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MAIN BEARING REAMERS + IGNITION TIMING.
Posted: Fri May 26, 2006 7:12 pm
by bigoink
Can anyone tell me the correct size and type of reamer to use for main bearing alignment........do all model seagulls have the same size mains ? Also what is the ignition timing (in terms of degrees) for the Silver Century Plus and Featherweight models...........
Bearing sizes.
Posted: Sun May 28, 2006 8:16 pm
by John@sos
The Seagull Manual lists the main bearings as 0.6245"/0.625"
Dealers had a special long in line reamer for this, it is adjustable...
I use one when I relap the halves of a crank. But only if the crank feels in the slightest stiff when I reassemble it. Takes the finest trace of metal off. Hand turned of course.
As for the timing, I don't honestly know! As the timing is fixed on the vast magority of Seagulls it is not normally a problem, just relocate srew into dimple in top half of casing...
The Marstons had variable timing on some models...
I bet some one has the answer to this though!
Regards,
John
SOS
Posted: Tue May 30, 2006 10:11 am
by charlesp
23 degrees BTDC I'm told for the earliest Villiers Magnetos (thanks to the other Charles for that). If you haven't got a protractor, fold a piece of paper along the corner for 45 degrees, and again for 22.5. That's good enough - the variable advance retard on the 'Special' models went a good few degrees either way of this...
If you measure the angle on an ordinary Seagull - one with the dimple to fix the timing, you'll be lucky to find one that's exact. After a canversation with Charles about this I had a look at a couple, and one is way out - but it runs well.