Cylinder Boring & Honing Survey

[Its been a long time]

Indeed, some cylinders, it's essential to bore and hone them in torque plates.

I haven't done a set of 650 cylinders so I don't know about those. Best practice anyway would be to mount them in torque plates, I think.

 

[grouchie77]

Indeed. In my spare time I designed a simple torque plate jig for the 650 cylinders, in case I wanted to bore mine out.

 

[gggGary]

Jeez y'all made me think, bolt em down to a junk top crankcase half?

 

[grouchie77]

Which would absolutely work.... but then how do you plan to secure the crankcase half to the machine?

 

[grouchie77]

I mean in theory you could just turn a head and rockerbox assembly into the top plate in the jig too by simply bolting that on and milling out 75mm holes.

 

[grouchie77]

Forgive the rudimentary photo, but this is my design. Simple enough to mount to a bed of a milling machine, whether it's a CNC or just a knee mill. Would clamp down just like any other plate.

 

[GPYamaha]

Lots of good comments about finding true bore centers and parallelism of the cylinder block. Nice ideas and remember that if you spend the time to do those checks what do you do if, things are a little off from the factory? If you try to correct a worn cylinder to blueprint specifications, you may run into a situation where one side of the cylinder is bored clean and the other side doesn’t clean up. Now you may have a set of junk cylinders. Whereas, boring on the original bore you can save the cylinders. One of the down sides to doing this as a business is the time it will take to do extensive measuring only to end up boring on the original bore.

Another consideration is I think it’s assumed that the cylinders are bored and honed at the factory after the cylinder liners are installed. I don’t believe this is the case. It would be more efficient to have a fixture that can hold and finish the liner and then simply assemble liners into the casting. Otherwise a cylinder that doesn’t pass inspection would require trashing a good casting. This may be evident in the information on the CB450 Honda service manual the lists factory oversize bored and honed liners that can simply be installed. My Yamaha service manual doesn’t list any special tool for clamping the cylinder for honing and doesn’t list a surface finish. It only lists runout clearances. Maybe someone has more information from Yamaha about this.

 

[GPYamaha]

I mean in theory you could just turn a head and rockerbox assembly into the top plate in the jig too by simply bolting that on and milling out 75mm holes.

Yes, I actually gave that some thought.

 

[RC4MAN]

If there's a press fit into the block it would affect the fitted size. I guess if you're building thousands you can figure for that shrinkage but the casual builder won't typically be able to do that.
My V-Rod uses wet sleeves so that's another avenue but it's a liquid cooled engine, air cooled engines require good physical contact for heat transfer.

 

[grouchie77]

Any pressing in of a bushing or cylinder or what have ye is going to affect its dimensions. I'm 99.999 percent convinced that the steel liners were bored and finish honed at the factory after being pressed into the aluminum cylinder block.

If I need a bushing to be perfectly round after being pressed into its housing, I bore it out .020 under (on diameter), install it, then finish machine it. That's the only way I know for a fact that the ID is perfectly round and on size.

 

[GPYamaha]

If there's a press fit into the block it would affect the fitted size. I guess if you're building thousands you can figure for that shrinkage but the casual builder won't typically be able to do that.
My V-Rod uses wet sleeves so that's another avenue but it's a liquid cooled engine, air cooled engines require good physical contact for heat transfer.

We would heat the cylinder up in an oven and the liner would just push out. The 2-stroke dirt bikes were always wiping out cylinders and replacing a liner was common. (going back to bikes pre water cooling)

 

[GPYamaha]

If there's a press fit into the block it would affect the fitted size. I guess if you're building thousands you can figure for that shrinkage but the casual builder won't typically be able to do that.
My V-Rod uses wet sleeves so that's another avenue but it's a liquid cooled engine, air cooled engines require good physical contact for heat transfer.

I only have a couple XS cylinders but I was looking at the sleeve to cylinder block fit a few years back on a Honda CB350. I have to go see if I can find it. I cut one side up but I think the other side is intact. Maybe I will bore it and then remove the sleeve and see what happens.

 

[AUTOMAN]

We would heat the cylinder up in an oven and the liner would just push out. The 2-stroke dirt bikes were always wiping out cylinders and replacing a liner was common. (going back to bikes pre water cooling)

If the sleeve IS shrunk fit.
Rare on '70's bikes. Usually it is cast with jug.
Starting in later '70's spray bores came in.

So, you must distinguish and determine if you can do for the profit.

Many complex things here.

 

[Jim]

The liners are a light interference fit. Heated to about 250° f and they'll just fall out.

https://www.xs650.com/threads/replacing-a-cylinder-sleeve-how-to.52354/

 

[Jan_P]

Hi Everyone,
I own a small machine shop that produces prototypes for products. My machines are also suited for boring cylinders. I have several of my own cylinders that I plane to bore in the coming weeks. A few people have suggested that I offer boring and honing as a service; however, I’m not sure this service is in demand. I would like to hear from members their opinion on the need for this service.

Thanks

I checked some years ago here in Europe there was suppliers selling a kit Cylinders with pistons the whole set
I am all for reuse but if the cost is the same for new I do that
The boring and freight and so.Made it a better alternative buy the set if a re bore was needed to just buy the set
The re bore seems overall cheaper in the US
Dont know the quality and never re bored yet the cylinders received a pass and was honed at the Yamaha Dealer
I don't believe they used any complicated equipment.

Maybe check who is doing it locally and what they charge. A market is always difficult to estimate.
And it depends on when the word gets out . Here the word spreads mouth to mouth among those have the interest.
If it is Welding aluminum / electric rewinding someone knows someone somewhere.
I did hear of some having lot of work .Being retired doing electrics for old and antique machines
long waiting time and chose what he took on.

I know very little of the complexity doing it but why not have the possibility But as mentioned above perhaps more customers for other bikes.

There is also exchange schemes of various kinds

https://www.heidentuning.com/xs650-...inders/cylinder-447-type-exchange-detail.html

 

[AUTOMAN]

Hi Everyone,
I own a small machine shop that produces prototypes for products. My machines are also suited for boring cylinders. I have several of my own cylinders that I plane to bore in the coming weeks. A few people have suggested that I offer boring and honing as a service; however, I’m not sure this service is in demand. I would like to hear from members their opinion on the need for this service.

Thanks

Which bores? xs650's only?

 

[GPYamaha]

The liners are a light interference fit. Heated to about 250° f and they'll just fall out.

https://www.xs650.com/threads/replacing-a-cylinder-sleeve-how-to.52354/

Ya, heat to 250 Degrees is what I remember

 

[GPYamaha]

Which bores? xs650's only?

650 Only

 

[GPYamaha]

If the sleeve IS shrunk fit.
Rare on '70's bikes. Usually it is cast with jug.
Starting in later '70's spray bores came in.

So, you must distinguish and determine if you can do for the profit.

Many complex things here.

Actually, the factory Yamaha 2-stroke GP bikes had single ring chrome plated cylinders and no sleeve. ...I know because I have one and raced it a longggg time ago! TA250

 

[AUTOMAN]

650 Only

Piece of cake!