Sleeve the bores? this aint a P51

[SE Road King]

Can a bad intake valve seal cause a significant oil ingestation on an '80 XS650 to give the appearance of high oil consumption?

I got a stock '80 XS650SG this past spring, cheap. The engine is out of the frame and the top end is stripped down. I inventoried the half-dozen or so boxes and cofee cans to my satisfaction that I was getting a whole bike.
The seller said that he was given the bike some years ago because his friend was no longer interested in it . I asked why it was torn down and the reply was "to re-sleeve the bores". I also asked the seller if the bike was burning oil, low on compression, was it running,,, ETC. and every response was "I don't have and idea why. So I made a decision to purchase it knowing that "resleveing the bores was just an un informed term that was not even possible on this paticular engine.
So now I sit to interpet what possibly had been the reason for stripping the engine. I measured the bores in 7 locations along the ring and skirt stroke areas of the bores both perpendicular and parrell with the crank journal axis, I measured the pistions and grooves and the cross-section of the rings. Pin fits are fine. All oil grooves and ports are fine. Valve seats/fits are in very good condition as are the stem clearances. Valve guide seals are always suspect on air cooled engines, but did fit the stems well and were seated properly. The cam is un molested. The evidence is that the surfaces and clearances, piston and ring condition and valve seats were all well with in serviceability limits. The only flaw was that the #2 cylinder intake valve had the compression spring around the top of the guide seal was missing. The carbon build up in the #2 combustion chamber was dark and soft compared to the left one, but that could have been from post tear down contamination.
I am wondering why a novice would attempt to re sleeve the bores, I lable the previous owner novice because he used the term "re sleeve". I have to think that the owner had witnessed burning oil from the exhaust and low power. If he had done a compression check first I am convinced that he would have seen satisfactory pressures. The fits are just too good. So good that it could go back together. I will break the glaze in the bores, cross-hatch the walls, lap the valves, re ring and reseal.
So, again I ask:
Can a single bad intake valve seal cause a significant oil ingestation on an '80 XS650 to give the owner justification to tear the engine down?
I could see if all of the valve seals were worn enough or have had age set to the point of sucking enough oil to justify the tear down. But it would have had to be all of them and the valve seals could have been repaired in the frame, I would think.

I do believe that there were a whole lot of "poor vehichle maintenance" owner/riders out there in the day as these things were reletivly cheap and in a way disposable to the diluted/green biker of the day. I am betting that a carb sync, valve adjustment and thourough servicing would have put a lot of these bikes back on the road.
I understand the term "re-sleeve the cylinder" was commonly used to identefy repairs nessesary to restore compression, and power and repair oil blow-by and piston slap.
Have you any theory to review given the evidence I've reported. I get that there would be a host of reasons for repairs that included removing the engine, but, the owner said "to re-sleeve the bores"

 

[retiredgentleman]

Here's my opinion for what its worth. First thing, forget anything the previous owner said. These bikes have passed through multiple hands over the years, with very little accurate knowledge being passed on.

One owner has a problem, tears the engine apart without knowing what the real problem is , quits the project, sells it to another person with some story that's not based on facts,..................maybe the next owner does the same thing, when he realizes he does not know how to do the repairs. After awhile, the true reason of the engine work, has been lost in repeated story telling.

You have an engine that is in pieces. What should you do? Read the Yamaha Service Manual. It contains the manufacturers specs. Measure what you have and compare to the specs.................that will tell you what parts need to be replaced and which ones need to be machined. Its that simple.

I did a top end re-build 5 years ago. I did not know which parts would need replacing before I opened up the engine. Some top end work needs a rebore and new pistons, but upon measuring, mine did not. Some top end work needs new valve guides, but mine did not. Some top ends need new valves, but mine did not.

Enjoy the re-build.

