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A standard off set squish cylinder head skimmed and re profiled for a TS1 with a compression ratio of 12.2-1

would you think that this is too high for a standard TS1

Is that corrected Mark? (says he trying to sound like he knows what he's talking about )

coaster wrote:Is that corrected Mark? (says he trying to sound like he knows what he's talking about )

Geometric on a standard TS1 225 (223cc) barrel approximately 180 exhaust timing on a 58 Stoke crank 107 rod 1.5mm squish clearance.

It would have been higher because it was originally getting fitted to a 231cc engine.

Capt. I'm surprised by you looking to run that comp ratio (comment based on previous exchanges with Capt.).

I'll be interested to see how you get on. Running advance/retard on this? Octane booster?

Adam

Adam_Winstone wrote:Capt. I'm surprised by you looking to run that comp ratio (comment based on previous exchanges with Capt.).

I'll be interested to see how you get on. Running advance/retard on this? Octane booster?

Adam

Hi Adam,
I was surprised at such a high compression ratio, as it was bought supposedly only having only 9.5-1.
It's not for my scooter but an engine that's having a new crank fitted and needed a new head that would suit the standard stroke (not recessed)

It had a combustion chamber volume of just under 16cc

Used like this on a standard port height TS1, I think it might have to run on 100 % octane booster to try to stop it pinking.

This is more along the lines of conversations that we've had in the past, especially the bit about stated compression of a head being nothing like the reality of the ratio. Interestingly, I've seen as many low comp heads as high comp heads recently, which might show the trend going the right way with today's poor fuels.

I've never run a 12:1 head on a std TS1 so can't give you any first-hand comment.

Adam

If you left the HT cap off it might run on diesel