Hi all Iv just bought an Australian ag175 about 1975 interesting thing is it has reed valve and a DT style expansion chamber (not like ct1) and 6 head bolts. Anyone know what is going on here and how much HP it should make and if I can get more from it?

Sounds like you have a later grasshopper agy but i thought they started nearer "80. Does it look like this. If so it's still a de-tuned version of a DT175 of similar cylinder design. Quite grunty & excellent farm bike but will lack the outright top end of the trail cylinder. Here's a link to the parts diagrams that you can change along the top. Far later model but is one of those models that never changed from the first grasshopper as far as i know, or no major changes. www.firstclassmotorcycles.com.au/partFin...175/cylinder#content

 

Yeah that's probably what it is. So are you saying a dt175 barrel will get a bit more top end? Do these Ag "grasshopper" have much of a power band? Would a dt175 barrel give one? Sorry for lots of questions
 

I'm no help as not done the swap but need to find a wrecker & compare cylinder for porting differences between the two. Looking on partzilla at the base gasket the numbers are different but the shape for fitting the studs is the same. Hope someone from oz comes on that's up on the play doing that sort of thing. So far as a true powerband goes you're never going to get that with an Ag or a DT175 without serious porting & a race chamber.

If you buy a new powerband get a blue one. They are better than the other colors. 

 

Don't take offence being ribbed about 'power band'. Sounds like you're reasonably young but hey we're here to help. If ya 'really' want to try a power band try my old over-modified 360, it's just un-rideable so i must tame it down--scares me.

Yeah no problem I'm fairly young. Just want to have some fun riding in the bush. A little "burst" of power would  add to the fun. But nothing crazy as it will be used for Ag farm use as well thanks all for the information
 

Interesting that it has 6 head bolts...  can you tell if it has 4 studs holding the cylinder?  A DT175 cylinder may fit and would probably boost the power some.

MX175 top end might fit but not sure how much better it is than a DT175 as MX in those sort of bikes, DT etc, doesn't mean much more than the trail bike minus lights & not a fire breathing motocrosser.