 

[XSLeo]

One bad intake valve seal will cause excess oil into the combustion chamber. Enough to need a rebuild? Probably not. A leaky headgasket can for sure. Often they can leak from thr cylinder into the cam chain tunnle and you won't lose to much compression but can suck excess oil into the cylinder.
But as RG mentioned it has passed through different PO's and PO's seldom tell the truth.
As far as resleeving, yes you can, the stock cylinders use a steel sleeve that can be replaced. Your stock sleeves can be bored out to 12 over, this gets you about 707 cc's.
To go larger you need to resleeve the jugs for larger sleeves. I think Mike's sells a set that use the pistons from his 750 kit. With these sleeves you can have a stock looking cylinder but have 750 cc's.
There are several bike engines that you can get sleeves from to do simular builds.
You remove the stock sleeves, bore out the cylinders to fit the bigger sleeves.
Leo

 

[GreasyC]

You're probably right that he had no idea what re-sleeving the bores meant. You're wrong that it's impossible though, it's done all the time. The stock sleeve can be bored out to a max of about 77.5mm for a 700cc mod. If you want 750cc you need to drop the stock sleeve, bore the aluminum block wider, and re-sleeve with a bigger tube from L.A. sleeves so you can fit an 80mm piston. About five years ago a company in holland started making a big bore aftermarket cylinder block that saved you the trouble, but until then the re-sleeve was the standard way. Of course you could also re-sleeve with a stock size bore if you wanted to, but a used block that still has life left would be cheaper so I can't see anyone doing that.

 

[SE Road King]

Holy grease gun XS-man. I will hold my tounge from here on out.
Ok "not probable". I will confess that I have machined many things that economics could not justify, mostly for myself. Rates were very high when I retired.
Most guys that run into needing a bore job to rebuild a motor will do just that. However, in my opinion, to other than really diehard XS'er or a HiPro builder, it wouldn't be worth it to resleeve a XS motor. Too many used and aftermarket parts out there if a jug set is beyond limits. The terminology was not the point here, I only droned on it to investigate an unknown about a really cheap basket XS.
This top end group measures up to well within Yamaha specs, and my own. The bores are so good that even after glaze break and hatching in the bores the pistons clearances are still inside limits. The combustion cavity in the heads hold solvent without springs on the valves very well.
Now the head gasket is one piece of evidence that is not there, and surely could have leaked to the chain cavity. It may well have been the reason. It would provide the evidence I need and would explain the teardown. I am going back out to the garage to look in the boxes agian for the head gasket.
Update: it is not there. If so the owner must have gotten to it quickly because there are no evidence blow by on the mateing surfaces. All of the original machining tool marks are 100% visible one both the jug set and head, no burning or discoloration. Gladly the head and cylinder mounting surfaces cannot pass my thinest taper leaf guage of .0015" against an inspection grade straight edge, in any position. I may charge a plate and lapp them before assembly anyway.
So, I am back to age set in the valve seals, well all seals and poorly adjusted valves. There were obvious exhaust header leaks and some oil stains on the external head surfaces, cylinder fins and cam cases.
The lesson on he said, then he said, then he said is a good one. that is why i'm here. Hopefully to reflect from your experiences and save a nickle or two.

 

[racerdave]

Screaming Eagle Road King? With what you said it sounds like everything is basically up to snuff. Like you and retired said, it has passed through other owners that don't have the whole story. Do you have the title, or can you prove somehow it wasn't stolen and torn down, then didn't get sold off for parts? Not making any accusations just asking. Anything is possible. I'd put it together with fresh seals and start it up

 

[SE Road King]

I will be laying it all out today for "before " photographs today. So far the only componet that I cannot fing is the old head gasket. The gent that I bought it from has lived in this community for a very long time and seems to be a straight arrow. His involvement in the community and the Crime Watch program lead me to beleve his story on this bike origin. I've seen nothing about his character that is suspect.
I did run the VIN in the states system and 'no records" was posted by the Texas DMV websight. My conversation with the county of previous registration was that the vehichle was unemcumbered. Having investigated the issue of getting the bike titled and registered with out lein has triggered me to re-build it and play with it. The only issue to me is that I may reassemble the critter and find the true fault that causes me to open it back up. I really despise duliplacating labor. The only inspection process I have not performed on the top end componets is to magna-flux or magna-glow check for cracks on the head, jug set and cam.

