Author Topic: 78 yz125 IT175 motor (Read 2133 times)

ozyditcher · « **on:** March 03, 2011, 01:15:34 pm »

I just pick up a 1978 yz125 with no motor. will a IT175 motor fit?

vandy010 · « **Reply #1 on:** March 03, 2011, 01:29:19 pm »

it should do.
so should the earlier YZ125C/X,DT125/175 {both monoshock & twin shock} or even a DT100/TY175 donk.
most of the engine mounts are the same,
it's just be the fiddly bits that'd need work.
like the carby size, if using the smaller stuff, which you probably wouldn't anyway.

Nathan S · « **Reply #2 on:** March 03, 2011, 04:42:43 pm »

The answer to the question is Yes, providing its a 1979 or earlier IT175 motor.

The longer answer is:
The twin shock motors and the early 6-speed motors (TY175, YZ125C/X) are wider at one of the mounting points (top rear, IIRC), which requires tweaking to fit.
The later DT175 motors are narrower at the top rear mounting point and need spacers to fit (or you could just crank the bolt up tight and pull the boomerang mount in, I guess... ).

The DT motors of all ages/capacities create hassles with getting an intake manifold/carby to join the DT barrel to the YZ airbox. There's tons of ugly ways to deal with this, but no nice ones.

Other than that, stuff like exhaust pipes and chain pitch and the like may require attention (depending on what you uses), but there's no real dramas there.

ozyditcher · « **Reply #3 on:** March 04, 2011, 02:09:12 pm »

Quote from: Nathan S on March 03, 2011, 04:42:43 pm

The answer to the question is Yes, providing its a 1979 or earlier IT175 motor.

The longer answer is:
The twin shock motors and the early 6-speed motors (TY175, YZ125C/X) are wider at one of the mounting points (top rear, IIRC), which requires tweaking to fit.
The later DT175 motors are narrower at the top rear mounting point and need spacers to fit (or you could just crank the bolt up tight and put the boomerang mount in, I guess... ).

The DT motors of all ages/capacities create hassles with getting an intake manifold/carby to join the DT barrel to the YZ airbox. There's tons of ugly ways to deal with this, but no nice ones.

Other than that, stuff like exhaust pipes and chain pitch and the like may require attention (depending on what you uses), but there's no real dramas there.

Thanks. I found a 78 IT175. can you make the IT run good as the YZ?