Need my head examined (beware monster pics)

[Guest]

I can see the dead moth on a piston.

 

[TheCafeKid]

Yeah, calipers and mics too. I just haven't got to that step yet. Good grief, I just got the cylinders off tonight before the game. (I got on base 3 times, 3 RBIs and a fly ball straight to me in right field and we still lost. Heckuva good game though.) Tomorrow I'll go 'round the corner to HF and get set up for the walnut shells. I might even go to the HW store and get a chunk of pipe to make a valve spring compressor. I have to cut the stupid grass tomorrow evening, though.

I bought a can of Berryman's to clean my front master cylinder back in the spring. I guess I can get the pistons started in there too. I heard somewhere that the snap rings that hold the wrist pins need to be replaced if you remove them. Is true?

Youre going to need to fabricate a wrist pin puller if you dont already have one.. I know how, but you'll need some supplies. Honestly, I would just go at it with some carb cleaner, a wire brush and some steel wool and fine FINE sandpaper for the piston skirts. Pulling the pistons is IMO unnecessary and time consuming. You just need to get the domes and the sides PRETTY clean, spotless, in this time frame, is a luxury. Just my opinion though.

 

[tkent02]

I've reused wrist pin clips with no problem.

Some of them bend a little when you take them out, the correct answer is to replace but that might not always happen.

 

[Nessism]

Replace the clips for sure on the side you remove. Regarding the need for a piston pin press, much of the time it's not necessary - I've never had the need.

I think some of you guys are jumping to a conclusion about the condition of the parts before everything is measured. When rebuilding my 1000 engine I checked three different cylinder heads before I found one with valve/guides within the service limit. Wound up purchasing a used head off ebay that was relatively low mileage before finding one that was decent. Pistons and cylinder bores wear as well. And sorry to contradict Josh but I'd never sand the piston skirt - you don't want to take off any material or the clearance will increase. Some scuffing won't hurt anything, just decarbon the pistons in carb dip and then measure them.

Good luck.

 

[Dogma]

Replace the clips for sure on the side you remove. Regarding the need for a piston pin press, much of the time it's not necessary - I've never had the need.

I think some of you guys are jumping to a conclusion about the condition of the parts before everything is measured. When rebuilding my 1000 engine I checked three different cylinder heads before I found one with valve/guides within the service limit. Wound up purchasing a used head off ebay that was relatively low mileage before finding one that was decent. Pistons and cylinder bores wear as well. And sorry to contradict Josh but I'd never sand the piston skirt - you don't want to take off any material or the clearance will increase. Some scuffing won't hurt anything, just decarbon the pistons in carb dip and then measure them.

Good luck.

Well, I didn't see anything that looked like scuff marks on the skirts. More like burnished. Looking back at the pics, #4 does look like it has some marks on it. I'll take a closer look when I inspect the rings. I am a little nervous about the idea of taking material off the skirts. I cut my finger on #3, so something is thin already.

Thinking about it now, instead of at 2:00 AM, if I can just brush the piston tops clean and be good enough, I'd rather do that.

Now here's a theory question: Why does the carbon have to some off? Is it likely to flake off someday and score the cylinder or something?

 

[TheCafeKid]

Well, I didn't see anything that looked like scuff marks on the skirts. More like burnished. Looking back at the pics, #4 does look like it has some marks on it. I'll take a closer look when I inspect the rings. I am a little nervous about the idea of taking material off the skirts. I cut my finger on #3, so something is thin already.

Thinking about it now, instead of at 2:00 AM, if I can just brush the piston tops clean and be good enough, I'd rather do that.

Now here's a theory question: Why does the carbon have to some off? Is it likely to flake off someday and score the cylinder or something?

Not to contradict Ed but since the piston itself never comes into contact with the cylinder wall, and your not sanding the ring grooves, and with some 1000 or 2000, or even 2500 grit sandpaper just to clean the burmishing (im not talking going to town with a Dremel on it) isnt going to take that much material off How much is that really going to change the spacing? ....but whatever. At any rate, Carbon shold be removed at the given opportunity because excessive carbon build up will actually change the compression ratio within the cylinder. Not to mention the fact that you let it stack up TOO much and you might start touching valves...HA!

 

[posplayr]

Youre going to need to fabricate a wrist pin puller if you dont already have one.. I know how, but you'll need some supplies. Honestly, I would just go at it with some carb cleaner, a wire brush and some steel wool and fine FINE sandpaper for the piston skirts. Pulling the pistons is IMO unnecessary and time consuming. You just need to get the domes and the sides PRETTY clean, spotless, in this time frame, is a luxury. Just my opinion though.