 

[XSLeo]

From what you have said, I would put it back together with a new set of rings and gaskets, seals cam chain, front cam chain guide. Then ride it.
Leo

 

[SE Road King]

From what you have said, I would put it back together with a new set of rings and gaskets, seals cam chain, front cam chain guide. Then ride it.
Leo

I had all but the cam chain on my list. For my learning pleasure: Is the cam chain and guide/tensioner a problem area as it relates to the XS?

NOTE to all, Pile on if you have experinces to share!

 

[jd750ace]

I would change the cam chain guide while you are there. The contact material is known to come loose from the aluminum base. The only issue I know of with the tesioner is folks get confused while adjusting. You seem to be mechanically inclined enough to figure it out though. The Guru's mostly prefer fine adjusting it while it's running.

 

[weekendrider]

The front guide and chain are wear items. 15K-20K miles.
To the list you might add copper or brass washers to replace the rubber backed head washers Yamaha used.

 

[SE Road King]

Yes on the copper hardware, thanks. Do I cold form (upset) the links together or is there a master style link?
I thought to go with Mikes XS on the parts, I assume to scource these parts there as well the chain and guide. Yes? ,,, No?
Unless some one can save me some coinage elsewere?

 

[SE Road King]

I bought a basket case XS650. After researching options of what to do with it I have elected to keep it, reassemble it and ride it to the bone yard.

I am a retired machinist and have owned more than my share of bikes. I will be staying stock, only upgrading where it is prudent for safety or reliability. I'll go thru most every thing because I like the work and want a very clean built, however, I am not going to do a %100 factory restoration.

I will start a build thread for the fun and comradery of it. Where should I start the thread, under build or restoration?

 

[retiredgentleman]

I bought a basket case XS650. After researching options of what to do with it I have elected to keep it, reassemble it and ride it to the bone yard.

I am a retired machinist and have owned more than my share of bikes. I will be staying stock, only upgrading where it is prudent for safety or reliability. I'll go thru most every thing because I like the work and want a very clean built, however, I am not going to do a %100 factory restoration.

I will start a build thread for the fun and comradery of it. Where should I start the thread, under build or restoration?

I'd say that would be a restoration. Its so refreshing to hear of someone that will be keeping their bike mostly stock

Sometimes I feel like I'm the only one on the site with stock exhaust, stock air boxes, stock carbs, stock suspension, etc.

Yes, I upgrade for safety and reliability to, however the stock buck horn bars were the first thing removed years ago.................ugly is ugly!

 

[xjwmx]

Somebody wrote an amusing post about resleeving the bores. Maybe gggary. You put the cylinders in the kitchen oven and leave them there until you hear a thunk, which is the sleeves falling loose.

re: the buckhorn bars, some ppl like them. The most accurate thing to say about them is "they are hated on the internet." I had to get rid of mine because they were giving me a clinical case of rotator cuff problems. I replaced mine with same era cb750 bars which are also "hated on the internet." Much better choice, including the fact that the palms face down, giving more power to the brake lever. But similar configuration otherwise.

 

[retiredgentleman]

Somebody wrote an amusing post about resleeving the bores. Maybe gggary. You put the cylinders in the kitchen oven and leave them there until you hear a thunk, which is the sleeves falling loose.

re: the buckhorn bars, some ppl like them. The most accurate thing to say about them is "they are hated on the internet." I had to get rid of mine because they were giving me a clinical case of rotator cuff problems. I replaced mine with same era cb750 bars which are also "hated on the internet." Much better choice, including the fact that the palms face down, giving more power to the brake lever. But similar configuration otherwise.

Yes xjwmx, I agree that some guys like the buck horns. My friend has an 1980 Special. We traded bikes once to compare, while riding. I did not like the buck horns on his bike, but he did not like my bike, which has the Standard type bars.

Yup, the buck horns are the Rodney Dangerfield (under 40 guys may not know who I refer to ) of handlebars..................they get no respect on the internet.

