What to look for when buying a Sloper

[Goldnrust]

Hi guys, I'm new to the forum and hoping to ask for a bit of advice!

I've decided that I like the idea of buying a prewar bike. I think it would be an interesting challenge to learn to look after and ride and, I find the old fashioned engineering quite fascinating.

I'm no stranger to classic vehicles, bike wise I currently have a customised '72 Suzuki T500 but I also have a '68 Daimler v8 250 and a '65 Fiat 500, all 3 of which were revived from 'barn find' type condition, but venturing into prewar vehicles is all new to me. I'm confident with mechanics and have reasonable welding and fabrication skills but don't have access to some of the serious engineering tools (milling machines, lathes, etc) that some guys do.

After browsing around online and doing some reading, one of the bikes that's coming to the top of my list of potentials is a Sloper. I'd be looking for a 500 OHV, as I think that I'd like the performance that the OHV engines offer to help keep up with modern traffic (and there's just something cool about seeing those exposed rockers working!) I'd be looking for a bike that's on the 'oily rag' end of the scale, or even a project bike, I like a bit of patina in old vehicles, and also to put my own touches on them, so better to start with something rough and leave the perfect museum specimens to those who really appreciate them. 

So my questions are:

1. Before I go look at any bikes, are there any pitfalls particular to Slopers (or prewar bikes in general) that I should watch out for? e.g. any impossible to find parts or common problem areas to be aware of?

2. It's going to be totally different to anything I've ridden (which is kind of the point of getting one!), especially the hand shift, any tips for getting the best out of riding the bike?

3. Any alternative bikes I should consider? I had also seen a couple of Blue Stars that caught my attention, I like the sportiness of them and appreciate that foot shift might be a little easier ride enthusiastically, but they were most 350s and I wasn't sure it would have the same 'thump' that a 500 would, which in my mind is part of the defining part of an old British single. Am I wrong to think that?

[David Samways]

My experience with restoring pre-war BSAs leads to to the following observations:

Completeness/originality: Whatever you buy make sure it is complete down to the last detail. Generic items like magdynos, carbs, wheel rims, headights, saddles etc. won't be a problem, but there are very few new spare parts available for pre-war BSAs. Tinware in particular should be complete and repairable. You might find guards that can be modified, but it's not easy. Complete sets of handlebar levers are difficult to find and expensive when they do turn up.

Wear: related to the above, make sure significant components aren't worn out. You'll probably be able to find a piston to fit the rebored or resleeved barrel, but worn rockers and spindles are a nightmare and extremely difficult to fix - even with a comprehensively equipped workshop. Big ends can be rebuilt and worn shafts plated or remade, but with heat treatment etc it can get very expensive - my Blue Star crank cost over £1K to restore. There are no new valves, guides or springs available as far as I'm aware. Apart from ballraces, new gearbox parts are non-existent. Worn fork links are difficult and time consuming to remanufacture. Wheel bearings can be extremely difficult to find for some models.

In contrast, I recently bought two Rudges - a 37 Special "special" and 38 Ulster. The former is complete and beautifully put together, the latter is a complete restoration project. The difference in spares and information support between the two marques is breathtaking. While this forum is full of helpful people, the club has no spares scheme and offers little in the way of solid information on pre-war machines. The Rudge Enthusiasts Club on the other hand has an extensive new and used spares scheme with almost any engine or gearbox spare available new as well as a vast number of cycle parts too. Technical expertise is abundant and the forum of both Rudge websites is extremely active.

Of course, we are talking chalk and cheese between the two marques. BSA was huge and produced a vast number and massive range of machines, Rudge produced just a handful of models and sold many fewer machines.

I have always had a soft spot for BSAs and have another machine to finish which I've owned for 30 years, but when the Blue Star is finished it will be up for sale and I'll not be getting another BSA in a hurry - unless it's exceptionally original.

Bit gloomy, and I certainly don't want to dampen your enthusiasm - where there's a will there's a way. Pre-war BSAs are fine machines, but they're not the easiest to restore. I hope this helps.

David

[Goldnrust]

Thank you David for that straight forward and honest reply. I appreciate it is sometimes hard to look past brand loyalties and often the people  you'd find on a single marque forum are a fiercely defensive of their brand of vehicle as they would be about their football team!

In this case the experience I'm looking for of what a prewar motorbike is like to ride, I'm still exploring what the difference between the different brands of bike offer in terms of experience and support, and am yet to nail my colours to the mast of a particular brand or bike, so that has been helpful information.

As you say BSA sold many many bikes and as such there are quite a few out there for sale, and I assumed that with a larger number of bikes still out there on the road there would be more support for a brand like BSA than for smaller brands. It sounds from your experience like that might not be the case.

Perfect original restoration is not really my thing, I'd happily run some alternative mud guards or incorrect levers, as long as they still convey the style of the bike in the right way, and would probably want to go my own way on a few of the more cometic choices anyway, so that side of things doesn't concern me.

Regarding your comments about the engine components, that does concern me more. I guess the other half of the equation is how likely it is that the bike might need new valves or valve guides as to whether their lack of availability is a problem. To me those parts are closer to regular maintenance components than say parts for the big end should be, and so I'd really like to think they were available! Without having a bike in pieces in my possession it's also hard to know if some 'generic' parts could be modified to keep things moving even if they aren't 100% original, or if the design of the valves or guides, for example, makes that difficult.

It's all food for thought , so thank you.

[David Samways]

I certainly take your point about originality. If you're happy with a bike that's not totally original, but conveys the spirit of the model then it will save you some cash - you'll pay a premium for a well restored Sloper or Blue Star, but there are plenty of others to choose from and machines with non-matching engines and frames will be somewhat cheaper. However, as you rightly point out, things like valves and guides are more critical and although it's certainly possible to modify valves and make guides getting it right isn't always easy - much nicer to know that someone else has made a batch to the right spec.

I'm more of a restorer than a rider, but I've done so many bikes that I now find it tiresome to have to make parts that I've made many times before - there's no interest in it and I'd rather just buy and fit. Where it gets really tricky is when you're talking about hardened parts that are not easy to replicate even in a comprehensively equipped home workshop. The rockers on these open valve BSAs are glass hard and run steel to steel on hardened spindles. Being open with only grease (when the rider could be bothered) for lubrication, they have a tendency to wear badly and are difficult to fix. The rockers can be honed out to a larger size but this is a very slow process and then new spindles need to be made or hard plated and ground to size - it all gets rather expensive.

Even relatively simple things like springs become a monumental PITA. You'll notice from my previous posts that the clutch spring broke on my Blue Star. I have a very good spring maker locally who tells me that square section spring material is now extremely difficult to find since the demand in industry has dwindled due to new ways of doing things. As it happens a round section spring will probably do the trick, moreover Cornucopia in Germany actually have new ones, so it's not the end of the world, but there are many other essential bits that one just has to wait to appear at an autojumble or on eBay. Patience is probably the greatest asset to a restorer!

If you're not too fussy about originality and fancy a project with a superbly rebuilt engine and more than 50% of the rest of the bike restored restored, then I will be selling a '37 Rudge Special project in the not too distant future. Let me know if you're interested and I'll fill you in on the details.

David