any help appreciated.
i understand B&J are doing this type of work.
they must be busy or out of town...

can the DT cylinder be used without hurting the bottom end power?

Re: TY175 - DT175 port timing and head differences

Postby David Lahey » Sun Jun 15, 2008 7:13 pm
Well I finally had a look today with a TY175 barrel and head and a DT175 of the same era barrel and head side by side.

Sad to report that the port timing and shape on both is exactly the same
Also sad to report that the inside shape and volume of the head is also exactly the same

There are differences of course. Both the head and barrell are made from different castings to the TY, with different finning and there is an oil injection port on the DT barrell. The DT head has an extra sparkplug hole and the head finning is cut away to fit the DT exhaust in a different pattern to the TY finning cut-away. The DT head also has lots of square holes through the horizontal fin much like a TY250 head. The DT barrell finning is the same shape all the way to the bottom.

The only performance differences I could see are that:
The DT motor ignition has a timing advance mechanism that rotates the points cam relative to the flywheel.
The DT flywheel does not have the additional steel disc fitted to the flywheel face like the TY.
The DT has a thinner head gasket than a standard TY gasket.

this is some of the response on Trials Australia forums!

http://www.trials.com.au/forum...opic.php?f=16&t=3666

Also you can do a search on trials central

hope this helps, Tim

PS number plate requirements for STRA are basically what ever you like on a twin shock. A,B or C would be fine.