cylinder, piston replacement choices, Poll!

[dps650rider]

Hard choice. I'm doing 706 pistons only because my 700 JE's and bores are worn out after 60k miles or so. 706 is the last size so I don't think I would do that if I were close to stock bore.

Too bad other sizes werent available.

 

[MrBultaco]

Did a little research today and $75/ hole is a great price...lots are in the $95-100.

 

[dps650rider]

For me I think it would depend on the bike it was going into and my budget considerations.

For a correct restoration on an early bike…..2nd over stock
If money is tight……2nd over
If money is not an issue……750 kit
Im not familiar with the cruising image 706 kit……..what’s in it? Price?

https://www.cruzinimage.net/2017/08/29/74-81-yamaha-xs650-706cc-bigbore-pistons-kit-78mm-447type/

 

[Mailman]

https://www.cruzinimage.net/2017/08/29/74-81-yamaha-xs650-706cc-bigbore-pistons-kit-78mm-447type/

Aha! Thanks for the link!

 

[46th Georgia]

Did a little research today and $75/ hole is a great price...lots are in the $95-100.

So you can see my guy @$300 for 4 bores is not overpriced

 

[arcticXS]

I wonder why there are no aftermarket 80 or 81 mm Nicasil cylinders. That would bring that part of the XS into at least 80's/ 90's standards. Nicasil is extremely wear resistant, and having no iron/ steel liner improves cooling. And you even save a little bit of weight as well. I pulled the cylinders on my 95 Ducati 600 at around 60 000 km/ 40 000 miles, to install a big bore kit. There were absolutely no wear lip near TDC, and the honing crosshatching was still very visible. These late 80's and onwards aircooled Ducatis have the rear head exhaust port facing aft, just like a Harley, so the cooling is not really optimal. But still no problem.

I have also been messing a bit with a 98 Suzuki 125, which has a traditional liner, and several big bore options up to 170 cc are available. I ended up with the budget option of a 61 mm/ 143 cc Wiseco piston. Only to discover later that Athena offer a 155 cc Nicasil cylinder kit. Which I definitely would have got if I knew.

 

[MrBultaco]

Yup 46th, I made a mistake...so I guess I really DO live in a bubble.

 

[gggGary]

My local guy now wants more for the 706 bores than the 1.0 over size. Says the liner gets thin enough to start flexing where it extends below the cylinders so he has to take thinner cuts as he gets closer to the final size. Might need to think about making a liner support for the boring operation.

Related? Made a low ball offer on these at the end of the Barber fleece market. damn he took my money!
Said they had only a few hundred miles but he had a oiling problem of some sort. One top ring is MIA. JE trademark, think he said they came from hoos.
was wondering how bad it would be if I honed and got that one ring, or new rings, sanded one piston with 600 put the other on the buffer, black on sisal. Otherwise the jugs would be fine to bore for a 706 kit.

 

[Jan_P]

Is there a scratch in the cylinder --the black line --- I would focus on that .perhaps get a
green light from a shop. I guess OK
Otherwise it looks fine.

 

[46th Georgia]

Yup 46th, I made a mistake...so I guess I really DO live in a bubble.

All of us over a certain age do. We simply remember when you could rebuild a 350 Chevy for a couple of hundred bucks and still have money for pizza and beer.

 

[gggGary]

On the theme..
Going to mess around with some old stock jugs and a cheesy spring type 3 stone hone I have. Think I can make a nice easy to control set up on the mill.
Yeah I know, ball hones. But that's an "oil thread class" debate! But hey these jugs owe me nothing, will prolly get bored out anyways, and it'll be fun...............
I'll try to follow up with some pics, mebby vids.

 

[jay760]

I think the option that quite a lot would go for isn't a choice on the poll, or should I say it is but it includes headwork at 1500, where most would buy the pistons and sleeves and have the sleeves fitted locally,
If I added up what my engine has cost I could probably have bought a very nice bike,

 

[jpdevol]

oil thread class

??

 

[Jim]

??

Debate/screaming match.... my oil's better'n your oil buddy.

In with both feet... used both types. Balls are no brainer. You'd have to be pretty incompetent to eff one up.
3 stone takes finesse. Pretty easy to eff a cylinder up. I'll use my 3 stones... thank yew very much.

 

[jpdevol]

Thanks! For some reason I didn't read "oil thread", I read "thread class" with oil inexplicably included. Thought we were gonna have a debate about thread (bolt) fit and oil hardening

 

[gggGary]

Gary H said he'll scrounge around, thinks he can find a ring or the ring sets for the jugs
with JE pistons above.
Kinda why I dragged out the old three stone hone those jugs need a little touch up...

 

[jpdevol]

Kinda why I dragged out the old three stone hone those jugs need a little touch up..

Ah...now I'm on the same page (maybe); yeah, IMO the scoring is a expandable hone thing - beyond the capability of ball hone (finishing, de-glazing)

 

[46th Georgia]

I think the option that quite a lot would go for isn't a choice on the poll, or should I say it is but it includes headwork at 1500, where most would buy the pistons and sleeves and have the sleeves fitted locally,
If I added up what my engine has cost I could probably have bought a very nice bike,

I hear you. I'm planning on going with a 700-JE setup with a ported head, welded crank Carrillo, blah blah blah... and yes, I can buy a much faster bike for less, but that's not what I want. Stupid? maybe, but the heart wants what the heart wants.

 

[gggGary]

So spent a little time with a VSR plug in drill and the bigger of my three stone hones on the 2mm over cylinders, it didn't take long to know these are beyond saving at the current bore. they should make nice 706 bore doners
Mr. bore can get a pile done "by spring" I'll inventory jugs and order up some piston sets.
Gotta go get the nesco in and start degreasing jug sets. Fun, fun, fun.


a set of stock bore jugs with a rust ring (typical)

 

[gggGary]

Rub a dub dub, scrub your jugs in the tub.....