Piston and valve bumpin

[kasey200x]

I'm buying this top end from a feller and he said that they put the wrong valve in it. He said that they put a "atc" valve in it, and it's an xr200. Little does he know, they all use the same valve. It obviously did have problems though. Any thoughts? I don't see how this could be. Unless the valve was bent maybe? You can see where the valve touched way higher on the piston that it should have.
If what's shown is the only damage, should still be good to go correct?
Thanks for any thoughts.

[tri again]

Someone else sure knows more but:

a) could be old damage and has nothing to do with the new valve
b) should be polished down since sharp edges are known
to cause preignition when they glow

Did it ever run?
or sounds like it blew up, valve got replaced with the "wrong'
one and never reassembled???

[ATCrider42]

So your just gonna use the jug and the piston? you are assuming that this will work on your trike i take it? If I were you I wouldn't mess around with buying used crap like this. Bore out your own cylinder and get a piston kit for your engine....then you'll be "good to go"

[edog]

Looks like it got bent with a previous head on it...then the was fixed...piston left in after problem...maybe?

[WilliamJ]

A bit of surface indentation on the piston crown shouldn't be a bother in itself - agreed it would be best to smooth off any sharp edges.

This looks a bit like someone tried to turn the engine over with the valve timing totally wrong. The first contact with the valve may have bent it a bit and then the second contact was a bit further across. The engine could never have run if the valve was like that so I should think the piston is okay. The marks are well away from the edges so the ring grooves should be fine. Check the rings slide in to their grooves check the ring gaps are within spec.

Check the clearance between the piston skirt and the bore at the top, middle and bottom of the stroke and check front and back and side to side - this shows if there's any taper or ovality in the bore and if the piston is a good fit. Compare with the specs in the manual. Check the piston and bore haves no heavy scuffing marks (machining rings should all be visible) and the wrist pin bearing is not sloppy. Might want to clean the gasket face up a bit to make sure it seals.

Bill

[kasey200x]

This cylinder and piston is brand new. From the bore and hone to the piston itself. Which is why i am buying it. I have the tools needed to polish the sharp edge's down and that will not be an issue. I think that it was off time as well. I most definatly will not pass this up. Even if the cylinder and piston won't work.. don't know why it wouldnt.. i will still have a head, cam, and carb out of a xr200 for A HUNDRED bucks. Which is a really good deal to me.

[edog]

This cylinder and piston is brand new. From the bore and hone to the piston itself. Which is why i am buying it. I have the tools needed to polish the sharp edge's down and that will not be an issue. I think that it was off time as well. I most definatly will not pass this up. Even if the cylinder and piston won't work.. don't know why it wouldnt.. i will still have a head, cam, and carb out of a xr200 for A HUNDRED bucks. Which is a really good deal to me.

Or the piston was installed backwards.....sound like a good deal to me!!

[rdlsz24]

How is the piston new if it already has a valve ding in it?

Rob

[WilliamJ]

This cylinder and piston is brand new. From the bore and hone to the piston itself. Which is why i am buying it. I have the tools needed to polish the sharp edge's down and that will not be an issue. I think that it was off time as well. I most definatly will not pass this up. Even if the cylinder and piston won't work.. don't know why it wouldnt.. i will still have a head, cam, and carb out of a xr200 for A HUNDRED bucks. Which is a really good deal to me.

Post some pics of the piston skirt and the bore if you can - it'll be easy to see if it's worn or picked up. Piston top looks new and at the very most, you only need to use some emery paper on the sharp edges of the dings, don't need to erase them. Sure, they'll fill with a little carbon over time but it won't matter at all.

[kasey200x]

That was something i also thought!

[kasey200x]

You right, pardon my bad wording. It was "fresh."
He Say's it had 10 hours on it and ran great. So I'm left to believe his cam chain jumped time and caused that problem. Sound agreeable?

[kasey200x]

Here is a few more photo's. The head looks really nice, aside from the paint. Which will be redone. Hopefully the valve wasn't bent.

[RapidRick]

Those marks just didn't happen from turning the motor over.

