Remove Seized & Stripped Screws From Motorcycle Engine Covers

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Introduction: Remove Seized & Stripped Screws From Motorcycle Engine Covers

About: Making and sharing are my two biggest passions! In total I've published hundreds of tutorials about everything from microcontrollers to knitting. I'm a New York City motorcyclist and unrepentant dog mom. My ...

Hello! Motorcycles are still new to me, and for my first project (after learning to ride, of course), involves getting to know my bike. What better way to familiarize myself with the parts of the engine than to replace all the old, seized screws from the side covers? I picked up a "complete set" of shiny new allen bolts from 4into1, but quickly realized it would be harder than expected to remove the old screws from my 1975 Honda CB200T.

Not only were many of them seized, but they are JIS (Japanese version of Phillips) screws, which are prone to stripping if you use the wrong (ie regular Phillips) bit. I definitely stripped at least one screw before even conceiving of the other steps in this guide.

So whether you're stuck mid-process or if you're thinking of attempting screw replacement on your vintage motorcycle, these techniques will help you deal with stripped and seized screws.

Step 1: Tools & Materials

This is a nice project to ease into-- you don't need all the tools at once to get started. Start with the easy-to-access screws and work up to the removal of the footpegs required to access certain screws.

Materials:

Tools:

  • wrenches for removing parts to gain access to obscured screws
  • flathead screwdriver
  • allen keys and/or allen screwdrivers that fit replacement screws
  • JIS T-handle screwdriver
  • manual impact driver
  • hammer
  • Dremel or other rotary tool with cutoff disc
  • eye protection
  • electric impact driver
  • rags/paper towels
  • left handed drill bits (if all else fails) and standard power drill

Step 2: Apply Penetrating Oil

About a week before attempting to remove any screws, apply penetrating oil to each one, as well as to the bolts holding on the footpegs (since we'll be removing them to access certain screws). Ride your bike around and get the engine nice and hot. Repeat 3-5 times over the course of the week so the oil has a chance to seep into the threads.

Step 3: Use the Right Bit for the Job

Before mangling your screws with a standard Phillips screwdriver, trust me that it really does make a huge difference to start out with a JIS bit in your screwdriver. These screws are pretty soft and very stuck, which is a combo that easily leads to stripped heads.

I ordered a three-bit T-handle JIS screwdriver from Amazon that worked perfectly for two thirds of the screws on my engine covers. If you are a bit stronger than I, you may get away with a regular shaped JIS screwdriver.

But if this driver strips your screw heads, don't worry. Next up we'll introduce more and more drastic methods for getting that sucker outta there.

Step 4: Try a Manual Impact Driver

A manual impact driver turns with high torque when it is struck with a hammer. Yours might work differently, but mine is dual direction and has to be twisted slightly in the direction you wish to turn the screw before striking a few blows with a hammer. Mine has standard Phillips bits since I couldn't find JIS bits for it or a JIS manual impact driver.

Since I'm not using the correct bit anymore and the screw is likely already mildly stripped, it will now likely either release or strip entirely. If it's the latter, don't worry! We're not giving up yet.

Step 5: Stripped? Cut a Slot

To work with a stripped screw head, the next step is to cut a slot in it with a rotary tool and cutoff wheel. Be sure to wear eye protection, as the cutoff wheels have a tendency to break and send shards in every direction. Hold the wheel as perpendicular to the screw head as possible, and dig in to cut a new slot across the head. This gives you better leverage.

Now you can use a flat bit and your manual impact driver to try again, or bust out the electric one in the next step.

Step 6: Electric Impact Driver

My friend happened to have an electric impact driver to lend me, which removed the last remaining stubborn screws from the engine covers. However this tool is really jumpy, and scratched the metal of the covers in a few places. If you don't have access to one, but have a standard drill, the left handed drill bits in the next step are a suitable alternative route, cost wise.

Step 7: More Drastic Measures

Left handed drill bits have threads cut reverse from normal drill bits, and will actually start backing your screws out as you drive them in. My bike did not require this more drastic step but your screws may be more stripped than mine.

When I mentioned I was working on a tutorial on this topic, many more suggestions came in so I will share them here as well!

