Classic & Vintage - Can this Miyata 710 be saved?

I was at the dump yesterday, throwing away some junk from the garage. In the scrap metal pile was a complete red Miyata Seven-Ten. Looks to be about a 1984. I took it home.

Best of all, it's my size. The paint is good, with no visible rust on the frame.

The drivetrain was frozen, and the chain was rusted. Other than that it looked OK, aside from the rather crusty tires (I later discovered that one of them actually did hold air).

When I got the bike home, I attempted to remove the stem and raise the seat. No luck. Frozen solid. Same for the stem. There also appears to be a slight bend in one of the seat stays. Finally, one of the pedals seems fused to the crank. Sad, because it's a 170mm crank (too small for me) and an MKS pedal.

I know there's a destructive method to remove stuck stems and seatposts. Any other methods?

The wheels are actually true. The rear is problematic in that many of the spokes are rusted. But the front is good to go - I've already repacked the bearings and it spins real nice.


I can't sink too much money into this project. Too much meaning slightly more than zero. My "accountant" insists that four bikes are enough so a fifth will have to be financed very much off the books.

I was at the dump yesterday, throwing away some junk from the garage. In the scrap metal pile was a complete red Miyata Seven-Ten. Looks to be about a 1984. I took it home.

Best of all, it's my size. The paint is good, with no visible rust on the frame.

The drivetrain was frozen, and the chain was rusted. Other than that it looked OK, aside from the rather crusty tires (I later discovered that one of them actually did hold air).

When I got the bike home, I attempted to remove the stem and raise the seat. No luck. Frozen solid. Same for the stem. There also appears to be a slight bend in one of the seat stays. Finally, one of the pedals seems fused to the crank. Sad, because it's a 170mm crank (too small for me) and an MKS pedal.

I know there's a destructive method to remove stuck stems and seatposts. Any other methods?

The wheels are actually true. The rear is problematic in that many of the spokes are rusted. But the front is good to go - I've already repacked the bearings and it spins real nice.


I can't sink too much money into this project. Too much meaning slightly more than zero. My "accountant" insists that four bikes are enough so a fifth will have to be financed very much off the books.

Time to fire the accountant! :p

Some have had luck using ammonia as a penetrant to loosen the steel to aluminum bond. It takes some time, and it gives off some nasty vapors, so it is best done outside the house. If you can get the crank removed, then you can pour some ammonia inside the seat tube and let it soak. For the stem, you can just invert the frame and pour it into the bottom of the fork.

Some have had luck using ammonia as a penetrant to loosen the steel to aluminum bond. It takes some time, and it gives off some nasty vapors, so it is best done outside the house. If you can get the crank removed, then you can pour some ammonia inside the seat tube and let it soak. For the stem, you can just invert the frame and pour it into the bottom of the fork.

I was thinking the same... invert the bike and spray inside the fork and seat tube. As far as the spokes...lube the nipples with a drop of chain lube from the outside and the inside. Pedals....lub the threads frm the inside and ride it. Liberal amounts of heat work as well.

Do you have access to a set of Oxy/Acetylene torches??? Heat it VERY slowly to avoid damage. This will obviously ruin the paint, but if the paint is shot already no big deal. If you lived near me I would let you borrow mine, but since I am in western MA that’s not an option…

The paint is fine. Quite nice, actually.

I tried the ammonia. Do I have to leave set for a while? How long?

I tried the ammonia. Do I have to leave set for a while? How long?


I'm in the same boat as you - I have a nice Nishiki mixte frame that has a stuck stem. I'd just build it up as-is, but the headset needs rebuilding and even if it didn't I wouldn't want to foist it onto someone else the way it is.

I've been soaking it in ammonia for 2 days now, and no joy yet. :(

Patience is required for stuck parts. Sometimes rusty chains and derailleurs can be brought back to life, with a healthy dose of penetrating oil ( I use a product called Moovit ). I've freed up a few stems using penentrating oil, usually a week or so of soaking, turning upside down, whacking with a hammer and piece of lumber, never tried ammonia though.
Only had 1 stem I couldn't free up out of about 15 or so.....

It took me a few days to loosen a stuck seat post. I padded a vise and clamped the seat post in the vise so that I could use the bike frame as a lever. Once it starts to budge just a little bit, you can be sure that you will succeed. That means you have broken the bond and only need to keep working the frame so the ammonia can find its way around to all the surfaces.

Ammonia in water is actually ammonium hydroxide. A very strong sodium hydroxide solution would also work but no odor. Reduce the rust, eat the aluminum. Ammonia is a gas.

If you can find Red Devil lye at the grocery store or hardware store, dissolve it in water, as much as you can. Then pour it down the seattube and wait.

PB Blaster has never let me down.

using lye (very dangerous to skin and eyes) IS that destructive method you mentioned. It will completely dissolve the aluminum parts if left to work long enough. It won't dissolve steel or other ferric metals, but I don't know want to picture what it will do to paint. Make lye your last-ditch effort when all else fails.IMHO and humble experience: the corrosion welding that cements these parts together is usually a combo-platter of both aluminum oxide and rust. So you often have to attack both: first with a long ammonia soak, then drain and dry and then spray the best penetrant you can buy. Shock (like whacking the nose of an old saddle with a mallet) can also help break the bond.
Chances are a bent stay can be straightened by an expert, as long as there's no "crimping" or buckling.
Good LUCK!

Success! A day's soak in ammonia, a day's soak in PB Blaster, and two more day's soak in ammonia. I drained it, put a flat bar in the stem clamp, braced the fork, and gave it a heave. The stem slowly broke free, and I was able to get it out AND salvage it, too.

As stated earlier, it does appear to have been a combination of rust and corrosion.

Last night, I set the frame upside down, filled the downtube and head tube with ammonia. I'll get back to it in a few days. If that doesn't work, I'll resort to the drill and/or hacksaw method suggested by Jobst Brandt.

The slight bend is an easy fix buy any frame builder. Lucky here in my town the local shop owner is also a builder and will do that kind of work for like $5 , thats about $2 a minute labor.