Enigma

If you can do the full 11 min.

And a side note . . . Some might wonder why I'm posting this story. It's a hunting and fishing site after all. Point being I divorced my wife when my boys were 8 and 10 yrs old. Turns out she liked the neighbor's Italian sausage more than my German bratwurst. I fought for custody but the legal cards are stacked against fathers and I didn't get to spend a lot of time with my sons when they were growing up. The prime time to introduce them to the outdoors was limited for me and with all their other sports interests teaching them to hunt didn't happen. We do some fishing when we can but they're both busy now with their lives becoming strong young men. No regrets. But we always try to find common ground and for my youngest and I its motorcycles. I hope this puts these posts in perspective.

I've made many test rides on this bike and she runs like a scalded dog. At mid to high rpms she pulls hard for a 440cc bike and scoots right along. The one problem that's giving me fits is the left cylinder plug is always carbonized and running "fat" while the right side plug is whitish and running lean. I've had the carbs apart more times than I can count and cleaned them many times over. They're clean. But no amount of tuning the carbs cures the condition. While tuning her up I've always noticed the right side exhaust has a lot more forceful output than the left. Went outside today to look her over and the oil was low. Then it dawned on me. The left cylinder rings are shot. Need to do a compression test and most likely another tear done to replace piston rings. Don't tell my son lol.

On these old bikes you have to sync or balance the carbs so each cylinder is getting the same amount of gas and air. These carbs happen to be Keihin CV36 or "constant velocity" (air flow) carbs. Various companies sell sets of manometer gauges to sync the carbs but I try to be resourceful so I built my own setup. It worked quite well but revealed another issue I have to deal with.

The front forks were harsh. Had no interest in tearing apart the front end to rebuild the forks. Settled on draining the fluid and replacing it. Had to build a tool to get the oil down in the bottom through a very small hole in the top of the forks. A syringe, 1/4" tubing and some electrical shrink tubing. Worked like a charm. Added 150cc 5w20, reinstalled the air plugs and charged them each with exactly 9lbs of air. Much better ride now.

Changed the oil, reset the idle mixture screws and idle adjustment and she snapped right back to life! My son had come home in late May and was really jonesing to ride "his" bike. We've made several trips to a local parking lot, got him out on a couple back roads with no traffic and he seems to be catching on quick. Having a blast he said. Funny how most kids today have no concept of a manual transmission. He's never had the opportunity to learn like I did back in the day. Clutching, shifting, rpms and throttle control. All new to him. But he's getting it. Just be smooth and take it slow I repeatedly tell him. Also signed him up for a riding course 'cause you know, Dad doesn't know anything. I figure let someone else teach him some pointers and show him some tips. Maybe he'll learn something new.

Had to remove the exhaust to get the cylinder head off. It didn't want to come apart. There's a crossover piece underneath that was rusted really bad. Unfortunately destroyed it removing the pipes on each side. I did the math and ordered a piece of stainless tubing with an ID that was close to the OD of the stubs on the exhaust. Cut some expansion slots in it and it actually went on fairly easy. Couple of U clamps tightened it all up.

Installed the new front lights and speedometer and cable. They all work well.

Noticed it was leaking oil at the tachometer port on the cylinder head cover when I took it apart. The mounting hole for the retaing screw had broke. Cleaned it up, JB weld and it held when I put it back together. No leaks now!

The old cam and top cam bearings were shot so I scrounged the parts from the donor bike. Luckily they were pretty pristine so reassembly was easy. Cleaned up the top end while I was at it. Before. After.

She was really pretty when we got her back.

Note the toasted exhaust valve and scoring on the cam surfaces. She wasn't going to last much longer.

I thought last year we'd burned an exhaust valve so I pulled the cylinder head. Turns out the cam and the cam bearings were scored pretty bad as well. Sent it to a guy in Oregon who's sole business is cylinder head and valve train repair on vintage bikes. He cleaned up the valves and recut the valve seats, installed new oil seals and cleaned up the cam bearings. Very happy with the work he did. Very nice guy as well.

Purchased some new parts as well. A NOS speedometer. Very cool for being 40+yrs old. Aftermarket speedometer cable. New front signal lights. Two wire with running lights. New key. OEM reflectors. OEM carburetor boots/holders. OEM air filter. The new battery I bought last year wouldn't take a charge this year. Even though it was one month outta warranty the nice lady at the store gave me a new one at no charge. And still scrounging what I can off the donor bike I got with the deal.