Vintage Honda 2-Stroke?

If the crank seals are dried out, you'll need to replace them.  If they're bad they will make it run lean and go bang.

Might not need a battery at all.  I didn't run one on my TS250.  Battery was only required for the stock lighting system.

In reply to bigeyedfish :

I came here to say the same thing .

Even XL250s of this vintage can be made to run without the battery. The OEM shop manual contains instructions for that, so I would expect the same thing is true for the Elsinore.

Following for the possible incoming updates!

It reminds me of Gonzo with the floppy front fender extension.

Mouse pee into the carb is very bad.

So, over the past weekend I moved houses. Dad came over to help move the garage stuff into the moving truck. He says "Here, let's roll this bike into the back of my truck".

"But there's plenty of room in the moving truck"

"You know, why don't I just take this home and start fixing it up"

"...But I was gonna do that"

"I got the handlebars if you push from the back"

"...but...but...okay"

I was so tired from moving all weekend that it didn't really hit me until later that evening. Dad stole my dirt bike! Damnit! 

Finally an update. Dad started taking it apart and sent me home with the engine and carb after Thanksgiving. He is having the frame blasted and powdercoated while I rebuild the motor. It shouldn't need much, hopefully just a cleanup, new gaskets, and seals. Dad is a "purist", and wants to restore this thing to factory perfect condition like he has done with his AMX and Chevelle. I just wanna ride!

I had a Honda 250 4 stroke  duel sport bike for a Summer , 

it was really too big for me to ride in the Pismo beach sand dunes but it was fun !

Sold it and bought a ATC 250R  which was a lot more fun in the dunes :)

Have fun with yours and try not to get it too nice so you do not want to ride it  !

I don't understand the "too nice to ride/drive" comments.....were they too nice to ride when new? So if it can be fixed now, why not ride it and if it gets scratched or broken, fix it again? But in the meantime you have a great looking bike to ride!

It would be one thing if it was a million dollar bike made out of unobtanium (doesn't stop those guys from racing their million dollar Ferraris at Goodwod, does it) but this is a Honda fer chrisakes!

Make it nice, then go have fun with it!

Great work getting it torn down! This gives me some motivation to start more on my shed find MB5.

In reply to MiniDave :

I'm in total agreement. I wanted to do the bare minimum to make it run ASAP, but dad wanted a new project, so I guess I'll go along with it.

Engine rebuild is underway, starting with the carburetor. This thing was really, badly varnished. Some repeated soaking and scrubbing with Pine-Sol took care of most of it. 

The internals may look wet in this pic, but in fact they are dry. The varnish was like a solid glass coating over everything.

Even after all the soaking, the float hinge pin was so stuck that I broke the bosses trying to get the pin out.

Hopefully JB Weld holds it together.

I did all I could with brushes and soaking, but had to bead-blast the outside to make it look new again.

New jets, float valve, needle, etc and it's ready to carburize again

The next piece on the engine was the oil injection pump. It lives in a compartment behind the chain, geared into the transmission. It's purpose is to pump oil from the separate oil tank, meter it appropriately based on throttle position, and force it through a jet between the carb and cylinder. 

The shop manual specifically says not to take apart the oil injection pump, and I cannot find any documentation of how to fix it online, so I took it apart. And good thing too, because it was completely seized up and full of 30 year old solidified oil. 

This unit is pretty wacky. It has a worm gear driven dual-profile cam on which ride two spring-loaded plungers. I didn't know they were spring-loaded because mine were stuck shut. After lots of soaking a scrubbing, I hit the plungers with a propane torch, burning away the oil solids, until they slowly rose from their bores, like zombie plungers. The cam disc height and therefore the oil metering rate is varied by another cam, which is turned by a lever connected to the throttle. All of these had to be torched to free them. Once I got everything clean and back together again, I loaded it with oil and spun the input with a drill until I could see oil pumping.

Now, off with the head...

Do you have the case splitter/install & crank removal/install tools? 
Hopefully the crank, rod & bearing are good, that is the complicated part on old 2 strokes. I rebuilt a '79 IT400. Separating the crank, pressing it back together & beating it back to true with a big brass hammer is an experience.  An old guy with many years experience & a shop showed me how. 
Some of the seals & bearings also weren't really available anymore either. Had to do lots of measuring & a couple bearings were sealed on 1 side & open on the other. So had to buy double sealed, then remove the seals on 1 side.

The engine came apart pretty well. I was able to source engine bearings, a kit with every seal, and a kit with every gasket. I don't think I'll have trouble pressing the bearings out. With this engine, one crank bearing is sealed inside the case and lubed by the case oil, and the other is sealed in the chamber lubed by the fuel/oil mixture. The fuel-lubed bearing is probably the only one that needs replacing, but I have both. The crank, rod, and piston popped out no problem as a single assembly. I will not bother with the rod bearings and piston pin as they seem fine. 

Clutches were all stuck together with more nasty solidified oil, but otherwise have plenty of life left. I think I can save them.

I ended up building my own case splitter. All I had to buy was two long M8 bolts. 

Shifter mechanism is cool looking

And that's a whole engine in one picture! Next steps are press out bearings, clean everything best I can, probably bead-blast the jugs and head, install new seals and gaskets, and bolt it back together for some fresh paint.

Freezing the bearings before dropping them in makes it a bit easier.

Case is back together with new crank bearings. I'm giving the clutch a chance by brushing all the rust and gunk off the discs. They is plenty of material but they were fused into one. I need to decide between painting it 1974-only brown, which is difficult to find in a high heat gloss, or 75-76 black which is much more common. 

Brown!

I went with black. It should look nice with the silver and orange tank.

I also salvaged the oil injection line. It was clogged up with more solidified oil, but a hot bath in the ultrasonic cleaner loosened it up enough to blow out with air.

Pretty much ready for dad to put on the newly powdercoated frame. Now I can start work on the Lotus again.

Dad has the engine back and has begun assembly.

In reply to Peabody :

I had a CR version back in the day and I would smile as my friends would try to start it and the kick lever would smack the crap out of the back of their leg if they did not push through. Good times. :) 

Update: Dad has gone all-in on this build. He and I are similar but different. We both love cars and working on them. I love fabricating and customizing and over-engineering. He likes restoring to absolutely pristine numbers-matching factory condition. So in my opinion he is overspending on a bike like this. But also, he is doing an incredible job and it seems to make him happy. He went to high school in the mid-70's in small town Colorado, bombing around the countryside on various bike like this, so this project hits him right in the nostalgia. For his birthday I went ahead and signed the title over to him. 

Brand new rims and tires.

I helped him fix the worn and cracked kickstand.

A few odds and ends left, but it should be ready to fire soon. He had the gas tank cleaned and coated, but his painter fell through so I might be doing the paint job. 

Hey is the tank still the hold up??? This is sweet!!!

That looks sweet! Given how many of these were used up and thrown away I'm glad your dad is restoring it to this standard. 

Dad decided to try painting it himself and it turned out great! Hoping for a first fire soon.