Tools for in-situ replacement of inlet valve oil seals / 'Advanced' fuels

Previously john_holmes wrote:

The left hand cylinder smoked on my 850, it was smoking badly on acceleration but not on cruising or slowing down. I installed a new set of rings and had the barrel honed, put the original pistons back in and no more smoke. If the inlet valve guide seal is gone then it will smoke on slowing down as that is when there is the biggest draw on the guides as the carb air route is shut but the engine still wants air. So check out when the smoking is worst and that will give you a clue as will a leakdown test.

Thanks, I'm only aware of it smoking at tick over and when I blip the throttle when stationary, I don't have any riding buddies to confirm smoking patterns and don't see smoke clearly in the mirror when riding, at all. Otherwise just a thin wisp curling out of the silencer when I shut the engine down, and the oil level in the tank is going down noticeably more quickly. On balance that makes me think of the oil seals, but as far as that goes maybe that's just what I want to think of! I'd still be keen on a set of tools, for the future, whichever way this goes. Cheers.

Previously gordon_robertson wrote:

Hello Colin,

I've got the tools which you are welcome to borrow.

Only problem isI'mnot in the U.K. and postage from the Czech Republic would be expensive especially if I send the rocker shaft slide hammer along with the rest of the tools.

If you can wait and aregoing to attend the international rally in Austria then I could bring the tools along with me.

I would then be in the U.K. around October so it would be less expensive for you to post them back to me at my U.K. address.

For many years I suffered smoking from theright cylinder caused by detached valve stem oil seals, which I finally sorted out when I recently renewed the valve seats, valvesand valve guides after a valve seat dropped out.

Thegroove in the offending valve guidehad not been machined deep enough to retain the valve stem oil seal properly.

As the cylinder head had been gas flowedand new seats,guides and valves fitted by an ex factory Norton'expert' some 30 years ago I never thought to question his work, but I suppose inferior parts can catch everyone out at some point.

Thank you Gordon, that's hugely kind of you, to even think of lending your tools! I should dearly love to ride to Austria, but it won't happen I'm afraid, for reasons that I won't bore you with. I've seen stories of these seals becoming detached, or never having been fitted properly in the first place. The seals presently in my engine were also installed by an ex-factory Norton expert, 17 or 18 years ago, I wonder if it's the same person! However 'my' expert's work has otherwise proven to be faultless over that time, and obviously I've yet to get a look at my seals, so who knows.

Can I suggest that either I reimburse you for your postage from the Czech Republic, or that I wait until October, if no-one's offered to make me a set in the meantime, when I could reimburse you for your postage within the UK? With a set of tools in hand, I'm pretty sure I might find a machine shop locally that would use them as a pattern to make a set of my own. By the way I have a rocker shaft puller. Thanks once again!

Previously gordon_robertson wrote:

Hi Colin,

Regarding the tools I've sent you a private message just in case you want to supply me with your address.

Further to my Norton 'expert' saga I found that the offending valve seat that had dropped out had been a standard sized valve seat which had been knurled around the edge to try and makeit a tighter fit in the cylinder head.

I learned that the correct method is to use oversize valve seats and heat shrink them into the cylinder which I now have.

I believe this Norton 'expert' is no longer with us.

Hi Gordon, I've just responded to your kind private message!

Gordon I've just emailed you to say the tools have arrived, thank you! Now to find someone to copy them for me ...!

Hi Christopher, I'm in Brighton! I think I've got all the bits together, except the bar to make the U-shaped, strongback bit and the wherewithal to bend it into shape ...

Yes, attention to pistons, rings and bores is simply second on my list of possible solutions. A bit of background, the engine's only done about 15,000 miles since overhaul by Norman White; but it stood unused and effectively out of reach for 12 years, until April last year, due to circumstances beyond my control (no, I wasn't in prison, nor have I ever been!). When I finally managed to retrieve the bike last year, I expected all sorts of trouble. With the help of this forum I refurbished the gearbox; but the motor was in fine fettle. The smoking only started recently, about 3,500 miles later. Maybe some conclusions can be drawn from that â my first suspicion is that those oil seals need replacing; but for anything else I'm prepared to wait and see. Anyway, all thoughts welcome!

Welp, with the essential assistance of Gordon Robertson's loan of special tools, with the sun blasting down, and another contributory factor â at last the council's given me and four other motorcyclists on the same street somewhere legal to park our bikes, after seven months of nowhere! (how do you growl thankfully?!) â I got stuck in and replaced the inlet valve oil seals this afternoon. Surprisingly easy to do, once you've worked out a routine, and have overcome a fear of rocker washers disappearing out of reach. They really seem to want to ...

However, all buttoned up again and I've just been for a blast, but it doesn't seem to have made any difference. Still smoking, mostly from the left cylinder, and I would now say with open throttle rather than shut. Never mind eh. BTW the valves didn't seem sloppy in their guides (I should hope not, after only about 15,000 miles).

So the next step, when I get around to it, is to strip the head and barrels off and see what's what. Done that before, and no need to borrow any tools. But summer's pretty much here, and the bike's running so beautifully, I may well put it off a while. If I had a garage to work in I might not, hey ho.

Huge thanks to Gordon for the loan of the tools, it's been an interesting experience, and it's something new I can say I've done! Still waiting on someone to make me the U-shaped, strongback part of the valve spring compressor, so that I have my own kit, but I've found someone local who's expecting me around the end of July (yes he's that busy), if nothing else crops up in the meantime. And thanks for all contributions to the thread so far. Cheers!