broken engine!! :(

The bolded sections are things you can do yourself with the right tools and patience. If you aren't confident or don't want to put in substantial time, go machine shop route for all of it. But some of it is really pretty easy like the lapping, seals, checking for true, and plasti-gauging. Obviously the other things can be done by a home mech, but they are way harder and require more skill & tools.

A good machine shop is better if you go and talk to them first, you can seek out advice on a good one, but my experience is call around and see which one seems interested in the work. Go see them, talk slow, and be nice-i.e. don't act like you need this done 'now' or your pushing - just try and get in their good graces and I promise you will get your work done right and reasonable. Most of these guys love to work on motorcycle parts as more than half the time they are dealing with much more cumbersome parts.

Don't get discouraged or take any advice personally. It's just love of motorcycles and experience that makes it sound negative. Just use what information you receive to your benefit and forget the rest. After all it really is all meant with the best intentions. And no doubt once it is all done you will have one very nice and practically new XJ head.

 

is grinding the valves the same thing as lapping? 2 of the shops i called seemed confused when i said lapping.

 

A machine shop should not be confused by this. Lapping is the finishing step, done by hand with the little suction cups on a stick fitz mentioned and lapping compound is used as the abrasive. You basically turn the stick attached to the valve (in its seat) rapidly between your two palms.

Grinding is done on a machine and it will take away far more material than lapping. grinding would be the first step, if needed.

 

I'll annoy everyone by suggesting that plasti-gauging the cams is not going to help you much. I thought you said that you had a set of cams with the new head, so you should use that as the parts will be worn in to each other. If the oil supply hasn't failed then the cams will be good enough. If the supply has failed then you will see the damage visibly.

The reason I say to skip it is this - you use plasti-gauge to check your crankshaft main bearings. Yamaha had a range of sizes that they ground their cranks to (presumably coping with worn machine tools and allowing for errors first time around) and there are shell bearing inserts that vary in thickness (just like the shims). You use the plasti-gauge to check the clearance to find the right shell thickness to use to get the right oil gap.

The camshaft bearings are line bored and the shafts run straight in the heads with only the oil to protect them. If the plasti-gauge says that the gap is too big the only option would be to throw it away. Unless you can see deep grooves (and even if you have deep grooves, you can still use them if you have no replacement, though I wouldn't buy the gasket kit to rebuild such an engine - I'd save that for when I had new bits) then the head and cams are okay to use.

If you are going to use the plasti-gauge anyway, do it first, before spending on anything else though.

 

You are not annoying me! While you are correct that there is little that can be done with a too-large gap, a too-small gap is more critical and can & will cause cam seizure and possible total engine failure. This can be corrected before engine assembly by align-boring, which is why I brought it up. And I believe he said he bought the head without the cams, though I could be wrong...

 

both cutting new angles on the valve and grinding the valve seat will change the shim size. hand lapping not so much. depending on your shim sizes now you may run out of sizes.
valve guides take specialized reamers that ain't cheap so if you go that route your going to pay for a little more, unless the shop already has them. do they even make valve guides for these ?
i think your best bet is hand lap the valves and put on some valve stem seals and call it a day

 

Good point. But we are advising him on how to install the head for minimal maintenance in the future, right?
Yes, the valve clearances may have to be adjusted now, but that should cover it for a long time.
On the other hand, I've gotten great results by hand-lapping using only thumb pressure on the valve and a piece of rubber tubing slid over the (unsprung) valve stem with good high-quality valve lapping compound. The proof is in the grey line left after lapping on both valve face & seat. Nice, wide even grey line indicates a good seal. You can check your results by filling the chamber with stoddard solvent and checking for leakage past the (unsprung) valve.

 

Unless the valve are burned I would not worry about grinding them. just lap them replace the seals and check the the head for warpage. Also check the cam bearings (first by the way) for any scoring. If they are scored bad the head is trashed.

As for hardware stores,,, I have never found any problem getting the proper bits and pieces for my bike. As a mater a fact I have better luck there than where I work at,,,,AUTOZONE. But those studs will be a specialty item that would not be at either place. Try Len, our online parts guru.

