[Steve_M90]

The story continues in topic "No compression on a Model 90"

[VicYouel]

Steve...... what progress?

Vic

[phutton]

Make sure that both valves are closed before you  start to undo the rocker box securing bolts. This takes the valve spring load off the box and avoids a common cause of the box cracking.

Paul

[singleminded]

As Vic said nothing really tricky.I assume you have the cast rockerbox..Make sure the push rod tubes are wound down a bit and that the oil tubes to the valve guides line up. Slacken off the tappets as far as possible and tighten the rocker bolts evenly ( also remove them evenly after slackening off the tappets).i have seen the 2 lugs that are at the 'back' of the rocker box snap off due to uneven tightening.I use a large C spanner to undo the finned nuts on my '32 9A an 90 engine..john

[VicYouel]

Nothing really tricky but put fixings back in the same order .... I've seen quite few cracked rocker boxes.

I use a copper washer for the exhaust flange...... http://www.ebay.co.uk/itm/5-X-42MM-COPPER-SEALING-WASHER-WASHERS-O-D-49mm-KW177-/270948455479?pt=LH_DefaultDomain_3&hash=item3f15c95437  should be ok.

I have a dissassembled 32/34 Model 9 engine if you want pictures or dimensions.

Cheers

Vic

[Steve_M90]

I've concluded I need to inspect the valves - thanks for all the previous comments. My Sunbeam books are quite clear about the process but is there anything I should look out for or be careful about? Will a C spanner (or hook spanner) of the right size be appropriate to dismantle the connection to the exhaust pipes? Is there any sort of gasket in this joint? The bike is from 1932. Thanks. Steve.