To split or not to split? That is my question.

[Chuckwagon]

Here are some photos of the head as I was planing it to get an even surface. As mentioned in a previous post, it was that badly warped that I could rock it back and forth when I dry fitted it to the cylinders. This photo is after I started planing it... the photo isn't that great, but you can see variances in the "sheen" of the aluminum that indicates where the head is making contact with the sandpaper taped to a flat surface (plate glass):


Here is a photo of the glass/sandpaper setup:


This is near the point at which I called it good... took it a little further than this:


I didn't get it absolutely perfect... I was on my last piece of sandpaper and had had enough. I basically planed it until I took the "rocker" out of the head. It took maybe an hour and a half of working the head on the sandpaper, checking, repeat. Rather time consuming but cheap, works well, and doesn't take off a lot off as much metal as a machine shop would. I'm not trying to increase compression ratio here, just trying to get a good seal. What little variance is left should be able to be dealt with by the head gasket.

[Chuckwagon]

No new progress on this project, besides a little work on removing the rotor from the crank to replace the oil seal. I had seen a few sources that state the OEM seal has interchangeable OEM part #s:

• 93102-25121
• 93102-25090

I was not able to find the first part number on eBay, but found several of the second part # on eBay, so I bought one. However when I received the genuine Yamaha part #93102-25090, I found that it is the same dimensions as the seal on my bike, with the exception that it is about half the width, and doesn't have a lip on the outside diameter that would locate/seal it in the crankcase halves. Not a big deal expense wise, but now I will be waiting to move forward until the correct seal, part #93102-25121 arrives next week. Anyone know what the deal is? Do later XSs (mines a '77) use a different seal?

Oh well. I still have more work to do. I decided to strip the lower crankcase half, as the paint job on that part didn't hold up as well as the rest of the engine. I still need to finish stripping, then clean, then paint. Not my favorite job in the world, so been procrastinating in getting it done. I promised myself I'd bite the bullet and get it done this weekend... we'll see.

Better news on the Benelli 650S project I'm working on... the cylinders and pistons are within service limits, so at least I don't have to worry about finding unobtainable first oversize pistons and rings for that bike.

[Chuckwagon]

I am moving right along with the rebuild project. Got the bottom case stripped and repainted:



I stripped and cleaned the valve cover... I'm thinking I will leave it "natural" even though the rest of the engine (minus the sidecovers) is painted black... We'll see when it is all put together... may change my mind


After several tries, I got good at fitting the crank bearings into their locating pins in the top case. I installed new seals, and meticulously cleaned the case mating edges and put a little three-bond on. Used all new copper washers as needed on the case nuts, and carefully torqued all 18 fasteners according to the sequence. I'm hoping that I don't have any leaks, otherwise this whole exercise will have been a waste of time!




Speaking of leaks, I had saved all the old copper washers and case hardware all in one ziplock bag, plus made notes as to which bolts got cap nuts and copper washers. Somehow, I had an extra copper washer in that bag! It looks familiar, yet I can't remember figure out where it goes. I'm almost positive it doesn't belong inside the engine case, and it is too small to fit any of the 18 mounting bolts, so that narrows it down a bit. But it sure would be nice to figure it out before I go any further with this to make sure I don't have to pull things apart to deal with the washer.
Here is a picture of it... it is the smaller ID / thicker washer on the right. The washer on the left is a case sealing washer just for reference:


Same two washers, now the washer in question is on the left and the known case washer (for reference) is on the right:


First correct answer gets an all expenses paid trip to Ukraine. No purchase necessary. See your local recruiting office for details.

[grizld1]

The thicker washer is part of your cam chain tensioner assembly. It fits on the rod between the adjuster sleeve and the spring.

[Chuckwagon]

Excellent - thanks Griz. Don't know how it got into that bag with the case fasteners, and not sure I would have figured that one out.

[grizld1]

You're very welcome, but I'll pass on the trip, thank you; I'm too long in the tooth to draw any interest from the recruiters.

