A few questions from a first time Rebuilder

Hello folks.

I know that most of these questions have, or probably have been asked and answered a few times over on here. In fact, i'm sure of it. But I figured it would be easier to ask again, then put a bunch of questions on a bunch of different threads both new and old, and hope for answers.

so here goes.

I am rebuilding my 1981 XJ550 Maxim and following the Clymer manual

1.) CYLINDERS (they look to be fine, nice colored, still cross-hatched, no real evident wear spots)
A.) easier to measure with telescoping bore gauge and micrometer, or dial bore gauge?
Can I use an old piston ring to measure the ring gap?
B.) if found to be out of spec, can you use oversized rings on the stock pistons,
or do the cylinders have to be bored, and oversized piston and rings used?
C.) If boring occurs, where can I buy the oversized pistons and rings? i've already ordered new OEM piston pins (probably should have waited) will they fit with an oversized piston? i've looked everywhere on the web at least and can't seem to find the information i need or find oversized pistons for this bike.
D.) Can i put the whole cylinder jug into a homemade sonic wash tub (the sander and rubbermaid method) without fear of ruining the inside of the cylinders? I am painting the engine components also and through internet research, found that method to be pretty cheap and effective.

2.) TRANSMISSION
A.) Is there only supposed to be a half circle circlip on each end of each shaft bearing?. did some owner before me rebuild this and skimp out, or is that the engineering of the thing?

3.) VALVES and HEADER
Coming soon....

I will take some pictures right now of cylinders and pistons and get them up here for some visual reference.

Thanks in advance.

 

so I lied.. the flash from my camera brought out some wear that a flourescent shop light and my headlamp could not.. there is plenty of wear inside these cylinders..

here is what piston (from left) 1 , 2 , + 4 look like






piston 3 has some serious scoring in the top rim











wonderimg now if this has any relation to why my no. 3 exhaust valve looks like this.. this is no. 2 - no. 3






any thoughts on that one?

 

Forgot about the cylinders..

here is 1





2







3







and 4

 

I'm thinking now that I am going to have to go for a bore, but could use some knowledgeable xj advice from ya'll fine folk.

here's one for fun.. my own little messy desk in my garage classroom.. I'm just glad it's not paperwork.. Hooray for new things!!

 

I just split the case and I only had one cir clip on each end.

 

Can you even get std rings? That's the first thing and even use original rings for end gap if they are in spec yo may get away with light hone and reuse
Pistons should clean up the measure everything and go from there

 

looks like a ghost in your #2 I see a face

 

I bet it's the ghost of the '81 xj550 Maxim... i called a local Yamaha parts dealer and he told me that in his yamaha database, he could not find any in spec pistons, oem or aftermarket, totaly obsolete. or any overbored pistons that would fit this bike. and only 6 full sets of new piston rings in the country.

So I guess i'm going to make like Moulder, and Scully on down to a precision shop to have these cylinders and pistons super duper precisely measured and honed, and if ok, claim one of those last few new sets of rings. If not in spec, the search is on, but it's cool... cause after all... The Truth Is Out There.

 

xjforever lists ring sets at this site upper right click logo

this link list rings
http://www.yamahapartsnation.com/oe...f8700209bc7879df/crankshaft-piston-xj550h-j-k
std ring part number
4GA-11603-00-00

this place too
http://www.yamahasportsplaza.com/oe...f8700209bc7879df/crankshaft-piston-xj550h-j-k


you can always try the UK for parts

 

i love you

 

so any ideas on where to find over sized pistons and rings that will fit my 81 xj550 maxim to bore it... it's looking like that's going to be my only option. I've talked to a few peeps that say get them custom made, sounds pricey, wondering if any of you know.. i'd appreciate the knowledge transference.

like any that could use my connecting rods, or not, whatever... i just want to get this babe back together and hit the rooooooooooad.

 

If you really do need oversized pistons, then my advice is to look for a used engine to throw in it until you can afford to have pistons made.

 

bahhhhhhhhhhh.... i was hoping that wasn't the advice... but thank you

 

do you know if there are any other engines that would fit into the 1981 xj550 frame without any modifications to the frame?

 

Another xj550 engine.

 

You could also slap it back together and run it. Unless you plan on racing the thing that engine still has some miles in it.

