Engine build help for newbie

[nickw1969]

I've built a couple of engines in the past, but am not mechanically minded, so apologies for any dumb questions

I have bought a 150 special engine which I plan on restoring,however there are some things which I havent come across before, which I suspect are down to Italians doing a bit of a bodge job,

The engine is a standard 150 special, however the piston has 3 rings, which I haven't seen before. Also the cylinder head had 2 spark plugs in it. One in the usual place and one in the centre of the cylinder head. It looks like the one in the centre has been carefully tapped out and the fins carefully and very tidily cut out, but I cant think why this has been done.

Has anyone seen this before, and can explain why? I plan on buying a replacement cylinder head, but am not sure if there is anything I need to take into consideration? Will one such as the below do the job



Any help greatly appreciated.

Cheers
Nick

[RICSPEED]

three ring pistons are normal mate ,get your self stickies manual as that covers rebuilds step by step and will help no end ,
not sure quite why two plugs but there are a few about

[nickw1969]

three ring pistons are normal mate ,get your self stickies manual as that covers rebuilds step by step and will help no end ,
not sure quite why two plugs but there are a few about

Thanks mate - Got stickys manual, and am ok with the rebuild in general. Its more of, do I need to get a specific type of cylinder head, or is a 150 head the same as any other?

I'm tempted to stick a new 175 kit on it, but I'm trying to stick to my budget, and if a can get a new 150 head for £20 off ebay,that will do for now.

Thanks again.

[sponge bob]

Can't help much with the tech side of things but with lammy parts you get what you pay for so cheap won't all ways do what you want !! So take your time and get the best parts you can, you will enjoy it better if you don't break down all the time .

[dapper]

Two spark plugs, two sparks at the same time.

[RICSPEED]

Two spark plugs, two sparks at the same time.

does i make any real difference?

[dapper]

Think I read summat somewhere where some of the old guys used to do this. Can't remember if it was a racers mod or what, or whether they used two coils or what. Someone older and wiser will be on soon who knows better.

[corrado]

if a can get a new 150 head for £20 off ebay,that will do for now.

Thanks again.

I'd ask on here first if anyone has a spare one knocking about, I'm sure someone will have the odd doorstop knocking around.

[Diablo]

Nick I think the twin spark plug thing is an old tuning mod from back in the day. Don't know if it has any benifit but someone will probably give you a few quid for it.
Seeing as you already have your TS you can probably get a decent turn off speed out of a little port job on the barrel. Give Chris a ring as we can get this done for you cheaply.

[nickw1969]

Nick I think the twin spark plug thing is an old tuning mod from back in the day. Don't know if it has any benifit but someone will probably give you a few quid for it.
Seeing as you already have your TS you can probably get a decent turn off speed out of a little port job on the barrel. Give Chris a ring as we can get this done for you cheaply.

Thanks guys

Diablo - Sorry, what is a TS? and which Chris should I contact?

Thanks
Nick