Miss November XS2 tribute

[Raymond]

This evening, village m/c engineer came and fitted five helicoils to the points housing:




Note cardboard 'wheel' and plenty of grease to catch the swarf?

Once I had cleaned 'er off, fitted Boyer rotor and static plate and went for a test run. Seemed to run a bit hot. Checked timing with strobe and too far advanced. Retarded it a bit and second test run. Probably ran better. Hard to say. Lots of popping and banging on the overrun. Carbs? Timing? Air leak in the exhaust?

And it blew the fuse for the starter circuit again. But enough for tonight.

At least it runs. Still holds back from closed throttle. But no oil leak from behind the points cover. AND at no point did the clutch let go.

So two-and-a-half cheers, I'd say.

 

[Jim]

Yer gettin' there....

 

[Raymond]

Yesterday wrote:

At least it runs. Still holds back from closed throttle. But no oil leak from behind the points cover. AND at no point did the clutch let go.

Well that was yesterday. Today, went for a long run - OK, ten miles each way - and there is still an oil leak from behind the points cover. Fiddlesticks!

Perhaps it's not as bad as it was? But gonna have to pull that area apart and see if I can tighten the screws a bit more. The helicoils are not a perfect fix, and the screws do not line up exactly so they tend to jam rather than tighten all the way in . . .

Might add a bit of Hylomar on the gasket as well, sort of belt & braces as we say.

And it definitely still holds back. To the point where traffic is not enjoyable. Went to see Tim, who did the vinyl XS-650 for the side-panels. He works in Kelso, which is not a big town but enough traffic to illustrate that a bike which needs a bit of positive throttle to get past 2½ - 3,000 rpm is in fact sick and not much fun when other people a) all seem to get in the way and b) wonder WTF you are up to.

However Tim, along with everybody else who has clapped eyes on the thing, thinks the XS looks fantastic with that paint job.

Well, that's something. Not much use, but something.

And she ran fairly well on the country stretches. And the clutch still seems to behave. Ho hum.

Couple of questions:

Ideas for a good solution to the points cover oil leak?

Is the holding back a transition problem, maybe pilot to needle jet system?

 

[MaxPete]

Regarding the removal of rust from clutch plates: I have seen two different methods mentioned on this forum. One method leaves the plates polished and the other leaves them with a sanded finish. Which is correct?

Yup, I would definitely not suggest polishing the plates. IMO, there are two reasons for this:

• polishing the plates would almost certainly promote the suction / stiction effect once the oil gets in there and this would increase clutch drag which makes shifting (and of course, finding neutral) much more difficult;
• the whole idea of a clutch is afterall, "friction - under control" and if you polish the steel plates, their resistance to shearing (i.e. rotary motion) the oil film would decrease which ultimately would decrease the friction with the interleaved friction discs and thus reduce capacity of the clutch pack to transmit engine torque.

Knowing Honda, they have studied and tested this matter "up the proverbial wazzoo" and if they found that a sort of "sanded" or dimpled finish was best, then that is what I would shoot for.

One thing that many Forum members have done to improve clutch performance is to slightly chamfer the edges of each steel plate so that there are no burrs left behind by the stamping process used to manufacture them. These burrs would act to "grab" the friction discs and that would make the clutch less smooth and progressive plus it would likely make shifting more difficult.

Pete

 

[Ozboy]

Hey Raymondo
Are you sure it's not the cam shaft seal inside? I had a small constant leak from mine and fitted a few new seals. I used a Speedi-Sleeve over the cam shaft end and fixed it once and for all. It only works with TCI tho with nothing inside the points cover ,unless you can somehow make it work. Check out SKF Speedi-Sleeve.

 

[Raymond]

Thanks, Ozboy, but I'm afraid it's the back face of the points cover, where it mates with the cylinder head and rocker cover. Last week I found this area was leaking because 2 of the mounting screws had loosened off. And I soon found that was because the threads were stripped. The fix - helicoils - seemed good at first but hasn't lasted. Suppose I'd better go and pull it apart again . . .

