piston pin removal tool

[jp233]

ok, so I broke a nice tool of mine thinking it would work OK to pull these damn wrist pins. http://www.motionpro.com/motorcycle/partno/08-0127

it felt like it was about to budge then snapped the end hook part off. Well I'll try to salvage that tool by bending and grinding it later (it really is the bomb when trying to stretch tough exhaust springs), but I need to fab up something to try to get these damn piston pins out. They seem REALLY stuck (engine has ~190k on it).

ideas?? None of the long L-allen wrenches I have are long enough to warrant trying to bend the end. Plus that would be hard anyways.

Or should I just split the cases as-is?... and piss on the piston pins.

Yeah, I have a piston pin removal tool also ( http://www.motionpro.com/motorcycle/too ... _pin_tool/ ) , but the smallest puller bit on it won't fit down the piston pin hole

[SiCkSTi04]

douglas vincent aka reddevil over at nasioc has a well put together thread with tons of photos on tearing a block down and a video on how to remove the piston pin's. i used the long screwdriver method with a motor that has 165k miles goodluck

http://www.youtube.com/watch?v=TR0Ed6qTIVQ

http://forums.nasioc.com/forums/showthr ... ?t=1435733

[93forestpearl]

Don't waste your time with that thing on an old motor. Get some .25" steel rod, about 2 feet long. Bend a very small hook in one and and shape as needed with a grinder. Bend a few inches 90 degrees to the same side as you did the other end. You can now hit the one end with a hammer. I like using my Estwing and hitting it with the skinny handle. Old motors can take some hefty force to get the pins out.

[SiCkSTi04]

Originally Posted by FuJi K View Post
rotate the crank until the wrist pin of cyl#1 is in view and remove wrist pin. You may want to rotate it so the rod on cyl#3 is slightly above or below so you can insert a 1/4" rod through service hole #3. Taking the LONG 1/4" rod.....punch out the wrist pin of cyl#1 by running the rod through cyl#3's service hole. The END of your rod will come in contact with the wrist pin of cyl#1. You use a hammer and punch out the wrist pin of cyl#1. Do the oppisite with cyl#3 by inserting the rod through cyl#1's service hole.

all done and said. You're all welcome!

[jp233]

yeah i broke my spring tool by hammering on it to try and get them to budge.

i was wondering if I got something long and skinny enough, to go thru the back of the motor and punch it out that way instead of trying to pull it out the front (and vice versa). I guess I'll give that a try, although splitting the cases sounds just as easy

OBTW that engine tear-down thread is here too

[93forestpearl]

Originally Posted by FuJi K View Post
rotate the crank until the wrist pin of cyl#1 is in view and remove wrist pin. You may want to rotate it so the rod on cyl#3 is slightly above or below so you can insert a 1/4" rod through service hole #3. Taking the LONG 1/4" rod.....punch out the wrist pin of cyl#1 by running the rod through cyl#3's service hole. The END of your rod will come in contact with the wrist pin of cyl#1. You use a hammer and punch out the wrist pin of cyl#1. Do the oppisite with cyl#3 by inserting the rod through cyl#1's service hole.

all done and said. You're all welcome!

If you are going to do that, you should put a notch in the end of the rod, otherwise it will be very easy to gouge the hell out of the pin boss in the pistons.

[jp233]

oh yeah knocking out the pins from behind was 100x easier.

i had an old broken 3/4" drill bit that broke a tip off, that was about a foot long. used to drill holes to fish wires through walls and floors and stuff. I knew I kept it around for some reason! hacked off the drill bit part and had a nice long steel punch.

it was easy and just being careful didnt knick up the rods, pistons, bore, case, etc. had to adjust the crank/rods a few times to make sure they came out straight and werent going to ding the threads of the access plugs.

that plastic piece on the rear of the engine is a piece of JUNK....

[Imprezive]

Here is the correct answer -

Source a long but skinny bolt (around 12", about 6mm diameter is what i used) in length. Something strong would be good. Do they make grade 8 bolts that long and skinny?

Round off the head of the bolt so that it will fit through the piston pin.

Find a good nut and washer for said bolt.

Borrow your friend's small slide hammer and take the slide off of it, slide it onto your bolt, then put the washer and not on.

Now you have an awesome slide hammer piston pin remover.

The retainer clips wont be re-used so you can just force your way past them.


Knocking the pins out from the opposite directs runs the risk of slipping and scoring the contact surface, make sure you grind the bolt down enough so it doesn't rub against the bearing surface.

If you need one I will send you mine, you'd just need to source the slide hammer part.

[wfoote]

This is very similar to what I did.

I took a long 12mm bolt and ground away most of the bolt head leaving a hook. The grinding is done with the axis of the bolt parallel to the surface of the grinding wheel which leaves a lot of support for the hook. I then shaped the hook so it would fit through the notch created by the inside circlip and then rotated the tool.

The bolt was long enough to allow using a prybar on the nut to gently pull out the pin. Just be careful where you are prying on the block.

Yet another way to skin the proverbial cat or in the case remove those stubborn pins.

[dzx]

or... you could split the block and remove the pins from the pistons after they're out and you can get to them easier.

[douglas vincent]

or... you could split the block and remove the pins from the pistons after they're out and you can get to them easier.

I had to do this on a motor. Freaking nightmare.

[jp233]

knocking the pins out from the backside was really easy. With the drill bit tool I used, the very end was skinny (the end you chuck in a drill). Basically 2 good hits and they were mostly out. I'd maybe have to readjust the crank just to make sure nothing got it. Took a few minutes but still took one hell of a shorter time than trying to "pull" the pins out using various methods.

getting this block apart, will be fun for sure. It's an old and tired motor, but damn do the bores look good. Pistons are FINALLY clean too, what a PITA to clean the ring grooves. Now I can inspect/measure them, if they are no good with groove sizes I'm going to be pissed that I scraped and soaked and brushed all the crud out.