New Life for Columbo The '80s G, Man

[3Phase]

I'm putting the early head, cams and pistons on Columbo so I needed the early mechanical advance to match the cams.

The parts arrived this afternoon: thank you, Andreas!


1978E Ignition Assembly



I'm also trying out my Onedrive account to see if the image link and URL stay stable or if one or both of them change.

All of the 'Cloud' services have their quirks and seem to believe that their service and presentation are more important than the actual user and the content, like the way the Taj Majal became more important than queen Mumtaz Mahal's coffin.

.

[mack]

whoooooohoooo

I canh't race you to the track, but man, I'm so glad your going to be in the saddle again. Wait, I could be still sleeping. Is this real?

[3Phase]

I canh't race you to the track, but man, I'm so glad your going to be in the saddle again. Wait, I could be still sleeping. Is this real?

Nope! You're not sleeping any more! Sorry to wake you up but I found a box of 'tuits and it's time to get to it!

I looked closer at the new parts as I cleaned them and they're not '78E, they're '79F or SF. Bummer.
I'll have to check the vacuum pot and see what it is.

I honed the cylinders today and scrubbed them down along with another cylinder head. I think I'll just burn my clothes, I'd have to use 100 gallons of hot water to get them clean enough to wear again and we're in the middle of a drought. It's time to get some new stuff to wear and turn some of the old stuff into work stuff.

.

[BA80]

Nope! I found a box of 'tuits and it's time to get to it!

You need a round to go with those tuits.

I looked closer at the new parts as I cleaned them and they're not '78E, they're '79F or SF. Bummer.

79 will be just fine. Pretty much the same as 78.

[3Phase]

You need a round to go with those tuits.

79 will be just fine. Pretty much the same as 78.

That's what I've got now that I got cleaned up enough to touch beer.

It's just where to set the base timing is the only difference, 10 degrees for a '78 but only 5 for a '79. I've got the parts soaking in EvapoRust right now because the advance and springs were rusty but they'll be done in about an hour.

Next I have to go through the '79 Special head again and make sure it's ready to go.

.

[mack]

Ya

my days start pretty early. I have to have my middle daughter to work by 5am so I'm usually up a 3:30 am to have a coffe and shake her out of bed. Teenagers take some effort to get them up. Not like us that just never went to bed. Good to hear from you although I can't recall any of the conversation.

[BA80]

It's just where to set the base timing is the only difference, 10 degrees for a '78 but only 5 for a '79.
.

Try both and see which makes the engine happiest.

The timing cover is only 4 bolts.

If 10 makes it happier I'll adjust mine too.

[IanDMacDonald]

I emailed Andreas looking for a '78 advance, and he only had the '79. I tried the '79 advance before, and saw no change in fuel mileage.

I just re-synced the carbs and re-torqued my axle nut and fork nuts hoping that was my wobble issue. Nope, it was not. However, it allowed me to notice that I had 20 & 15 psi in the front and rear tire. Smooth move on my part. Added an inch to the ride height. I think my timing wheel is nowhere close to spec in degrees. Can't remember where, but I remember riding it at 10, and it was happier than 5. Felt like I was towing a ship, it was so boring to ride.

[3Phase]

Mack, it was about the Headlight Relay and the RLU.

You sort of forgot to mention that it was for someone elses's bike and I totally fudged up the time difference for the Left-Coast vs back East and up in TGWN.

BA,

It's the different mechanical advances. The '79s both add 5 more degrees than the '78 but of course I'm going to play with the base timing anyway just because I can; probably the vacuum advance pot too.

I'll see how much advance it likes/can take, then fill the reluctor slots so it doesn't ping itself to death on a long pull on a hot day. If I like it I'll dial in the '79 Special engine too when I get it back together. Right now I'm checking ring end gaps and I'm already seriously tired of changing pistons and cylinders.

.

[3Phase]

Nope, I've never forgotten to put air in my tires! No, Sir! <dodging tomatoes>

Ian, which advance did you try, the mechanical advance, vacuum advance or both? It doesn't really matter if you use the '78 or '79 advances but the vacuum advance pot should at least try to match the mechanical advance.

The mechanical advance won't do as much for fuel economy as the vacuum advance other than if you don't have it the engine will have to run with no advance all the time no matter what. That's not really good for fuel economy or power either.

If I remember you bought your XS with the vacuum advance locked out, the mechanical advance slots were welded up for a 20 degree(?) base timing setting and it had a special valve grind and valves that got munched. After that just about anything would seem like towing a ship and the iceberg it rode in on too!

You can spend a lot of time and money trying to adjust and tune the handling on a bent bike. Before you go knutz, have you checked the frame to see if it's straight, the swingarm is centered and both tires are tracking correctly?

.

[3Phase]

FinRpr1.jpg: Broken lower left rear fin repaired.

The crack was cut with a Dremel diamond cut-off bit, then four 1/8" holes were drilled through the crack and JB Weld was poured.

FinRpr1.jpg


FinRpr2.jpg: A previously broken fin was welded. These jugs have had a rough life.

FinRpr2.jpg



FinRpr3.jpg and FinRpr4.jpg: The cylinders and Pistons are almost ready.

FinRpr3.jpg


FinRpr4.jpg


.

[BA80]

I'm already seriously tired of changing pistons and cylinders.

.

What are you using to hone the cylinders?

[3Phase]

What are you using to hone the cylinders?

The new rings are moly so I danced the two-step with a #280 three-stone hone and 30wt oil to knock the glaze off, then scrubbed it down and followed up with a set of #400 stones to finish it.

I used a cordless drill to run a nylon brush CCW in the bores with soap and water to remove most of the grit, then kept wiping with rags until they came out clean.

Uh, why? <he asks nervously>

.

[BA80]

LOL....Because iron rings seat much easier than chrome molly rings. Pretty much all you need to seat iron rings is a glaze breaker (mulberry bush) but chrome molly needs a real fine finish to seat and the cylinders need to be pretty much perfectly round Mollys won't seat on a rough finish or a worn cylinder.

Not sure of what grit stone you might need, it's been a while since I've built an engine. You might want to check with a builder. I always liked the iron rings for a rebuild though. Just for that reason. They are much more forgiving.

[3Phase]

Whew! These are the spendy, brandy new Yamaha 3J2-11610-00 stock-size rings.

I'm not 100% sure what the Top ring is made of -- feels like steel with a moly coat and no sign of any chrome so I went with the two-stage fine finish for moly. The #2 ring is black-coated-something-or-other that breaks if you look at it wrong. If it's not moly-coated that's too bad, it'll have to deal with it.

I got all of the pistons in without breaking a ring but it's hairy scary for what one set of rings costs per hole.

.