[Chuckwagon]

Update... took the bike out for a 20-mile test ride yesterday, after a few adjustments. For one, I set the valves according to my Haines manual, which was a mistake. That manual specifies 0.15 INCH clearance for the exhaust valves, which seemed a bit loose to me. Started the bike up which sounded normal, other than an obnoxious amount of valve noise! Referencing other sources for my information proved useful in that the clearance should be 0.15 MM not Inch! Freakin' aftermarket manuals.
So the bike is running well, and best of all, no leaks (so far). Being that it was warm, but there is 6" of snow on the ground that is melting and there was a lot of water and salt on the roads. So I washed the bike when I got home to get the salt off... usually washing the bike produces an oil slick in the driveway, but no sign of oil. Time will tell.

My starter still slips, but not as badly as before. My plan is during the next oil change to pull the return spring that sits underneath the bendix. New gear and I tightened the spring tension as much as possible, so not much else to be done about it.

The only disapointment is the clutch. It engages well (better than before) and doesn't slip. However, the shift "quality" isn't as good, and neutral is actually harder to find than before. The changes I made were:
Adjusted the shifter mechanism to center it (eccentric screw underneath left side cover).
New clutch friction plates, one new steel plate, all others verified to be flat)
New clutch springs
new thrust washer and bearing
removed grooves from hub and outer basket
put steel plates with smooth edge all facing out
single (long) pushrod and new ball bearing on clutch side
new pushrod bushing and seal
removed, cleaned and greased release arm... seems in good shape

The only thing that isn't brand new is the clutch cable, which I plan to replace. I did clean and lube it, and it is relatively new with only about 4 years and 5k on it. It is an "easy pull" cable sold by MMM. The problem I have with it is the free length has always been too long. After adjusting the clutch pushrod, I have to back out the barrel at the perch almost all the way out and still have a lot of free play. So I plan to go back to a stock cable. Only consideration is that I have flat track style bars, which are wider than stock (I think 34" wide). Anyone have a recommendation on a correct length cable to order... do you think a stock lenght cable would work if I do some creative routing?

[Chuckwagon]

Oh, and forgot to mention... I did drop the cash on the ET performance breather valve. Kind of a painful expense, but hoping it is worth it. I noticed i can hear it... much noisier than the old brake booster valve. The bike seems to run stronger than before, but there are too many changes made at the same time to definitively attribute it to the valve... I lapped the valves, changed to a 132.5 main jets and made very slight adjustments to the float levels. My main hope is that the breather valve prevents leaky seals, base gasket etc.

[5twins]

Get a Motion Pro clutch cable. It's a bit longer than the Standard cable, more like the slightly longer Special cable. The O.E.M. Yamaha one now uses the thinner inner cable just like the ones that MikesXS sells, the ones that can break in as little as 400 miles. I won't be buying O.E.M. clutch cables any more.

[grizld1]

Aw. c'mon, 5twins, let's show the poor guys at Mike's XS some mercy here. I have never, ever seen one of their clutch cables break--the lever end pulls off the wire before that can happen!

[5twins]

Yes, that's right, I forgot. It's been years since my MikesXS cable bit the dust but that's exactly how it did so. I got near 5K out of it which I guess is good for that cable, but it's not normal for most clutch cables.

[Chuckwagon]

I can't believe I'm dealing with the same problem I was dealing with last year. Last year I rebuilt the engine solely to fix oil leaks. I finished the engine rebuild and rode it a little bit, and all seemed good... no leaks. Then I had shoulder surgery that kept me from doing much of anything for a few months. Once I was healed, I got back on the bike in the spring and soon enough, my pants leg was oily from the oil mist being thrown off the top end! That was such a bummer, words can't describe the defeat I felt. The bottom end leaks are gone, but the top end is as bad as it ever was. That was really frustrating, and after all the effort/time I put in and lost time from surgery, I decided I needed to move on to home repair projects that were overdue, other aspects of life, and forget about leaky motorcycles for a while. I ended up riding my suzuki and KZ650, and the XS sat in the corner all summer.

