FIRST TIMER - top end re build.

[650Greaser]

hi all ! i now have in possession a 1980 xs650 . I was told it needed a little work when i got it, and the more i am working/learning on it, just turns into more work. i have the time right now, but not the money.

hoping for some sage advice on the best rout to take with my cylinder . it apperes to be savagely pitted . is it beyond honing , what is the coast involved with re sleeving . i found a the top end of a 1970 on ebay just across the border for $60-70 .


as for putting the engine back together . from my limited knowledge/experience all i have to insure is the timing mark on the rotor+stator line up to tdc. (both pistons will be equally centre) and the camshaft sprocket mark should be at the top on the right .?

some clarification and confirmation would be greatly appreciated .

when i took it apart to orient the camshaft the right way(the threads on the right ) to support the p a m c o ignition i got . nothing was lining up as it should . the last rebuild was done by some one with less knowledge than me it seems. time will tell.

* * * also . what seal kit should i order from mikesxs (the only place i know that sells xs stuff)

aswel - what else do i need to replace . i will order 4 copper washers for the top ..

thanks again for any light someone can shed on my ramblings.

i am hoping to get this machine on the road this spring. the shop i am using is temporary

 

[CDNTX650]

Basically, when the mark on the crank is at the T, there is hole on threaded end of the cam for the advance locating pin that should be at either 6 or 12 o clock (and the notch on the cam should be on the same plane as the flat of the rocker box gasket surface.

 

[650Greaser]

Basically, when the mark on the crank is at the T, there is hole on threaded end of the cam for the advance locating pin that should be at either 6 or 12 o clock (and the notch on the cam should be on the same plane as the flat of the rocker box gasket surface.

thank you for that cdntx650 , i know exactly what you are talking about.

Standard size Cylinder Sleeve-75 mm. is $100 each. soooo that is steep . i will find out tomorrow if the pitting can be fixed with a good honing .

also valve clearance adjusters have some pitting and discolouration on the contact points. can i just clean those up or do they need to be replaced . also the ends of the valves.

thanks

 

[desmodromic]

First get a manual. I would check the smaller end of the con rods forwear, since you are going to remove the cylinders, check the rods for play. Check the valve guides for play, measure your springs, lap valves, inspect cam and rockers for wear. Just follow the manual. Go on ebay or post a wanted in the classifieds for a cylinder. Ive seen them go for $50-70shipped, then hone it and measure the x and y axis and see if you need oversize pistons.

 

[sonicarb13]

Have you considered havin the jugs bored out? You would have to buy pistons kits but then you are sure of what you have. As desmodromic said, definately get a manual first. The castings on that '70 you mentioned will be much rougher than the one you have so keep that in mind when looking. I have done complete re-builds on a couple and have another in processs, expect to spend $600-$1200 to do it right. When in doubt, replace it.

 

[desmodromic]

I second that, when in doubt replace it. I know this sounds stupid but replace all engine seals (if you go into the bottom end), Ive seen people try to "save" money by not replacing them and then having to tear down the motor to replace that seal they cheaped out on. If you are doing this on a budget buying used cylinders is best thing to do.

 

[JP50515]

^^^ Agreed....when in doubt it's simply best to replace in this case.

If you want my 2 cents...make sure you clean every mating surface very well. I got lucky with mine, but when I rebuilt my engine the base gasket was seeping oil because I didn't get all the caked on gasket off, luckily after a few heat cycles, re-torquing the acorn bolts, and a bit of 3bond on the outside it sealed itself up nice....it had me nervous for a while though. Sonicarb said expect to spend $600-1200 to do it right.....I'm not so sure I agree 100% with that, I mean it depends on what your want to fix/upgrade. If you are like me and just want to fix poor compression, replace the valve guide and seals and get a broken sharpie cap out of the engine that your buddy somehow managed to snap off in the spark plug hole, then it can be done for around $150-$300.

Anyway go slow, don't let the cam chain drop, and have fun.

P.S. I had good luck with the Athena gasket kit...although i've heard others haven't

 

[desmodromic]

I would not remove the valve guides unless you really have to. If you remove the guides you have to send out your head so the seats can be cut to match you valves because you never truly put the valve guide back in straight. when you lap the valves make sure none of the lap compound goes down the valve stem into the guide. I would replace the cam chain, "a chain is only as strong as its weakest link" lol. I too used the Athena gasket kit with no problems. When I rebuild motors I like to document everything I do. I measure everything I take apart and write it down, so in the future, if you need to tear back into the motor you can see how much wear has occurred or which way a concave washer goes.

 

[desmodromic]

when you remove the valves, make sure to label where they go,you don't have to but I prefer to put things back were they went.

 

[Tim of DO THE TON]

Where are you located?

 

[650Greaser]

great info guys! thanks big time!

if there is one this i know going into this, it is if a seal is broken a new gasket goes in, and the matting surfaces better be spotless. i work in commercial refrigeration .

* * * update - i just picked some jugs. then i got a used cylinder and pistons in good shape. cleaned up and scored . standard size + .25 so i will need 1 over sized rings. Ya?
$224 after the tax man. from BENT BIKE. in Langley B.C. off #10 = great find.

@ desmodromic - i have a yamaha manual . and i just read a page of a clymers today. what a great book. going to see if the local library has one. they are available on mikes xs.com for $35 would that be the same edition you are talking about? (650twin clymers)

@ Tim of DO THE TON - i live just out side vancouver, british columbia. why do you ask?



needed :

Athena gasket kit
Intake and exost valves (mikesxs out of stock)
Piston Ring Set - 1st. Oversize - 447 and 533 engines
Piston Pin Clips for 447 pistons
brass head washers
copperwashers for top end
Headpipe Exhaust Gaskets

questions:

what are the major advantages of the Polished Stainless steel valves (just stronger, better for non leaded gas? ) are they worth the price ?

