Laverda 750 SFC 1974 replica

if that was an acceleration type dyno, you can add roughly 10% to that to find engine power (so roughly 90HP).

Friend owns a 750 SFC that had a complete re-design of the internals with several hundreds of working hours of the owner on the engine alone. That one pulls - I think, but Piet can confirm - 92 HP on a braked type dyno, still with Dell'Ortos. By far the most powerfull Laverda 750 twin engine of the Breganze times I have ever seen. My 110 HP Jota had a hard time keeping pace with him during acceleration on a german Autobahn...  :o Might have to do with weight, too, as he is a very sporty 78 Kilo guy while - err....- my Jota is to heavy...  :-[
 
Today i was making spacers for wheels

dsc01561.jpg
 
Dellortoman said:
A few days ago, I ordered some dirt cheap coils from China. It'll be interesting to see if they work, and if they do, how long they last. Not expecting much, but for about $10 each they're worth a try. What could possibly go wrong?  :D
Click to expand...

Well, the cheapo Chinese coils I bought on ebay were completely useless. Although they did actually produce a spark, it was such a dismal, barely visible little spark that it wasn't strong enough to ignite the fuel mixture.

As a comparison, I hoooked up an old TEC coil and it made a big fat spark. The engine fired on first press of the starter button.

I've actually had a few wins with cheap stuff from China, but the coils weren't one of them. So if anyone is considering trying the cheap coil option, don't bother. I've consigned the ones I bought to the rubbish bin.

Cam
 
Any info about grey carbs ?? looks same as stock laverda 36mm carbs except float bowl  and MS letters + ''chromed'' sliders

dsc01821.jpg

dsc01831.jpg


Sliders have lead weights in them ?? not original but there any positive side about weights?

dsc01861.jpg

dsc01881.jpg

dsc01891.jpg
 
I know that i don't intend to use them i'm just curious why somebody put them in there??  What do you get with heavier slides?

I'm searching on internet but i can't get any info about those carbs?  http://www.ebay.it/itm/2-St-Dellorto-Vergaser-PHF-36-MD-MS-neuwertig-NOS-Ducati-Kowe-Laverda-750SF-/151647738170 

One has md stamped on it second one has ms
 
ludiluka said:
I know that i don't intend to use them i'm just curious why somebody put them in there??  What do you get with heavier slides?

I'm searching on internet but i can't get any info about those carbs?  http://www.ebay.it/itm/2-St-Dellorto-Vergaser-PHF-36-MD-MS-neuwertig-NOS-Ducati-Kowe-Laverda-750SF-/151647738170 

One has md stamped on it second one has ms
Click to expand...

To stop the slides sticking open I imagine?
Paul
 
Another question i have two sets of sliders 60/1 and 60/3  i noticed that there is difference in pump action 60/3 has more linear motion than 60/1

How does this effect engine? what is better for racing? if my logic is correct 60/3 is better or am i wrong??
 
ludiluka said:
Sliders have lead weights in them ?? not original but there any positive side about weights?
Click to expand...

We used to do a similar thing on the speedway bikes, not as crudely though.

Theory was that if the cable broke she'd shut down real quick. Slide spring tension was always super light. We used to call them: Rat-traps.
 
ludiluka said:
Another question i have two sets of sliders 60/1 and 60/3  i noticed that there is difference in pump action 60/3 has more linear motion than 60/1

How does this effect engine? what is better for racing? if my logic is correct 60/3 is better or am i wrong??
Click to expand...
Correct me if I'm wrong, but SFC's never came with pumpers - take out the plunger rod and throw them away - I just tossed the ones from the SF1 I rebuilt and noticed zero difference. Racing - even bigger waste of time - and they increase resistance on an already overly heavy throttle action.

I made up bronze slides and had them hardchromed for my Dells when they wore out (bored out the carb bodies). Much lighter action, much less friction, no wear. Unfortunately I made them 70 cutaways, and need to make newies with variable cutaway ... but now I have FCR Keihins to fit, it's all irrelevant!!
 
Correct with one exception, the 1973 works SFCs had PHF carbs, but for 1974 they switched to non pumper PHB carbs.

Marnix
 

Attachments

  • 2014-12-26 15.48.16.jpg
    2014-12-26 15.48.16.jpg
    114.3 KB · Views: 92
I will keep those carbs for now because i got them cheap :D maybe i will later change them for mikuni rs 38

I have to figure it out what jets i need for 900ccm ??

current setup
Pilot jet
65
Choke jet
75
Main jet
160
Needle jet
265 AB
Needle
K3,
slider 60/3
 
Get hold of a setup guide for Dellorto carbs. Surely find it on the net. They are about as simple as a carb gets. Start at the idle and work your way up. I am deaf to the pumper crowd and would not fit levers. The 60 slide is a good starting point. The 265 needle jet is about std for every bike with these, and the choke is not a fine tune item. With std K2 needles (SF1-3) anything over 160/165 is restricted by the K2 (run without main jets makes no diff. K3 are richer, your big motor may need them, and main jet is the danger area. Best to start at about 170 and work down, remember richer is safer. Pay for dyno time and save yourself a lot of risk (if you can find one that can set up non FI).
Is your build getting close to that stage?
 
You must log in or register to reply here.
Back
Top