Hey y’all, you may remember my first post about my newly bought CT3 crank bearings being bad. I followed advice I got from that thread and was able to split the case today (after lots of time lost to stripped bolts, should have waited for my JIS bits and impact to get here but oh well). 

When I cracked the sucker, these pictures show what I found. Looks like there was water in there while it was sitting, which definitely caused the bearing to go bad and rusted part of the crankshaft assembly too. 

  

One thing that worries me is that I stuck my finger into one of the thru holes in the crank and found some metal shavings. I’m wondering if this along with the rust everywhere is enough to warrant a full rebuild of the crank or if I can get away with changing the bearings and going from there. Also wondering what’s going on with the connecting rod, it looks like it’s flash rusted due to the weird orange color. Any advice?

 

you could clean crank up and roll the dice, but I would rebuild crank and install with new main bearings cause it would suck to do it twice.   Or find a nice used one on eBay

Send the crank out and have it rebuilt. Rod kits are very easy to find for the 175's.

Mr. Crankshaft has done great work for me in the past at a good price. It's been a few years so not sure if he's still around.

Best to have the crank done. If you can support it on something--two wooden pieces & revolve it holding the rod you might feel roughness. Or just swing the rod slowly through a full turn feeling as you go. Luckily i can do my own with my press but not done one for a long time.

I would get it checked over by a motorcycle engineering shop.
Crank seal area looks to have corrosion, so not sure your crank seal will actually seal.
I had a similar condition crank on my CT3 which I had refurbished, big end, con-rod and pin and also had the seal area diameter machined down 1mm to take and alternative seal.
Cost was £115.
Here's the thread, might be helpful.  Help needed CT3 crank - Page 2 - Vintage Enduro Discussions (yamaha-enduros.com)
Best of luck.

Appreciate it Pete, some good info there. I did send some pictures asking for a quote from Mr. crankshaft (thanks MarkT) and they said the same thing about the corrosion making it difficult to rebuild. I had read in a previous thread that people had tried sleeves over that area, but I had the same thought about a different ID seal and machining down the crank. Do you happen to remember where you sourced the new seal from? Looking on Partzilla I don't see engineering drawings or anything to show the dimensions I'm looking for. Did you use a standard part from a different bike or source it from Mcmaster-carr or something? Haha

I got mine from Simply Bearings in the UK but there must be similar suppliers.
Standard seal is 25x40x8. I used a 24x40x8 double lip seal

My CT1 looked just like that when I opened it up. Suspect it was pressure washed then put away... for 20 yrs. Anyway, I went all out and sent the crank to "Crankworks" in Arizona. The job was teardown, derust everything, grind, weld up the shaft, and grind back to original dia, new YZ 125 rod, assemble, align, weld the stub ends to webs, and balance with my piston. While waiting, I went through the the gearbox area on my own. Have the right side of engine all done and workint on left - soldering in new condensor with points. Hope to button everything up and stick back into the frame in a wk or so.
Regards,
Joe M

Is the crank for a CT1 and CT3 the same? I have a core motor that still has the crank in it that I would sell if you want to go that route. I can pull the crank and see what kind of shape it's in.