Big Bore On Stock Steel Sleve

[Tecate250]

This might be a stupid Question but I cant find anything on this on 3ww anywhere. I have 2 max bore 1985 Tecate cylinders. Now Ive looked around for a bigger bore system and there are pistons out there that can work for a big bore. Now is there a ratio for the thichness of a steel sleeve? I mean can you bore out a 72 mm bore to say a 73? If not then a big bore sleeve would be to over bore the cylinder to accept a larger bore sleeve? I hope this makes sense.

[C.J]

Thats basically what you do. With our suzuki's we can resleeve them with a thicker than OEM sleeve but it costs a lot more because the cylinder itself has to be bored to accept the bigger sleeve OD. Also, we can put a 72mm jet ski piston in a 87-92 cylinder with stock sleeve and it becomes a 270,, mine right now is a 265,,,, but if you bore a stock thickness sleeve that far it will trash the actual jug when ever the bore is worn out. It'll cause it to warp and the cylinder goes untrue and all.

I would assume the same would happen with a tecate. I'm sure you can get a thicker than OEM sleeve and have it bored to your preference,, then you can bore a thicker sleeve one or two times more and have a "big bore" like 270-275 maybe,,

[Tecate250]

Yes but how thick must the sleeve walls be to be able to safely run a piston?

[LastFoolerInVA]

Talk to John Tice on everything2stroke.com , I've read a few of his posts & this kinda thing is right up his ally & may even be able to make a customer sleeve for ya...

[manbearpig]

Hit up Rob Selvy on facebook. hes doin up a couple big bore T3 motors and has decades of big bore and tuning experience

[barnett468]

Yes but how thick must the sleeve walls be to be able to safely run a piston?it depends what the bore is. you can run a thinner wall on a 90 cc than you can on a 250. any bike is designed to go 1 mm [.040"] over so yes if you have a cyl that is 72 stock you can go to 73 with no prob..

[El Camexican]

If I understand your question correctly you want to know how thick the sleeve of your big bore cylinder needs to be? If so I would say that you need to measure the OD. Of your stock sleeve and the current 2 over bore of the I.D. Then whatever you want your new big bore I.D. to be just add that amount and a little more to compensate for the example of a larger bore needing more material like Barnett said. That should work in theory, but in reality you have to consider that you might be getting close to your studs and water jacket. You would also be decreasing the volume of your transfer ports by doing this.

If you are sure you want to do this mod I suggest you contact Mark at Kustom Kraft. He can do whatever you want including a 290 kit from what I see on his site. Tell him a guy in Mexico sent you and that he expects his cut!;)
http://kustom-kraft.com/KAWASAKIKITS.html

[Tecate250]

Thanks. Were getting there. I know I didnt explain myself enough here. But Barrnet is close to my answer. So Why can you run a thinner wall on a 90? Lets just say both engines have stock bore Sleeves. And both engines have 150 psi. So with that i mind. Is there anything bad on boreing out the sleeve to its max? Reduceing the sleeve's wall thickness by alot. So would a thinner steel wall be better then a thicker wall? How thin on a steel wall is too little? I mean a nika Plated cylinder like the tecates only have a very small linner in the aluminum cylinder. Is this process better? And on the same note. Other then bridged exhaust ports are there pros and cons of boreing out a nika plated cylinder and getting it re plated? Like heat transfer?

[John Tice]

I’m a little late on this thread but I just joined. Sleeve material; Sleeves are all made of some alloy of grey cast iron. Some are Ductile iron which is a slightly different mix of cast iron. We use both centripetal & green sand castings; both types work well if the casting is sound & solid. SLEEVES ARE NOT & I DON’T THINK THEY WERE EVER MADE OF STEEL. Cast iron contains around 6% carbon which makes it as slippery as your #2 pencil lead.

Years ago at my Dad’s Kart shop we took in a trade & the rig had an 820 West Bend engine. If any of you folks go back that far; West Bend 820 engines were one of the first which had a chrome plated cylinder. The guy who traded in the kart attempted to resleeve the cylinder with seamless steel tubing. It took so much oil in the 2 stroke fuel mix that the engine would hardly start. I learned this lesson at the age of around 12 in circa 1960 or so. :wondering

Back to the big bore or any other sleeve liner thickness. The mechanical strength & gasket sealing abilities are one of the main considerations of the cylinder & the sleeve thickness. When we sleeve a cylinder I like to reline thick enough so the cylinder can take a +.080”, or 2mm overbore. With oversizes aside I feel that a .100” or 2.54mm sleeve is thin enough. For 2 strokers the bottom of the sleeve which slides into the crank case is also a consideration. Lastly the shrink fit of the sleeve into the cylinder is #1 for strength & heat dissipation. We shrink fit a sleeve anywhere from -.002 clear up to a -.010” depending on whether or not the sleeve can be removed or twisted for port alignment. With 2 strokeres we also must consider the function of the power valve. When we sleeve a 2 stroke the power valve must also be supplied in order to make sure that the PV still works.
As far as the maximum thickness goes; the sky’s the limit, keeping in mind the skirt clearance required for the cylinder & piston to live with one another. I think that about covers it all for starters.

Round & straight

http://i1152.photobucket.com/albums/p497/johntice1/January%202015/P1011474.jpg (http://s1152.photobucket.com/user/johntice1/media/January%202015/P1011474.jpg.html)

What’s the secret; is plating better than an Iron sleeve. It’s cheaper to manufacturer a cylinder without an iron liner. There are reasons for both; Do you want to do extra port work? Iron liner. If nothing else is to be done? Plated. With the new CADD systems, many can design a quality cylinder, it still needs a liner for the piston to travel thru. Plating / Sleeve; which is cheaper? Think / decide for yourself.


