What did you do to or for or with your Laverda today?

piranha-bro2 said:
Shaving the head or fitting a smaller base gasket will raise the compression (yes, by reducing the combustion chamber volume) but won't alter the shape. I shaved 1mm from my SF head and ran a 0.15mm base gasket to get 10:25 CR - I'd buretted the chamber and it only had an actual CR of about 8.5:1. Simple way to reduce CR is to fit thicker or two base gaskets. Raising CR and not rejetting raises the risk of holed pistons. I wouldn't have thought 10s in plugs was necessary, but whatever works. I still wouldn't run 8s in an SF unless it was going to be dawdled.
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Thanks, as far as I know no radical changes were made after the rebuild other than a re-setup of jets, ignition, spark plugs, to match the CR etc. Mine has the 2 base gaskets -also had to do with the cam chain tension. Glad it was in that magazine so they measured compression for me :)
Tippie said:
There are many factors to count in when shaving heads or otherwise modifying the top end of an SF. You will have to be very careful if and when you freshen it up. Shaving the head more than a small amount can bring the top lip of the cylinder sleeves in contact with the head surface, which can cause gasket problems. It can also bring the squish band, the flat part around the outside of the piston crown with the corresponding flat in the combustion chamber, under the vital 1mm minimum clearance needed on these motors. It also brings the valves closer to the piston, sometimes causing contact, depending on cam type or timing. Adding more base gasket material helps in some ways but is not the ideal solution. Then the motor needs carburation, ignition timing and advance that suits. There are many things to be measured and checked, it can't just be thrown together with bought parts (your dad had advice from Gijs), but hopefully you will never need to go there. As it is going great and does not appear to have any problems, just enjoy it.
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Thanks! Apparently the engine was thrown together before my father got it, though it did run, for a while anyway (it came from a running GT). But didn't last long with the heavy side car apparenty. It was only after it broke my father found out about all the things that caused it & rebuilt it with advise (and work, e.g. crankshaft) by Gijs. It was many years ago and it has run great all those years after it was correctly set up and maintained.
So other than doing proper maintenance and sacrifice the occasional goat on the Laverda alter (it is now the minimal clearance value, so it can't be shaved any more should it ever need that) to keep it in this shape, there's neither a need nor a plan to open the engine :)

Thanks for explaining, everyday is a school day :)
 
Been having an issue with the ignition on the 71 SF. Would pop and bang, often cut out under load.
Did all the checks, valve clearance, carb balance, ignition timing ( Boyer) and spark plugs ( NGK B9ES).
Mate up North recommended to try Champion NC3 instead of NGK.
All problems resolved, no popping or banging, pulls like a train.
Bad batch of NGK sparkplugs?

Gerald
 
Gerald said:
Been having an issue with the ignition on the 71 SF. Would pop and bang, often cut out under load.
Did all the checks, valve clearance, carb balance, ignition timing ( Boyer) and spark plugs ( NGK B9ES).
Mate up North recommended to try Champion NC3 instead of NGK.
All problems resolved, no popping or banging, pulls like a train.
Bad batch of NGK sparkplugs?

Gerald
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Hi Gerald, did you buy online or at your dealers shop? You find a lot of fake NGK spark plugs in www.
www.ngkntk.com

Fake or not?

How to identify counterfeit spark plugs: Check these 5 features: 1. electrode, 2. cutting marks on caulking, 3. Smudges, 4. LOT number, 5. c-groove marks
www.ngkntk.com www.ngkntk.com

Ciao, Gert
 
lavgert said:
Hi Gerald, did you buy online or at your dealers shop? You find a lot of fake NGK spark plugs in www.
www.ngkntk.com

Fake or not?

How to identify counterfeit spark plugs: Check these 5 features: 1. electrode, 2. cutting marks on caulking, 3. Smudges, 4. LOT number, 5. c-groove marks
www.ngkntk.com www.ngkntk.com

Ciao, Gert
Click to expand...
Gert,
Online from a dealer I have been using for a long time.

Gerald
 
Yesterday, actually.
Balanced the carbs. I had bought a triple set of gauges from Davida many years ago. I finally got around to using them last week.
Clem's reservations about multiple gauges were justified. Two of the gauges were close, the third reading much less. I was able to establish, by switching the hoses that one was indeed duff. Unfortunately, by then, I had put the adjustment way out.
So, I bit the bullet and ordered a new Morgan Carbtune Pro 4. It requires a little fettling: cutting and fitting damper tubes in the hoses, but they did their job and the carbs are back where they ought to be.
It's time to replace the original Dell'Ortos with a set of Keihins.
If Keith's consumption claims are correct, the switch should pay for itself within a couple of years.