 

[MaxPete]

Thanks, Ozboy, but I'm afraid it's the back face of the points cover, where it mates with the cylinder head and rocker cover. Last week I found this area was leaking because 2 of the mounting screws had loosened off. And I soon found that was because the threads were stripped. The fix - helicoils - seemed good at first but hasn't lasted. Suppose I'd better go and pull it apart again . . .

I know that you have mentioned it in a previous post and I concur. Hylomar Blue my boy - Hylomar....that's the ticket!

If it was good enough for Rolls-Royce, it should be good enough for us!

One thing is clear - that whole camshaft seal and points cover area has been a leak problem for quite a number of people on the Forum for a long time. One member (the late RobinC) had a leak there on his beautifully restored '77D and it darned near drove him up the wall. My own 1976C (the dreaded Lucille ) has pulled a lot of nasty tricks on me over the years, but she has never spilled a drop of engine oil from that area.

Anyhow, I'd guess that there must be a burr on the casting or maybe it isn't flat or something like that and a little dab of Hylomar will seal it up nicely.

 

[5twins]

Thinking back to when you assembled your topend, did you seat the cam bearings in as deep as they would go on both ends of the cam? When you look at it, it looks wrong because the bearings hang off the inside of the casting a little bit, but they must be installed this way to allow enough room for that stepped portion of the points/advance housing to seat into the head deep enough and seal .....

 

[TwoManyXS1Bs]

...Ideas for a good solution to the points cover oil leak?

Is the holding back a transition problem, maybe pilot to needle jet system?

Ditto with 5twins' post above, possibly the cam bearings aren't fully seated.
Take your cam endcover, remove the gasket and o-ring, and fit the plain endcover back in there. See if it seats, or sets outboard a bit, perhaps more than gasket thickness.

Our cams have an aggressive profile, long timings and overlaps, to make effective use of "scavenge supercharging". It's possible that an advanced cam would open the intake prematurely, and cause a momentary reverse flow in the inlet tract, interrupting induction.

As a test, you could try temporarily setting the intakes with more clearance, say about 0.020", which would delay their openings. If the running improves, consider a rethink on the advanced cam...

 

[Raymond]

Thinking back to when you assembled your topend, did you seat the cam bearings in as deep as they would go on both ends of the cam? When you look at it, it looks wrong because the bearings hang off the inside of the casting a little bit, but they must be installed this way to allow enough room for that stepped portion of the points/advance housing to seat into the head deep enough and seal .....

Oh, blast, I just can't picture how it looked when I sealed it all up. You may well be right and I don't have the bearings far enough 'in' to let the points housing seal against the head. I will use 2M's suggestion as a way to check . . .

If it needs to be rectified, that means engine out again. But I might need to pull it out anyway to get the damaged holes re-engineered. The helicoiling job is, uhm, less than perfect.

 

[MaxPete]

Oh, blast, I just can't picture how it looked when I sealed it all up. You may well be right and I don't have the bearings far enough 'in' to let the points housing seal against the head. I will use 2M's suggestion as a way to check . . .

If it needs to be rectified, that means engine out again. But I might need to pull it out anyway to get the damaged holes re-engineered. The helicoiling job is, uhm, less than perfect.

I may be way out in the weeds on this Raymond (and I know that someone will tell me if that is the case ) but if the cam bearings turn out to be NOT fully seated, could you not simply (and gently) drive them inboard a little with something like an appropriately sized socket or piece of PVC pipe?

I would back-up the other end of the camshaft with a heavy block of steel or something similar of course - but you are likely only looking for a fraction of a millimeter of axial movement....

Just a thought....

Pete

 

[Raymond]

Well, it's been a good day with the XS so far.

Couple of test runs and as of now no oil visible on fins near l/h spark plug. Doesn't mean the problem is solved but given the leak a bit more to think about. There is very slight oil misting on l/h side-cover - but I guess this could be coming from one of a number of places?

Pete, I see your suggestion for tapping the bearings home. Mmmmm. I don't much like the idea with the cylinder head bolts torqued down - shouldn't be much scope for the bearings to shift. Will bear this in mind though (no pun intended). But while the oil don't flow, the problem is avoided.

