Plated Cylinders

[doordie]

hughes,

I look into your pic?s of cylinder and YOU have to ask yourself some
questions.

1.Will I use this bike alot?
2.How much money for a replate?
3.How long time have you run with this piston already?

You can use this cylinder IF it?s in service limit,but don?t change piston,
only rings.Then save for a proper service with a portjob,replate and a new
piston.Ports are very bad matched stock as you see and electrofusion is
s**t....
You will loose some compression with all scratches,but a new set of rings will seal good anyway `cause no
scratches at end of stroke.
Measure at top of cylinder were rings turn for down stroke of piston.
Inspect piston for damage!
This is just my opinion,I`m not respons.....


//doordie

[hughes]

hughes,

I look into your pic?s of cylinder and YOU have to ask yourself some
questions.

1.Will I use this bike alot?
2.How much money for a replate?
3.How long time have you run with this piston already?

You can use this cylinder IF it?s in service limit,but don?t change piston,
only rings.Then save for a proper service with a portjob,replate and a new
piston.Ports are very bad matched stock as you see and electrofusion is
s**t....
You will loose some compression with all scratches,but a new set of rings will seal good anyway `cause no
scratches at end of stroke.
Measure at top of cylinder were rings turn for down stroke of piston.
Inspect piston for damage!
This is just my opinion,I`m not respons.....


//doordie

Questions:

1) Yes I will use this bike alot

2) I need to check with some companies for prices.

3) I have used this piston/bike for about 30 hours. Knowin g the condition of the bike I would say that the top end in this bike was original.

My questions to you.

1) Why reuse the piston and just replace the ring My piston is in pretty bad shape. Look in work in progress album for piston pictures.

2) I have a new top end kit already. Do you think I should use it  

I think this is what I may try. I have ordered a 360 grit ball hone. I am going to try some light honing to clean up the bore(Scratches) and measure for service limit. If plating starts to flake off then off it's goes to replate company.

[jdv500]

hughes,
in one of your pics in the gallery, you were asking if your piston was near seizure, you notice, gauging by those marks and discoloration... that is from your old piston worn in it's circumference and now is oscillating/ teetering inside the bore during the stroke. notice the scored areas are 180 degrees from each other  fore/aft and hi/ low, and that they are inline with the roll/ radially with the rod bearing. the piston in your pic is in great shape considering what it's been thru, how old it is. you said you have it all apart now and already have the complete top-end kit.? great, use it..
oh, and the cross-hatch that you mentioned not being present in the bore.?? the cross hatch micro lines are only there for the initial setting of the rings with oiling and only last a few mintues after the first crank up.......
..jdv

[doordie]

Hughes,

Oki, you have answered your own questions and it sounds to me IF you would use your bike alot
the answer is replate.
My opinion were,Why put in a new piston in a worn cylinder with nearly no limits left?
But if you wants a LITTLE more ours out of it,reuse piston and only change ring.
Worst case, a sieze and old piston goodbye.
After that can you use your new piston and replate cylinder:wink:
(make sure they trim/filing all ports before replating,save many ours on piston)

//doordie

[hughes]

Thanks guy's for the info and help. I am going to get some prices for plating. I want to ride this bike alot. I have put to much time and money into it's reserruction.

[gowen]

Hughes, a few people have had good experiences with Eric Gorr and his replating (he uses US Chrome), you could have him to some porting while it is in his hands too. Who knows, maybe even a big bore.

[hughes]

Thanks I was am going to send him an e-mail right now. What will a port job do for engine if I keep the standard bore size

[gowen]

Well, you can choose where you like the power, low-mid range hit, or a mid-topend hit, or what you call Mo-Better which he just works the ports to give power everywhere, like a spread out type deal. I had mine ported for mid-top hit, but that was cause he was doing a big-bore which usally tends to rob the top-end power. It is better to call him than to e-mail, he has never returned an e-mail from me. You could also post on dirtrider.net under the Eric-Gorr forum.

[hughes]

Thanks, I was just on his site and looked up the porting for diff. powerbands. Looks like I will call him. Porting looks to be $200.00. It would be nice to have some port work done to smooth my power. This 87 500 has a tubo powerband. I think I will need to just get re-plated bore.

[hughes]

My honing turned out good. The plating did not flake at any of the port openings. I'm going to install the new top end and replate later.

[John]

I checked this up and it's around ?110 to get some welding (for any deep cuts) and plating done on a KX5 cylinder here in the UK. The plating only is ?85. I think that's good value considering the price of a new piston is more...

//John