NBT- My 1970s Muscle bike!

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NBT- My 1970s Muscle bike!

Post by Tricky »

For quite a while I’ve been toying with the idea of an old(ish) big four-stroke twin, and specifically one of these-

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Yep, an early 70s Yamaha XS2.
Now I know from previous comments that I’ve read that at least one or two on here don’t think that much of them , but that’s not me- my old man bought the ex-press test bike back in 1973, I have many enjoyable times on the back of it, and a few years after that, rebuilding the motor with my dad when the gearbox went pop, I thought it was such a cool bike and as a result they've always had a sepcial place in my heart

I nearly bought a US import one from those DK bandits a year or so back, but it didn’t work out, I’ve kept an eye out for a half-decent one ever since, but TBH the ones that have come up have been a bit shit, and (IMO) also significantly over-priced, so it hasn't happened

So I’d sort of stopped looking, until by chance, a couple of weeks back something came up that caught my eye, and I also have a childhood fondness for ( even though I’d never sat on one) and TBH was perhaps even more desirable to me, this one has most excellent provenance and history and I decided I had to have it

And here it is, and I absolutely love it, even though I’ve not made it more than a couple of miles around the lanes on it yet
Spoiler
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For anyone that doesn’t know, it’s a 1975 Laverda 750 SF2.

People that do know, will know that the motor is a bit of a big-bore copy of the 1960s Honda 250/305cc CB72/77.

The CB77 is a bike close to my heart, as my brother Kev will testify, my having (not particaulrly well ) rebuilt his CB77 in the 70s, and the SF's big brother, the 3-Cyl Jota was one of my poster bikes back then, if not THE bike I lusted after beyond all others as a 13 or 14 YO, so this one was off to a good start, even if it rode like shit.

But it doesn’t ( well, apart from some rough low-speed running from some gummy carbs currently which is easily solvable) - it is a cracker.
A very fecking heavy cracker, admittedly, but well, I can forgive it that as I absoloutely love how it looks and sounds.

I have a bulging history file with it, including the original dealer purchase receipt ( the original owner was allowed £500 part-ex against his Velo Venom back in 1975), and a thick wad of receipts that make me smile just looking through them (there’s a dealer bill to remove and re-fit rear wheel to fix puncture in 1975, grand total was £20.50 that included a new “ heavy duty Dunlop” inner tub @ £3.50 :-) )

I picked it up the day before I went away on holiday, so haven’t had a chance to do anything with it yet aside from that very breif run around the block before I went- It’s last owner had it some 15 years and looked after it and on the face of it , is in very nice original and unrestored condition. It starts on the button sounds gorgeous, and runs very well with the choke on, but knock the choke off and it dies low down so needs a good carb clean ( fuel in there stinks too) but that’s easily sorted.
I’ve given it a quick once over and TBH it really doesn’t need much but current jobs I have on my list are:
  • Cure poor low-speed running off choke (clean pilot jets)
  • Check and adjust if necessary valve clearances, points, and ignition timing
  • Replace tyres- it’s got decent nick BT45s on, but me no like and it’s getting Conti Classics
  • Properly secure the (new) battery
  • Fit smaller bore front master cylinder ( brake feel is rock hard , far too wooden)
  • Re-build /cosmetically refurb the (Koni) rear shocks
  • Cad plate a few bits (wheel spindles/nuts/spacers etc), and polish all the lovely 70s ally!
That’s as far as my list has got so far- more to follow as I get in amongst it, and maybe even a little vid or too so you can hear just how manly it sounds – like a 70s Bonneville or Commando, but just so (so so ) much cooler 8-)

Oh and the absoloutely fecking ginormous cherry on the top of this purchase was, I have taxed, MOTd and insured (fully comp with no excess) it for 12 months for the grand total of £71 - old bikes rule! :banana-dance:

Here are a few more pics of my beautiful big girl in the meantime, more to follow as our relationship progresses and I get time :thumbup:

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Re: NBT- My 1970s Muscle bike!

Post by Taipan »

Effin lovely! Top purchase! :thumbup:
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Re: NBT- My 1970s Muscle bike!