 

[XSLeo]

On the cam chain and front guide, most of these bikes didn't get very good maintainance over the years. The cam chain tension should be checked at 2000 mile intervals. I doubt most got any or only when the noise got too loud.
This excessive play promotes excessive wear on the chain and front guide.
The front guide fails in two ways, if the chain tension is left too loose, the chain flops around. The flopping breaks the edges of the groove the chain runs in off. You find these in the sump as long pieces of black plastic.
As they age the plastic gets brittle and breaks off easier. This aging also effects the glue bonding the plastic to the alloy backing. Sometimes the plastic part comes unglued and can flop around, banging on the alloy part, this creates a noise very simular to a loose chain.
The chain if properly adjusted at the proper intervals will last a very long time. How long? I can't say but much longer than the 15k-20k as mentioned earlier by Weekender.
Most replace the chain and front guide when they have the engine apart, much easier doing it then than having to tear it down a second time to replace it.
Some chains come as and endless chain That can be installed with splitting the lower cases. These chain can be cut and a master link used. The master link isn't like a drive chain master link. You need to peen the pins to hold the side plate on.
Some chains come cut with a master link and can be installed without splitting the cases.
As a retired machinist you know about clearances and how to bore if needed. The repair manual list reguired clearances.
Good luck with your build. I'm sure you will enjoy the process as well as riding the results.
Leo

 

[weekendrider]

The chain if properly adjusted at the proper intervals will last a very long time. How long? I can't say but much longer than the 15k-20k as mentioned earlier by Weekender.
Leo

I wish someone could testify to this. You would think after what, 5-6 years, watching these boards(multiple forums) we(you and I, Leo) would see someone saying "Mine has been working well for XXX miles well past the 15-20K mark".
John's out, he couldn't leave things alone long enough.
Pete put some serious miles on his first standard?
Tomterrific I believe has a high mileage bike iirc.
And then there is xjwmx living the "free and easy" Bronson biker life making Sunday riders like me look like arm chair coachs. Racking up some serious miles
How bouts it some of you high milers have some input here?
Have you gotten 40K out of the chain and guide?

I'd also like to throw out that chains don't just stretch there is a certain amount of sideways lash.
Anyone have an old chain and a new one? Place the ends together then pull the other end to the side the price of doughnuts and coffee says the old chain WILL bend further to the side than the new one because the pins and rollers are worn.
We can't see this because the chain is enclosed. If you need to see it happen find someone with a round baler ask to watch the drive chain as it is turning.

 

[SE Road King]

On the cam chain and front guide, most of these bikes didn't get very good maintainance over the years. The cam chain tension should be checked at 2000 mile intervals. I doubt most got any or only when the noise got too loud.
This excessive play promotes excessive wear on the chain and front guide.
The front guide fails in two ways, if the chain tension is left too loose, the chain flops around. The flopping breaks the edges of the groove the chain runs in off. You find these in the sump as long pieces of black plastic.
As they age the plastic gets brittle and breaks off easier. This aging also effects the glue bonding the plastic to the alloy backing. Sometimes the plastic part comes unglued and can flop around, banging on the alloy part, this creates a noise very simular to a loose chain.
The chain if properly adjusted at the proper intervals will last a very long time. How long? I can't say but much longer than the 15k-20k as mentioned earlier by Weekender.
Most replace the chain and front guide when they have the engine apart, much easier doing it then than having to tear it down a second time to replace it.
Some chains come as and endless chain That can be installed with splitting the lower cases. These chain can be cut and a master link used. The master link isn't like a drive chain master link. You need to peen the pins to hold the side plate on.
Some chains come cut with a master link and can be installed without splitting the cases.
As a retired machinist you know about clearances and how to bore if needed. The repair manual list reguired clearances.
Good luck with your build. I'm sure you will enjoy the process as well as riding the results.
Leo

Thanks for the primer on the chain related... and the good will. I really enjoy these kinds of things. The 15k statement had me wondering, I am thinking it should last longer than that, good to know that it could.
So, if there is a choice, I'll choose the upset pin style of link, I can handle the chain well. It is more robust and I've no reason to split the cases.
I wondered about the 30+ yo bond in a hot and cold oil envrionment. And I'd bet the bond is far, far better today. Having 100's of thousands of parts in the sky by my own hand, I've bonded a few. Bonding is a real science. I cannot tell what the wear strip is, maybe micarta or paper or linen phenolic. I will just buy one from mikes XS.

 

[SE Road King]

I sure hope that my XS came with socially acceptable bars. Or, at least bars that don't get me any internet haters... LOL