RODS !
The FP & FSR 40 ( & FSR 45 & LA 46 ? ) Con Rods Are all the same .
The VF Rod is Longer by 1/2 m.m.
Im thinking the FS Rod is the 34.5 mm one, as per VF . But unsure on that .It IS the FSR / FP bush bore size match though . The VF Rod ISNT .
So theres a choice on ' factory ' rods , anyway .
BUT , With the ' Two Port ' Liner , a Wedge Chamber'd get you a 46 Ball race ' Big art ' ish injun.
Was actually a Big Art SF 46 in classifieds here , a week back . Ive no idea what He did to them though . Similar to the FP youd guess
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O.K. dug out this drivle last night . While reading Sherlock Holmes . the Hound of the Baskervilles .
The SF STROKE 40 & 46 are THE SAME .
HOWEVER , the FSR Cranks , T T $^ Cranks & SF Cranks will interchange .
Bar latters bigger flywheel would need lessening for smaller FSR Case Bore .
So for the 18.4 m.m. " LA 46 Stroke " , Youll need to use a FSR ( or Clone ) SHAFT in the SF to get the LA 46 Bore / Stroke .
The BUGBEAR on the Overbore is the TOP LINER FLANGE . Often need NOTCHING to clear pitch circle diameter of head bolts ,
And the Obvious sub piston induction induced if you lengthen the stroke .
The Std. LA 46 piston appears only to have maybe 8 thou covering S P I ,
No Idea if the GARDNER set up is a longer piston .
THOUGH the SF Case & Rod get the Timing at 140 Ex compared to the LA's 148 or whatever .
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SO , a SF Rod & a FSR 40 Crank are likely prerequisets .
Pile of tables below , all relevant as the FSR 40 & FP 40 & 35 cylliners interchange .and heads . ( Anyone for a FSR 35 ! ? )
The FSR 45 , GP 44 , and to a extent , HP 40 Cylinders interchange . And Heads .
The SF & LA 46 liners interchange , to a degree , also with the VF . But Gudgeon & crankpin are larger on the VF
The VF Diameters match Como 51 & X 45 ! tho there rods the 34 not the 34.5 ! .
Whats happened is designing engines compact , the pistons cut to clear the crank at B D C , and therein lies the S P I conundrum whilst strokeing the stroke. or increasing it . The Bottom of the piston skirt is lifted . Often above the lower exhaust lip in the sleeve .