Valves

[CarolynS]

Cosmetics

Malber is right, and funny you mentioned that because the 'Old Man'-John-said that I really need to consider swapping everything to the other bike. However, that entails: swapping the front end-does all the wiring for that unplug or are we talking redoing it all, not to mention now removing the fairing and replacing the original headlight; rear brake caliper, rotor and the line, plus the master cyclinder-it locks up and won't release; fixing the battery pan and all the rust on the frame from it; changing the exhaust over-this one is a Kerker with a huge hole in one header pipe, the 80 has the 4-2 that I want besides so I can have my center stand; figuring out why the left hand turn signal won't work-not to mention the headlight; and once that is done, I can concentrate on why it will kick up and run at 3000rpm and backfire. We won't even go into the cosmetics at this point...Oh and both shocks are leaking, so they have to be replaced and what will I find while going through this process?
OR
I can take the head off the 80, check for piston damage and such; take the head off the 79 and send it out for a basic valve job-buy parts, pay the labor-and throw it on, replacing the cam chain in the process.
I really don't know what to do. We were looking it over a little while ago, and in my frustration(or indecision)barked at him that "THAT head (79)GOES on THAT bike (80)! Now I log on here and find that he could be RIGHT!! AaaaRrrrGGggg!!!!
Any opinions are welcome and I promise not to bark about it.

[DiverRay]

Carolyn,
As I said on the other post, just swap the '79 engine into the 80. The ONLY thing that would NOT be a plug and play is the pickup coil assembly. They can be switched in about 20 minutes, less if you do it while both engines are out of the frame! You can then part out the "bad" bike, work on the engine that belongs in the 80, and ride while you do that!

[Flatlander]

What is wrong with the 80's head?

Why are you switching heads at this point?
Oh, and which thread are you going to post the cam timing at?

[CarolynS]

Fresh!

We found that all of the intake valve clearances are at least 24mm out. The concensus is that the cam chain slipped somehow-either on it's own or someone 'helped' it-and bent at least one valve. The exhaust valves are all wide but still within the specs. We did a compression test and the gauge didn't even move.
The 79 head will go onto the 80 engine, but the valves don't interchange-so I don't know how that works, but I trust the people here implicitly and if they say it will work, that is good enough for me.
My question is that it is recommended that the 79 head be sent out for 'cleaning' up and reseating. I wonder how much more it would cost for the 80 head to just get the full Monty valve job?

[prometheus578]

Carolyn, empty your PM mail box. it's full.

[CarolynS]

It is NOT

I put all it in an old folder. Isn't that how it works? The inbox says empty!!

I'm so lame!!

[prometheus578]

Old folder is still taking up space.
Empty the in box, the sent message box, and the tracking box, if anything's in there.
Oh, and that folder box.

I have to do this at least once a week due to the volumes of fan mail I get.

[CarolynS]

I deleted everything, will that work?

[prometheus578]

Yes

[tarzan]

I read this whole thread and kind of wonder if you take the head off the '80 ,why you wouldn't just send it for the rebuild?Is a 79 head better?It seems to me that one rebuilt head is as good as another if done right.Valves if bent can't be that expensive to replace.Anyway ,I was just curious.

[Dragon Tamer]

Just don't understand the problem, you have a rat bike that runs but with some small problems (probably carbs) and a concours bike that does not run, spring is here.
I had a nice pickup truck with a bad engine and a pickup that had been rolled over with a good engine. In one afternoon I had a nice pickup with a good engine and a junk truck I parted out, engine change is simple!
My main concern if I was in your place would be the fact that I was burning riding time!
Don't get me wrong, I am not yelling at you, just trying to explain that one big part is easier to change than a bunch of small ones.

[prometheus578]

"Tinkerer, tailor, soldier, spy."

Check the profiles of the posters to this thread, and then check Carolyn's profile.
Does one see anything remotely mentioning mechanical training of any sort?
Not only is this her first bike, but quite frankly, she's also a... girl!
(But she is trying to overcome this the best that she can)
She has already removed, thoroughly cleaned and adjusted the carbs. She has many hidden talents, but let's not overwhelm her.
She doesn't also have a lifetime of accumulated tools at her disposal, nor good available garage space to spread out two bikes. The '80 is at her workplace
We are all thousands of miles away... The current male she's bonded with owns a Harley, so we can consider him (and his bike) mechanically useless.
Pulling the carbs(which she's already experienced at), removing eight nuts for the headers and then unbolting the head she can handle in an afternoon.
Pulling two engines, swapping them and then hooking them back up again... might not be as much fun.
Recall that she also wants to lower the bike. This means that she's petite...
The old joke, "She's got everything a man wants... big muscles and a moustache" may not apply to her. Engines are heavy, bulky and stubborn to move about gracefully.
She's also smart, attractive(she knows about cosmetics), and is extremely wealthy.( she owns two bikes, not just one).
It might be simpler to just pull the '80's head, have a machine shop replace the bad valves with new, do a valve job and valve seals on the rest, and be done with it.