 

it's all good.. everything is in spec anyways... i'm a bit of a perfectionist and this is my first time.. i didn't take it apart just to slap it back together if it could use something done.. it's more of a knowledge conquest.. and boy am I learning.. ha

 

RE:-
2.) TRANSMISSION
A.) Is there only supposed to be a half circle circlip on each end of each shaft bearing?. did some owner before me rebuild this and skimp out, or is that the engineering of the thing?

I had the same thought.. I received my XJ900 engine as a big kit lol and thought I was missing some too. The book shows only one where I had one, and two where I had two. So I'm fairly confident you are good to go.

 

righteous... thanks dossbag

so effin stoked...

i have everything all gathered.. taking the weekend to paint up my frame, tank, and crankcase covers.. then reassembly begins... yeahyeahyeah

 

good luck man.. I got my crank and gearbox all torqued down.. Fitting the cam slides/guides is a pain as the manual kinds skirts over it. But yeah.. it's a rush.. electrics gonna be fun too haha

 

electrics confusion levels terrify me... time to face that fear i guess... learn to love it

 

HELL YEAH!!!!

the time has come to re-assemble.. thanks to Len I've got all the parts I need to get it going. thank you..

today I had to do a few things like tap new threads (hy-vo chain guide bolt snapped during tear down) and I am going to clean everything up a final time.. I figured I would wait until tomorrow to actually begin to assemble, so I could ask a few questions tonight and get some responses before i dive on in..

 

i unfortunately lost the cell phone that had all of my tear down pictures, 'my memory joggers' which sucks, sooooo, thanks ahead of time whoever decides to give me some input.



here my sweet baby is last summer on a trip I took from Portland, OR to Phoenix, AZ and back.. what a great month.. this was on the east side of the Sierra's, down around yosemite.



here is when I returned to Portland, right before tear down.




here we've got some re-painting (whoever said black and brown doesn't go together... will change their mind when I'm done)



and here it is today.... exploded and all over my living room ha..

 

cool road trip pics! love your living room.

 

and so begin some questions...

the first, I can't seem to find information anywhere, on where these tranny clips go. There are only 4, and 8 possible locations..


I am wondering which side gets which clip in which half of the case, or if it matters, it looks like they maybe would use that little channel to move around slightly?

 

thanks! i do too.. nothing like the smell of engine oil and hot coffee in the morning..

 

well... what's the roller coaster of life without ups and downs.. this morning, I was at the apex of a climb, hands up in the air, smile on my face, ready to get my baby back in action..

then i fudged up, screwed the pooch if you will.. attempted using a cheap tap and die kit to fix a pretty integral part of the crankcase.. the hy-vo primary chain top half guide. The furthest back bolt snapped off during tear down..

i haven't the slightest idea on how to go about fixing it, so i guess i am now in the market for a new crankcase.

before i buy one, i wanted to see if anyone had any ideas..

i am super upset, but happy to learn a lesson.. take your time, use the proper tools. never will this happen again hooooo saaaaaaaa

 

Noooooooooooo! ouch.

 

Oof. We sell cheapos at work and I'm always tempted to pick one up 'in case', but I just never do. There are certain tools ya just need to be quality.

 

A machine shop can repair that for around $100.00

New cases will be less expensive, but the bearing shells won't be (unless you get lucky and the replacement cases come with the shells that you need to fit the crank properly).

I went through the same problem this past winter, and got very lucky. I snagged Maxim cases for $21 shipped and between those and my existing cases had all the bearing shells that were needed, and the crank clearances were in spec when I did the test fit. Did I mention that I was very lucky? Bearing shells alone would have been over $200 had I needed a full set.

 

i have a full set here.. and the cases i am looking at also have them in.. as long as the clearances were ok with my bearings and the new cases, or vice versa.. i'd be ok?

 

and when you did the test fit, is it necessary to put everything in the cases (tranny, starter clutch assembly, shift assembly)? or just the bearings, crank seals, and crank since thats the measurment you are looking for..

 

1. Just because the cases have bearing shells does not mean that they are the bearing shells that you need. Each crankshaft journal could have one of four sizes of bearings, and that is determined by the necessary thickness to make up the difference between the bearing journal in the case and the corresponding bearing journal on the crankshaft. The bearing shell makes up the difference to provide the required clearance so the oil film can form and allow the crankshaft to run without the crankshaft journal ever touching the bearing shell. This is a critical item.

