motor build beginning!


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Hi All, after a long, long, long wait I am finally looking at building my Shadow motor.I have most of the parts I need, refurbed,replaced, painted, and ready.
I have never built a vincent motor before,and will obviously be starting at "crank in and casings together " What pitfalls await me? Any pearls of wisdom re assembling the cases? The mains are reclaimed and new brgs. Flywheel assy. is new.Do the cylinder studs need a sealant on the lower threads-speaking of which-any recommendations as to a suitable sealer for the crankcase joint ? Cheers, Bob.


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Before using sealant, put everything together "dry" first.
Make sure the primary main bearing outer and ball race is in position with circlips, and oil scroll is on the mainshaft
Once you´ve got the cases together, assemble engine sprocket, ESA etc and do up tight, and make sure everything rotates freely, and the rods are central in the bores.
Once you´ve crossed this hurdle, dissasemble, oil, apply sealant (i use the green stuff from Kawasaki, or well seal) and reasemble.
Until you know everything is as it should be, stripping and reasembling is a pain in the butt with sealant and oil everywhere.
Don´t trust your judgement until that ESA nut is done up real tight. Only then will you know if everything is as it should be (even half tight can hide a clearance problem which will be difficult to source later as the whole motor is fairly tight)

Main Pifalls:
Main race outers to wide (rubbing on the crank)
Reclaimed housings insifficiently relieved (rubbing on the crank)
Rods out of centre (various causes)
oil scroll wrong dimensions (ball race inner will be forced inwards causing drag, or outwards preventing inner face contact of the cases)
Drag on inside of engine sprocket (if a mainshaft seal has been fitted and insufficient clearance present)

(I´ve had all of the above)
Last edited:

Big Sid

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For Bob . Put sealant only on the upper portion of threads , the upper section that screws into the cases , of the large cylinder studs , not the lower section . All must be clean and tried first to be sure they will go all the way home . Might need being swapped around to fit nicely . Sid .


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Bob. Make sure that you have fitted part no G39AS Ratchet shaft bevel assembly into the gear box half as well as g54 bevel return spring and g55 return spring retainer screw. Before you put the assemble the cases. I would also offer up part no g40 gear ratchet shaft to check the movement for changing gears.

Now the interesting part of assembling a Vincent twin starts and you will not know were the time has gone at 12.00 midnight as you get the engine assembled.
Loads of satisfaction as the engine gets bigger.
Good luck I hope it goes together OK