Any other questions; Fire away www.smallenginemachineworks.com
503-593-2908

The “Old Dog”

:beer
JT

[John Tice]

I’m a little late on this thread but I just joined. Sleeve material; Sleeves are all made of some alloy of grey cast iron. Some are Ductile iron which is a slightly different mix of cast iron. We use both centripetal & green sand castings; both types work well if the casting is sound & solid. SLEEVES ARE NOT & I DON’T THINK THEY WERE EVER MADE OF STEEL. Cast iron contains around 6% carbon which makes it as slippery as your #2 pencil lead.

Years ago at my Dad’s Kart shop we took in a trade & the rig had an 820 West Bend engine. If any of you folks go back that far; West Bend 820 engines were one of the first which had a chrome plated cylinder. The guy who traded in the kart attempted to resleeve the cylinder with seamless steel tubing. It took so much oil in the 2 stroke fuel mix that the engine would hardly start. I learned this lesson at the age of around 12 in circa 1960 or so. :wondering

Back to the big bore or any other sleeve liner thickness. The mechanical strength & gasket sealing abilities are one of the main considerations of the cylinder & the sleeve thickness. When we sleeve a cylinder I like to reline thick enough so the cylinder can take a +.080”, or 2mm overbore. With oversizes aside I feel that a .100” or 2.54mm sleeve is thin enough. For 2 strokers the bottom of the sleeve which slides into the crank case is also a consideration. Lastly the shrink fit of the sleeve into the cylinder is #1 for strength & heat dissipation. We shrink fit a sleeve anywhere from -.002 clear up to a -.010” depending on whether or not the sleeve can be removed or twisted for port alignment. With 2 strokeres we also must consider the function of the power valve. When we sleeve a 2 stroke the power valve must also be supplied in order to make sure that the PV still works.
As far as the maximum thickness goes; the sky’s the limit, keeping in mind the skirt clearance required for the cylinder & piston to live with one another. I think that about covers it all for starters.

Round & straight

What’s the secret; is plating better than an Iron sleeve. It’s cheaper to manufacturer a cylinder without an iron liner. There are reasons for both; Do you want to do extra port work? Iron liner. If nothing else is to be done? Plated. With the new CADD systems, many can design a quality cylinder, it still needs a liner for the piston to travel thru. Plating / Sleeve; which is cheaper? Think / decide for yourself.


Any other questions; Fire away www.smallenginemachineworks.com
503-593-2908

The “Old Dog” Your Cylinder Man

:beer
JT

[John Tice]

I’m a little late on this thread but I just joined. Sleeve material; Sleeves are all made of some alloy of grey cast iron. Some are Ductile iron which is a slightly different mix of cast iron. We use both centripetal & green sand castings; both types work well if the casting is sound & solid. SLEEVES ARE NOT & I DON’T THINK THEY WERE EVER MADE OF STEEL. Cast iron contains around 6% carbon which makes it as slippery as your #2 pencil lead.

Years ago at my Dad’s Kart shop we took in a trade & the rig had an 820 West Bend engine. If any of you folks go back that far; West Bend 820 engines were one of the first which had a chrome plated cylinder. The guy who traded in the kart attempted to resleeve the cylinder with seamless steel tubing. It took so much oil in the 2 stroke fuel mix that the engine would hardly start. I learned this lesson at the age of around 12 in circa 1960 or so. :wondering

Back to the big bore or any other sleeve liner thickness. The mechanical strength & gasket sealing abilities are one of the main considerations of the cylinder & the sleeve thickness. When we sleeve a cylinder I like to reline thick enough so the cylinder can take a +.080”, or 2mm overbore. With oversizes aside I feel that a .100” or 2.54mm sleeve is thin enough. For 2 strokers the bottom of the sleeve which slides into the crank case is also a consideration. Lastly the shrink fit of the sleeve into the cylinder is #1 for strength & heat dissipation. We shrink fit a sleeve anywhere from -.002 clear up to a -.010” depending on whether or not the sleeve can be removed or twisted for port alignment. With 2 strokeres we also must consider the function of the power valve. When we sleeve a 2 stroke the power valve must also be supplied in order to make sure that the PV still works.
As far as the maximum thickness goes; the sky’s the limit, keeping in mind the skirt clearance required for the cylinder & piston to live with one another. I think that about covers it all for starters.

Round & straight

What’s the secret; is plating better than an Iron sleeve. It’s cheaper to manufacturer a cylinder without an iron liner. There are reasons for both; Do you want to do extra port work? Iron liner. If nothing else is to be done? Plated. With the new CADD systems, many can design a quality cylinder, it still needs a liner for the piston to travel thru. Plating / Sleeve; which is cheaper? Think / decide for yourself.


Any other questions; Fire away www.smallenginemachineworks.com
503-593-2908

The “Old Dog” Your Cylinder Man

:beer
JT

[onformula1]

^ Welcome John, I am glad you made it over here, I have told a few guys on this forum about your awesome work!

I love your posts on everything2stroke.com

Keep up the great work.

[onformula1]

Note- To Billy Golightly and/or the mods.

Can we get this gentlemen full access and possibly a star so he doesn't have to wait the 2 months or 10 posts, I am sure there are many people that can learn from him and he is always willing to teach his trade.

[John Tice]

Onformula; thank you for the comments. We need more people to take up the cylinder trade. If you can hone a cylinder Round & Straight we need you. If you don’t know how to hone Round & Straight, stay tuned & you will learn. My retired mission is teaching the trade; none of us know everything, all of us know something. (Stay Focused) We try to be the best in the small engine cylinder business.

http://i1152.photobucket.com/albums/p497/johntice1/image-54.jpg (http://s1152.photobucket.com/user/johntice1/media/image-54.jpg.html)

Thanks Again
:beer