 

ok so i just got my gasket kit (which came really fast! even from Japan) and i recognize a lot of the gaskets that are there, clearly the head gasket and valve cover, and im guessing the larger round one is the clutch cover. but there are some that im just not too sure about where they and im wondering if there are any that i should give to the shop when i get my valves lapped?

these are the one i am unsure about.
the large square one (oil pan?)
there are 4 of the round copper color ones, what are they?
the 8 tall green ones?
there are 4 of the flat round one with with little wings (intake?)
the 2 tall black rubber one those i recognize from under the head.
the 4 large rubber o-rings?
all of the other small o-rings, 2 red ones, 2 larger one and 2 really small ones?
and the 2 (green and grey) flat gaskets?

let me know what i have here, unfortunately it didnt come with instructions or a contents list. still calling around to find some one to do the lapping

 

The 8 green ones are the valve seals, the ones with the wings are intake boots, guessing the coppers are crush washers for your fill and drain plugs? Round ones should be timing cover and clutch I think. No idea on the o-rings. Square should be oil pan.

 

It has been some time since I had to worry about this, but to fill in where I can:
the large square one (oil pan?)Yes
there are 4 of the round copper color ones, what are they? Sorry - not sure which ones I'm meant to be looking at - not the exhaust pipe gaskets 6-7mm thick and 30-32mm across ?
the 8 tall green ones? Valve guide seals
there are 4 of the flat round one with with little wings (intake?) Could be - I was going to say camchain adjuster, but not if you have 4 of them (my 550 has rubber inlets
the 2 tall black rubber one those i recognize from under the head.
the 4 large rubber o-rings? Not sure - two i would have said the starter motor - I'm not doing very well at this..
all of the other small o-rings, 2 red ones, 2 larger one and 2 really small ones? Check around the YICS system
and the 2 (green and grey) flat gaskets? Crankshaft end covers - one over the pick-ups and the other blank.

Realistically - pay attention as it comes apart - there are o-rings needed along with the head gasket that you will see as you take the head off (you have it off already, don't you - do a dry run and see if you can see where they are all used.)

EDIT @ CaptainKirk - you're right - I looked at the EBay page and he bought it without the cams, so I'd either use the plastigauge or lightly oil it and check they turn by hand.

 

Greg is right on the copper exhaust gaskets.

 

See if this image helps. I forgot that there are o-rings around the barrel skirts
http://www.powersportspro.com/pages/OemParts?aribrand=YAM#/Yamaha/XJ550H_-_1981/CYLINDER_XJ550H_J_K/XJ550H_%281981_MOTORCYCLE%29/CYLINDER_XJ550H_J_K_%28XJ550H_-_1981%29

 

yup most if not all of the o-rings go under the head, didnt notice them at first because they stuck to the underside of the old when when i removed it. should i bring the valve guide seals with the head to the shop when it gets lapped? i hate for them to have ti all apart and not put fresh part in there, or have them buy parts that i already have.

thanks for the image Greg it helped alot!

 

Get the shop to install the seals when they put the valves back in. Once the springs and valve collets (collets are pairs of wedges that keep the spring-retaing-cap in place) are on you won't be able to get them - the shop would be expecting you to have them.

 

ok ive been doing a lot of reading (and watching different videos) on how to do the valves and i think i am going to attempt it myself; by first trying to remove the springs on the broken head just in case something goes arry. it will be good to have some practice too and see how it all goes together/apart. got the next two days off to figure it out, wont have the money to bring it to a shop for a few weeks anywho, so might as well see if i am capable of doing it before i spend the cash on something i could do myself. i'll update more as i continue. wish me luck!

 

is there a "home remedy" for cleaning the block? i could soak it in some sort of cleaner once i get it all disasembled. its not super dirty but i figure since its off i might as well make it look nice too. isnt there some sorta electro-somthing-or-other that can be done? id just trying to think of things to keep me busy. i already cleaned off the oil pan and exhaust.

 

For a home remedy a can of engine decreased and a tooth brush have always worked for me or if you have access to a large enough ultrasonic. If your thinking of electrolisis where you submerge said part in a conducive solution and hook up a battery charger. That only works on ferrous materials. Ie: steel and cast iron

 

Maybe i missed it in the replies, but MAKE SURE TO NOTE---there are two thick flat copper washers, and they are to go on the head as you bolt the engine together. Make sure to note which side of the head they go on. They are specific to those two studs.......

Dave F

 

there are 4 of the round copper color ones, what are they? The 4 copper gaskets inside the square oil pan gasket are the exhaust outlet gaskets.
the 8 tall green ones? Valve stem seals
there are 4 of the flat round one with with little wings (intake?) correct
the 4 large rubber o-rings? Cylinder base o-rings
and the 2 (green and grey) flat gaskets? green= generator cover, grey= timing cover.

Just a note about the cam chain: If you happen to let the chain fall loose of the crankshaft. You can remove the oil pan to guide it back into place.

Ghost