3 piece cranks a no-no . Though with titanium bolts ?? Left shift cranks metric bearings , but will turn down to std .
72 Crank is 72 % ballance , Squareish profile X section flywheel & counterweights.Is factory raceing balance factor .
Commando cranks have been fitted to B.S.A.s , 1/4 steel plate centre with bolt on counterweights , 270 deg.set-up.
Gets you a 7mm stroke increase.
Dunno if the 722cc 750s still had the long rods , if your going for a rev'er , a Big Bore Kit on a 650 has a better
length / stroke ratio in the rods. To much angularity limits revs through side thrust on pistons .
A good 650 can be got to rev past 8.000 something like reliably .
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Wide Lne frame ?? RIDGID chain Case gets optimum motor / box positioning , even in slimline .
One in Aus. was 800cc 8 stud , streamlined , dunstall discs , 32 Dellorottos. 159 mph down conrod.But on Methanol .
Used This motor / box spaceing , Dunlor KR raceing tyres .
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Really you need to look at the use it will be put to on decideing spec . Road Bike , Hillclimb ? Raceing ?
Clean , mint , matching big bearing cases mandatory . 5T may machine out for sleeves if base stud pattern matches .
Anything over the 0.5:1 pisrtons mask combustion , and make things awkward .
Close Ratio Triump box or re worked ( re ratioed ) 5 speed is a better place to start .
60s cams were less ' square ' than late ones though two of the right ( int or ex ? ) Left Foot ones are equivilant of 73 ' hot ' cams .
W&S spring set ( for Yam XS 550 - 750 4 valve ) fit Tri & Comm. and are fine for past 8.000, & come with race quality fittings & shims .
Degreeing cams , 3/8 gear wheels , drilled ? & polished . 750 oil pump ( reversed or Hi Capacity job , a decent Magneto ( SR2 ! )
short roadholders & good shocks , Progressive rate springs F & R are better priorities than a irrascible motor .
Frame will break without a head steady .
Most exhausts are trash, Hi Pipe was Std on later Manxes .
Late rods are heavier and slow accelleration .
P.M. for 8 stud tuneing specs .
Were some 8 stud heads about a time ago , early series cracked . 61 cast mark wont unless abused . A good T110 61 or 62 or T120 C or R
if available .
:cry: or build to specs from ground up. LOW TIME parts preferable.Triumph lifed rods @ 60 Hr.
Some ' N.O.S. ' parts COULD be production seconds / cast offs that wernt scrapped .
Left Shift Bing parrallel intake Bonnie Head was only worthwhile part THEY produced ( Co-Operative . Co operating with Wot . Idiot polititions to the tune of 14.000.000 pounds . :shock:
Leave of the Jap Parts . They all fell off the Bonnie inside of a week , usually . :?