2. You test fit and measure (with Plastiguage) with the crank and bearings in place and the case bolts surrounding the crank tightened to spec. The cases can be bare otherwise.

3. YOU NEED THE FACTORY SERVICE MANUAL ON HAND IN ORDER TO SELECT THE CORRECT BEARING SHELLS FOR YOUR CASE/CRANKSHAFT COMBINSTION AND TO DO THE JOB CORRECTLY.

4. If you don't take care of #3 you won't have an engine for very long.

5. The bearing shell colors (sizes) are indicated by a strip of paint on one edge of each bearing shell. The color of used bearing shells can be difficult to read as the engine oil effects the pigment, so be very careful when figuring out what bearing shells you have on hand. You can figure out what your current engine has based on the numbers that are engraved on the end of the crankshaft and on the engine case, but unless the new cases come with the crankshaft you will only have the strip of color on each bearing to go by. If you have any doubt about what color is on the shell, assume that it is not the size you need. There is literally no room for error here.

 

thanks again dude..

to be continued...

 

Or do as i did when this very thing happened to me around the same time it happened to k-moe...drill and tap (i tack welded a nut on top of a tap chuck in order to reach the hole) the hole then wait a couple weeks for a 6mm 3D insert from the UK (auto parts don't sell inserts long enough to bottom out).

Gary H.

 

Look at his photo above. The drilling went all sideways
It's a welding job now.

 

Ahhhh, ok. I couldn't tell.

Gary H.

 

new case ordered.. $75 shipped.. a drop in the bucket of what i've spent and will end up spending by the end of this awesome undertaking..

all the gold and silver, could never bring a value to our lives... but it sure can buy motorcycle parts...

a week delay, though my body experiences time in a linear form, my brain does not. so whateva, more time to research..

getting an 80cc bicycle conversion to transport my flesh in the meantime.. four wheels just don't quite do it for me anymore..

 

i don't know where that broken bolt is but could you drill it through and use a nut and bolt

 

There's a knot on top of the case directly behind the alternator that collects the depth of the that bolt. It's also directly above the oil nozzle for the starter chain. Imo a bolt through the case wouldn't be wise.

Gary H.

 

new case arrived this morning... and boy is it filthy.... all the gasket gunk is gone though i know what I am doing today

 

Make certain you allow the loctite to fully cure on the guide bolts prior to re-assembly. Also after you dis-assemble and clean the oil pump pour some fresh oil into it, rotate the sprocket and make certain it is flowing oil as it should (the oil should flow in one direction).

Gary H.

 

thanks for the suggestion... will do....

question for k-moe... i'm about to test fit the crank in the case.. should I put the crankcase guide dowels and crank seals in as well or just the bearings, crank, and bolts around the crank?

 

nvm.. just looked back at your previous comment... crank, bearings, and bolts around... check....

p.s. purple power is my new best friend... damn near spotless in about 30 minutes of spray, scrub, rinse, reapeat

 

Following your story! Good luck.
If I had all that in my living room my wife would probably help me lose 125 lbs.
If ya get me lol.
-EM

 

i can think of a few different scenarios haha..

amazing news... test measurements prove positive.. no taper in the crank.. and each journal with exactly .0019" which is on the room to grow side of specs... hallelujah, praise jeebus, hare Krishna, and the buddha's a fat guy... time to assemble...

i smudged that one with my finger... not a taper..

still have a question regarding transmission spacers... which half of the crankcase do they go in on either side (as in output:Big/upper, little/lower) or vice versa....

 

Most Loctite threadlockers cure aerobically. The parts have to be assembled wet for it to fill the airgap in the threads completely. There is an air-dry threadlocker for use on "kit" parts, but I've always had to special order it.

Adam, I may have mentioned using Loctite 515 or 518 in place of Yamabond. It is much easier to use and there is no risk of squeezout breaking off and damaging the engine.

The half rings (spacers) go into whichever case half will be stationary on the bench (which would normaly be the upper).

 

I was trying to tell him to let the installed bolts cure prior to assembling the rest of the case halves. I didn't know there is a air dry thread lock...well, i know now. Thanks, you're a smart dude.

Gary H.

 

i put those bearing retainers on the bearing then put the bearing in so they will go in both sides of the cases. that way they hold the bearing alignment true to both sides