So, now here I am. I'm telling myself "You can do this", but so far experience is proving me wrong. I am ready to try again, but a part of me is also ready to punt it to a real mechanic and shell out some money for labor (which is unusual for me).

What seems to be leaking is the base gasket, possibly the head, as well as the seals/gaskets at the ends of the cams. This is as far as I can remember. It has literally been since May 2015 since I've bothered with the bike, I was that frustrated. This will be the third try to pull the engine apart to fix oil leaks. The only glimmer of hope is that the bottom end is oil tight, so that is a slight improvement.

Here's a rundown of what I did the last time (I'll skip the bottom end details, since that isn't coming apart again).
Made sure all mating surfaces were spotlessly clean and undamaged
Used Vesrah gaskets, and used replacement seals from Mike's
Used gaskacinch on the base gasket (clear stuff that looks similar to rubber cement)
Used permatex spray copper gasket sealer on the head gasket
Lighltly resurfaced the head to remove slight warpage... taped fine grit sandpaper sheet to a piece of plate glass, then resurfaced the head on the sandpaper using a figure 8 pattern until the surface of the head was uniform and couldn't see any gaps when dry fitted to the jugs
resurfaced the "inner cam covers" in the same way... these are the aluminum pieces that are held in place with screws at the end of the cam
replaced the cam bearings, and seals. did my best to make sure the bearings and seals were centered
Used 3Bond on the valve cover
Used gaskacinch on the cam end gaskets
Torqued the head according to all specs, let it sit on the bench for a week, and checked/retorqued as needed
Ran the bike, then let sit and retorque head
Used a recommended positive crankcase valve (can't remember the name, but it was f***ing expensive, and used it on recommendation from members here as added insurance)
Used brass washers on the top of the valve cover
used new copper washers where needed
filled engine with recommended amount of oil... I can't remember, but probably used Rotella T, which has been my go-to for a long time.

Some issues that could be causing me problems
maybe the head is still warped (my guess if it is at this point, it would be a very minimal amount, if at all)
I have non-stock stainless hardware for some of the head bolts and acorn nuts. The originals were rusty/ugly, so I had replaced with stainless steel the first time I rebuilt the engine (back in 2011). This is something that has been letting my imagination run wild... perhaps the head is not torqued properly because some of the stainless bolts stretch differently than the oem steel bolts. Maybe some of the stainless acorn nuts are not deep enough, and are bottoming out and giving me a false torque reading. Who knows. I have a feeling I should order replacement top end hardware kit from Mikes to eliminate that as a potential problem. What is the quality of the Mike's top end hardware kit? Any known issues with that?

Give me your suggestions, critiques or questions. I'm all ears at this point. Obviously, I'm doing or using something wrong, as I can't get this thing to be oil tight.

Mark

[grizld1]

Mark, the very first thing you need to know is exactly where the leaks are. I suspect that you nailed the problem when you thought of the head nuts lacking depth. And right, stainless steel fasteners will be weaker.

But before you do another tear down, find out whether the base gasket is leaking; you don't want to disturb it if you don't have to. If it's good you can separate the head without breaking the base seal by using wood carpenter's shims. Then run the cam chain adjuster down snug to hold the head in place, remove the top end fasteners, and lift the rocker cover. Then slack the cam chain, pull the bearings, remove the cam, and tap in the shims longways, front-to-back between the fins at the split between the head and cylinders. Keep stacking shims until the head clears the dowels.

I bought a set of Mike's top end hardware before he went online; Lalonde mailed paper catalogs and took phone orders back then. The stuff was just fine. But I don't know what they're selling these days. I've heard some ugly tales of oil tube banjo bolts breaking, but whether that was due to bad parts or installers going neolithic on the wrench, I couldn't tell you. I reuse all that stuff.

