Correct cylinder head SR 185 kit ?

[tippo88]

I just picked up an SR 185 kit from my local dealer in Kuala Lumpur and noticed that the head has 175 cast in it as per attached photo. On checking all the kits the dealer has in stock they were all the same and the head looks different when compared with a standard 175 head. Question is do they take all the heads from a 175 mold and then machine differently for 185 or do I have the wrong head? Any measurements I can take to confirm either way?

Thanks !


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[bristolmod]

just measured a standard Innocenti TV175 head- comes in at 62.52mm across the "bowl"

A "186" piston is 64mm give or take- you should be able to get the edge of the head radiused by say 1mm locally to suit if required.

That looks like an Indian casting- the standard bowl diameter could be anything from 62 ish to 64 ish anyway

Chris

[rosscla]

You really need to lap that gasket face before you put it together.

[tippo88]

Thanks ! Will check measurements tonight and will also lap the gasket face.


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[tippo88]

Checked the measurements and the bowl is 63 mm . Piston is 64mm Is it worth getting the bowl opened by 1 mm? If so any particular instructions to give the machine shop?

Thanks!


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[bristolmod]

depends!

build up the top end and see how far the new piston protrudes above the cylinder top if at all.

Use a head gasket which will raise the cylinder head slightly (Scooter Restorations do "186" head gaskets in various thicknesses)

As an added precaution, run some emory cloth around the edge of the bowl to radius the area slightly- after all you are only looking for another 0.5mm each side.

You've probably got an Indian generic 175/186 head.

Alternatively take the piston and head to a local machine shop and explain the situation.

Check your squish.

Chris

[tippo88]

Chris,
Thanks for your help much appreciated . Doing a full engine rebuild , my 1st Lambretta or 2 stroke and will be couple of weeks before I start the actual build. It's an enjoyable learning process and want to get as good an understanding as I can.
Could I be cheeky and ask you to take a look at the last post in my thread on Li3 125 Upgrade options ?

Cheers

Tippo


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[shocky]

Chris,
Thanks for your help much appreciated . Doing a full engine rebuild , my 1st Lambretta or 2 stroke and will be couple of weeks before I start the actual build. It's an enjoyable learning process and want to get as good an understanding as I can.
Could I be cheeky and ask you to take a look at the last post in my thread on Li3 125 Upgrade options ?

Cheers

Tippo


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ifyou put your location on your profile you might find someone close by who can help you out even if its just being there as you do it

[tippo88]

Good idea will do that !


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