[TopCatGr58]

Prom, you forgot Sailor....ex!

Carolyn, oh boy, where do we start? Let's see if my CRS won't interfere and I can recall the specs correctly!

The 79 head has smaller valves(1mm), but hotter cams vs. the 80. The intake chamber head piston domes are smaller, so it can possibly provide a little boost in compression.

Doing a simple head swap would be cost effective except for the fact that you are also going to do a head job, and since you are not doing it yourself, $$$. A machine shop likes to regrind the valves and seats, but unless they are severely burned/pitted, then a simpler and much cheaper lapping procedure would do just as well..IMHO....a few bucks for the double ended suction cupped lapping "tool" and some lapping compound vs. the fees for grinding the valves and seats not to mention other labor tearing it apart and putting it back together.

Now, since you are pulling the heads, you're getting a complete gasket set which includes the valve seals! They normally cost $8.00 EA from YAMAHA, and the OEM head gasket runs ~$80.00, so with the "KIT" from PNM, you essentially are getting the seals for free, along with ALL of the other nifty precut gaskets and seals!!!

IIRC, there is a tech tip(s) on making homemade valve spring compression tools from an 8" C-clamp and piece of PVC pipe etc., again about $10.00 worth of parts, along with needle nose pliers for getting to the valve keepers, and you've got all the tools you need to recondition the 79 head yourself.

You've tackled a bank of carbs, many folks here would rather tear down their engine than work on carbs, so I think you've got the right STUFF to do this job instead of outsourcing it to a machine shop.

With the 80 head, bent valves, you'll find that the valves are not cheap, easily $30.00 each! Hopefully the valve guides were not damaged. A few of mine got bent, but not at normal engine speeds, so my guides were okay, and didn't have to have the guides reamed, the new valves matched perfectly diameter wise, just slid right in.

So....IF you are independently wealthy, then yes, you can send the 80 head out to get refurbished and then just put it back in. Or you can get a little adventurous and tear apart the 79 head yourself, lap the valve/seats, replace the valve seals, and then put it on the 80 engine, and possibly save yourself many hundreds of dollars!

BTW, you'll need to recheck and readjust the valve clearances once you get the head(whichever one) back together!
T.C.

[skids]

Re:

Prom, you are an equal opportunity offender! I give Carolyn a lot of credit.

[i]
Not only is this her first bike, but quite frankly, she's also a... girl!
(But she is trying to overcome this the best that she can)
She has already removed, thoroughly cleaned and adjusted the carbs. The current male she's bonded with owns a Harley, so we can consider him (and his bike) mechanically useless. [/B]

[CarolynS]

I'm full of surprises

TC, you make that sound so easy! It makes sense, but I have to complete a recommendation from someone of 'great authority' before the diagnosis is confirmed and I proceed. It all sounds do-able.
I had to give up all the tools and my Volkswagens-air cooled 68 double cab, among others-when my husband died. Had to downsize. Luckily I inherited my mechanical brain from my grandfather, and I can figure out how just about anything works given a half an hour to think about it, move it around, see how it goes together. An inline 4 is different than a horizontally opposed 4, and that is where most of my knowledge is or, was. However, that said, internal combustion engines are all relatively alike, unless they run on diesel-compression pressures are vastly different with them. I drove a semi for the last 20 years, still do. You don't last that long without knowing what's going on. I just have to learn this technology's nuances, and luckily I found all of you to steer me from the pitfalls of Clymers manuals.
Unfortunately, I AM female and my biggest flaw is questioning my own ability. All of your wives, girlfriends do it. 'Oh, I couldn't do that!' C'mon, how many times have you guys heard that? The other problem is a bunch of lesser men than I found here on this site asking me stupid questions every 5 minutes when I am trying to work on the bike. The most popular question is 'YOU'RE not doing that by yourself, are you? Dopes!
Bear with me. In a short amount of time, I will catch up. I'm shooting to be the first female 'Guru' on the site!