Yz125d crankcase interchangeability

[Big Scotty]

G'day
My 125 has crankcases with the prefix3H8- originally would have been 1W1-,does anybody know what model and year these would have come from and what other model cases would fit,or is there anyone that can repair the steel inserts were the big end bearings sit
Thanks Scotty

[mainline]

There's a guy up here in brissy who can fix the insert problem for you. He's done the exact same job for others

[Ted]

G'day
My 125 has crankcases with the prefix3H8- originally would have been 1W1-,does anybody know what model and year these would have come from and what other model cases would fit,or is there anyone that can repair the steel inserts were the big end bearings sit
Thanks Scotty

Hey Big Boy, Don't let Scrivo know your ride is in hospital, you'll never hear the end of it

[gt96]

3H8 = DT175F 1979

Other common (I think):
1978-81 DT125 DT175
1977-79 IT175
1978-79 YZ100
1979-81 MX125
1977-79 YZ125

Model codes here:
http://dropbears.com/y/yamaha/modelcodes.htm

[crossedup2]

Hi Scotty

There are several cases that will fit. The one you have I think is a about the 1980 DT. Any of the case fit from 1977 through to about 1981 but the real Expert is Nathan S can fill in the total range. The DT cases have the neutral switch on top YZ and IT's are blank. Other cases that fit are the IT's from 1977 to 79.

I have a set of DT case I can bring up to the CRC you can have.

Regards
Peter B
Heaven Number 253

[Big Scotty]

Thank  you gt96 and Peter,sounds like a good deal to me,mine does have the neutral switch,took the barrel of today,crank has shitloads of sideways play in it,not enough time to rebuild it this week so will be nursing it as usual on the weekend,may not be able to catch them alloy armed suzuki riders though.

[Nathan S]

3H8 = DT175F 1979

Other common (I think):
1978-81 DT125 DT175
1977-79 IT175
1978-79 YZ100
1979-81 MX125
1977-79 YZ125

Model codes here:
http://dropbears.com/y/yamaha/modelcodes.htm

IT175 cases don't work, because the transfer ports don't line up.
DT175 cases use 125 sized transfers. Recent discovery for me...

That list is otherwise correct (although you won't find many 1979+ MX125s in Australia).
I'm almost certain that all monoshock DT175s can be added to the list, along with 80/81 YZ100.

There's four recesses in the cases under the base gasket. In one of them, there's 1W1 cast in, regardless of the exact model of cases - be worth checking.

WRT the steel bearing inserts cracking out, I don't know of a good answer. I've got a set of cases that have been welded and cracked again.
I tried to JB Weld a set, but it didn't work - basically, you can't get the liquid into the crack. I kinda think it would work if you could.

I've still got the set that's been welded. I'm wondering if I can make something work with grub screws. The thing I haven't figured out, is how to centre the insert in the cases, so that both inserts are concentric.

[mainline]

3H8 = DT175F 1979

Other common (I think):
1978-81 DT125 DT175
1977-79 IT175
1978-79 YZ100
1979-81 MX125
1977-79 YZ125

Model codes here:
http://dropbears.com/y/yamaha/modelcodes.htm

I've still got the set that's been welded. I'm wondering if I can make something work with grub screws. The thing I haven't figured out, is how to centre the insert in the cases, so that both inserts are concentric.

Grub screws are part of the fix that I've seen used by the local machinist

[Big Scotty]

I have three sets of cases all with the same problem,might enquire at the local bearing shop about bigger od bearing and do away with steel sleeve,but in lieu of that ill start collecting some spare cases,thanks  everyone for  the info,gives me a wider range to search for
Cheers Scotty

[jimg1au]

scotty
greg ball in kirrawee can fix them for you
great bloke and can fix anything