A65 primary chain cover

Started by Mike Farmer, 16 Jan, 2021, 11:52

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Mike Farmer

16 Jan, 2021, 11:52
 :) :) :)

I assume that it was very difficult to strobe the early A50/65's without the timing aperture. So if it was possible   How????.

I confess that I seldom strobe cos I figure that if it wasn't necessary on the early models it isn't an actual 'necessity'. just a bonus.

I do understand that it can make a difference, but I wonder how much difference, providing you have a good method of measuring piston position etc. I very much doubt that to most of us a couple of degrees retarded aint going to make that much difference. You'll notice advanced with the kick start.

Mike 8) 8) 8)

AdrianS

#1
16 Jan, 2021, 13:41
I think it is safe to run the engine for a short time with the cover off, do the timing and then refit the cover and top up the oil.

Mike Farmer

#2
16 Jan, 2021, 15:34
 :) :) :)

OK I've got that. But the datum mark/pin appears to be fixed to the case. So if you take the case off what timing mark do you line it up with.??????????/.

Mike 8) 8) 8)

JulianS

#3
16 Jan, 2021, 16:08
You need to attach a degree disc to the crankshaft and make a pointer.

Mike Farmer

#4
16 Jan, 2021, 19:40
 :) :) :)

Thanks Julian. I read about that once and never took it any farther.

My method. Before replacing the head take the correct measurement down the bore My book says .309" so I actually do it to .300 so its not correct by 9thou. Then I mark the idler pinion and the casing on the timing side with a slight tiny dab of white paint. its there for ever. I can't find the pic at mo

Mike 8) 8) 8)

Nanonevol

#5
18 Jan, 2021, 14:27
Quote from: Mike Farmer on 16 Jan, 2021, 19:40
:) :) :)

Thanks Julian. I read about that once and never took it any farther.

My method. Before replacing the head take the correct measurement down the bore My book says .309" so I actually do it to .300 so its not correct by 9thou. Then I mark the idler pinion and the casing on the timing side with a slight tiny dab of white paint. its there for ever. I can't find the pic at mo

Mike 8) 8) 8)

Is that just for your reference? You can't strobe it by those marks.

Mike Farmer

#6
18 Jan, 2021, 16:34
 :) :) :)

Purely for my reference. Its a "by the book" start point and has indeed always stood me in good stead. Certainly before I even knew the word "strobe".

It would be interesting to know just how many guys have never strobed an engine. (I have only done it once or twice) I fact I havn't got a clue where my light is.

Mike 8) 8) 8) 8)

chaz

#7
18 Jan, 2021, 16:40
only ever strobed my Vauxhall Viva HB and Hillman Hunter engines, rebuilt myself back in the seventies and eighties, still got a strobe but never used since.
with the BSA's I just set up as the workship manual said, luckilly the Japanese dont usually need re timing.

Bess

#8
18 Jan, 2021, 16:48
Hi,
    For an option to strobe the A10 I fitted a plate adjacent to the drive pulley (no shock absorber fitted). Before fitting the head, measured the piston position with a depth gauge and marked a line on the pulley and plate with a scribe the timing marks I wanted. Something similar could be made up for the A65 I guess.

Best wishes...

Mike Farmer

#9
19 Jan, 2021, 14:44
 :) :) :) :)
Hopefully this will show what I meant by putting timing marks on the idler and casing

I know the definition is not good sorry

Mike 8) 8) 8)

DAVE BRADY

#10
19 Jan, 2021, 15:41
Hi,

That is not a bad idea for determining a starting point for setting the timing statically.  Once the points or EI is fitted this mark would be mark be obscured?  A mark on the case would help.
I think if you want accuracy then a large degree disc works well for getting good marks.  The mark on the rotor and the pointer in the later primary cover are useful but because of the small radius cannot be 100% accurate but as has been said a small amount out, especially a tad retarded is not going to make that much difference when riding on the road.  I usually static time once the marks have been verified with a large degree disc.
I must admit I do not like revving the engine to 3500 rpm when stationary, one because of the noise and the other because the bike starts wandering about.

Dave.

Mike Farmer

#11
19 Jan, 2021, 16:47
 :) :) :)

My sentiments exactly.

In truth I doubt that a couple of degrees out is not going to be noticeable at our level of use. Unless its too far advanced then it could cause probs.
But as I said previously I think very few of us actually strobe.

I might just set up a little survey to find out.

Mike 8) 8) 8)
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