Has anyone to wrestle off a stuck breaker cam? Mine is REALLY stuck....

Not a common problem because very few models have them. Must be a burr or something?

I personally wouldn't mess with it too much... if cam rotates it's fine. If it or the linkage is messed up then I lock in "full advance" position. Parts are not readily available and a lot of them are seized/rusty/broken. Yours looks great.

It's only used for starting and I can't tell the difference between one that works and one that's been locked to full advance.

It’s totally seized, and it’s retarded. If I could even get it into the full advance position I’d put some loctite bearing retainer on it, but I can not. If you could see it up close, it’s rusted on. Does a MX, YZ, or IT rotor have an advance unit?

Only replacement is for your model. I think 74-75 DT175 is the same. 76 DT175 is a different ignition.

If you haven't rotated the cam from the "start" position, lock it down there. It will be fine.

No sure what size engine you have but guessing a 175. be careful swapping flywheels as on my old 360 with that setup the advance cam is a fat one & therefor the points sit further out on the base plate & plate is only specific to 'that' flywheel. If 175';s did that on your model then--be careful. MX's & YZ's should be cdi so flywheel won't work. Then again, MX covers more than just race bikes in some models so 'maybe' there's one magneto model.
Changing tact, can you move the base plate & re-drill it, but probably only half a hole needed. Other thing i've done & only worked because i'm a 'brute' at overtightening. I left the crank key out of my IT200 using a points flywheel on original cdi stator as bought it minus a flywheel. Cam did nothing & i worked out the firing point with a strobe then set the crank accordingly to get 2mm btdc or whatever & did flywheel nut up b&^%y tight & never ever slipped. That's enuf bad ideas for one day or i'll be teaching you bad habits from down under.

Wouldn’t it be fully retarded for starting in an idle position with the advance unit slack? The advance unit swings out at rpm advancing the the cam into running position. You set the timing on a DT175 with advance unit pulled out to get timing at a running position. So if I leave it where it is now it will be constantly retarded, much like me. Wouldn’t a 74-75 MX175 be the same rotor minus the advance unit?

Timing is by setting points to open when the piston is a specific distance BTDC. If cam is fixed so it can't move and is still located within the stock range of travel you just set the timing correctly and it will be correct.

I've already mentioned what flywheels I know can be used. Do some research and it should be immediately obvious why a 74-75 MX175 won't work.

Maybe there is another flywheel out there that will work? Nothing obvious comes to mind. If there was something, I'd mention it.

I understand points timing, but on a DT175B (mine anyway) you can’t really adjust the timing all you can do is set the breaker gap. And yes I realize the you can slightly manipulate timing with gap it’s not the same as having a slotted breaker plate that you can change the index in relation to crank position. So I can’t lock down the breaker cam in the retarded position and just adjust the timing without slotting the plate to be able to rotate it. So I have to either find a way to get the cam freed up, slot my breaker plate, or find a new rotor.

You don't have to slot anything, free the cam up, or find a new rotor (if the cam has not been rotated out of "factory" range.)

Quick summary: You don't adjust the points gap to some "spec" on your bike. You set the timing by adjusting the points to open at precisely the right time. Then you check the maximum points gap to see if it's in range... .012" to .016" by memory. Gap will be in range or close enough if you haven't rotated the cam from the stock range of motion and if your points are correct and not worn out.

There's a good reason there are no slots on the 175 and there don't need to be. I don't have the patience right now to completely describe how the ignition system works in detail... I will say slotting the plate can mess up the critically precise factory magnet to coil relationship and result in weak or no spark. (I've posted a lot about the topic if you're interested... try a search.)

Beyond that... it's okay if you don't believe me. It's your bike and your money.

My apologies for my last post... I'm not having a good day and usually this forum is an escape for that... today it seems I'm letting my bad day bleed over into my posts...

RustiePyles... if it came across that I was attacking you personally, it wasn't intentional. You might understand the points perfectly... I just might not be understanding what you said. I will say that I have adjusted the timing on "stuck cam" 175's and they ran fine whether the cam was stuck retarded or advanced.