new member with a 750 - random musings, questions & updates. :)

How old is the rear tyre? I'd be replacing that long before I saw cracks in it! Tyres deteriorate over time, even if they look fine. My philosophy is to never compromise on tyres.
When I got mine going after thirty odd years standing I of course went round the block on it. Tyres & tubes were knackered, both brakes had clamp on nipples on cables but the brake shoe linings were hanging off the shoes- fell out when I took wheels out. Check/ change all safety items before riding . My scooter had 3 puncture repairs on front tube!
 
How old is the rear tyre? I'd be replacing that long before I saw cracks in it! Tyres deteriorate over time, even if they look fine. My philosophy is to never compromise on tyres.
I agree! In this case the rear one is from 2020 and about ~40% worn off I'd estimate. The front one was outright dangerous... According to the dot code it was from 2006 and had dry cracks pretty much everywhere. On top of that the inner tube was ancient as well, when removing it the valve simply fell off. The bike was not used for a few years, so this was already old when it was put away. The idea was probable not to store it with a new tire, but replace it when it would become in use again -which I'm now doing. Didn't want to drive it anyway with a front tire that old. New BT46 & inner tube are fitted now, just need to get the wheel back :)
When I got mine going after thirty odd years standing I of course went round the block on it. Tyres & tubes were knackered, both brakes had clamp on nipples on cables but the brake shoe linings were hanging off the shoes- fell out when I took wheels out. Check/ change all safety items before riding . My scooter had 3 puncture repairs on front tube!
We checked the chain, brakes, cables, fuel lines, etc -all are still in good order (or fixed/replaced), except for that leaky old SF tank and the ancient front tire. Brake linings look great, according to my dad they were not that old and fitted to the drum with a lathe. Sometimes it helps if a bike stays in the family and you know it's history... Hopefully in the next week or so when I get the wheel back & have flushed the GT tank (& fitted it) I can finally sit up front rather than at the rear as I did for so many years! :)
 
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BTW, I got an admonishment from my oldest son (13)... I replaced the old brake fluid on my wife's CB500 (PC32); but had to change the oil too. Started it up and let it run for a little, then dry-tested the brakes, hopped on (private pathway) in my overalls w/o helmet to warm it up and test the brakes carefully.

He (correctly!) called me more or less a fool for riding the Honda in my overalls, without gloves, helmet and whatnot, to test the brakes I just fixed. Agreed with him; he made me promise not to do that again ;)
 
So, last week, with a few days off and gorgeous weather we finished up the last jobs -at least I hoped we had. After the oil change (and cleaning the magnet my father installed in the filter) the cover leaked so today i cleaned everything spotlessy, re-drained the oil, cleaned everything up again and used a good sealant to aid the gasket. Not sure why it leakes, but according to Gijs van Dijk the covers often miss a corner and are sometimes malformed. Not a huge fan of sealant, but it is what it is. At least seems, so far, to be leak free.

I also swapped the fuel taps from the leaking SF tank to the GT tank, but afterwards they leaked a bit as well... Read somewhere on the forum here fibre rings can be found at hardware stores so got some fitting ones, cleaned everything again and re-installed the taps. Filled the tank up with a few litres of fuel again, seems to have worked so far but tomorrow I'll be pretty sure -they did not leak at first it seemed but next morning they were moist with fuel. Not a massive leak fortunately, and even more fortunately, not tank itself...

And speaking of tanks, picked this one up after a 300km single drive... It's been restored but does not seem welded, it does have relatively heavy coat of paint (and is clear coated) but a magnet test felt the same as on the original orange one so it doesn't seem to have been filler smeared and painted quicky for quick money. Still a lot of money, whether it is expensive or not I don't know, I do know having the orange tank fixed was going to cost anyway... only disadvantage is that I did not get to choose the colours -the bike was blue before the accident and had the orange tank afterwards. Might need some getting used to -reminds me of my Guzzi V50 former Italian Police bike, but it seems to have been done decent enough. The blue is painted by the way (and really nicely/symmetric) For now it's going in storage while I look at the rest & fit the GT tank for now. If that Spanish gallion wreck loaded with gold ever turns up in my backyard (we live on former seabed, "polder")... who knows :)
 

