and pretty cool to hear about the keg embossing connection.

Feels like material progress although I know there's a lot to go.  Most of the work so far has been methodically disassembling stuff and figuring out my preferred methods for rust removal and cleaning.  I'm now the proud owner of an ultrasonic cleaner and have been playing with Evaporust, Simple Green, vinegar, and Chem-Dip for all the obvious reasons.

Compression!  I knew the engine wasn't seized but didn't have any data points on compression.  Turns out (y'all surely know this but it was new to me) a cheapo compression tester that works great for a nice big 302 is a lying POS when it comes to a very small engine.  I got a reading of ~75 psi and was expecting to need to do some serious engine work but fortunately read up on things a bit and realized that for an engine this size you need a Schrader valve in the adapter right up against where you screw it into the spark plug hole - otherwise the volume of air in the hose of the tester is large enough compared to the cylinder volume that a car-style tester reads way too low.  I sprung for a better tester where buried in the Amazon reviews was a mention of the Schrader valve and boom! I was able to read 125.  Guessing that's not quite 100% but also guessing it's good enough for the engine to start once I get everything else sorted out.  Strangely, the shop manual doesn't spec compression, so I'm just assuming what it should generally be.  I'll be taking the top end off anyway and while I'm in there I may end up replacing rings or whatever else is needed.  Stay tuned, that will be a while.

Pulled the air cleaner and the old crappy foam had basically fused into the rusty metal.  Lots of time in the ultrasonic cleaner sorted that one out.

My rectifier is good.  Small victories!  Back when the shop manual was written nobody had diode testers on their meters.  Voltage drop 0.533V in the "correct" direction, open circuit in the "backwards" direction.

Next - pulled the carb.  Now the shop manual PDF I have describes a _different_ carb from what I was seeing.  I started thinking that someone had put an aftermarket one on, but again with more Googling it turns out that the shop manual - despite being a combined manual for the AT1, CT1, and LT2/LT3 - only had a picture of the carb for the somewhat more popular AT1, and not the one for the LT2.  Mystery solved (and it turns out I _did_ order the right carb rebuild kit).

It was all there, but wow - what a gummy mess.  I obliterated the swaged button off the end of the throttle cable - need to replace that cable anyway - trying to get the thing off as the round throttle slide is and remains completely gummed up to the body of the carb.  I pulled off the float chamber and the few drops of liquid left in there (along with a bunch of semi-solid hydrocarbons) smelled like a combination of the La Brea Tar Pits and the faux-maply-syrupy aroma of a bag full of Sausage McGriddles.  For the record, that's not a bad smell in my book, it's just... notable.  Others may differ.  I left it overnight as I had to pause and do other stuff, and the smell of just having that on my workbench with the garage door closed seeped up through the whole house until I opened some windows the next morning.  Fortunately my wife was out of town and the kids didn't complain.

After pulling off the float chamber and what jets / screws I could access with the slide gummed shut, I was about to drop everything into the Chem-Dip when I realized that the floats looked like plastic and that the Chem-Dip would probably eat them.  So into the Simple Green and ultrasonic cleaner the carb body went, as I wasn't even able to move the floats much less figure out how to get them off.  Soon I was able to move them and enough schmutz was off the pin connecting the float assembly (two floats connected by a thin metal piece) to the carb body that I was able to tap out the pin with the bent remnant of the tip of a 1/16" roll pin punch held in Vise-Grips.  Floats off, everything else visibly plastic removed, and some more soul-searching.  The outside of the carb seemed to be painted.  Did Mikuni paint their VM20 back in the day?  Did Yamaha paint it?  Did my feckless relatives lovingly paint the carb matte black?  I decided that there was no possible reason the paint would be functional so into the Chem-Dip it all went.  Checked a bit later and still can't tell whether it was paint or just a remarkably uniform layer of schmutz on the outside, but the Chem-Dip was definitely taking it off.  

On that topic - I'm pretty sure I was imagining things, but I think I could feel my DNA curdling whenever the Chem-Dip lid was open, even with gloves and goggles on and not breathing too much.  Good thing we've already had our kids.

Pulled the reed assembly and proudly set it on my workbench while the Chem-Dip works its sketchy magic.  Next update: will my slide move freely, or will I have to take a torch to the carb?  And if it's the torch, will I remember to close the lid on the Chem-Dip before playing with fire?  Onward!