classic motorcycle forum
Motorcycle Discussions => British Bikes => Topic started by: iansoady on November 09, 2015, 12:02:23 PM
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I just wanted to check the compression ratio on my Sunbeam Model 10 so had the head complete with valves upside down on the bench. I heard a tinkle and there was one of the exhaust valve collets lying there. I wasn't quick enough to stop the other one shooting across the workshop and of course it's vanished.
Just in the hope (a) that it's shared with another model and (b) that someone has one lying about its dimensions are:
Length: 0.463"
Bore: 0.250"
Major diameter: 0.600"
Minor diameter: 0.412"
My parts list suggests that this part is, like so many other, unique to the model but I can live in hope.
Otherwise I'll have to try to make one and I'm not sure my machining skills are up to it.......
I have to say it's a good job this happened on the bench not when the engine was running.
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Hi Ian,
Paul Milner seems to sell a lot of Sunbeam bits on Ebay?
http://www.ebay.co.uk/sch/thecrocodile25/m.html?ssPageName=STRK%3Anull%3AMESOI&_trksid=p2060353.m1438.l2654
worth an enquiry ? pnmilner@yahoo.co.uk
Regards
John
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Yes, I've asked Paul before but he doesn't have any Model 10 stuff. I've just reread Radco's book and think I'll try to make some new ones....
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I've just reread Radco's book ....
My bible - where would we be without it? If anyone is having a go at restoration this is the book to consult before each job. It's called "The Vintage Motorcyclist's Workshop" by Radco, and is just back in print. I can't recommend it too highly. Easy to find in the usual places.
Good luck Ian.
Leon
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Yes, it's so much better than Jeff Clew's book - strange as in the foreword Radco (Frank Farringdon I believe) mentions Clew as one of the people who encouraged him to write it. I've used the wheel building jig several times to good effect. What I like is the practical approach rather than the theoretically "correct". A bit like L H Sparey's lathe book.
Further examination shows the valve is rather chewed up around the collet area so I suspect that's why the collet dropped off - so some tidying up there required as well. I'm trying to work out how to hold the valve in the lathe to clean up the groove at the moment then will attempt the collet manufacture using a HT bolt as raw material.
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Success!
Held the valve in the 4-jaw with the head behind the jaws and cleaned up the groove with a Dremel in the toolpost & a fine grinding wheel. It took very little to restore it to round and cylindrical.
I was scratching my head trying to work out how to establish the outer taper on the collets and then to cut it. The former I achieved by filling the collet with Plasticine then measuring that as the internal dimensions were tricky to measure accurately.
Then set up an old HT bolt in the 3 jaw chuck and used the compound slide to set the angle. Did this by setting the cross slide to zero at the end of the blank with the tool touching the blank, then winding the compound slide along till the length was correct and using the cross slide to wind in the tool till it touched again. I could then read off the lateral distance.
I thought that would be much more accurate than using a protractor.
Then turned the taper, drilled (6mm, the new diameter of the recess in the valve), parted off then sawed the resulting part longitudinally on opposite sides. Cleaned up and it fits very well.
It wasn't as hard as I thought it might be.
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Well done.
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Hi Ian,
Have we had an update on the Sunbeam? On the road yet? We're expecting photos!
A Sunbeam-owner friend has been passing "Beaming" (mag of the Marston Sunbeam Club & Register) on to me. I find it the most interesting of the club mags I've seen in recent years. It's amazing what a good magazine can do to spark interest in a particular topic.
Cheers
Leon
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I believe it's been featured in a mini series in RealClassic magazine.
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And you can read all about it here:
http://www.iansoady.org.uk/Sunbeam/restoration.html (http://www.iansoady.org.uk/Sunbeam/restoration.html)
I've still been plagued with a slight oil leak and slipping clutch, both of which are undergoing intensive care as we speak. I must say I have been very pleased with the way it runs.
But I suspect I will be restlessly looking for something else come the Spring......
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Brilliant. I hope you're planning to go even older next time? Perhaps some thing pre-1931 for the Banbury Run, which can make way to a veteran for the Pioneer Run?
I do like the little Sunbeam.
Cheers
Leon
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I haven't decided yet. And I'm also dithering about my next "modern" bike....
I have always had a yen for a Scott after hearing one yowling along the lanes in the Dales, probably 50 years ago. And I also have a very odd feeling I might like an Ariel Arrow. Strange as I've always hated 2 strokes.
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A biscuit-barrel two-speed Scott would be worth trying. We only live once!
Cheers
Leon
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I have always had a yen for a Scott after hearing one yowling along the lanes in the Dales, probably 50 years ago. And I also have a very odd feeling I might like an Ariel Arrow. Strange as I've always hated 2 strokes.
Scotts are incredibly addictive and nothing like screaming RD's or ride-to-work pop-pops which are the usual typical two-stroke scenarios. Will you be selling the 'Beam?
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Yes. Interested?
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I could be very interested. Would you like to PM me?
Thanks.
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Well done, nice machine.