Discussion in 'The Garage' started by Raymondo, Jun 13, 2019.
Aw, c'mon Pete, I ain't exactly got money to burn . . .
Neither do I Raymond, and neither did he.
I think it was a crie de coeur for the notion of “Live your danged life to the full - this isn’t a rehearsal”.
You’ve done a great thing bringing that old gal back glory (I like to think that we all have in many respects) and you will reap the rewards for a long time to come.
(still searching for sleep in Germany)
I wish I had kept track of how much I have spent on nuts and bolts alone. Staggering. But still a hell of a lot cheaper than buying a new 700.
The annoying leak from the points housing has not completely gone away so today took a Look. Also had a Think - always dangerous . . .
Originally, leak due to points housing not compressing the gasket - I hadn't pushed the cam shaft bearings far enough in. So, on advice, loosened the cylinder head bolts and tapped the bearings.
But another problem was that the holes for the housing screws were poor - two of three housing screws would not tighten fully and the two holding the Boyer plate weren't too happy either. Got the village m/c engineer to helicoil them - all five.
Unfortunately, that appears to have introduced two new problems.
The first is that the holes he drilled are not accurately centred. If we were talking about normal bolts that might not be a problem, but the housing screws have a tapered head which fits conical recesses in the mounting. Having the holes slightly miss-aligned means they won't screw down fully. I have been thinking that this is why there is still an oil leak.
But taking the Boyer plate off today it was apparent that the oil is coming from one of the screws:
I wiped the oil away before taking the picture but that's where it's coming from. Which suggests to me that perhaps the helicoiling job has breached the cam box - this is the second problem. If the enlarged hole has breached the cambox, oil will leak and find it's way along the Boyer mounting screw. The spacer tube around the screw is full of oil and enough has collected in the housing to account for the leak. May be wishful thinking but there doesn't seem to be any oil coming from the gasket behind the housing.
And now a question for the XS experts.
Is there a way to repair the threaded holes and restore the cylinder head and cambox cover?
I have been thinking along the lines of taking it to an engineer, along with the points housing for reference, and getting them to drill out even further, fit metal plugs and then drill & tap - on correct centers this time - for the screws.
Another solution would be s/h cylinder head and cambox cover. But that would be hard to find in the UK, expensive, and even if the mounting holes are in good condition it is likely that a forty year-old cylinder head will have some other problems.
Thoughts & suggestions?
nightmare ! I have to say this is exactly why I trust no one these days to take sufficient care to do a proper job so I do everything myself as far as possible.
How on earth could an 'Engineer' manage to drill holes off centre ? they have computer programmed high precision milling machines for crissakes .I would definitely not take it back to him to sort the problem out thats for sure.
have you removed the helicoils to check that they are the right length ? sounds like he didn't use blind end drills and taps for the inserts.
I guess there are only 3 options really . take it to another Engineer and ask them to sort it. Buy another head and hope that it has no other faults or try and rescue it yourself. I'd try the latter as you have little to lose really.
Its difficult to advise without being able to see the problem clearly ....if its just a minor weep I might try removing the helicoils and reinserting new inserts with Locktite that would seal the inserts to the head at least. Then use some non setting locktite on the screws. You'd have to thoroughly clean and degrease everything prior to applying the locktite. https://www.ebay.co.uk/itm/Helicoil...hash=item2ac3c3138a:m:mJNqGu8qD6qWxYnR8FX6BIQ
cant take it anymore lol.. still cheering for you and that so pretty XS.
Curious as to the cost of shipping a head and rocker cover etc half around the world to you from Washington State USA 98661 ?
If you clean it out with brake cleaner you should see if it’s broken through, if it has, put a drop of silicone on the screw, only a drop mind, then assemble and check.
Seems a shame to go to the trouble of changing the rocker box/head for something so small. Removing a helicoil insert once installed is a drama, ask me how I know.
Pity your not nearer.
Rasputin, thanks for that. Might be best not to rush into anything. If a bit of silicone will fix it, that's a lot less drastic than some of the ideas I've been cogitating.
The village m/c engineer came to my garage and fitted the helicoils - he just used a hand held electric drill to enlarge the holes. Said he has done this many times, which is probably true. But I feel with hindsight that this method is not appropriate for the taper-headed screws on the points housing.
Hindsight is a wonderful thing - wish I had invested in some before I let him loose on my XS's engine. But, thinking about how things might have been done a different way is pointless. Am still thinking about what the best and most permanent repair.
For example, can the holes be filled with weld and re-drilled?
Would recutting the screw heads to a more accute angle using a lathe be a possibility. Then put a thin lead washer under the screw head to squish and fill the gap.
yes you could use low temperature brazing to permanently weld fill the hole but you'd need to remove the head and strip it to do that at which point you might as well get the holes Tig welded .
The key to filling the holes is to thoroughly cleaan the aluminium of oil which again would require the head stripping and placed in an ultrasonic cleaner to remove the oil that seeps into the pores of the aluminium which would prevent a sound weld or braze.
Another possible option might be to redrill the holes in situ using an attached drilling template and then glue/drift/screw in some brass threaded inserts some of which are self tapping.
I like the idea of using a simple quick cheap liquid option first with silicon , Locktite or Threebond etc
Thank you, Peanut, some good suggestions.
I think I might dismantle anyway, to investigate. Rasputin, I think you believe the hole might have broken through at the bottom? Perhaps, but I am thinking it might have breached at the side. There is not a lot of metal between the thread holes and the interior of the cam box?
Not doing anything just yet. But if the parts need to go to an engineer it will have to come apart anyway. I suppose there's plenty of time now with the Great Salt.
If that engine needs to come out, I don't want to lift it like last time. So have taken a leaf out of Mailman's book - and no doubt others on this forum - and invested in a chain and pulley system.
pity.......this engine lift is a great solution . At least two of our members have made this solution
Uh huh, have seen the various ingenious lifts devised by XSives on this forum. But most of them require metalworking and in particular welding which is beyond my tools & experience. I think with stout beam and secure attachment across garage rafters, I might be able to cope with lifting the lump using a pulley.
Time is on your side, fair enough. It seems an awful lot of work just to fix a dribble. Looking forward to the story all the same.
True. Maybe I should just put up with it.
Couldnt you find an o-ring or similar to seal the leak around the bolt? Honda uses them on bolts that have oil behind them, like the stater cover...seems to work just fine. The o-ring gets crushed as its tightened down. Dont see why it couldnt work in this scenario?
Mornin, sheesh (American for you guys still talkin bout screws)
I would only pull the engine again to Replace head components. No more fixin.
But in reality, Yamabond to the rescue!
Thank you, Brassneck. But, and why is there always a but, there is a step in the back of the points mounting just where the bolt passes through. Boyer Bransden use a loose alloy sleeve to position the sender plate out in line with the magnetic rotor. This works because the bolt doesn't carry much load. The sleeve sits right on the step, so much of the sleeve is supported but there is a gap. Plus, a lot of the oil I found was inside the sleeve so even if it could be sealed at the inner end it would probably need further sealing at the outer end
I'm not making difficulties here, just looking for the best solution.
Machine, we crossed in the post. Would gumming it with Yamabond work?
I like Yamabond. And do not consider it to be gummy. Yamabond actually sets up fairly hard. More so than silicone and such. Did you find Grey Yamabond anywhere inside your engine seams ? I’ve used it in the past on case seams where gaskets are in corners and such. I may seem to be simple but it’s true, somehow my bikes do not leak.
Yamabond has been in my tool box always for many many years.
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