Morgan Carbtune Pro 4 column throttle body carb synchronizer.jpg
 
The Sock said:
Yesterday, actually.
Balanced the carbs. I had bought a triple set of gauges from Davida many years ago. I finally got around to using them last week.
Clem's reservations about multiple gauges were justified. Two of the gauges were close, the third reading much less. I was able to establish, by switching the hoses that one was indeed duff. Unfortunately, by then, I had put the adjustment way out.
So, I bit the bullet and ordered a new Morgan Carbtune Pro 4. It requires a little fettling: cutting and fitting damper tubes in the hoses, but they did their job and the carbs are back where they ought to be.
It's time to replace the original Dell'Ortos with a set of Keihins.
If Keith's consumption claims are correct, the switch should pay for itself within a couple of years.

View attachment 97545
Click to expand...
Nice one Hamish,I use a Morgan Carbtune too brought mine second hand from a guy who had 2 sets that he used to tune some V8 engined Capri up with.Anyway he was happy to split the pair up and sold me one.

First thing I did on receipt was to overhaul it and polish up the rods,next thing was to down load a user manual that stated "do not polish the rods"!! :unsure:
I found out its a lot harder to make things dirtier than cleaner.

Keep us posted and good luck on the Carb change, are you going standard size?
 
Speaking of spark plugs, those B10s my GT has are special order which I'm not too fond of. Local guy (mostly mopeds/scooters) has Champion & a conversion table, but was wondering if something more common can be fitted to my bike with it's history of non-standardisms...
Champions in that range are also special order & may take a while.

Any advise? I can of course order B10s & keep the current ones as spare, but something more common may not be a bad idea.
Pistons are as far as I know standard GT type but compression ratio is ~9:1
 
"First thing I did on receipt was to overhaul it and polish up the rods"

Not like you to polish things, Steve😉

Keep us posted and good luck on the Carb change, are you going standard size?

Mine’s been on OEMs smooth bored to 36mm by Phil Todd, when he Motodded the engine back in the ‘80s.
Prepared by Motodd.JPG
 
Finally my spares arrived yesterday for the Jota after a supply chain issue with the couriers.
New seals fitted to both legs,secured and re assembled,so much easier leaving the stanchions in place this time round.
Wheels,calipers and mudguard were next, wheel partially tightened until forks could be relied on for brake centering.
Both fork legs topped up with 10W weight fork oil,the most fiddly part of the job really as the handlebars need to be removed along with the clocks in order to remove the fork caps and the fairing makes it a little restrictive on space.

Fully assembled,bounced on and check tightened she's now back on her legs and ready for that all, important test ride 😎
 

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Yesterday, rode the 1969 750 GT 1.5 hours down to The Ged at GCS, cruising at an altitude of 5000 feet to avoid motorways. Beautiful sunny day. Fantastic ride. Did the whole ride in comfort thanks to the sheepskin seat cover.

So, the GT is getting a post run-in oil change, service, shake-down check and tighten up, with various parts being fitted. Namely, the Clem 'easy clutch' now with casing brought back to factory cast spec - minus inspection hole and looking very purposeful - please see pics.

Plus, new as in re-chromed 'teak infused' original luggage rack (pic) to be fitted. Engine protection bars, with Halcyon mirrors on stalks, as the Halcyon bar-end mirrors just don't suit and detract from the wide touring bars. Longer reserve fuel filters from Shaun. New grips to replace the ones that have been cut about to take mirrors.

As Ged said when chatting with him yesterday, the GT is not a pretty bike but this somehow makes it more appealing in a way. If it were a child, it would be one that only a mother could love.

adbe6326c23924290a48f268c474cde4.JPEG44497844-4C29-494D-92DA-4A056420498D.JPGIMG_3882.JPG
 
jko_78 said:
Speaking of spark plugs, those B10s my GT has are special order which I'm not too fond of. Local guy (mostly mopeds/scooters) has Champion & a conversion table, but was wondering if something more common can be fitted to my bike with it's history of non-standardisms...
Champions in that range are also special order & may take a while.

Any advise? I can of course order B10s & keep the current ones as spare, but something more common may not be a bad idea.
Pistons are as far as I know standard GT type but compression ratio is ~9:1
Click to expand...
Running 9:1, is there a reason you want to run 10s??? Or have we discussed this already? Surely 9s would be fine? i've run 10.5:1 on 9s, zero issues.
 
piranha-bro2 said:
Running 9:1, is there a reason you want to run 10s??? Or have we discussed this already? Surely 9s would be fine? i've run 10.5:1 on 9s, zero issues.
Click to expand...
Lean it out far enough and one might even NEED 10's... :rolleyes:

Should run fine with Champion N3's/NGK 8's if carburation is correct, N2 if compression has been raised. Most SF1-3 cope quite OK with Champion N3 for tootling around, N2's should be considered for hooning high-speed use.

piet
 
"Mine’s been on OEMs smooth bored to 36mm by Phil Todd, when he Motodded the engine back in the ‘80s."
realy! 36mm bores on standard 32mm bored PHF's??? my memory was that this cant be done, (half moons of fresh air showing left and right of carb slide) did you mean 34? typo?
CLEM
 
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