668 or 500 donor bike to make a custom?

A

Alexb83

Full member
Location
Northumberland
Hello all,

So whilst I float around on the far side of the world - I realise there's not much more to do to my Jota when I get home aside from tart it up a bit, and I have started thinking about another project.

Something smaller and lighter than the triple, that looks the part, but feels a bit more modern.  No, I don't want to go and buy a Thruxton or a Ducati Sportclassic. The new little Guzzis aren't exactly light or nippy. I could not sneak a new Norton past my Mrs.
But if I spend time in the garage clattering about tinkering with old bikes, she keeps bringing me cups of tea at regular intervals and it does not seem to arouse too much suspicion about exactly how much money I am spending.

'What about a replica Montjuic?' I start to thinking - Alpinos seem to pop up now and then at reasonable prices, and I dont think it would be outside my technical capabilities to upgrade one (with a bit of help). I love the look of the Monty, but if I'm putting a bike together do I really want something with 70/80s handling and braking? And if I'm already thinking about modernising, why limit myself to making it look like a Montjuic (which it will never actually be)?

Then I think 'what about a 'retro' looking 668 custom?'.  A 668 should be a budget buy for a donor bike. It has nice big brakes and USD forks which should help on the 'feels modern' front. I guess I could see about getting some suitable inlet stubs made and converting it to carbs to make it look 'right' with a suitable fuel tank on top. But I can't get my head around how to make that 90's frame and subframe look the part.

But then browsing through old forum threads about 500 customs I spot a 668 engine in an Alpino frame. Interesting - but it is sporting drum brakes and I can't see much point in it. Unless there's an Alpino frame laying around somewhere, now I'd be looking at butchering an Alpino to shoehorn in a 668 motor, at the cost of two donor bikes. Again, why bother? Is the 668 engine really that much better than a 500 with some appropriate modifications? Couldn't I just spend the cash to have some Australian/Scottish technical wizard work on the 500 motor and have a souped up Montjuic replica?

Would some engine upgrades, modern brakes/suspension and some Monty-alike bodywork on an Alpino be the most sensible way to go? Is this even feasible? I have seen pics of the XTR Pepo Monty which seems to say 'yes it is feasible' although it isn't quite what I was aiming at, but is in the same vein.

Could I shoehorn the front and rear end off a 668 onto an Alpino frame with relative ease?

Are there mechanical considerations/improvements in the engines that really recommend the 668 over a 500?

Are there other frame options out there for the 500/500-derived motors that I should consider?

 
If the 668 had turned out to be a bit more reliable, it would definitely be a worthy sucessor to the 500.  But, unfortunately, Zane messed that up big time...  Far too many issues to get around, would be better as a museum piece.

Imho, aa Atlas OR600 engine would probably fit your bill quite a bit better.  Granted, not many of those around, but fitting an OR lump into a 500 frame is very straightforward, with very little hassle concerning carbs and ignition systems.  A 10hp gain with a stock engine over the 500 will liven the bike up nicely, and the OR engine is just as reliable as the 500.

The FI engines are largely based on the original 500, but push the envelope just that little bit too far.

piet
 
sfcpiet said:
If the 668 had turned out to be a bit more reliable, it would definitely be a worthy sucessor to the 500.  But, unfortunately, Zane messed that up big time...  Far too many issues to get around, would be better as a museum piece.

Imho, aa Atlas OR600 engine would probably fit your bill quite a bit better.  Granted, not many of those around, but fitting an OR lump into a 500 frame is very straightforward, with very little hassle concerning carbs and ignition systems.  A 10hp gain with a stock engine over the 500 will liven the bike up nicely, and the OR engine is just as reliable as the 500.

The FI engines are largely based on the original 500, but push the envelope just that little bit too far.

piet
Click to expand...

Thanks Piet - is it an easier/cheaper proposition though to get a 500 (complete) and have it worked on to achieve something like an OR600 engine spec, than it is to find an Alpino rolling chassis and an Atlas engine separate?
Definitely that would be easier to register in the UK.
Then on the wheels/brakes/suspension front there are all sorts of options to consider from a breakers yard, that I'm sure could be attached.

Is the 668 motor beyond saving or could someone who knows what they're address the crank issues?
There are a few trellis frame 650/668 Ghosts and Diamantes around for ~1/2 Alpino money (I much prefer that frame to the wrap-around ones). To my untrained eye this seems to be what Laverda Corse are using as the basis for the SFC/4

Ultimately what I'm aiming (in my mind) to achieve is probably something like an SFC/4 in terms of cycle/motor specification, but looking more like a Montjuic in appearance.

I suppose it will all come down to what's laying around in peoples sheds (that they are willing to part with).
 
Hi Alexb83, some pix for your inspiration - a 668 engine in a 500 frame, build up as a Barcelona replica racer!
Ciao, Gert
 

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Very smart Gert, thanks for the pictures!

Did the tank need modifying to fit the carbs in underneath?

A 500 frame definitely looks like the 'easier' option. Like the XTR Monty there is always the option to convert it to a monoshock, and it will suit nearly any tank.

Whereas the 668 trellis frame will want a custom tank and a new subframe/seat unit.
 
was your picture taken in the sports centre behind the church in Breganze Gert?

and many thanks for useful advice on how to avoid prison (YES PRISON) for a speeding ticket I got in Austria
CLEM
 
Hi Clem, no it was taken at the Vallelunga race track near Rome in 2016 - Italian Classic Endurance Championship. Owner and builder is my friend Hermann Ansorge, member of Pieros LAVERDA Corse team. The Italians call him "Il Professore" because of his meticulous work on engines and bikes.
Ciao, Gert
 
I do know of a 500 with some Montjuic parts that is coming up for sale, it has the exhaust (genuine) and seat, plus clip ons etc, its not a genuine monty, and is not mint, but OK and rideable.
CLEM
 
CLEMTOG said:
I do know of a 500 with some Montjuic parts that is coming up for sale, it has the exhaust (genuine) and seat, plus clip ons etc, its not a genuine monty, and is not mint, but OK and rideable.
CLEM
Click to expand...

Not a Monty and not mint is fine by me, Clem - It'll never be a Monty and it wont be very original after I get through with it.
The more I think about it, I am liking the idea of re-fettling a 500 more than the idea of re-engineering the 668.
PM me the details? Although I wont be in a position to buy it until I get back into the country in May, so if the seller wants shot of it quickly, I'm no use to them
 
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