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175 valve sizes
Posted: Sat Jul 11, 2026 10:58 am
by ranton_rambler
Does anyone know the valve diameters for the various 175 motors?
I have a 175TS and gave up on my "sports" camshaft as I think the valves are too small to get the proper benefit from it.
I have seen a head advertised as a 175 Sport head, with valves 31.5mm exhaust and 34mm inlet.
I don't seem to have a note of mine, and the various books I have don't tell me either.
Re: 175 valve sizes
Posted: Sun Jul 12, 2026 7:46 am
by Eldert
have a look at the Lacey Ducati website
they list sport valves 34 / 31.5 and TS as 32 / 30 mm
Regards Eldert
Re: 175 valve sizes
Posted: Mon Jul 13, 2026 7:54 am
by ranton_rambler
Thanks Eldert. I think the performance gain will be quite small and as I currently have a completely oil-tight motor I think I will leave it alone.
Re: 175 valve sizes
Posted: Mon Jul 13, 2026 4:20 pm
by Chewythekneeslider
I'm interested in this topic, as I currently have my TS175 engine in bits. I can confirm that the TS valve sizes are 32mm and 30mm stock. It would be interesting to see if it was possible to upgrade to 'sport' spec with the Sport valves and a high compression piston? Is the camshaft different too?
Cheap and cheerful tuning that works is always desirable!
Has anyone actually done this?
Re: 175 valve sizes
Posted: Mon Jul 13, 2026 8:32 pm
by ranton_rambler
I don't know if the camshaft is different but my factory book says the TS has 11hp and the Sport has 14hp.
I think the pistons that Nigel/Doug sells are all high compression but you would need to check.
My motor is a bit of a hybrid with a high compression piston and PHB24 carb, plus I have raised the gearing by 1 tooth on the front sprocket.
It is OK but sometimes a bit more go for getting up hills in the Peak District would be nice.
This is the listing if I have done the link right - includes a camshaft.
https://www.facebook.com/groups/ducatis ... 1191822398