classic motorcycle forum
Motorcycle Discussions => British Bikes => Topic started by: mistert on April 12, 2006, 05:33:50 AM
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hi my father in law has just aquired a volkswagen engined sunbeam s7 and he would like to know if anybody out there has any info on this particulaly about the clutch mechanism ie does it operate like bike or car out of the rear or side of the casing thanks
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MisterT, I presume you had no replies to this post ?! Did your father-in-law subsequently sell on this bike -- I have just bought a VW engined S7 (POC nnn)........it was sold by VRN Ltd (?) in 2012 and I have just bought it from that owner.....unfortunately it is now 'dismantled into boxes'. I'd be interested to hear anything that you found out about the bike. Did it run when your father-in-law had it ?!
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i think this machine used to belonge to a person in worcester , he was a vmcc member so a add in that mag could bring up some history as he had it for many years attached to a chair , and it looked and worked well .
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Any pics available?
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This is how it looked.........but "in boxes" now:
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Nice. I'd love something like that. ;)
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very nice and not the same one , how has the worm and wheel faired with the extra power ? i can see this being a weak area
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To be fair it was a weak point on the standard bike as I recall
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The VW engine installed is, I believe, a 1955 1200cc Beetle engine which produces an arm-wrenching 25hp.......exactly the same as the original Sunbeam 500cc motor does. I'm sure I've read that the Sunbeam worm-drive isn't actually as bad as folklore has come to suggest......and anyway, some gifted engineer from the SOF has produced a v limited number of Ural bevel-drives adapted to fit Sunbeams......and I happen to have one of them !
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The bevel drive problem is another Net myth, isn't it? As I understand it if you use the wrong/no oil it soon wears, but that goes for most things.
Should think the Urinal (fitted with some real ball races) bevel would last well though.
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I restored one for a friend about 6 years ago and the drive was fubared, hence the comment.
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its not a bevel , its a worm and wheel underslung and the 1200 vw engine will produce far more power than the sunbeam could dream of , they did ware at an alarming rate and if the oil dropped low more so , 25bhp for the vw sounds about right but for the sunbeam sounds high , i had one for a short while and it was a well built slug , a m20 ,vb , m21 , (infact must be one of the slowest 500 ive ever owened) etc would leave it standing , looks like a nice project and vw parts are easy to come by , never seen the hub conversion you talk of but sounds prommising and worth fitting
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As I recall, I went down to Nottingham and visited Gaggs and they supplied me with a lot of the bits I needed. The two brothers are a right pair of characters and the shop is worth visiting even if just for the crack!
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I think neat Lucas Heavy Duty Oil Stabilizer is the SOF oil of choice for the bevel drive. No sulphur to attack the bronze ?
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bronze .. so your sticking with the Archimedes screw , thought you had a bevel conversion . bmw do a great dif and plenty about you might want to look at , the standard worm will suffer i think .
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I have a standard S7 (in which I use the Lucas heavy Duty Stabilizer oil)........and the VW/Sunbeam 'in boxes' which will be fitted with a Ural conversion bevel drive.......eventually.
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sorry it sounded like you where new to s7 , have you done many miles on the one you have ? dont see many about now , how is the worm holding up
http://www.sump-publishing.co.uk/sunbeam%20s7%20and%20s8.htm sounds good , and also says no problems with the worm , but the one i had would not do 75mph
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I've had the S7 a couple of years -- not done too much with it: 180 mile round trip in a day is about the max. I'm not much of a mechanic so I'm happy that it's proved reliable, comfortable etc so far. But asking 75mph of it is a bit too optimistic (!) -- it'll cruise "all day" at 55mph quite happily. It's the SOF's 50th anniversary this year so I hope to get to a few of their rallies. Lovely bikes -- wish I had an S8 too.....the best value British classic bike you can buy now ?
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We bought a Douglas Dragonfly once from a man who raced it on the beach and used to win, we never used it because we didn´t need to, this was fitted with a VW and he said it had Porsche cams, 356?, I realise the Douglas was chain drive but he had no problems with the transmission. Very light sidecar of course.
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heres one
http://www.bonhams.com/auctions/19163/lot/283/
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I have done VW into BMW conversions in the 70s.They all fail on drive ratio.Motor bikes have 5/1 ,VW motor needs 3/1 like a Harley.Unless you want to haul a triple adult sidecar,its no good,too slow.I even had stupid quotes on gear cutting,like four times what the bike was worth.Happy hacking,Regards John.
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drive ratio ............... where you useing the vw gear box ?
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The reduction in high gear between the engine and wheel.In a Sunbeam its listed as solo 5.3/1,sidecar6.13/1.The 1955 VW motor is rated 30hp at 3400 revs,the later 1200 motors were 36hp and 40hp at the same revs.The road speed corresponding is 51.5mph solo, 42.9 mph sidecar.At 4000 revs solo is 58.4.This would be redline for a standard VW with its whippy pushrods and cast conrods.Regards John.
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Well, that's made me feel a lot better (NOT) -- seeing that VW engined Douglas went for just £402 at Stafford ! My VW Sunbeam (£2k ouch!) uses the Sunbeam gearbox (not sure which ratio) and the VW clutch....via a Bendix servo. I'm still waiting to hear from a VW guru whether the engine is OK or not.....meanwhile other projects call.
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The biggest problem seen with VW motors now is crankcase warpage.This usually retires a motor through cost.Dont feel too bad ,people often spend large ammounts buying buggies,only to find the motor cactus.Did you know all pre 59 VW motors had magnesium crankcases,reputedly made from crashed allied planes.Hence the term" Hitlers revenge".Regards John.
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i see waht you mean i think , the vw will not rev high enough , the only way round (easy that is ) would be to change to chain (ive seen this done on BMWs , moto guzzi and a xs1100 ) , i think the power from the vw engine could be used 88 Nm (65 ft·lb) (9 kgm)
at 2400 rpm, i have had some vw and find them easy to work on (just as well really) parts are still cheap , complette engine 1300cc £130 this was a late alternater motor and when stripped in good condition .
as for the term "hitlers revenge" , in birmingham it was the bombing of coventry in revenge for the bombing of Munich six days before , may mean different things in diff parts of the world
http://www.bonhams.com/auctions/19163/lot/283/
mph figures sound quite high here
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I've had Gandhi's revenge in Birmingham but I'm guessing that I'm not in the same ball park...
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some of them ladypool road balti houses are a bit iffy , stay away from the special meat baltis , theres no cats in the area now .
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ROFLMAO!
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Looking into this a bit further,the Sunbeam gearbox is all indirect,with top being 1.39 to 1.For a drive ratio of 3to1,the rear bevel set you fit would need to be about 2.1 to 1. A 3to 1 ratio will give app.60mph at 2400,70mph at 2700 and 90mph at 3400,peak hp.If your motor has twin carbs,it will develop more hp than the car,as the long manifold is very restrictive.Regards John.
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2.1 to 1 ......... do bmw do a bevel set this high (crown and pin ) i would love to re gear a k100 , i like the single carb setup on the vw best as less to go out of tune (also the oil filled filtter works well but not fitted to any twin carb engine ive seen to date ) , the long cross over rods always feel lose after a while to me .
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Id be looking at some of the giant Jap cruisers with shaft.Some must have very quick ratio bevels,and there would be parts at the wreckers.Or buy a secondhand Gleason bevel cutting line ,and work out how to use it.Regards John.