Tag Archives: Model 90

Pistons now available from Sunbeamland shop

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I’m pleased to say that we now have the recently manufactured high-quality, lightweight forged 7.5:1 pistons available on the Sunbeamland Shop in +0.020″ and +0.040″ oversizes.  Modern materials and CNC machining mean that all-up weight is within a few grammes of the original Marston’s item and I’m enjoying the experience of running one in on my own 1930 Model 90. They should fit any of the late 20’s early 30’s 500cc OHV bikes and we hope to be following up with production of a small batch of 6.5:1 pistons aimed more at the Model 9.

Forged piston for Sunbeam Model 9 and Model 90 7.5:1 compression ratio

Forged piston for Sunbeam Model 9 and Model 90 7.5:1 compression ratio

New forged Sunbeam pistons arrive at Sunbeamland

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Sunbeam Model 90 forged piston, pin and rings

This little beauty arrived today and I couldn’t wait to put a post up on the blog here at Sunbeamland. It is the first from the box of a batch of forged Sunbeam Model 90 pistons. It is modelled on an original Sunbeam 7.5 : 1 piston and, unlike some alternatives that are available, weight has been controlled so that the combined weight of piston, pin and rings closely matches the original.

Sunbeam Model 90 7.5:1 piston

Next job is to bore a spare cylinder to suit either of the +0.020 or +0.040 sizes we have produced and get some testing done before winter sets in.

Sunbeam pistons and cylinders

 

1930 saddle-tank Model 90 comes out of retirement

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I can’t describe how excited I was to make contact with John Rooney from north of the border who has acquired this stunning and impossibly original Sunbeam Model 90.

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The bike was originally registered to the Marston factory before being sold on two years later. It has webb-type forks fitted rather than druids which would suggest late 1930 to 1931 but it was common practice to fit the later, improved forks to earlier models.

The bike has been in the same ownership for the last 50 years before John rescued it from a shed and I am delighted to say that he plans to get it going with only the minimal necessary work. New tyres might just be required but the bike has many of the original fittings and fasteners that are so difficult to find or replicate.

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There is currently little paperwork but of course being a UK registered Marston bike we all want to know what racing history the bike has. The engine number of the bike is only 2 digits different from my own saddle tank 90 (shown below) which has TT and MGP history, so is it possible that this bike is from the same 1930 team?

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Although the frame numbers of the two bikes are further apart, the two bikes share left hand filler oil tanks, foot-change box, tulip shaped frame lugs, lack of sidecar lugs and the unusually absent gearbox drawbolt adjuster.

If anyone can shed any light on the history of John’s bike, please get in touch and let us know.

 

VMCC Festival of 1000 Bikes

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Brough Superior SS100

A fine sight indeed. And the Brough looks good too. Kenny had a fine time on the SS100, taking no prisoners on track and making the most of the fabulous weather. The Brooklands cans were made especially for the day and gave the bike a magnificent bark to match its bite. Of course Archie couldn’t be kept off track completing all the sessions on his 1928 Sunbeam Model 90.

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One or two other ‘beams were spotted around the paddock, for example this tidy Model 8 saddle tank looked purposeful and is presumably an easy starter without its decompressor. Not sure of the year but druid forks and saddle tank would could mean 1930 or so.

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I also spotted this gentleman seemed once or twice having fun on his twin-port Model 9 but didn’t manage to get any on-track photos.

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With lots to see both on and off track, this really is an event for all the family.

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But for me, the day really belonged to Nottingham’s finest. The Brough just never fails to impress and it is a credit to Archie and Kenny who use it in the way that they do.

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ex-Graham Walker 1927 Sunbeam Model 90

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Carsten was kind enough to send me some photos and information about the history of his fascinating Model 90. The eagle-eyed may spot that it is the same bullnose 90 featured in Robert Corden Champ’s book “The Sunbeam Motorcycle”.

