Laverda 750 sf2 doesn't start

Once i had a triple that constantly wetted one plug, yet it had spark and obviously fuel..... incorrect shim fitted to the suspect cylinder, the owner had ridden the bike to me ( on two cylinders for over 100kms ) the inlet valve was held open by 0,1m.m ie compression though very low as it cranked. Basic checks will as ever yield answers to what appears as "weird" no fault is ever weird, it is based on engineering and combined issues. HTH j.
 
I think you’re already on the right path, keep investigating the lack of vacuum 👍
I know it was running when it was put away, but you could still have stuck valves or split intakes?
 
If the bike was running when it was put away, it should run.
If it doesn't, it's dirty carbs.
Or that electronic ignition thing, particularly if you've rewired it.

Paul
 
Wido Veldkamp said:
Already tried this, no luck. It just doesn't suck in fuel some how
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Odd that both cylinders are not getting fuel at start up. It should at least run a bit using aerosol spray. If the cylinders are getting air through the carbies 'correct compression' but no fuel then I would be looking at blocked carby jets.
If the cylinders are not getting air through the carbies 'low or no compression' then they won't be sucking in fuel either. I would be looking at the valves opening and closing correctly.
Your exhaust system looks nice.
 
BlackJota said:
Odd that both cylinders are not getting fuel at start up. It should at least run a bit using aerosol spray. If the cylinders are getting air through the carbies 'correct compression' but no fuel then I would be looking at blocked carby jets.
If the cylinders are not getting air through the carbies 'low or no compression' then they won't be sucking in fuel either. I would be looking at the valves opening and closing correctly.
Your exhaust system looks nice.
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Tnx i'll have another go at it tommorrow. Thanks everybody for the suggestions
 
A good first move here, dry cylinder compression test on both cylinders. Wide open throttle dont forget, ground out the plug HT leads or disable ignition circuit. j
 
Ok think i found the issue....my dad has Alzheimer, and somehow he taught it was a good idea to put some paper underneed all the valve covers.....but now i noticed that one of the valve adjustment screws was broken. Back at it tommorrow
 

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Looks like you may have found the problem .......

With ref to the plugs staying dry I was wondering what the response was if you tried the " choke " full on with the throttle closed ....... the starting circuit should allow fuel through , by passing the pilot and main circuits completely ...... hopefully doesn`t matter now ......
 
Paper under the valve covers? Never heard of anyone doing that before. I presume that's only when the bike is laid up for a long period. Perhaps to absorb moisture?

PS: Considering that the scrunched-up paper has busted one of the valve adjusters, it might pay to check for bent pushrods too.
 
motoddrob said:
it might pay to check for bent pushrods too.

Push rods ???????????
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Sorry. I was getting confused. Been working on my Guzzi :rolleyes:
I was thinking of the wrong end of the rocker too. Having a senior moment I reckon.

Actually, my mind is somewhere else today. I'm a bit stressed about my cat. He's at the vet being operated on.

Anyway, now that I have a mental picture of the correct engine (I think), I doubt that the busted rocker adjuster would have prevented the bike starting. The valve wouldn't necessarily have been so out of adjustment that it wasn't opening. That would only affect one cylinder anyway. Perhaps Quentin might be on the right track. Valves not fully closing so it's not making any compression. Was there so much paper in there that it was holding the valves open? It would have to be jammed in pretty damn tight. Still got no clue what the paper was for.
 
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Andy said:
No. Neither did his Dad. Alzheimer's is the absolute worst.
My Dad's got it too...
Hope I take after Mum!
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Alzheimer is terrible... but a small side note. The engine was removed from te bike because 2 mounting points of the frame were broken. Still dont understand why, but i assume he did put in the paper to prevent any junk from coming into the engine. The mind gets pretty f*cked up by the Alzheimer. But we keep working at it and I'll keep you updated tnx
 
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