  • Heating with a torch, rapping with a hammer
  • Drill and re-tap
  • Screw extractor/remover set
  • Take it to a shop! If all else fails, ask for help from a professional.

Step 8: All Done!

When the screw finally does come out, here's what you can do to prevent that situation from happening again! Use some heat resistant anti-seize lubricant on the threads of the new screws when you install them.

My new screw set was one screw shy of what I needed, and two of the screws were too long and needed to be ground down to fit. But now I know my bike a lot better and will be ready to take on more advanced repairs in the future!

Do you have an experience with stripped or seized screws to share? Post a comment below!

Check out more of my motorcycle projects:

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43 Discussions

JIS impact bits:

http://www.vesseltools.com/hand-tools/screwdrivers/impact/view-all-products.html

Yes JIS bits are the best because they are designed to not "cam out" at a specific torque like Phillips heads do. Now if I could just find an impact rated JIS bit nothing would stand in my way!

The only addition I can give to this is I once talked to a guy who'd ended up welding a "bolt extension" onto the tip of a burred off head to allow him to remove a really tricky bolt. I assume he drilled into the original then fed the new one into it a bit.

Hey, Nice clean looking old CB! Good solid little machines!

There are various routes to removing seized screws , stripped heads etc.

If you use a blind punch on the screwheads before you attempt to unscrew them you can dispense with most everything else.

The blind punch will compress the material of the screwhead just enough so that a manual impact driver bit gets a good purchase on it.

I've worked on motorcycles since my youth and never , except maybe once , had success with "Easy out" extractors.

A good manual impact driver , a blind punch , and some bits will remove most except the most stubborn of screws.

The only proviso is that your blind punch must be equal to the diameter of the screwhead - two good raps with a hammer and the blind punch before putting a screwdriver to the screw and it will like as not, simply unscrew with a regular screwdriver.

Just a caution on stainless cap head screws and aluminum , they don't go well together , it is advisable to use some "Copper slip" on the threads before inserting.

'Copper slip" is also good in high temp applications like exhaust studs as it is pretty heat resistant.

On the subject of exhaust studs - some penetrating oil applied before is always a good idea , also when trying to loosen them , do not try to simply unscrew them directly , i use what i call a " Wiggling " technique , that is , very slight rotation , wiggling in the tighten / loosening direction until at least one full turn has been completed. After that it will usually unscrew without much incident , if it stalls coming out , simply apply penetrating oil and run it back in , then progressively out again.

Some 6mm taps would also be a good idea for thread chasing to clean up afterwards.

2 replies

Could I ask for clarification as to what a blind punch is you refer to please?

No reference to them via google.

Thanks

Sorry! Blind punch = Pin punch

I am old skool , have just always called it a blind punch

http://www.harborfreight.com/5-piece-long-drive-pin-punch-set-93111.html

Hi,

that's a beautiful engine you have there. In the '80's we used to ride these cycles. The first engine was a CB 90 one cylinder. Later on we used to ride a CB 200 and 360. I preferred the 360. Four cylinders, one exhaust pipe (four in one). Marvellous sound.

We did the same you are doing now. Only, we didn't have WD40 at that time, I think. Oil and a little bit of gasoline did the job. We lost some of the bolts, because we didn't know (at that time) we had to tighten them with a certain force (Newton Meters). Nowadays I drive a BMW K75. I always check with what kind of force the bolts, nuts and screws need to be tightened with using a torque wrench to prevent loosing them or leakage. In the engines maintenance manual or on the Internet you can find info about the force you need to tighten the bolts with.

Nice job! I always get a little bit nostalgic when I see engines like these. Keep them rolling.