Today's runs bring total mileage up to about 96 so starting to get a little bit used to the bike. In fact, today's runs, I was almost able to just ride the bike and not spend the time worrying about clutch, engine, timing, carburation and all the rest. Well, not too much.

The hesitation is not very noticeable if I give a more positive amount of throttle to pick up the drive from say 2,000 rpm. We're only talking giving maybe 1/4 throttle instead of just gradually opening. I'm always gentle with the throttle whatever bike I'm riding, never been in the habit of just whacking the throttle open. Even when overtaking a long lorry, I just feed in a bit and add more as the revs go up. That's just my riding style.

By 60mph the engine is starting to feel very busy. The exhaust is louder than on the W800 and the gearing is lower. I reckon on 14mph per 1000 rpm but on the Kawasaki that's more like 18mph per 1000. So at 56 -ish on the XS the engine is turning 4000, which would be 72 on the W.

Feels more of a beast though!

Seems to handle and steer well enough. Have been thinking a little bit about that SR500 top yoke. 5twins noted that there might not be enough room for the forks to compress after they are lifted that much through the bottom yoke.





To measure how much they move, fitted a cable tie just above the dust cover, with bike on side-stand. Pulling the bike upright and sitting on it gives sag of 33 mm. After one of those test runs today, the tie had moved up to 96 mm. So, 63 mm of suspension travel on a 'normal' run.

This leaves further 47 mm of fork leg below the bottom yoke. Which sounds like enough for a bigger than average pot hole or some frantic braking, but taking 25 mm off if I fit the SR yoke might cut things too fine? Possibly fit progressive springs. Or more/heavier oil. Or reduce total fork travel by an inch - I know that is possible but don't know how just yet. Also, there are other problems such as the fork shrouds which hold the headlamp would no longer fit properly.

Best put that idea on the back burner for now.

 

[Paul Sutton]

Once I made the mistake of not pushing the cam bearings in far enough. I found the bearings were very tightly pressed in place by the rocker cover so eventually had to release some tension from the head bolts. I cannot remember if the motor was in the bike frame or not due to the passage of time (1986).

 

[5twins]

As Paul just mentioned, you can loosen the head bolts going through the top cover, acorn nuts too, if you need to tap the bearings in more. This could all be done with the motor still in the frame, just with the gas tank removed.

Fork travel is speced at 150mm, or just under 6". If you pull the springs out, you can slide the lowers up as far as they'll go and see just how much space is left on the tubes below the tree. I've done that and I can tell you, it isn't much, maybe 5/8" to 3/4". That's why I only raise my tubes about 1/4" in the trees .....

More oil really helps - do that. These forks just plain work better with a little bit more oil in them. I'm not talking lots more, just a half to 3/4 of an ounce more. And I don't feel the need for heavier oil, I just use the recommended 10wt. It's the larger amount that really does the trick.

 

[Raymond]

Once I made the mistake of not pushing the cam bearings in far enough. I found the bearings were very tightly pressed in place by the rocker cover so eventually had to release some tension from the head bolts. I cannot remember if the motor was in the bike frame or not due to the passage of time (1986).

As Paul just mentioned, you can loosen the head bolts going through the top cover, acorn nuts too, if you need to tap the bearings in more. This could all be done with the motor still in the frame, just with the gas tank removed.

Fork travel is speced at 150mm, or just under 6". If you pull the springs out, you can slide the lowers up as far as they'll go and see just how much space is left on the tubes below the tree. I've done that and I can tell you, it isn't much, maybe 5/8" to 3/4". That's why I only raise my tubes about 1/4" in the trees .....

More oil really helps - do that. These forks just plain work better with a little bit more oil in them. I'm not talking lots more, just a half to 3/4 of an ounce more. And I don't feel the need for heavier oil, I just use the recommended 10wt. It's the larger amount that really does the trick.

Gentlemen, thank you both! Helpful advice.

As I said earlier, today I have been enjoying the Yamaha and not feeling too overwhelmed by the constant problems. There is no doubt that I would be sick and fed up by now without the support and advice from this forum. In addition to that, the need to report progress on the issues acts as a powerful motivation. Plus, trying to explain the issues to people hereabouts really helps focus and analyse what is happening with the bike.

