New owner with a 1971 750..

O

OTR002

Junior member
Location
Brisbane, Australia
Hi all, I've just purchased my first Laverda and I'm getting it ready for it's roadworthy (Brisbane, Australia) and fitting indicators. The wiring in the head light is somewhat...rudimental with three-core flex and gaffer tape amongst other issues. I have a few requests of the knowledge base to help get this 750 back on the road asap!

Interesting!
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What is this?
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I've seen the ignition cover and spring available new, would someone have a set in Australia, good second hand would suit the bike


I do need a fuse cover once again good second hand is great.Yep i'll be getting to this, nice spare fuse and O'rings.
VLV37nul.jpg


Cheers
Rod
 
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Nothing very much wrong there.
Replica Bosch type fuse boxes are available easily or install a blade type fuse box.
Are indicators mandatory on a bike like that over there?
Paul
 
That in pic 2 with an earth wire and an active wire (to the brass tang) probably went to a parking lamp globe holder. Another couple of globe holders floating around in there too, probably from warning light in the headlight shell. The wiring diagram for this model is readily available, very simple and quite ok as long as the terminal contacts are good. If it were me I would damn the riveteers and fit a modern spade fuse box. Blinkers not required at this age, but might be handy in traffic.
 
The Green Book contains schematics for the 750GTL and the 750SF- PM me and I'll email you those if that will help you. DAM Classic Racing is in Australia and has lots of Laverda parts
 
Tippie said:
That in pic 2 with an earth wire and an active wire (to the brass tang) probably went to a parking lamp globe holder. Another couple of globe holders floating around in there too, probably from warning light in the headlight shell. The wiring diagram for this model is readily available, very simple and quite ok as long as the terminal contacts are good. If it were me I would damn the riveteers and fit a modern spade fuse box. Blinkers not required at this age, but might be handy in traffic.
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Thanks mate, I wasn't sure what it was and as you guessed correctly it aligns with a hole for a parking light! as for the rest it's a mess so will be fixed and corrected as i go.
Cheers R
 
Well it's registered and will get its first test ride Monday or Tuesday, I'm hoping it'll go well and behave. Oil cleaner run through the engine, filter cleaned and a rare earth magnet place inside to catch any metallic bits. Carbs cleaned, synced and balanced, fresh fuel and all fingers crossed. I've cleaned up the wiring so it works and will tackle its repair/rebuild later in the cooler months.
Just need to give it a good clean, polish and ride it!!
 
Well the test ride was great fun. There was some buzzing through the foot pegs initially but it seemed to go after a few K's and then the neutral light started working!!

Issues..
The throttle is quite stiff and overly sprung, I have a Guzzi with the same carbs and its throttle is quite smooth and well sprung. I was looking at adding some 90deg bends at the carb top and maybe ditching the single to twin pull cable for a twin pull throttle, anyone done this or is there a better way?

The regulator is playing up, the light will sometimes go out till around 3000rpm then come back on again! but at others time will not go out. I put a multimeter on the battery and it's charging 12.54V at idle then 12.88 at 3000rpm, but the ignition light stays on all the time now. It seem to have a regulator issue.
Before i start spending $ on a new regulator is there any special tricks people have done to up grade the charging system?

lastly did they ever make KPH Smith speedo's? The popo's are a little savage around here!
 
I think there are 3 different carb springs with varying strengths you can get. At 4k it should be closer to 14volts. Sounds like you gelling with the bike. Check the yellow wires down on the alternator for rotting insulation. Were in Oz are you
 
Great to get it out on the road, it doesn't sound like any major issues.
With the charging light coming and going and fairly low charging volts it would be an idea, especially seeing the state of the wiring generally, to go over all the connections related to the charging system, and the bike generally going by the neutral light thing. There isn't much to the charging system, it is easy to trace from the wiring diagram. The generator light has power to one side of the lamp and it "earths" through the regulator. It is also vital that the earth wire to the regulator itself is good.
There are links to thoroughly testing the generator output if you do a search. That said it is fairly common that the regulator itself is the weak link. Make sure also that the belt is good, on my SF once it turned out that the belt that felt tight was actually slipping. Those little LED volt meters are dirt cheap and might be a good idea to fit at least while you are sorting it out.
On an SF with PHF need you to almost dislocate your wrist to get full throttle and don't suffer from being too stiff, but someone else can shed light on how it is with your square slides. The cables need to be in good condition regardless. There is no point introducing another bend, the straight lift as standard is fine, as is the system with he splitter and single cable to the twist grip.
 
