Hello, is it possible to convert a dt 125E 1977 type 1G0 to a content of 175?
I got a cylinder from yahama at 175 according to all the information it should fit.
Is it enough to replace only the cylinder and piston?
Are the other parts the same?
Is it necessary to put a bigger mikuni carburetor 26mm or 28mm, or is it enough to just put a jet?
Next, I got a second exhaust and I want to open it up and gut it, will that improve the performance or at least the sound?
Thanks for the anwers.
Regards daniel

Yes a 175 cylinder and piston will fit. You will also need a 175 head, as while the 125 will fit, compression would be pretty high.

Also 175 piston would ]likely] touch the 125 head as it overlaps 10mm--well 5mm depending how ya think. Comes out flat where piston angles up. Machine the head out there for high comp.
Na--get a 175 head. 125 head won't have much gasket surface left after machining out to 66mm.
Sorry just confusing things--shut up 'me'.
Talking exhaust, my old Rat Bike 175 has a mostly gutted exhaust as all fell apart within 40 year ago & goes like a rocket--albeit a bit noisy.
But going back to when i rode a CT1 to work i bought an MX175 chamber exhaust through our importer redundant stock. Think MX175 were a through the frame style rather than along the side. So modified it to fit & about doubled the performance.
Just thinking, if your E model is monoshock it'll be totally different to the exhaust i'm thinking. I'm a year out.

Since I am on my kindle I have access to my official yamaha DT125/175 E book of words.

Fitting a 175 barrel, head and piston was a popular mod when the 125 learner law came out in the UK, so yes they will fit.

Reed block is the same as is the carb body.

Exhaust is the same.

Difference is in the carb.

Main jet goes up from the 125 110 main to 130 or 140 on the 175.

Needle jet is changed from N4 to O-2 on the 175.

Needle itself is the same.

Carb slide cutaway is 2.0mm on the 125 and 2.5mm on the 175.

Float height remains the same.

Air jet remains the same.

Primary jet remains the same.

Starter jet remains the same.

You also need a 175 piston pin and bearing, both are wider on the 175.

Thank you for your reply.
I have already looked at the heads and understood the differences.
I still have to buy more
As for the exhaust, I have the 1G0 model exhaust is "flat" on the right side with a crici grille.
I bought another piece so I don't destroy the original one.
I'm going to open it up and gut it
I'm curious what I'll discover in there.
Anyway if I take out the baffles it should be ok?
Do you think it is tuned to the engine?
Can it reduce the power when I remove the baffles?
Thanks for the help.
Daniel