Last generation dt175 mods

[James Lee]

I recently picked up a 93 dt175 for my nephew who recently moved in with us.The bike needed a top end,I noticed the massive closed section in the exhaust port so I removed it and the bike goes really flys now,appart from the 250 mx silencer the rest is stock,anyone else playing with these?Id love to hear of any mods as Im going to put another together but would like to get it to go really well so I can give my nephew a big shake up.

[William Doe]

Is this the section you removed James ?



I always wondered why they have that big lump in the top of the exhaust port and how removing it would improve performance.

The rest of the porting looks good and you can fit a big reed block and carb 

[cyclegod]

Biggest improvement is replacing the massively restrictive stock exhaust.

http://www.bossonperformance.co.za/

[80-85 husky]

I would split the cases, match the crankcase to cylinder transfers. plug up any balance holes in the crank weights and then smooth all the port edges and get a Geoff Morris exhaust. finally slip a 2 - 4 mm bigger carb etc and it will fly.
don't ride over bumps and don't ride toward solid objects

[James Lee]

That's the part I removed Bill,what carb and reed block fits?
I heard from a young bloke that a certain year yz 125 exhaust is a close fit to the dt but a new gmc one would be nice.
I'll be opening the engine on the next one I put together so will have a go but what would you use to plug the ballance holes and what's the advantage to it?
Cheers,James.

[80-85 husky]

plug them with corks and epoxy over them. this reduces the volume in the cases which increases the primary compression a bit. I did this to a TS 125 years ago and it gave it a noticeable lift.

[vandy010]

the stock exhaust has a "massive" restrictor in the "fat" part of the expansion chamber. if you're keen? grind the expansion chamber apart along the seams, look for the "spot weld"  marks on the chamber as the restrictor is spot welded in obviously, so now with said restrictor removed, weld the chamber back together and your pipe is now a "goodie" that looks stock... and yeah, 32mm carby from a YZ/IT, open up the airbox, machine a bit of weight from the flywheel etc