On my 1100 it was pretty carboned up and it was a PITA to get the wrist pins out. In fact in hitting on the side of the piston with a mallet, ended up bunging up the pin hole entry and required some delicate garage machine work to get the pins to float again. All that is past me now as I bought a BB kit. Accoroding to RapidRay those pins should just glide and between the carbon and bunging up the ends of the piston gliding may not be there.

As far as sand paper, I have used 1000 grit to clean up carbon in cam journals on the ED with nice results. What looks like wear is really seems to be embedded carbon and a few rubs with the 1000 grit cleans to so it looks new. I guess the same could be done on the pistons. Even if you soak them, the hand held walnut blaster is nice because it just gets into all the places that you would have to Brush or scrape. It did a nice job of decarboning my old pistons after pulling the rings. Also sooting down teh intake and exhasust runners is nice without the real possibility of damaging the seats.

I think I would stay away from any engine with steel wool. Not something I would want to get near the inside of the engine. Even using the the sand paper, keep it away from the engine and clean the parts well after sanding.

 

[Nessism]

Not to contradict Ed but since the piston itself never comes into contact with the cylinder wall, and your not sanding the ring grooves, and with some 1000 or 2000, or even 2500 grit sandpaper just to clean the burmishing (im not talking going to town with a Dremel on it) isnt going to take that much material off How much is that really going to change the spacing? ....but whatever. At any rate, Carbon shold be removed at the given opportunity because excessive carbon build up will actually change the compression ratio within the cylinder. Not to mention the fact that you let it stack up TOO much and you might start touching valves...HA!

Hey Josh,

The piston skirt contacts the cylinder wall (with a cushion of oil in between) with every stroke. The skirt gets scuffed up because of this contact. The skirts don?t tend to wear much but still, I can?t see any good coming from sanding on them. Regarding removing the carbon, carbon often gets into the top ring groove so inspect for that carefully. Carbon build up will bind up the rings so removing all the carbon is always a good idea.

 

[Dogma]

Gonna have to disagree with my mechanic on this one. The skirts are there for no other reason than to touch the cylinder wall and keep the piston straight. Otherwise pistons would be nothing more than the face, ring grooves, and wrist pin mounts in order to keep the mass down and get higher revs.

Do I sound like an engineer? Head full of information and opinions, still can't do it myself (yet).

 

[tkent02]

Gonna have to disagree with my mechanic on this one. The skirts are there for no other reason than to touch the cylinder wall and keep the piston straight. Otherwise pistons would be nothing more than the face, ring grooves, and wrist pin mounts in order to keep the mass down and get higher revs.

Do I sound like an engineer? Head full of information and opinions, still can't do it myself (yet).

One other job the skirts do is to transfer heat from the piston to the cylinder walls through this contact.

Sanding contact areas on pistons is commonly done on two stroke pistons, don't know if most folks do it to four stroke pistons. I have only done it to clean up very rough areas.

Cleaning carbon is nice to make your engine pretty inside if that's important to you. Unless there are large enough deposits to cause preignition or alter the compression ratio it's not a problem. I like to clean them before it all gets disassembled by running a little water injection through a hot engine.

 

[TheCafeKid]

Ok, what I SHOULD have said is they are not what one would generally consider a "worn/replace" part, such as a piston ring wrist pin clip, etc. (of course if they get bad enough, you'll probably have to pitch em) however, polish beget polish, for piece of mind *I* would smooth the edges. Having seen what happens to upper fork tubes when the bushing gets a polish going, i can only assume the cylinder wall suffers for it. Again, im a shade tree mechanic, so I may be completely wrong. At any rate, you'll likely hone the bores so it probably doenst much matter, do what you think is best, and I will continue to do what I think is best

 

[Dogma]

...do what you think is best, and I will continue to do what I think is best

Everyone gets to be right here at the special school!

 

[Dave8338]

I've even machined piston skirts to rid some rotating weight. Just say'n...

Clean them up with degreaser and a Scotch Brite pad and let er buck!

 

[Dogma]

Arright. I had a couple little wire wheels so I did it Steve's way. I can see the T-shirt now: "GS riders do it Steve's way". Anyhow, the results are the same as his, so I didn't take a picture.

I also got some inspecting done. Piston diameter at the skirt, ring to groove gap, and free ring gap were all easily within normal limit, not even the service limits (according to Clymer). Consistent across all four, too. Basically, it's like new in there, except for the carbon. I didn't take the rings off and stuff them up the bore to check the gap there though. Not looking forward to that chore. How easy is it to accidentally break rings removing them? I'm thinking I should use snap ring pliers to expand them.