If the valve was making contact with the piston because of mistiming of the cam it wouldn't have turned over by hand with the spark plug out in the first place.

Also, those marks are in slightly different places on the piston dome. Seems to me the marks should all be in the same place.

[oscarmayer]

i think the piston is in backwards. i think the intake port is on the wrong side. that or it;'s the wrong piston all together. if the valve touches the piston it bends the valve. so you will have to replace it. the only other thing I can think of si they did not proeprly aling up the timming marks on crank and then on the cam. that is a common issue as well if your like 2-3 links out.

I would not trust he was honest about the engine starting. I think he attempted to start it and found out he did something wrong. then it also looks as if they did not use oil to put it together and then tried to start it w/o using any oil and even with the plug in.

I would at this point not trust anything they told you. take it appart do it right and start fresh.

[kasey200x]

Maybe it jumped once, then when the valve hit the piston it caused it jump more and more, Until it just stopped. That would cause this to happen correct?
And oscar, like i said, even if the cylinder and piston do not function correctly, i'm still getting alot of other stuff that is going to be included. So either way, i may get real lucky, or get off just satisfied.
Kasey

[WilliamJ]

Maybe it jumped once, then when the valve hit the piston it caused it jump more and more, Until it just stopped. That would cause this to happen correct?
And oscar, like i said, even if the cylinder and piston do not function correctly, i'm still getting alot of other stuff that is going to be included. So either way, i may get real lucky, or get off just satisfied.
Kasey

Yes you could be right there.

Piston looks new and bore looks fine - check the clearances. Piston is correct way round, the larger cutout for the inlet is on the correct side.

The head gasket faces (head and cylinder) look a bit rough and may need re-facing.

Bill

[kasey200x]

Should i be able to polish that down? With the speacial pad stuff suggested earlier? I don't want to get into taking anything off the surface because i know i can't take off an even amount and i don't have the money to get it done right now. If it get's here and is beyond my repair capabilities it will wait until i can afford to get that done.

[bcredneck]

i did that once forgot to tighten the cam chain i got lucky and nothing broke the easy way to test valves is to pump air into the spark plug hole and see if air is comeing out the intake or exast ports

[oscarmayer]

i have never seen a valve that kissed a piston not be bent.
valves are cheap. $34 gets you a black nitrate coated ones off ebay.

it's cheap insurance to ensure it'ts right. also while the valve is out, check to make sure the valve guide did not crack due to the connection of the too.

[bcredneck]

like i said i got lucky damb lucky

[WilliamJ]

Should i be able to polish that down? With the speacial pad stuff suggested earlier? I don't want to get into taking anything off the surface because i know i can't take off an even amount and i don't have the money to get it done right now. If it get's here and is beyond my repair capabilities it will wait until i can afford to get that done.

If you lay the gasket in place you need to see if there are any pits or scores under the the metal sealing ring. (If there are any lumps they can be taken off very easily.) A good way to clean the faces is to find a really flat surface (best is a steel surface plate as they are ground but not many people have one of those laying around) but a good alternative is a plastic laminated panel but you need to check its really flat with a straight edge. Stick a piece of 240 grit carborundum paper on it and using a thin spray lubricant rub the head (or cylinder) face gently to and fro. You need to avoid rocking it as that will take more off the edges. You can't take very much material off this way but it will show immediately where the indentations are. If they are under the sealing ring it will need machining. If they are outside or inside the critical area then the gasket will work fine.

[kasey200x]

Thank's for all the tips guys, will keep all this stuff in mind when putting it back together. I have a few set's of valves. And a complete head that i have been using with zero issues. Would just like to use this one if i can because it's obviously been cleaned and wen't through recently. Just can hopefully correct the few small mistakes that has happened to it.
Oh, btw picked up my first truck today. Turned 18 tuesday and went today to get it. Woop woop. It's a '84 custom deluxe in amazing shape. The ONLY problem is the shifter(It's a three on the tree- even better) I have to adjust the linkage tomorrow. It get's stuck on 2nd and 3rd and is hard to get back to 1st and R sometimes. Other than that, the little six banger is awesome. Espicially at 20mpg. Not to mention the interior is Near PERFECT.