Valve timing on 1957 350 cc single

segt · Post by **segt** » Sun Dec 23, 2007 12:09 pm

I am having trouble starting my 1557 350 single since completing an engine rebuild. Can someone please confirm the correct alignment of cam mark alignment for this model. Best wishes to all from country Western Australia.

SPRIDDLER · Post by **SPRIDDLER** » Sun Dec 23, 2007 1:35 pm

G'day, Peter.
I've just lifted this from ITMA's post on this Forum from 2005. (Click on 'Forums' above. Choose 'Search Forums'. Enter 'Dots' . Search).
It's how I found the following:

<<Set the dot on the small pinion to 12 o/c, now turn it to the left and align marks as per book, OK ? now turn small pinion to the right and repeat with appropriate marks for your engine.
return small dot to 12o/c then one complete turn to right 360 degrees. you are now on firing stroke,both cams with their arse in the air so to speak.
With mag at FULL advance, time at 3/8 btdc, that`ll give your engine and your right leg an easier time.Use rear wheel in 4 gear to pull engine back on firing stroke then turn forward again back up to 3/8 mark. Dead easy. More accurate with the head off.Set tappets on this stroke.

Cam markings [write out 100 times]

up to 1948 cams dot + dash
1949-50-51 cams 1&2 use 1 on matchles engines , 2 on AJS
1952-3 all cams 1&2 but use no 2 all engines
1954-55 cams H or HL 1, 2, 3, on 350cc use3 inlet;2 exh; on 500cc use 2 both cams.
1956-8 use3 inlet, 1 exh; on 500cc use2 inlet, 1 exh
This is of course if you have the right cams, if not use noddle; suck squeeze bang blow.
Tattoo these numbers on your left arm so you know where they are in future.
Lesson two; the cost of free advice from grumpy geezers is eternal sarcasm,happy new year.[:)>>

Sprid

Biscuit · Post by **Biscuit** » Sun Dec 23, 2007 1:39 pm

Without knowing the details of your cams, ie markings or keyway or not keyway etc. The following method works for me when fitting cams from God knows where to engines of equally doubtful provenance.

With the mark on the half time pinion (HTP) at the top, the piston is at TDC, this will be TDC at the end of the exhaust stroke, where the exhaust valve has just closed, and the inlet is about to open.
Turn the engine back until the mark on the HTP points to the inlet camshaft bush. Take the inlet cam, and with the cam peak pointing to the right as you face the engine turn it anticlockwise until the cam is forced against the tappet foot. Identify which cam wheel mark is nearest the HTP mark, that's the one you want.

Similarly with the exhaust cam,turn the engine forward until the HTP mark points towards the exhaust camshaft bush, but this time have the
cam peak pointing to the left and turn it clockwise against the tappet foot, again identify the mark nearest the HTP mark and insert.

Never fails for me, and you don't have to worry about which mark, which year, mag in front or behind, whether the cam has a keyway or whether the cams were original fitting.

My missus has recently arrived back from Perth WA, and she feels cold!!!Edited by - Biscuit on 23 Dec 2007 1:42:15 PM

paul knapp · Post by **paul knapp** » Mon Dec 24, 2007 4:42 am

36 Deg. today in Perth, 38 Tomorrow.
..and what aussie goodies did you recieve?

Biscuit · Post by **Biscuit** » Mon Dec 24, 2007 12:01 pm

Nothing yet Paul, see what tomorrow brings. She brought a cold back though, and passed it to me.

Don Madden · Post by **Don Madden** » Mon Dec 24, 2007 4:50 pm

We are suffering in our Winter weather here in Southern California. Forcast is for 77F, (25C), & snow only on the mountain tops.

Merry Christmas! to All Don.

Biscuit · Post by **Biscuit** » Mon Dec 24, 2007 5:07 pm

Don't mind the cold, it's the un-relenting gloom, damp and mist that get me.

If I knew how this country would turn out 40 years ago, we might well be neigbours Paul.

paul knapp · Post by **paul knapp** » Tue Dec 25, 2007 11:00 am

Heaven forbid.

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