Is there any after market ignition systems for a 1981 Mx 175 ? All I can find is dt175 kits ?  

DT175 would be the same as would many other options.  You'll have a lighting coil that you just leave disconnected.  I would use this kit as it's the cheapest I've found www.treatland.tv/HPI-CDI-mini-rotor-igni...ha-p/hpi-210k072.htm

Treatland has free shipping and a 15% code this week, PM me for the code if you decide to go this route.

Hi Mark,

Would you happen to know if this ignition would work on a 1980 mx175 ?

Thanks

I posted it because if HPI made it to fit the models listed, it will bolt right on to pretty much all the magneto 125 and 175's sold in US 1974-on.  They all have the same 130mm stator diameter and basic crank taper.  (I did a lot of research and testing for Powerdynamo to come up with their ignition kits for the 125/175's)

This includes 1974-1981 Yamaha DT175, MX175 or YZ175 as well as any 74-79 Yamaha MX125 or YZ125 ignition.  78-81 DT125 (monoshock) and 77-79 IT175 will fit too. 

Some of the YZ models had tiny internal rotor ignitions and corresponding small covers so you wouldn't be able to get the YZ cover to fit over a DT flywheel. But obviously you can get the small YZ ignition under your large external rotor ignition cover. 

Note that some of the above are points and not CDI.  Some of the YZ's had internal rotor and no lighting coil.  Even the 1990's RT180 system will fit...  but may need a little grinding for clearance. 

And I'll say this now even though I shouldn't have to...  I'm talking about complete SETS.  You can't mix and match stators, cdi box, and flywheels from different model and styles of ignitions and expect it to work. 

You need to have the skill to install and set timing on the HPI. 

Some of the factory Yamaha ignitions are just "bolt on and go"...  primarily the 78-81 DT175 CDI and 80-81 DT125 ignitions.  (If using a DT CDI, I'd stick with the 80-81 version)

Thank you