I note that you are using WD40 as a penetrating fluid. Personally I will not use this as I prefer a substance called 'Plus Gas'. It's better than WD40 in that it works faster and more effectively. It is roughly about the same sort of price but is a dedicated penetrating fluid rather than a catch all lubricant and penetrating fluid just in case :) The best way of working with any penetrating fluid is to soak the fitting over a number of days. Every few hours give it a little spray. Maybe heat the fitting first with a heat gun as this will draw some of the penetrating oil into the recalcitrant fitting. If this is done over a couple or three days it should (fingers crossed) make easing the screw out a lot easier. Nice little bike (I remember them from the 70's) and very good instructable, thank you :)

2 replies

It's just wd-40 brand, but it is a dedicated penetrant type formulation (not plain ol' wd40). agreed it's not as effective as some other brands like Blaster PB, but it was what was available to me at the time and besides, otherwise you'd have nothing to comment about! =D

Ah, I didn't know that WD40 were now doing a 'dedicated' penetrating fluid. Good news in that case. Though, I'm an old fuddy duddy and will stick to my 'Plus Gas' ;) Hope that motorcycle's behaving :)

Ah soft Phillips Head screws on old Hondas. Brings back many memories :-) WD40 is not great for this but way better than nothing. Penetrene, Inox, CRC etc are much better. An impact screwdriver used properly will work on all undamaged screws. Replace any that are looking bad, use a nickel antiseize rather than a copper based one. (water around the combination of copper & aluminium leads to spectacular corrosion)

Another tip: a pin point butane torch applied to the screw head while a wet rag on the surrounding casing will often work well too.

Third tip; gasket sets can be hard to come by for these old bikes; reuse the old gasket but coat all mating faces with Permetex No3, wait 5 minutes & assemble. Use a torque wrench set to correct value. Traces of the Permetex will enter the screw holes & work as antiseize & friction lock. The Permetex will also prevent the gasket sticking to the aluminium & fill those tiny imperfections on the mating surfaces. It cleans off completely at next disassembly with alcohol. Much MUCH better than using silicone.

I'm another one who's been through all of these tips in my time. I'd add that after the penetrating oil has been left to work give a tap or two in the tightening direction before trying to loosen them. It helps break any seal / corrosion between the threads and helps to reinforce the cross head screw shape- all helping the loosening process.

Good instructable!

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Jakwat

2 years ago

I had a bolt that had broken about half an inch into a fitting, I drilled a hole into the bolt and tapped a star bit into the hole with a hammer. The bolt came out easy, it wasn't a real tight fit though.

I was given a green and black Honda CB200 as a birthday present back in 1977.

Be careful when using those tapered screw removers. They need an almost perfectly centred hole to be drilled in the stuck screw or bolt and then they can actually cause more problems than they solve. If that extractor breaks off, and they are harder (more brittle) than standard drill bits, then you may end up with a piece of very hard metal stuck and a drill bit will not bite into it :( I know of a lot of professional mechanics who will not even allow those things into their workshop....

I knew I recognized you. You work for Adafruit, right? I love your projects. They're always well written and informative.

1 reply

Used to, now I work at Instructables! and Thanks!

A trick that will work "IF" it is an exposed screw head is using a small cold chisel and hammer. (You have to replace the screw after this) first get a good penetrating oil and soak the screw really good and let it sit for 15 minutes or so (long enough to work yet not so long it evaporates, Next morning is too long) Start a cut straight into the head from the side using light strikes (this is just to get it marked and shock the threads loose as mentioned in a few other posts) then as the cut deepens, swing the chisel angle in the direction you wish the screw to un-turn in (Haven't run into any Japanese left handed threads but I did get myself turned around (righty tighty, Lefty loosy) a few times. this generally works when the screw head has completely cam-ed out and there is nothing to grab with a driver tip. Well Done on the write up!

If you insert your screwdriver exactly into the screw head, then give it a good rap with a hammer, you will drive it fully into the screw head and also shock the entire length of threads to help separate the screw from the casing. When all else fails, try to grab the head with a Vise Grip plier, really biting into the head, then try to turn it.

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AlfS7

2 years ago

If all else fails, and I really mean ALL, grind the whole head off the screw so you can get the cover plate off (or whatever you want to shift). Use a good quality HSS drill to drill into the aluminium casing all around what has now become a stud. This will allow you to remove it, but leaving a big, untidy hole. Fill the hole with good quality 2-part epoxy, as it starts to go tacky, screw the new screw in, let it set for about 12 hours - you should be able to unscrew it then, leaving a nice neat threaded hole. Leave it to set for 3 days. This will work only if you don't need to undo the screw very often, AND ONLY if it's not load-bearing, and it is a last resort. I did this to replace a seized broken carb mounting stud on a 1953 250cc BMW.