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74 MT Stator condition and repar/replacement question
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Author:  MT250GUY [ Fri Nov 18, 2016 5:16 pm ]
Post subject:  74 MT Stator condition and repar/replacement question
The images below show the conditions under the left side cover were pretty bad. Lots of crud, disconnected wires from two of the coils, and the left side seal is not installed properly. I posted before that the left side cover was impacted by the chain and about an inch long piece of the housing next to front sprocket is missing. Furthermore, the backside aluminum rim of the flywheel seems to be chewed up a bit or eroded too. Of special note is the large amount of fine metal shavings mixed in with the oil and dirt throughout the compartment. If you zoom in its really obvious. It would seem the most obvious explanation for all this damage and metal shavings is it was the chunk of housing that did the damage and some of it was ground up.

Should I even try to clean up and repair the stator, or junk it and find a another one? If I do get another one, are all the years of the MT250 interchangeable?

Thanks!

Attachments:
Left seal not flush.jpg
Left seal not flush.jpg [ 2.59 MiB | Viewed 7692 times ]
Flywheel erosion.jpg
Flywheel erosion.jpg [ 2.24 MiB | Viewed 7692 times ]
rear of stator.jpg
rear of stator.jpg [ 2.62 MiB | Viewed 7692 times ]
front of stator.jpg
front of stator.jpg [ 2.52 MiB | Viewed 7692 times ]
Author:  rayivers [ Fri Nov 18, 2016 5:58 pm ]
Post subject:  Re: 74 MT Stator condition and repar/replacement question
It seems to me your stator is (quite literally) toast. It's difficult to be 100% certain from a photo, but it looks to me like fuel/2t oil leaking from the seal may have been ignited by a sparking stator wire, leaving what looks like burnt areas in your last photo. I agree that if the chunk of case got caught up in the rotating flywheel it could very well have caused the stator and wiring damage, along with the aluminum chips (which look to be stuck to the 2t oil from the leaking seal).

If it were my bike I'd throw on what I call a 'real ignition' (PVL #70032, or Honda p/n 31010-381-810 if available) and LED lighting, but otherwise MT250 stators (same all years) show up regularly on eBay. You could try cleaning up your stator and testing/repairing the coils, but it looks like that thing's been through the wringer and replacement would absolutely not be a waste of money IMO. The flywheel may be OK, but a very thorough inspection is in order before making that call.

Ray
Author:  MT250GUY [ Sat Nov 19, 2016 9:21 pm ]
Post subject:  Re: 74 MT Stator condition and repar/replacement question
Thanks!

I bought a new (used) stator from a 76 on ebay that looks pretty good (FWIW). I do ultimately want to go LED on the bike but think it can be done with out much fuss, but first I've got to finish testing it and put the thing back together. I've tested the other electricals (switches, rectifier, etc). I figured out that the rectifier diodes are one way (despite the HORRIBLE explanation in the shop manual.) What I don't know is what readings should I get when I test the circuits? I'm getting between 3.13 and 3.28 across the wire pairs.

Thanks
Author:  rayivers [ Sun Nov 20, 2016 6:08 am ]
Post subject:  Re: 74 MT Stator condition and repar/replacement question
Without a Honda coil-resistance spec to compare against, there's really no need for an accurate resistance measurement (which is difficult to get on coils anyway, unless you've got a really good meter). I'd make a continuity check to stator ground on all coils (they should all be grounded at one end), and read the resistance across them as well as you can. There will be a huge difference in resistance between the ignition source coil and the battery-charge coil (the damaged one on your original stator). I'd also repeat these steps on the damaged stator, which may help confirm the first set of readings and hopefully give you some indication of the original problem.

Ray
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