Saving Old Seagulls

I think you'll find 3 different types of pin, part number 1412, brass, softish stainless steel & a steel roll pin, all about 1" long & 3/16 diameter. The roll pin comes out easy if not too rusty. The brass one is the most difficult as the ends seem to flair out big time & can require careful drillin...

I'll wager some of your crankshaft will have turned blue, from the heat, has anyone got a pic to illustrate?

That sounds like friction from the bottom main bearing, might be slack or bent crank.

Crankshaft end float of between (50 to 100 thou) is a standard feature .

Check out John Williams or ebay a good 102 crankcase & crank won't be expensive.

Where does the hot gas come from & which locating screw?

Are you running 25:1 or 10:1 fuel mix ?

All 102's were fitted with an Amal 46 twin jet carb, heaps of pics on here.

Except a few very late models (post late 80's)that were fitted with an Amal 416 concentric float carb & CDI ignition.

All of the classic prop shafts are the same diameter, 1/2" & there are 3 different thickness hardened steel thrust washers so that adjustments can be made to ensure the crown wheel & pinion teeth mesh quietly & properly!

Here in the UK aluminium scaffold tube is 50mm OD, I have an 8 inch length that I turned down 4 inches of it to 44.8 mm OD, all you have to check is does the big end of the con rod fit up the tube, then you can drive the stuck piston up the bore towards the area with the most wear, & use plenty of l...

Search for "racing seagulls" or "seagull racing". Where is that located Andrew? That cutaway in on a real Seagull stand. If your going to visit them Stinch, go at race time, it's a good day out with a very friendly bunch all with a common interest & rumours of the islanders still eating human flesh ...

All the really stuck head bolts, I've had problems with seem to be locked in place by aluminium oxide, that horrible white powder that seem to hold the much tighter than Loctite, in the head itself not in the threaded part of the cast iron cylinder. After I've cleaned the holes in the head, I now al...

Stinch, what do you think was causing the head screws to stick in place so tight?

Thanks for an informative thread that doesn't involve the use of a big hammer & an electric drill!

Have you tried the engine identifier page?

It might be cheaper & less scary to have a custom piston made.

Well that's a standard early OA Piston.

I've lent my bore micrometer to a mate, I'll get it back & measure the bore.

Can you post a picture of the crown of your Marston piston & the diameter of the wrist pin, as I've never heard mention of over size pistons & cylinders. I've worked on more than 25 Marstons of all flavours & provided tech support for many of owners on the register & just wonder if someones tried fi...

If you press the contact 3 dots speech bubble, the envelope is an email link.