Vintage Dirt Bike Q & A

Hi guys,

Been lurking for the past couple of weeks, looking back through a couple of years worth of some great posts, and great advice. Now, I'm hoping for some advice on removing a broken stud from the cylinder of my '76 CR250M.


After I got the head off, there was enough thread left on the stud to double nut the stud and try to turn it out after liberal amounts of PB oil spray, but that didn't work and the threads that were left were stripped. Next I tried the old vice grips, and that only made it worse. My thinking now is that the cylinder, other than the sleeve, is aluminum, so if I baked the cylinder in the oven for about an hour at about 215 degrees, this may expand the metal around the stud enough that I can turn it out with vise grips. Any thoughts on this?

The bride is away for a couple of days, so I can use the oven without hearing about it for the next 25 years.

If this doesn't seem advised, I think the next effort would be to weld a nut on the stud and try that route again.

Here's the bike in it's sorry state of disassembly.

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Steve Amling

1976 CR 250M
1980 Yamaha DT100G
1980 XR 200
1981 CSR650

Heating it up is a great idea. You are working your way down the progression we all follow sooner or later.

If you can get one of old style stud-removers that uses a cam style wedge, that would be great. That is, if you have enough exposed stud left to grip it. Crafstman #4458P is one of them. There are some wedge style pliers like this on the market now that are much smaller and may work with that little nub you have left. Hmmm, give up?

I've never seen anyone try welding a piece to the stud. If you do try this, be mindful that aluminum melts at a whole lot lower temperature than that steel stud. I'd try to avoid the welding out of pure fear. Still, a skilled welder might get away with it.

Try an easy-out style broken stud remover. Grind the end of the stud flat. Center punch it. Drill it. Then drive the easy-out in nice and firm with a hammer. Then heat 'er up. I've been happy with a propane torch, but the more even heat you get with an oven is of course better. A hot plate works too, and the heat from the wife if much less. Watch the fumes ignition factor. When she's nice and hot (the part), tap the easy out a couple more times, spray a bit more penetrant in the hole, and commence removal.

If that doesn't work, it only gets worse. Then it is time to drill it out and either retap the perfectly drilled hole (1 in 20 odds there), or install a thread insert. If the tap breaks off inside the bolt, you'll need a diamond point bit to get through it. Thankfully, they are much cheaper and easier to get from just about any hardware store or tool source. If you can do the drilling in a press, your repair will be that much better. A nice straight hole makes the motor fit together a lot easier.

Enjoy!
Jon

Thanks for the thoughts Jon. I tried the oven tonight. It heated well, but the stud wouldn't budge. I think tomorrow it will be off to the hardware store for some additional stud removal tools and a couple of easy outs. Somehow I end up breaking one out of every two easy outs I try, so I'm a little shy of them, and they will truly be the last resort.

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Steve Amling

1976 CR 250M
1980 Yamaha DT100G
1980 XR 200
1981 CSR650

Yep, I don't have a great deal of luck with them either. We'd probably save a bit of frustration moving straight to the thread inserts. They work great.

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Michael Stiles
1979 Honda CR250R Elsinore | 2006 Husqvarna SM510R | 2007 Service Honda CR500R-AF

Thanks RedRocket, something like EDM was going to be my next step, after trying a couple of other things first. A neighbor is a welder/machinist, and mentioned something like EDM, but said that he would need some time to work on it. I tried two other methods I heard about, and one worked! Or, maybe it was a combination of the two.

First, another machinist told me that WD40 wasn't good for much, but when it comes to loosening steel in aluminum, it works better than anything he knew of. He said to heat the Aluminum up to about 350-400, work as much WD 40 as possible around the stud, and try tapping counterclockwise on the exposed part of the stud with a hammer and chisel. I tried that and didn't seem to accomplish much.

Then I tried a type of stud extractor that slipped over the exposed part of the stud Called the Power-Grip, from Irwin.

The ad copy says

It worked pretty well. My first attempt after driving one of the extractors onto the exposed part of the stud resulted in breaking off another eighth of an inch of stud in the extractor. I ended up having to put the extractor in a vise and drill out the broken off stud parts with two progressively larger holes, then use a standard type EZ-Out to remove the rest. The second attempt at the stud was successful. after hammering it on firmly, I put a few pounds pressure behind a wrench on the extractor, and I got a hot little geyser of WD-40 and steam out of the recess the stud was in, and it started turning right out.

Now, to find a replacement stud.

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Steve Amling

1976 CR 250M
1980 Yamaha DT100G
1980 XR 200
1981 CSR650

I'm the local weld a nut on it guy.
Of course if you don't have access to a mig or tig it isn't going to happen.

Welding a nut on really heats up the part, much better then just using a torch. I also use an air impact wrench as it is less likely to break the bead/nut off. It is the most violent method a home mechanic can use but most successful. You really want to use an impact wrench and welding a nut on is about the only way it is going to happen right.The couple of hundred tiny hammer blows a minute is less likely to strip stuff then a long handled breaker bar.

If you have a really stuck part while it is more likely to melt the case it is less likely to strip the threads when you get the stud removed. I've had some come out with other methods where it pulls the threads out with the stud.

Rick

I'm a weld a nut/bolt on guy too!! Mig welder w/gas, one of my smarter purchases!

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Garry Mainer
#33m (retired)
Honda Cr250r 1980
Honda Cr250r 1980
Yamaha TY250C 1976
Arctic Cat 650 H1 2007

I like the welded nut also.
We have a tool at work called a burn out that is the deal for bigger stud or tap/drill removal.

Good luck on finding a stud.

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1979 CR 250R Basket Case

The OEM stud was an odd one. 7mm threads at the bottom and 6mm on top. Found a 7mm on both ends and figured I could swap it back out for the original when I find one. Put her back together, but still waiting for a kick starter pinion/gear/spindle, and a brake pedal. The original spindle broke quite a few years ago and my brother took the old parts out, bought a new spindle, and then misplaced everything. She's barn fresh after over 25 years. Thanks for all the replies on the stud. A lot of great advice and guidance.


With the new top end, the compression is now great, good spark, and expect decent fuel from the rebuilt carb. Half tempted to plug the Right cover, fill her with oil, and push start her to putt around the yard, but without the rear brake, would likely seriously injure myself, since I doubt I would stick to the yard and would likely hit our trails as well.

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Steve Amling

1976 CR 250M
1980 Yamaha DT100G
1980 XR 200
1981 CSR650

Sweet, have fun with her and good luck ...Van

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1980 Honda CR125R