Post by KungFooBob »

Twin horns, for extra horniness!
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Re: NBT- My 1970s Muscle bike!

Post by Cousin Jack »

That looks ace!
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Re: NBT- My 1970s Muscle bike!

Post by Le_Fromage_Grande »

An interesting choice, I'm assuming it was registered over 40 years ago so it didn't need an MOT or tax
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Re: NBT- My 1970s Muscle bike!

Post by Tricky »

Le_Fromage_Grande wrote: Mon Sep 18, 2023 8:55 pm An interesting choice, I'm assuming it was registered over 40 years ago so it didn't need an MOT or tax
Yup, there's a clue as to its age in the title, and one or two in the OP too ;)
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Re: NBT- My 1970s Muscle bike!

Post by KungFooBob »

Koni Dial-a-rides too!

I'm most impressed that someone bothered to tape the headlamp so it dipped the right way, surely if it doesn't need ant MOT why worry?
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Re: NBT- My 1970s Muscle bike!

Post by Tricky »

KungFooBob wrote: Mon Sep 18, 2023 9:00 pm Koni Dial-a-rides too!

I'm most impressed that someone bothered to tape the headlamp so it dipped the right way, surely if it doesn't need ant MOT why worry?
Yup, Konis are 8-) and agree RE the headlight taping- I haven't looked far enough to see whether it dips the right or wrong way yet, but either way it will be coming off :thumbup:
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Re: NBT- My 1970s Muscle bike!

Post by weeksy »

You're the best kind of crazy with your purchases. We taking it out at Pembrey?
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Re: NBT- My 1970s Muscle bike!

Post by mangocrazy »

I'd never realised just how much of a copy of the CB72/77 that SF2 motor is. Does it even have the centrifugal oil filter? Lovely looking bike - enjoy!
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Re: NBT- My 1970s Muscle bike!

Post by Demannu »

Goy-juice
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Re: NBT- My 1970s Muscle bike!

Post by Tricky »

mangocrazy wrote: Mon Sep 18, 2023 9:28 pm I'd never realised just how much of a copy of the CB72/77 that SF2 motor is. Does it even have the centrifugal oil filter? Lovely looking bike - enjoy!
Cheers- RE the oil filter, thankfully no, it has a (sort of) more conventional one - a big cylindrical non-disposable gauze thing in the sump, but that's it as far as oil filtration goes.

I put a (compulsory for a pre-1980 bike IMO) silver and black pressed ally number plate on it a week or so back, but that's as far as I've gone with it so far due to other things getting in the way, but it's going to get some serious garage time today (and tomorrow if needed) to sort the low speed running, secure the battery mounting, and any other jobs I discover as I go through it so more to follow in this thread over next few days
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Re: NBT- My 1970s Muscle bike!

Post by Tricky »

A couple of hours in the garage yesterday had the old girl running beautifully- the carbs or at least the float bowls are fairly accessible on it and easy to remove with the carbs in place, so that’s what I did as a first pass, with the idea that I’d remove all the accessible jets and the air screws, blow it all through with the airline and see if that cured it before taking the carbs off and breaking out the ultrasonic bath.

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I ended up taking the tank off anyway to chase through the wiring ( the horn wasn’t working) , which gave me flashbacks of my old Morini 3 ½ and the absolutely atrocious quality of the loom and connections that had, but although the Laverda is still, well, 1970s Italian build style, it’s appreciably better in terms of the quality of the wiring, switches, and other components, with all of the ignition system and dynamo being Bosch, and switches etc being 1970s Nippon Denso/Suzuki

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The horn fault turned out to be the contacts in the button itself, which I managed to sort with a bit of 1200 wet&dry and a new small washer, but the ancient (Fiamm) relay, although working fine, is looking a bit corroded and scabby and is visible as it sits down between the horns so that will get replaced over the coming weeks.