 

[Tim of DO THE TON]

Just curious as you mentioned the border. I'm in Toronto.

Its late now, but if you're going up a size in pistons your old cylinders might have been fine.

The pistons you got are in good shape? Do you have a machine shop already picked out?

Boring the cylinders will run $70 or so per hole.

 

[desmodromic]

great info guys! thanks big time!

if there is one this i know going into this, it is if a seal is broken a new gasket goes in, and the matting surfaces better be spotless. i work in commercial refrigeration .

* * * update - i just picked some jugs. then i got a used cylinder and pistons in good shape. cleaned up and scored . standard size + .25 so i will need 1 over sized rings. Ya?
$224 after the tax man. from BENT BIKE. in Langley B.C. off #10 = great find.

@ desmodromic - i have a yamaha manual . and i just read a page of a clymers today. what a great book. going to see if the local library has one. they are available on mikes xs.com for $35 would that be the same edition you are talking about? (650twin clymers)

@ Tim of DO THE TON - i live just out side vancouver, british columbia. why do you ask?



needed :

Athena gasket kit
Intake and exost valves (mikesxs out of stock)
Piston Ring Set - 1st. Oversize - 447 and 533 engines
Piston Pin Clips for 447 pistons
brass head washers
copperwashers for top end
Headpipe Exhaust Gaskets

questions:

what are the major advantages of the Polished Stainless steel valves (just stronger, better for non leaded gas? ) are they worth the price ?

keep your oem valves. No need in SS valves in a stock motor. They are good valves. Ive smashed them into the piston before and the piston/crank got damaged not the valves. Clean them and lap them. I think I have the Clymers manual (blue cover).

 

[650Greaser]

Basically, when the mark on the crank is at the T, there is hole on threaded end of the cam for the advance locating pin that should be at either 6 or 12 o clock (and the notch on the cam should be on the same plane as the flat of the rocker box gasket surface.

just the make this crystal clear i have to ask about the other way i have seen folks on the interweb lining up timing marks. i would much prefer there being one way

i have seen multiple youtube vids of lining up camshaft mark (notch/punch mark) at 12 o clock . this is different . . .

when i looked at my orientation of cam and marks, your description of it being on the same plane as the flat of the rocker box is what i was seeing .

thoughts...


and here is a pic of the ends of my valves and adjuster screws .

i need
Elephant Foot Valve Adjuster Screw x4 = $20
Front Cam Chain Guide Stopper

as long as i can keep moving forward i will be happy, and as long as i can collect ei i can pay for parts. this little project is whats keeping me sane .

 

[desmodromic]

I agree with Tim, boring is not cheap. You could of bought new pistons w/rings and a cylinder, and honed it for about $150 total.

 

[desmodromic]

ziploc bag and label everything! that front chain guard is no good. I'd keep the stock adjusting screws if they are not too bad. I cant tell by the picture but if your finger nail gets stuck on the smooth surface its usually bad (scored or pitted)

 

[650Greaser]

keep your oem valves. No need in SS valves in a stock motor. They are good valves. Ive smashed them into the piston before and the piston/crank got damaged not the valves. Clean them and lap them. I think I have the Clymers manual (blue cover).

k i will stay with stock . the smash test wins again. i am only thinking of changing em because of the wear on the ends that meet the rocker. can i just round that off. or will that go beyond the hardened finish.

ajuster screws got to go. all of them are not bad. one is definite garbage. i just can't find where i would by replacement of the style i have . i only found elephant foot type. i know the front cam chain stop is garbage. got a replacement with my cylinder today.

OK.

@ Tim of DO THE TON - take a look at my first pic of my cylinder. its F'd - deep pitting (form sitting along time, then starting up with lots of moisture?) . and if it was to be bored out i would need a new piston. . it's ok i learned to run different sized pistons today.

where would i get "new" cylinders and pistons with rings for $150?????????
i have the respite still!.

i got all that for 200 +24 in tax. they are used but in great shape and honed . with rings ( i was told never reuse rings) i guess i could check the spacing eh?

i could really use that 74bucks though

 

[desmodromic]

go on the classifieds section of this forum and post a wanted cylinders add, you can probably buy good ones for like $50-60 shipped at most. I think you can buy a set (2) pistons and rings and clips for $80 on ebay. Just so we are on the same page. The cylinder is the finned casting that the sleeves fit into. Autozone sells a honing drill attachment for like $30. I recommend you buy a micrometer, feeler gauges, vernier caliper (digital ones do mm and in and are easier to read), telescopic gauges and a dial indicator w/stand for your build. I'm sure you can find used valves and adjusters in the classifieds. Someone is always tearing apart something and selling it. Remember when in doubt replace it. I have like 11 complete heads that I'm hoarding, lol, and several valves laying around, I'll look n see if I got some extra oem valves.

 

[5twins]

There are two marks on your cam's sprocket. There is a notch on the left side and that should face straight up. There is a dot on the right side and that should be in line with the gasket surface. Most of us go by (and use) the notch when assembling.

 

[5twins]

A pic to illustrate .....

A few more things ..... exhaust pipe seal rings come in the Athena gasket set along with valve guide seals and all the o-rings. Regular oil seals will need to purchased separately if needed. Mike's has a kit for those as well. You really don't need any seals to do a top end. Personally, I don't replace the seals in the little points and advance housings unless they're obviously bad and leaking. Those housings can be removed and the seals replaced any time in the future if need be with the motor in the frame.

I re-use the copper washers and have never had a problem. As far as piston pin circlips go, you only need to replace any you've disturbed or removed. Only remove one from each piston (the outer one) and you'll only need 2 new replacements.