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Bit of a continuation from this bit, started here, but don't really want to mess up the photo thread with more bull ;)

So, yesterday went out with my oldest son (13). There was still some old fuel in the tank, but it was nearly empty so I filled it up with new BP ultimate or whatever the oil companies marketing departments call their own brand of 98 octane stuff and added some lead replacement stuff. When riding does not seem to make much, if any, (subjective) feel-able difference, for what's that worth. Still runs nice when driving, vibrations about the same as my BMW. I'm sure there's a scientific explanation for it which I don't know, but it was warmer yesterday than last week, had new fuel, or whatever else, it seemed to run a bit faster at idle (~1000rpm) which makes it a bit smoother for want of a better word.
As Paul noted in that other thread, if you do revv on the stand it'll walk away indeed.
Went along my dad yesterday during the little tour, showed it to him, and as far as he's known the bike it's always been like this vibration wise. But he has one of those ignition timing lamps & carb sync meters so we'll be doing some tuning up just to be sure.

I noticed the bike got more noisier -turned out the exhaust clamp on the damper was getting loose. Didn't really measure trip distance this time, just went left, right, hey look there, until we got to the fish restaurant I'd made our destination. Had some fish, talked some, hopped on a again and went home via a similar touristy way in an area where I grew up. Really growing to like the bike -corners really nice even if driven touristy, pulls when needed, and the shorter GT tank/seat gives a bit more room when taking someone on the back. Oldest likes the seat/footrests, took him a few times earlier on my wife's Honda, that has a more stepped seat & higher footrests. Gives him a better view over my shoulder, but more wind and the knee bend isn't that comfortable. However, if I keep the GT seat on, it'll definatelty need some new foam, as the 1971 stuff in there now is still in my arse's shape after 15 minutes.
Forgot the photo's but was a nice morning out :)
 
Bit of a continuation from this bit, started here, but don't really want to mess up the photo thread with more bull ;)

So, yesterday went out with my oldest son (13). There was still some old fuel in the tank, but it was nearly empty so I filled it up with new BP ultimate or whatever the oil companies marketing departments call their own brand of 98 octane stuff and added some lead replacement stuff. When riding does not seem to make much, if any, (subjective) feel-able difference, for what's that worth. Still runs nice when driving, vibrations about the same as my BMW. I'm sure there's a scientific explanation for it which I don't know, but it was warmer yesterday than last week, had new fuel, or whatever else, it seemed to run a bit faster at idle (~1000rpm) which makes it a bit smoother for want of a better word.
As Paul noted in that other thread, if you do revv on the stand it'll walk away indeed.
Went along my dad yesterday during the little tour, showed it to him, and as far as he's known the bike it's always been like this vibration wise. But he has one of those ignition timing lamps & carb sync meters so we'll be doing some tuning up just to be sure.

I noticed the bike got more noisier -turned out the exhaust clamp on the damper was getting loose. Didn't really measure trip distance this time, just went left, right, hey look there, until we got to the fish restaurant I'd made our destination. Had some fish, talked some, hopped on a again and went home via a similar touristy way in an area where I grew up. Really growing to like the bike -corners really nice even if driven touristy, pulls when needed, and the shorter GT tank/seat gives a bit more room when taking someone on the back. Oldest likes the seat/footrests, took him a few times earlier on my wife's Honda, that has a more stepped seat & higher footrests. Gives him a better view over my shoulder, but more wind and the knee bend isn't that comfortable. However, if I keep the GT seat on, it'll definatelty need some new foam, as the 1971 stuff in there now is still in my arse's shape after 15 minutes.
Forgot the photo's but was a nice morning out :)
I’ve run mine on E10 - still got original shut off valves in carbs, no difference. I don’t like mine idling too slow, nothing to be gained.
Primary chain adjustment made a huge difference to mine, smoother tick over, better gear changes. All sounds spiffing!
 
