Would you trust this crank?86 200

[GKBO]

At some point a PO had sucked water into the cases and left it there.Doesn't seemed to have affected the big end bearing at all.No up down play and not much side to side.Was going to try some Evapo Rust to clean to off.

The view from the the front.

This seems to be the easy bit to take care of.Machine it down and rethread to the next size down.Local dealer gave me the number of a local retired machinist that does stuff like this.

A picture of the cases.Yeah I need new mains

[rbates9]

I would look around for a "new" crank and see what you can find. By the time you get the threads fixed (and I would do the big end bearing) you might be up to about what a good crank would cost. The rust wouldn't bother me as much as the threads.

[Julien D]

I'll agree with rbates. I'd price out your rebuild of the crank. This means cleaning the thing up, buying a rod kit, and labor to rebuild the crank and fix those threads. Most decent shops wouldn't charge you much extra, if any, for repairing the threads. Compare that cost to a "new" used crank. You can likely repair cheaper than replace, especially if you can't be sure your new used crank won't end up needing rebuilt sooner than later.

[GKBO]

Hmmmmm...... seems like a shame to replace a perfectly good bearing.Nobody thinks the rust is an issue either?I'm a bit surprised by that.
One other question then,in my build thread(see sig) it came up that the crank from the E might fit in the C.Is that true?Open up a search quite a bit if it is.

[Julien D]

The rust on the crank lobes itself should not be any issue. Just clean it up. The bearing however, even if it seems "perfectly good", is almost definitely not going to be good after a few hours of riding. Once the rust wears off and leaves pits on the pins it will wear in short order...

[GKBO]

If the bearing looked at all rusty I would have not be questioning this.The crank locked near TDC and the big end was above the water line by quite a bit.ARGE....... I'M STARTING TO HATE THIS PART.

[Julien D]

If you're confident the bearing is rust free, clean up the crank, tap the end, and run it. Just keep an eye on the flywheel side for play over the first few rides.

[pumpguy]

What you can't see is the condition of the crankpin and rod bearing race surfaces. I can't see how they could possibly be in good condition considering the rust on the wheels and main bearings. It would be one thing to just run the engine and wait for it to start rattling, but since it's already torn down, and you're going to put new bearings and seals in it, it would be foolish not to do the rod too. No offense meant, just IMO.

I am curious how the bad mainshaft threads would be repaired, weld and re-cut them?

[GKBO]

Why I'm asking questions here pumpguy soliciting opinions as I've never really done a 2 stroke before.As for the rust on the crank there's a quite distinct rust and something else (premix ) line on it that I can't get in pictures.Unfortunately that line is 1/2 way to the the big end bearing.Looking at this pic:

All the rusty junk was actually the top WTH is going on with that?I was thinking all the junk on the wheels came from water and other stuff on the bottom of the cases Good thing I took pics before taking it apart.Goody add a big end bearing or "new" crank on to the to do list
Edit:I was thinking weld and rethread to PG but was warned off by a member on another forum.After welding you'd need to heat treat it or it may be brittle.Best answer I've gotten seems to be machine it down 1 size and rethread (16 to 14mm in this case).Also suggested to do a normal thread instead of the fine.

[fuzzy]

Definitely rebuild the crank....Looks quite doable.

[GKBO]

The Boss made the decision for me.Rebuilding the crank is what is going to be done.We where at the local dealer(Kenco) and she said order a new rod kit.She was getting tired of my waffling about what to do with the crank.

[GKBO]

On a related question I got a set of main bearings at the closest bearing place.

They are sealed bearings but as you see the seals just pop out.

I know 1 side needs to be open like ^^^.The question is should I leave the other side sealed like this or does it need to be open as well?

[GKBO]

My seemingly never ending crank saga continues,I emailed the member that helped me get the airbox.He has a good 87 crank that even with shipping to Canada will be quite a bit less expensive than doing the rebuilding mine.Monetarily it's a no brainer.On the other hand doing the rebuild I would KNOW I'm good for a LOOOONNNNGGGG time.I repeat ARRRRGGGG......I HATE THIS PART!!!

[Julien D]

If it were me I'd rebuild what I have, however, if its a good deal, buy it, use it, and rebuild yours to have a spare. Both seals should be removed from the mains.

[GKBO]

My wife says do both to but I just can't justify that in my mind.Even the seller told me I'm better off redoing mine,sounds to me like that's what I should do.I feel like I'm coming off as flaky flip flopping around like this.I honesty NEVER thought this crank could be saved,in a 4 stroke it would be dead.I'm definitely A 2 stroke noob.Thanks with the confirm on the mains.I 1/2 way thought so but...........

[royadams]

You need to make shure those are the right bearings. The crank bearings on a two stroke are diff than a bearing that is meant to run with grease or oil.

[GKBO]

You need to make shure those are the right bearings. The crank bearings on a two stroke are diff than a bearing that is meant to run with grease or oil.

They are C3 bearings.

I cleaned off the rust with Evapo-Rust and I need some reassurance this crank will be OK.


A bit worried about these score marks and the rust pocks on the journal in the first pic.

[rbates9]

If that is where the seal rides then you will have problems. You could try some "speedi sleeves" but it may be time to look for a crank.

[GKBO]

Close inspection says the pocks are indeed where the seals run

[KDXGarage]

Get a used crank and get a connecting rod kit for it. That crank is junk. Why fool with it??