If I were you I'd use dye or (just as good, really) marker on that head and work it flat. Now remember, that top surface has to be flat too, and so does the rocker cover! There's not a lot you can do about the top surface of the head; if you remove any significant amount of material, you'll mess up fitment on the bearings. If the rocker cover is warped, a member here (can't recall who, but a search will turn him up) posted the professional fix: bolt the cover down firm to a known flat hunk of steel plate and stick it in the oven at 450* for a couple of hours.

Oh, and one more thing--before you push the panic button, make sure it's not something simple like a loose valve cover!

Good luck!

[Chuckwagon]

Yesterday I put the bike on the stand and took a better look to see what I could find. I used athlete's foot spray powder to highlight the oil leaks. I can't remember where I heard of this trick, but it works pretty well. The old joke about rolling fat girls in flour comes to mind, but I digress.

I found that the major leaks are coming from:
rocker inspection cover
both cam end seals (oil found inside the covers vs seeping out behind the covers)
possibly the head gasket
possibly the base gasket

I say "possible" on the head and base gaskets, because it seems as though the leaks from above those gaskets were that bad they ran down the engine, and it is hard to tell. The base gasket sticks out of the engine, and when the bike was on the side stand, the oil collected on the base gasket, which acted like a rain gutter and ran it all to one side of the engine.

Before running the bike, I checked the torque on the head, and sure enough several were needed to be torqued. I first checked the 10mm bolts with the wrench set to 30 ft/lb, and nothing was under, nor were any of the other smaller bolts at their respective torque values. I then bumped the torque wrench up to 35 ft/lb, and the acorn nuts started moving. after torquing the acorn nuts down, I moved on to the smaller fasteners, at 16 ft/lb and some of them moved a little. It took a few times of repeating the process/sequence until all of the bolts were to torque specs. So hopefully that will take care of the head and base gasket leaks... if there are any leaks at those gaskets, it appears to be minor seepage. I cinched down the bolts on the rocker inspection covers, too.

As for the cam end seals... I remember taking my time with those to ensure they were installed straight. I did replace the cam bearings and remember driving them on to the cam with either a socket or a seal driver that matched the diameter of the outer races.

I then ran the bike, which surprisingly started easily, despite not having drained the gas after I rode it last. I did put a good dose of stabilizer in it and ran it through the carbs way back when. I took it for a 10-15 minute ride, then inspected it, specifically at the head and base gaskets. It is tough to tell... the base gasket seemed no worse, the head gasket slightly oily. I'm going to clean the engine to remove as much old oil as possible, retorque and ride again today if I can beat the rain. Hopefully that will show whether or not the head and base are leaking.

So a few questions:
1. I'm pretty sure the cam seals can be replaced without pulling the engine out of the frame/pulling the valve cover off... right?
2. I've read about making sure the cam bearings are centered/installed all the way to prevent seal leaks. Can someone explain the right method for achieving this, and can it be done with the engine in the frame/valve cover on?

Mark

[grizld1]

Mark, 30 ftlbs. is more than you should need, and 35 is entirely too much!

As to the cam seals, of course they can be done without pulling the motor. Remove the ignition, remove the screws (3 on each side) that hold the aluminum cam covers on, and have at it.

Camshaft bearings must be installed all the way to the stops on the camshaft, and the camshaft must then be centered. This is done by measuring the distance by which the edges of the outer bearings are inset in their journals. The overlap should be the same on both sides. If you have to center it, the camshaft can be moved without breaking down the motor. Loosen the cam chain adjuster. Calculate how far the side with long overlap must move to equalize the measurements. Set a block of wood against the opposite end of the camshaft and tap gently; you don't want to overshoot the mark. The bearings on the side you've moved may not have moved with the cam; measure to see if that happened. If it did, find a socket that fits the outer race, and tap the bearing gently.

Cam seals are tricky, and one of the problems is that vendors sell difference widths, ranging from 5 to 7 mm. Use the wide ones.