I’ve run mine on E10 - still got original shut off valves in carbs, no difference. I don’t like mine idling too slow, nothing to be gained.
Primary chain adjustment made a huge difference to mine, smoother tick over, better gear changes. All sounds spiffing!
Because I'm superstitious, I try to stick to E5 but haven't noticed any difference when using E10.
I found that I had to go down on the idle jets on all my Laverda with high alcohol fuel. They're likely too rich on the main jets, but I'm a country tuner.
I haven't used lead additive for donkey's years.
Paul
 
You don't need lead free additive.
Paul
I remember from contacting BMW regarding this they indicated if it had been running on leaded for a longer time (which it had) it wasn't needed, so I never used it on the BMW.
However, some years ago my 750 had it's head removed and the valves re-grinded after which my father always added the lead additive, so I just assumed it was needed as it had been running on lead for a long time, but the grinding would have removed the coat, film, or whatever it is called.
Are seats etc hard enough even after they have been reground?
I’ve run mine on E10 - still got original shut off valves in carbs, no difference. I don’t like mine idling too slow, nothing to be gained.
Primary chain adjustment made a huge difference to mine, smoother tick over, better gear changes. All sounds spiffing!
I don't mind either -it's not a H-D. My BMW used to run very slow at idle, which made the whole bike go left & right so I adjusted it up. Much smoother now but BMW purists don't seem to agree. Not that I mind, the purists don't like the DellOrto's on it either.
:)
Because I'm superstitious, I try to stick to E5 but haven't noticed any difference when using E10.
I found that I had to go down on the idle jets on all my Laverda with high alcohol fuel. They're likely too rich on the main jets, but I'm a country tuner.
I haven't used lead additive for donkey's years.
Paul
My BMW doesn't like E10 (E95), especially when the weather is warm. (pre-detonation I think it is called in English?) Although that has a (much) higher compression ratio it seems than a 750GT engine. S(F) seems to be nearer to the BMW, but I'll immediately admit I'm not knowledgable enough about the really technical matters... I can imagine there are more variables at play since the BMW works on E10 when it's cold and not when warmer outside.

Might give E10 a try -just to see (feel) the difference. Currently runs nice, plugs are a nice grey-brown-ish colour as well. I'm just not sure what's in the engine parts-wise, in it's long history prior to and under our family ownership it was opened up and rebuilt at least once. (My father specifically advised my not go up a dijk vertically as all the oil moves in the back of the engine... )
It's been a long time but maybe he remembers what is in there.
 
Fiddled with the wiring last week -speedometer light wasn't working due to crumbled wiring, at the same time it turned out after repairing that some other wiring in the headlamp is old as well and due to the fiddling in there some more had come loose or broken off.
Repaired it as best as I could, but I sense building a new wiring loom sometime in the future.
I have the Green Book and a diagram, unfortunately it does not have any colour coding for the early models. Or did the factory just use what they had on hand as well ;)

The blue light for high beam (?) isn't working yet, I since the wiring is OK now, but perhaps it's just a matter of a broken bulb. The light itself is working. Can't be that complicated I think.

However, another thing I've been wondering about is the neutral switch. According to my father the neutral light has never worked (and it's not really needed, too, but....)

Few questions as I like to diagnose the problem first before throwing new parts at something:
  1. Am I correct in thinking, after reading the above, it is located underneath the rhomboid shaped cover underneath the oil sump?
  2. I assume removing the cover and the switch drains the oil. Does this also happen already when I remove the cover only?
  3. Am I correct in assuming the light on the headlamp is ground/minus switched since the switch on the pictures does not seem to have wires o on it and I should be able to measure if it does what it is supposed to be doing (complete a circuit)?
I'd like to know since I can then have a look at the light in the headlamp to see if it's all OK, or if it's a broken switch.
I can accept optical defects, or as Vince put it, Battle Scars, more easily than having technical things on it that don't work :D

Thanks in advance!
 
The neutral switch should be taken out with the oil drained. The cover is just a cover and does not hold oil. The switches can leak through the centre with age, an annoying leak but won´t drain the engine.
On the ND instrument models the high beam pilot is just a wire taken from the high beam circuit to the pilot bulb in the instrument where it is earthed after the globe to the earth wiring under the instrument cover.
 
Thanks! I assume I can measure the switch by removing the cover & see if it completes a an earth/negative circuit? I can then incrementally measure from switch to light to see if I can find the fault if the switch turned out OK.

For the high beam control light, I have the Smiths counters & old BMW-style Bosch headlamp, but the principle would be the same, only small difference would be that the control light is in the headlamp and not in the instruments. Since all wires are now connected how they are supposed to be it can't be that hard to find the fault with that...