Otherwise it would be tempting to just see the bike as a bunch of problems.

So today, after I had taken the points cover and Boyer unit apart to apply blue Hylomar and reassemble as tight as I could, I felt quite relaxed. Because, if that doesn't work, can try seeing if the bearings are keeping the points cover from sitting fully 'home'. And if that doesn't work, then it's gonna have to be engine out and seek out a properly engineered solution to fixing the mounting holes. I'm sure there is a way, and I'm sure somebody here has the experience.

Cheers, Raymond

 

[Jim]

Raymond,
here's a pic I took to help Robin when we suspected his cam bearing weren't seated.....

When properly seated, there's no gaps across the whole assembly. Bearing are tight against the cam shoulders and points housings tight against the bearings without gaskets or o-rings (green arrows). In my top end Tech thread, I recommend tightening the points housing without the seals and the head un-torqued. This will properly center the cam and seat the bearings. You can do this (if needed) with the engine in place.... just loosed all the head fasteners first, center everything with the housings... remove housings and install seals, reinstall housings and re-torque when done. All with the engine in place.

 

[Raymond]

Thank you, Jim. Looks like a job I ought to do soon. Very glad it can be done with the engine in situ though I'll probably wait for now and see if the pesky leak has gone . . .

If I've understood what you, Paul and 5twins are saying, just remove the tank, loosen the head bolts, remove and refit the points & advance housings - without gaskets - and re-torque the head bolts. Finally, refit the housings with gaskets and tank back on.

I'm annoyed that the helicoil job has been a bit bodged though.

BTW total spending since buying the bike - parts, services etc - £1773.37

 

[Raymond]

Yesterday, a good day with the XS. Today?

Took the bike out intending to see if the oil leak from the points housing really has been cured. Engine started readily. Warmed up for a couple of minutes and set off. Except the bike wouldn't even drive up the street. Attempts to give any throttle just made it die. Stop. Stall. Ain't goin' anywhere.

Pushed back into the garage and tried to have a wee think. But not my strong suit, so decided to do the oil leak job anyway. Tank off, points housing off. Yup signs of oil still leaking down the gasket despite blue Hylomar.

No leak on the right at the advance housing. Measured the depth each bearing inset from rocker box cover face. R/h 4.5 mm, l/h only 3.8 mm. These are approx figures measured with a rusty old vernier caliper.

Removed head steady, loosened cylinder head bolts. Given the dodgy thread repair, didn't think it good idea to inset the bearings by tightening the housings up against them, so instead, tap them in with suitable size socket:



Which worked. Gentle use of that large hammer moved both bearings slightly to a depth of about 4.8 - 4.9 mm:



That looks like damage next to the top hole, but must be an artefact of the photo 'coz the face is reasonably smooth. And with the bearing moved in by about one mm, the housing can now sit up against the head:



Again, it doesn't look it but it pushes up flush.

So, reassembled everything. Smear of Hylomar on gaskets both sides, belt & braces again. Also, took the opportunity to improve the routing of the clutch cable.

Started the bike up again. Now, I haven't done anything to sort the problem from earlier. And it's just as bad.

Attempted to check timing with strobe - I've had everything apart - and it's about right at tick-over. But I can't check full advance because the engine just won't rev. Open the throttle and try to make it go past 3,000 rpm and the engine dies. Stops. Stalls.

I don't know why. Have given up for today.

 

[Paul Sutton]

Have you checked out that Rare Earth Magnet topic were the ignition does not work well due to the magnet on the rotor going weak from age and being overwhelmed by the rotor's electromagnet field? If this is the issue then the bike should run nicely if you temporarily disconnect the rectifier/regulator unit. Apologies if this has already been done.

Blue Hylomar: I am not sure if anyone has mentioned how if this sealant is used in excess and gets squeezed into the engine oil it forms slimy bits that can block filters and fine filter mesh. It is then very hard to wash out of the fine mesh on the oil pump intake mesh.

 

[5twins]

I'm pretty sure he has a Boyer fitted so the rotor magnet wouldn't matter. But, being older than a 1980, his bike wouldn't even have a magnet in the rotor.