MAIN BEARING REAMERS + IGNITION TIMING.
Moderators: John@sos, charlesp, Charles uk, RickUK, Petergalileo
MAIN BEARING REAMERS + IGNITION TIMING.
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.
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
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
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.
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.