hey thanks guys
I've checked on the EPC, its apparently the same as a DT125 bottom end with DT 175 cylinder... slightly lower compression, no real chamber, well there is a diverging section that has a diffuser effect, but no converging /baffle section to provide the power kick that the DT's had... that and the dt porting is probably a little more aggressive, a slightly higher exhaust port (greater top rpm) and longer transfer duration,..
same mikuni 24mm roundslide... a bunch of other things similar to the 125 - silent block swingarm mounts etc
I think the internal gear ratios are all the same between all variants but the ag 175 got smaller front sprockets to provide lower gear ratios,... I will upgrade the front to a 17t or so to get longer gear ratios...
the bike will get some boyesen dual stage reeds, some porting work and an expansion chamber made by a guy who used to race a dt125 (lives around the corner from me!) probably also a mikuni 28mm flatslide...
so got 2 bikes, a 75 and a 79 *(parts)
first pic is how it came
second pic is strip down and new tyres
third pic is how it is now - needs silencer, chain guard, and indicators and brake light switch etc etc etc to get on the road
motor is ok, good compression but think the crankcase seals are bad, thing is smoky as hell with autolube disconnected so must be sucking gearbox oil.. that and the mikuni needs a rebuild kit (leaking) probably needs float height set etc...
magneto - with points - never been set - this will be the plan over the next few days...
the bike may just need to be run to clear all the old oil out of the crank case...