I also picked up ingredients for a valve spring compressor. I hope to get the valves out before I take the head to Pearson's on Saturday. I sure hope he can get it done on Saturday. I'll be in great shape if I can get the seals and valves back in this weekend.

Speaking of seals... the left fork seal decided to make a puddle sometime in the last 24 hours. Just wonderful. Well, Jim predicted those pitted tubes would cause an early failure. Time to swap on the new set, I suppose. That'll give me something to do if I don't get the head back this weekend. Let's hope those seals are still good.

 

[Nessism]

You can remove the valve locks by placing a socket over the retainer and giving it a good wack with a rubber mallet. Stuffing a wadded up rag in the combustion chamber helps by keeping the valves seated. I've used this trick several times with success. Lynn mentioned this trick in a thread a few years ago so she gets credit.

 

[p_s]

You can remove the valve locks by placing a socket over the retainer and giving it a good wack with a rubber mallet. Stuffing a wadded up rag in the combustion chamber helps by keeping the valves seated. I've used this trick several times with success. Lynn mentioned this trick in a thread a few years ago so she gets credit.

+1 but also stuff some paper towel in the socket. I also used my hands to put them back on instead of a home-made compressor--but I'd guess that's much easier on a 16-valve 550.

 

[Steve]

Arright. I had a couple little wire wheels so I did it Steve's way.

MY way??? What are you talking about???

The posters, so far, in order of appearance:
Dogma - Dale
First timer - ??
Posplayr - Jim
Nessism - Ed
Steve - Steve
TheCafeKid - Josh
Chef1366 - Bill
Dreef1999 - ??
Tkent02 - Tom
Dave8338 - Dave

I seem to be the only "Steve" so far, and all I suggested was smaller pictures. :-k

But, ... since you are under the impression that I suggested wire wheels, let me confirm that impression.
This is how we cleaned the pistons in #2 son's 850 last summer:

.

 

[TheCafeKid]

Arright. I had a couple little wire wheels so I did it Steve's way. I can see the T-shirt now: "GS riders do it Steve's way". Anyhow, the results are the same as his, so I didn't take a picture.

I also got some inspecting done. Piston diameter at the skirt, ring to groove gap, and free ring gap were all easily within normal limit, not even the service limits (according to Clymer). Consistent across all four, too. Basically, it's like new in there, except for the carbon. I didn't take the rings off and stuff them up the bore to check the gap there though. Not looking forward to that chore. How easy is it to accidentally break rings removing them? I'm thinking I should use snap ring pliers to expand them.

I also picked up ingredients for a valve spring compressor. I hope to get the valves out before I take the head to Pearson's on Saturday. I sure hope he can get it done on Saturday. I'll be in great shape if I can get the seals and valves back in this weekend.

Speaking of seals... the left fork seal decided to make a puddle sometime in the last 24 hours. Just wonderful. Well, Jim predicted those pitted tubes would cause an early failure. Time to swap on the new set, I suppose. That'll give me something to do if I don't get the head back this weekend. Let's hope those seals are still good.

I have a spare set I am about to send back because they werent the right ones for the 550 i just did. They WILL work on your 850 tho. Changing the fork seals takes me about an hour, Ive got lots of practice in this week...lol Let me know if you need them, if you can by tomorrow, and I wont send them back. I take it you DID get ahold of Pearsons after all?

 

[Dogma]

I have a spare set I am about to send back because they werent the right ones for the 550 i just did. They WILL work on your 850 tho. Changing the fork seals takes me about an hour, Ive got lots of practice in this week...lol Let me know if you need them, if you can by tomorrow, and I wont send them back. I take it you DID get ahold of Pearsons after all?

An hour for fork seals? That sounds about right, if you hustle. Yeah, hang on to those for me please. We can do the new forks, seals and progressives at the same time. But some time after it has a whole engine again.

Yeah, I did get hold of Pearson's. I'll drop the parts off with the man himself Saturday morning.

 

[Dogma]

MY way??? What are you talking about???

The posters, so far, in order of appearance:
Dogma - Dale
First timer - ??
Posplayr - Jim
Nessism - Ed
Steve - Steve
TheCafeKid - Josh
Chef1366 - Bill
Dreef1999 - ??
Tkent02 - Tom
Dave8338 - Dave

I seem to be the only "Steve" so far, and all I suggested was smaller pictures. :-k

But, ... since you are under the impression that I suggested wire wheels, let me confirm that impression.
This is how we cleaned the pistons in #2 son's 850 last summer:

[pics deleted]
.

Them's the pics I saw somewhere. I thought it was here. Maybe they were posted in one of hte linked threads on wlanut shells? Thanks for clarifying for those who must have been wondering.