Truthfully, the original wiring was completely disintegrated so it was replaced almost fully -my father has many talents... but wiring....However, most of the wiring is functional, but lets say it isn't very consistent colour wise or fitted very neatly ;)
 
Had a look this weekend after looking at the rev counter first and took my youngest son (10) for a ride, his first ever on the back seat of a motorcycle, so it better be the Laverda ;)

Didn't get as much done as I hoped due to a pair of swallows entering my shed, going up the next floor, and not being able to find their way back out again due to the small staircase opening.... eventually with help from my wife and oldest we managed to close them in and they fortunately found their way back out again. :)

  1. high beam control light didn't work due to detached cable -fixed that as mentioned earlier but turned out it was a matter of a broken bulb (when I inserted the small bulb from the headlamp it worked).
  2. Neutral switch cover removed, turned out somebody I know well snipped off the wires and removed the bulb from the control light -spoke to dad about this and turned out the light had it's own mind and it's not really needed so that was that. Switch, when in neutral, shows no resistance to ground as well as in gear, so it's either a bad switch or it does not get actuated properly. I'll leave that until the next oil change so I can remove the switch and measure it out of the bike & see if the actuator pin is there. Perhaps it's just a matter of a thinner seal ring as I read here on the forum.
First 500km are in the books :)
 
Thanks! Yes, he really liked it, we stopped several times to ask how it was going, until we were both getting sore ar$e$ from the 1971 seat foam. He was a little anxious for the first time, but he has done a few years of BMX so has a good feel for speed and balance. :)

Somehow our route ended up with lots of little tunnels and underneath viaducts and somehow the Laverda always requested me to downshift and throttle up there 😆 Went out early Sunday morning and was back by midday to avoid the cyclists, Sunday car drivers, bike carrier crowd, campers and caravans and whatnot.

Might as well get them indoctrinated so as to keep the Laverda in the family 😇
 
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Little update, other than what we and I fixed earlier I put in some new Champion sparkplugs (N2C's). Seems a little bit more eager, on updating my maintenance history it showed I have ridden well over 750km by now, solo and with kids. As I wrote earlier, getting to know it better and better, and loving it more and more -it corners really nice for such and old and fairly heavy bike (reminds me a bit of my V50 but that was much smaller & lighter)
I've finished up the important bits on my R90S as well after a near full rebuild, but having a running bike does kind of remove motivation to finally have ride on that somehow. Wierd how that goes -I haven't ridden the BMW in 10 years, still like it, but somehow I end up taking that ratty looking old Lavada when I go on a ride.

Speaking of ratty, father found a bunch of parts, including nearly new exhaust system from which the previous owner removed all the damping material, but with most of the tech stuff sorted and (other than the neutral switch, fork seals and pretty worn carburettors) out of the way with nice shiny parts coming up (and the tank I got earlier) I'll have to start thinking about what I want to do with it. I don't want to lose the character, but readily admit it does look a bit too ratty now. Some parts will also need new chrome (headlight mounts, mudguard brackets, GT tank luggage rack for example).
With a full restoration it'll lose it's character (and won't be worthwhile probably with all the custom modifications, non-matching numbers, mix of SF/GT parts, etc etc). I don't want it looking too pretty as well, as I won't put the tankbag on and ride around as it damages the paint, and I think not using it as much will be a shame as that's what it was made for in the first place?

But as long as I get thumbsups from white new BMW X5 owners it has charisma and patina enough for now :D
 
Found out the Laverda is not as nicely balanced as the BMW on the stand, so the wheel added some counterweight in case you're wondering wth that wheel's doing there ;) Axle stand with a block of wood under the oil sump.

Fixing the fork seals, my father had an extra fork with nice black powder coated sliders, so I'll put those on as they look much better than these. Had hoped to get it back together today, but I my hex bit is not long enough, and a normal hex key with a spanner in the short end would bend and twist just a bit too much for comfort ;) Shop's closed, so better luck next week. Old fork oil looked more like tar than oil, was probably in the for a ages...

So despite parts at the ready, still massively standing in the way!
fork-wheel-sealfix.jpg
Removed the tank and seat, as I also want to replace the rattly carburettors with better ones while I'm at it.
 
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