Start the Week topic january 31st

[guest7]

As time moves on and cams wear, bores expand and camchains rattle, will we start running short of good usable air-cooled big singles?

Anyone who has rebuilt a big Jap thumper will tell you that the costs can be very high and it doesn't always make economic sense to repair an engine when a secondhand engine from a breaker would be cheaper. The trouble is, have you tried sourcing a big single from a breaker recently? Trail bike motors like the NX650 can be hard to find in good condition, at the right price.

Just look at our Wanted forum to see any number of adverts for replacement motors or, at least, serviceable top ends.

I think we have to accept the SRX/XT and XBR/NX were the last decent big aircooled singles that the Japanese factories offered and what we have now is a reducing pool of spares.

RIP the big air-cooled single?

Thoughts?

GC

[el vencejo]

Apart from water-cooling allowing higher power output, noise is also a reason why the big manufacturers stopped developing airheads.
Sadly, I can't see any more being made outside India.   

[guest868]

I think that the time for aircooled singles has long passed. That's not to say I will miss them, as I will. Things move on. For one though, I shall continue to carry on using my big singles, rather than squirrel them away in some vain hope of antiquity. I am on the look out for another SR500 though, I enjoyed building the last one, and it will go nicely with my TR1.

[andy230]

I know its not the same, but by the comment "RIP big singles..." we wouldn't see any ES2's, Velo's, Goldie's etc about either.  And thats not the case.  They are just a bit more pricey, and ridden a bit less.

And while they (the later two anyway) have entered the realms of "exotica", they were not so in the 70s.  Just old bikes that no-one wanted.

A bit like SRX's, XT's, XBR's etc are now.  When my old man bought his ES2 in 1978 (sympathetically to my mother, 2 weeks before I joined the world and started ruining his life  ) spares were generally not available.  I mean, who wanted a 59 ES2, even if it had a good chassis, in 1978??  Thus it was (I believe) Vauxhall piston rings, self-made valve guides, NOS valves, etc etc.  I still have quite a lot of correspondance, drawings and receipts for these items.  In fact, going through his "treasure" after he went away to the big garage in the sky, I found about 20 ES2 phosphor bronze valve guides, which he had made at the expense of his employer, (unsurprisingly the now defunct!) Hoover plc.

I agree that probably no more will be made, but there are loads around.  They will be junked/ scrapped/ broken until they become rare enough for people to take an interest again.  Because people really do seem to love them, road singles anyway....  You know, the comments and admiring glances at the lights?  Even my ugly old skorp gets interested people enquiring....

(not to hijack the thread, but scimitars are the same- unloved, quirky and generally worthless.  But people seem to be interested)

All the better for us I say- they are cheap and usable, and (with contacts) you can still get parts.  Much easier now with t'interweb than writing away to the club magagzine, for publication in 2 months time,  to let the community know that you want a conrod for a Vinnie Comet...

a

[Andy M]

The trouble to me seems to be that XBR's and the like have so many different components. I remember buying some bit for the old boys ER-5 (think it was a clutch cable or maybe brake pads). I didn't know the frame number so it was like playing twenty questions. We finally got it down to an ER500-2 made in 2001 but I didn't know if it was a Tuesday so we had a choice of three! It probably didn't matter if the Thursday one was longer than the rest and would have fit anyway, but we don't seem to have people who know that in my very limited experience of these things. The place I get such bits from is OK, if it's wrong they'll send it back, but you can't do that on e-bay or at the breakers.

Brit bikes seem to have used the same dimensions for years and you even seem to get bits that moved from model to model for years and years. If someone knows a Vauxhall Viva piston will fit a BSA, chances are it'll work on some sort of Norton too.

Aircooled twins seem better served. Guzzi are going to be making them until at least 2012 and Triumph have turned out basically the same one for a decade. The biggest problem with Bonneville bits is all the people trying to cram them into leaky Triumph frames.

MZ is maybe the pattern the Japanese singles will go, there are maybe two breaker/dealers still in the game (and boy don't they know it). Still, MZ's didn't change much, so a bit tends to fit hundreds of surviving bikes with no fuss identifying which.


Andy

[guest7]

Of course when I started this thread I realised that there are tons of Brit one lungers still rolling around out there, but they were produced in much higher numbers than the final Jap aircooled and, let's face it, nowhere near as trouble free as a jap lump. What I was getting at is that if you want to run a big Jap aircooled, it's fine for now, but may get pricey in the near future.

And there's little available after that.

A 450 mini thumper might be just as powerful as a Manx, but is a 450 short stroke motor really a true thumper? (cat amongst pigeons there  )

GC

[el vencejo]

A 450 mini thumper might be just as powerful as a Manx, but is a 450 short stroke motor really a true thumper? (cat amongst pigeons there  )

GC

My first bike on the road was a BSA C15 250cc, don't remember the year, reg 48 RTU, had the mushroom type contacts... adjustable timing on the run 'cos the holding screw thread was stripped....
But that humble 250 was more of a thumper than my 644 RFVC

I still want an M21 or an Ariel VB    Real thumpers 

[beeman]

When I first started biking old sloping panthers were called big thumpers most british singles being 350-500cc.
Jap singles seem to be more 500-650 cc in size so what do we mean by mini thumpers being 450cc when brit iron was often smaller? I also seem to remember people skimming flywheels to make them lighter and rev faster/higher

Having just bought a new bike it is interesting to see how in the last couple of years early jap singles rocket in price compared to later ones. Yet the later bikes were nearly always an improvement on them. Is the sr 500 so much better than an srx.

Rareity and rose tinted glasses seem to cloud our judgement. Mind you I am as guilty of buying with my heart and not my brains as the next person. Buying bikes is not a science where the we let the hard facts get in the way of our dreams!

I think there is still plenty of old british bikes out there. They are in garages, never run and just collected by old men pretending to be in their youth but now able to afford to buy their dream machine but too scared to risk them on the road for which they were built. (not you Bruce)

 
Any way I thought we were a riders club not worried about the age, condition, make or size of our bikes.

beeman



 
 

[andy230]

A 450 mini thumper might be just as powerful as a Manx, but is a 450 short stroke motor really a true thumper? (cat amongst pigeons there  )

Nope!  My DR just gets snatchy low down, whereas the nice big Brits do thump along quite pleasantly...

a