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Underneath the tank, the paint and state of the wiring and cables etc is generally good, with just a slight bit of paint lifting on the RHS of the frame paint, so was pleasantly surprised with what I found.
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And while it was on the bench, I changed the plugs and checked the points and ignition timing.
The points themselves looked in decent nick, so they got a clean and the gaps set, after which I checked and slightly adjusted the static ignition timing;- slightly irritating process on this bike as the points are on the opposite end of the crank to the timing marks so you have to walk backward and forwards when adjusting then re-checking, but not exactly the end of the world, and is all done.

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And after that little lot, I secured the battery with some off-cuts of wood and a new rubber strap, whacked the tank back on, and hit the button :-)





How cool and just dripping with manliness is this bike eh 8-)

And then took it out for a very pleasurable 30-40 miles around the B roads here.
it rides just so well for a nigh-on 50 YO bike- ticks over beautifully, and will pull smoothly from under 2k in top gear, if you want with no coughing, shaking or shuddering, quite astounding really.
And no oil leaks anywhere - we take that for granted with modern bikes but pretty much every 1970s Brit bike leaked from multiple places even when brand new) :roll:

Yeah the riding position is quite, sort of quaint with feet seemingly a long way forward (may look into rearsets), and the front brake requires a vice-like grip ( that will be sorted very shortly with a swap to a non-OE smaller bore MC), and it vibrates a bit, but less than I was expecting TBH and it performs well- I didn’t go over 80 on this ride (4k in top is ~ 75 on the speedo) , and doubt I will often, if ever as that really isn’t the point of it, but it felt like there was plenty more to come, and overall it is really quite impressive when we compare it to its peers.

I guess riding this gives me the same sort of feeling that Potter gets with the Rudge, and Savio with the Hipster Harley- just makes you feel good - am very happy and she’s a keeper!

Oh and the cows I met on my ride seemed to like it too- doubtless attracted by it’s excessive levels of beefy manliness! :lol:

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Re: NBT- My 1970s Muscle bike!

Post by weeksy »

You're a clever/skilled boy... Impressed !
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Re: NBT- My 1970s Muscle bike!

Post by mangocrazy »

Top banana! That's looking and sounding very sweet. The only thing that triggers bad old memories are two sets of contact breaker points - I used to dread having to adjust the points gaps on my CB77 - it was a nightmare to get right.
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Re: NBT- My 1970s Muscle bike!

Post by ogri »

Probably vibrates less than the xs, well done :)
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Re: NBT- My 1970s Muscle bike!

Post by Skub »

Looks and sounds lovely.

There's something very satisfying about older bikes,a level of involvement we had forgotten. We all want our bikes to be reliable,handle well and all the rest,but in doing so there's some fundamental aspect of biking which is lost.

Some of it may be rose tinted goggles and deliberately forgetting the shitty parts of bike ownership back in the day,but perhaps in our striving for perfection,it's also a case of 'be careful what you wish for'.
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Re: NBT- My 1970s Muscle bike!

Post by Rockburner »

Fabulous!

Hope to see it out and about at some point! (we're close to needing to do a classic bikes RTTL meet up.... although I'm not sure we have enough vans...)


BTW - in the video - the chain drive on the RHS of the engine wasn't running.... What's that driving? (I don't know these engines well - how many things are being driven off the crankshaft?)
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Re: NBT- My 1970s Muscle bike!

Post by Lutin »

Rockburner wrote: Tue Sep 26, 2023 11:38 amBTW - in the video - the chain drive on the RHS of the engine wasn't running.... What's that driving? (I don't know these engines well - how many things are being driven off the crankshaft?)
I think that you'll find that's the starter motor drive to the crank.

Great bike! Looks like you've got a real corker there. Look after her.
Blundering about trying not to make too much of a hash of things.
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Re: NBT- My 1970s Muscle bike!

Post by Rockburner »

Lutin wrote: Tue Sep 26, 2023 11:46 am
Rockburner wrote: Tue Sep 26, 2023 11:38 amBTW - in the video - the chain drive on the RHS of the engine wasn't running.... What's that driving? (I don't know these engines well - how many things are being driven off the crankshaft?)
I think that you'll find that's the starter motor drive to the crank.

Great bike! Looks like you've got a real corker there. Look after her.
Ah - right - that would make sense! :D
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