OTR002 said:
Well the test ride was great fun. There was some buzzing through the foot pegs initially but it seemed to go after a few K's and then the neutral light started working!!

Issues..
The throttle is quite stiff and overly sprung, I have a Guzzi with the same carbs and its throttle is quite smooth and well sprung. I was looking at adding some 90deg bends at the carb top and maybe ditching the single to twin pull cable for a twin pull throttle, anyone done this or is there a better way?

The regulator is playing up, the light will sometimes go out till around 3000rpm then come back on again! but at others time will not go out. I put a multimeter on the battery and it's charging 12.54V at idle then 12.88 at 3000rpm, but the ignition light stays on all the time now. It seem to have a regulator issue.
Before i start spending $ on a new regulator is there any special tricks people have done to up grade the charging system?

lastly did they ever make KPH Smith speedo's? The popo's are a little savage around here!
Click to expand...
I don't think that there are alternate carb springs for the VHB carb.
For your charging light, check the wiring and connections first. Check voltage out of the dynamo, I forget the figures but you should get quite a high voltage.
The regulator can be cleaned up. Open it, there is a points system inside. The points can be cleaned up.
As Tippie says, check the dynamo belt, if it slips at certain revs, the charge light will come on. You can't upgrade the charging system, it's perfect.

I have planned to put a twin pull throttle on one of mine, to address synch problems, not a heavy throttle. I know a few people who've gone down that route. If, with perfectly routed and lubed cables, you still find the throttle heavy, which you shouldn't, you'll have to cut back the slide springs.

Paul
 
Tippie said:
Great to get it out on the road, it doesn't sound like any major issues.
With the charging light coming and going and fairly low charging volts it would be an idea, especially seeing the state of the wiring generally, to go over all the connections related to the charging system, and the bike generally going by the neutral light thing. There isn't much to the charging system, it is easy to trace from the wiring diagram. The generator light has power to one side of the lamp and it "earths" through the regulator. It is also vital that the earth wire to the regulator itself is good.
There are links to thoroughly testing the generator output if you do a search. That said it is fairly common that the regulator itself is the weak link. Make sure also that the belt is good, on my SF once it turned out that the belt that felt tight was actually slipping. Those little LED volt meters are dirt cheap and might be a good idea to fit at least while you are sorting it out.
On an SF with PHF need you to almost dislocate your wrist to get full throttle and don't suffer from being too stiff, but someone else can shed light on how it is with your square slides. The cables need to be in good condition regardless. There is no point introducing another bend, the straight lift as standard is fine, as is the system with he splitter and single cable to the twist grip.
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Tippie, the bike is a 71 SF with the 36PHF's, I'll pull them off and do a full clean and lube if that doesn't cure the stiff pull, I may just fit a twin pull Tomaselli throttle.

I did check the belt and it seems tight, but i'll now do a more involved test of the belt and test the generator at the same time. I did laugh to myself when riding as I had thought that the belt was slipping, strange to say the belts slipping on my bike!

The regulator is the original 1971 one as fitted so may just need to be tossed and replaced with new parts, but i will do a full test first. I do like the idea of fitting a volt meter..

Cheers
 
Paul Marx said:
With square slides.
No alternate springs available to my knowledge.
Paul
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Paul, it an SF with PHF's. It looks like I'll need to strip the whole assembly, throttle, cable and carbs and give them a good clean.

This is my first Laverda and I'm just learning it's quirks! But it did pull hard to 90mph until...
 
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71 SF wouldn't have come with 36mm pumpers. It should be a 'small-valve' head with 32mm square slides, smaller inlet ports and valves and a more horizontal intake angle on the inlet port than a later 73-76 SF1/2/3. No need to toss the reg, as already mentioned. They are a repairable item.
 
piranha-bro2 said:
71 SF wouldn't have come with 36mm pumpers. It should be a 'small-valve' head with 32mm square slides, smaller inlet ports and valves and a more horizontal intake angle on the inlet port than a later 73-76 SF1/2/3. No need to toss the reg, as already mentioned. They are a repairable item.
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This was a question I was getting to, is there any way to identify if a bike was an GT, S, SF etc from factory.

My engine and frame numbers (matching) list the bike as 1971 and it was sold new in England. From what I've read these were sold in kit form in the UK (Wikipedia) so were they also modified at that point or as I suspect, it's over 50years old and has been upgrade throughout its life.
 
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