This fine looking machine is reputed to be the one ridden by Graham Walker at the German Grand Prix. I presume this would have been the Grand Prix d’Europe at the Nurburgring in 1927 as Walker left for Rudge at the end of the year. As it happens, amongst other successes Sunbeam did go on to win the German GP in 1928. Bought from the UK in the early 60’s by race bike collector Dr. Helmut Krackowizer, the bike then did time in Austrian Walter Brandstetter’s Race Bike Museum before moving to the Hockenheimring Race Museum in the mid-1980s.

It seems Carsten has had a few issues along the way and, although outstanding a few parts, the bike is now running with a spare 1927 gearbox. I really hope we get to see Carsten’s bike over here in the UK one day soon.

 

 

Annual Sunbeam Rally 2013

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A beautiful weekend for the annual Marston Sunbeam club rally this year with some iconic models on display before the Saturday morning run out.

With the damper at the top, the druid forks fitted to this beautifully restored bike would date it around 1930. The twin port head suggests Model 90 but the valanced mudguards point towards Model 9.

This immaculate restoration won John Phizacklea an award at Stafford this spring. The bike is John’s take on the perfect Sunbeam green-laner. You can see more of John’s works including the amazing 95R on his website : http://www.johnphizackleamotorcyclerestoration.co.uk

Ready for the off, a magnificent site with the sun beaming down.

This rare 350cc Model 10 made an appearance having been ridden down by the owner from Runcorn. It seems the Model 10 shares few parts with other Sunbeams but its smaller dimensions create a stylish, sporting lightweight.

 

Pumping oil

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Original Sunbeam pistons are thin on the ground and it seems that the rings to go with them are scarce too. The 1930 Model 90 was fitted with a 7.5 : 1 piston of Australian manufacture. This works well enough but is around 80g heavier than an original. We suspect that this accounts for the increased vibration that is apparent when compared with the Dodson bike or any of Archie’s for that matter. It’s really not a big deal but as we had a spare 7:1 Sunbeam piston and cylinder left over from the 1928 rebuild we thought we’d try it out for the summer – should we have one this year.

The bore of our spare cylinder although worn was deemed serviceable and after a light hone we sourced a set of three plain NOS compression rings. A stepped oil scraper would often have been used in the lower position but none were available. The top ring height was 2.35mm whilst the other pair were 2mm but the ring gaps were huge running from 0.015″ to over 0.020″.

Ever helpful FW Thornton located a brand new set of 80mm rings which were supplied un-gapped and with a stepped scraper to boot! Happy days, until I tried to slip the piston into the bore. Just as I reached for the mallet to help things along I realised that the radial depth of the new rings was too large for the piston. Sure we could increase the ring depth of the piston but there’s not a lot to play with and we really don’t want the top to come off.

Peter Woodward came to the rescue with a stepped scraper of the correct radial depth and height which I duly collected along with a handy selection of other rings with which to experiment. This ring also gapped massively and, ever the perfectionist, I ploughed on and fitted it together with the best of the compression rings that could be mustered.

Hey, what do you know, we made a super-efficient oil pump! And although the smoke was horrendous at least it was dense enough to cover my shame when stopped at traffic lights. After 20 or so miles the situation hadn’t improved, the plug quickly oiled up and after a £10 taxi home I collected the bike in the van.

The bike felt good with the lighter piston and the loss of 0.5 : 1 compression from the Australian item was not immediately noticeable. In an ideal world we would use a 7.5 : 1 as per the one in the photo at the top of this post. If anyone has a good ‘un available, please let me know. These are a little heavier than the 7 : 1 but should work well on today’s fuel. Interestingly, the Sunbeam pistons are stamped with a “7” or “7 5” on the inside of the crown to identify the type.

Failing that, we may have to get some new pistons manufactured if we can find a cost-effective supplier. So, watch this space or contact me to place your order….

Charlie Dodson’s Model 90

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Some time ago I was lucky enough to take a few snaps of the bike I understand was used by Charlie Dodson to win the ’28 Senior TT. Archie Beggs later rode the bike at the club Centenary rally and also at the 2012 festival of Jurby. More pictures are stored in the gallery.