Piston Install

[robert1]

I am not a chainsaw mechanic but I do have a large tree and the dealer won't fix my saw so I guess I have to try. Can anyone tell me how to remove piston from a 410? I don't know how to get the snap rings off the wrist pin. Thanks for whatever anyone can help me with. I've had this saw on bench in garage all winter and now it is getting warm enough out there to spend some time.

[bobby167]

Doe's this piston have one side oval hole & other side with a cutout down at bottom of piston pin hole? I think it should, but can't remember.

[robert1]

Thank you for the reply! It has a sideways oval hole on top and centered under that is the wrist pin hole. On one side of the piston those two holes have a channel in between them. On the other side they do not.

[bobby167]

Your description sounds like what most pistons are like. You need to remove the clip from the side that has, for lack of better description, the odd shaped hole on piston. Start on bottom, using a pry-pick, slowly bringing clip out of the groove it is in. Might take some time to do it. Careful, it could fly out. The other side, you can leave clip in piston. Drive out the pin, sometimes they will come out, with very little effort. My suggestion is to get a piston with wrist pin with it. Used one? Do Not reuse the clips! Get new ones, if not included with replacement piston. Take your time! One more thing. Mark piston to rod, so you know how new piston goes back together with connecting rod.

[robert1]

Thanks bobby. I got it out. Now to get the new piston on. A new set of bearings for thee wrist pin came with the piston. What are the chances that those need replacing? I also should tell you that I've not taken the rod off the crank. Trying to do this without getting to deep into it.

[bobby167]

Yes, Replace them.  What I was talking about marking piston to rod is to put new piston on same way. The clip you removed to take piston pin out, to same side as it was on rod. Hope this makes sense to you. If you don't have a IPL or repair manual, go to home page, go down to Homelite repair manuals. Search for your model. Take your time, you can do it. Suggestion for you, use your phone to take pictures, that way you have a reference to look at if you have a problem. Did you get new clips for wrist pin?

[robert1]

Oh great. I already put the new piston and pin on the rod assuming olld bearings would be OK. I was careful to put the piston on with same orientation to rod as old one. Now I am looking to figure an easy way to put new snap rings in grooves. Is there any special tool you'd suggest? So far no luck with dental pick thing and fingers. Mini pliers?  Tweezers with rubber tips maybe?

[bobby167]

Start one end with your fingers. Then, holding in, use flat screwdriver to push it in. Working your way around the clip. Might take you couple tries. Watch it doesn't fly out, they aren't fun to find. When you get clip in, use a small punch / screwdriver to gently push ends of clip, to make sure it is seated in grove. As I said before, take your time.

[robert1]

thanks bobby. I that done. Only lost one clip and thankfully found on floor and not in mechanism. I put the gasket and am trying to put the jug over the piston. Do you have to have a mini ring compressor or what is the trick on this ?

[bobby167]

Yes & no, I have the tools. Try this, but be very carful. Slowly start piston in cylinder, pushing first ring together, compressing. Ease in to you get to 2nd ring. Do the same thing. Crude, but I have done it before. Again, be very careful, don't force it to go in cylinder.

[robert1]

Like you said earlier, go slow. Unfortunately I just found the shop manual you referred to and I'm afraid I have to take it all apart again. Should be quicker the 2nd time at least. I just measured the pin bearing width that came with the new piston I put on and it is the later, wider bearing that checks in at .570 if I am reading my caliper right. So I guess the piston I put on has the wider boss measurement which means the saw will shell out if I run it with the old bearing. Like you said, I should have taken my time.

[bobby167]

Yea. Check, recheck & check again. I have found over the years that the box might list proper part number, but part wasn't the correct one. Quick question for you, I noticed on another thread, you posted picture of snap ring's. These were not in saw's piston were they? The ones I'm aware of are part number 64813. They look like a "C". If they came with piston, better check that it is correct piston assembly for your 410.

[robert1]

I don't think I did that. I remember posting something twice and then it disappeared and I could not find it again. Then I found my way to this board. The snap rings that came with the piston were C shaped, made of thin round wire and had no holes at all for snap ring pliers to go thru.

[bobby167]

Sorry, I wasn't paying attention to what was in that thread. Yea, check / recheck / check again. That was what I should have done when I read that post.

[robert1]

Have you got any suggestions as to how to get the old wrist pin bearing out of the rod without taking rod off crank? Also how to put new wider ones in?

[bobby167]

Could you post some pictures of new & old pistons/ bearings? I can tell you how / what I use, but if you never done one before it could go bad real quick. Keeping in mind that the saw is turning over 9,000 RPM's. If something isn't correct, your going to end up with a parts saw. Suggestion to you would see what a local machine shop or small engine shop would charge you. Also, if you have access to old rod you could practice on it. Not too bad to remove bearing, but.

[robert1]

I'm either going to have to take the rod off the crank to swap wrist pin bearings or take to someone with the right equipment.

[robert1]

I got an old style piston installed with the old bearings. I notice the top ring is staked so that it only moves a fraction of an inch in the groove.  Is the bottom ring supposed to move freely or is it staked too. Mine doesn't seem to slide in the groove.

[robert1]

Apr 29, 2022 15:56:25 GMT -5 robert1 said:

I got an old style piston installed with the old bearings. I notice the top ring is staked so that it only moves a fraction of an inch in the groove.  Is the bottom ring supposed to move freely or is it staked too. Mine doesn't seem to slide in the groove. I got the ring out of the groove and chased the groove so the ring moves freely in it now. I  must have pinched the groove with my makeshift equipment when I pressed the wrist pin out. Now I think that is fixed so next is how to compress the rings so I can get the jug over them. I haven't looked at the manual yet. I hope I can find it again and I hope you don't need a special tool. Right now I am using an RC can that I have cut into pcs.

[robert1]

I looked at the manual and could find no reference to how you get the jug over the rings. What do you use for a piston ring compressor? Any advice appreciated. I would post a pic but haven't figured that one out yet. I figured it out.