dt250 piston

[gaz_powell]

Have seen the DT and IT175 piston used in ts1200 barrels with rd400 conrod but has anyone looked at dt250 which is 70mm to use with a 225 ?

on visualy they look okay but not sure about peg positions, height and gudgeon pin size

got a barrel on the bench which needs sleeving or relining (not sure which to do yet) and just looking a piston options

look forward to some comments

happy new year to you all

gaz

[grimspeed]

ive got one in a dave webster lined ts1 225.
ports are pretty much standerd.ie position of the finger port.ill have a look later and
see if the ring pegs have been moved.but they should be ok in a std cylinder.

[J1MS]

I picked up one of these pistons many years ago, it has a Dykes top ring on the one I bought, (only remembered I had it when looking for a long stroke crankshaft that's gone missing) I got this piston at the Stafford show in 98 for a fiver, always intended checking out the dimensions with the thought of using it in something Lambretta with a boost port in the inlet...
I can measure this one and give you the measurements if you need, as its in the garage now and not lost in the boxes that she who must be obeyed has move/hidden or maybe thrown out.... ????

[gaz_powell]

thanks J1MS and grimspeed

looks like it might be a goer!

anymore info would be gratefully received

cheers gaz

[shocky]

ian at taffspeed will know*warning* he talks for hours

[grimspeed]

dt 250 piston has a 30mm compression hight .so 116mm rod is perfect if useing bronze bushes old school style.i recomend a 115 rotax rod.

[J1MS]

Measured the DT piston...

The one I have is A genuine Yamaha 3rd oversize 70.75mm piston, the measurements I took below;

Bottom piston ring width 1.4mm wire chrome edged.

Top Ring Dykes 2.5mm across the face of the ring 3mm deep dykes top edge is 1.5 mm thick, with a chrome edge.

From piston crown to top face of Gudgeon pin = 24mm
to bottom of gudgeon pin = 42mm = 18mm gudgeon pin

These measurements also give a compression height of 33mm from gudgeon pin centre to crown.

Skirt length =72mm
narrowest part of the skirt measured across the chord at the base of the piston, exhaust side of the piston = 56mm and inlet side = 52mm And has two windows in the inlet skirt.

Hope this helps

[davidblythe]

2.5mm packer on a 116mm 18mm rod

pegs clear the boost port

only issue is reprofiling the head

one dyke ring and one normal thin ring

£30 for a piston in plentiful supply

same weight as an asso on kitchen scales

[gaz_powell]

J1MS and David thanks for the info - it looks like its worth a go

gary