Hyway Cylinder Quality

[slim reaper]

Anyone had issues with Hyway cylinder not honed full length of the barrel.

Had this one delivered today, my eye was first taken by a mark the full length of the barrel and while running finger around to see if it could be felt , felt some roughness around the full circumference of the bore from  about 5mm below the decompression port to the head that escaped honeing 

 

[adw]

Another quality cylinder from China, unfortunately you get what you pay for, if your not happy with it send it back.

[spudulike]

And their cylinders are some of the better ones out there although I did have some poor port casting on a 460 kit once but just reamed if out to make it work OK

 

[slim reaper]

1 hour ago, spudulike said:

And their cylinders are some of the better ones out there although I did have some poor port casting on a 460 kit once but just reamed if out to make it work OK

 

I was a bit concerned about honing it in case it didn’t all come out and then couldn’t return to, Ireland

Edited November 18, 2023 by slim reaper
ad pics

[slim reaper]

2 hours ago, adw said:

Another quality cylinder from China, unfortunately you get what you pay for, if your not happy with it send it back.

You'd expect better for just shy of a ton with postage to add 

[bmp01]

Knee jerk reaction was;  reject.

Remembered I have a 390XP Hyway kit, unused, ready to fit. Had a look at that, its the same....or nearly, this one has obvious non-clean up on the exhaust side. It has next to no depth to the NCU and on the plus side its likely got the full plating depth.

 

From a manufacturing perspective you can see how it happens - its impossible to hone to the top of the cylinder. To get around this the cylinder is machined tapered oversize at the top so honing tool will always run into cIearance. Where you get NCU a bit too far down the bore theyve got the clearance taper a bit big. We're talking microns tolerance here.

 

Ideally you'd have a honed cylinder up as far as the rings run, dont think you need it any higher. If there is partial honed surface where the rings run it's likely ok mechanically, you might loose a little cylinder pressure. Be interesting to see what happens after a few hours running if you choose to run it.

 

Probably not as bad as it seems, not the best. You could ask your supplier to have a look at other stock to see if they are all the same, take it from there.

Edited November 20, 2023 by bmp01
Thought about it now.

[slim reaper]

6 hours ago, bmp01 said:

Knee jerk reaction was;  reject.

Remembered I have a 390XP Hyway kit, unused, ready to fit. Had a look at that, its the same....or nearly, this one has obvious non-clean up on the exhaust side. It has next to no depth to the NCU and on the plus side its likely got the full plating depth.

 

From a manufacturing perspective you can see how it happens - its impossible to hone to the top of the cylinder. To get around this the cylinder is machined tapered oversize at the top so honing tool will always run into cIearance. Where you get NCU a bit too far down the bore theyve got the clearance taper a bit big. We're talking microns tolerance here.

 

Ideally you'd have a honed cylinder up as far as the rings run, dont think you need it any higher. If there is partial honed surface where the rings run it's likely ok mechanically, you might loose a little cylinder pressure. Be interesting to see what happens after a few hours running if you choose to run it.

 

Probably not as bad as it seems, not the best. You could ask your supplier to have a look at other stock to see if they are all the same, take it from there.

Ive already checked and the ring run extends well into the suspect area . Supplier has been sent photos and has dispatched another one....finger's crossed! 

I have my own 262xp to do next so will see what the replacement looks like before deciding what to get.

Edited November 20, 2023 by slim reaper

[slim reaper]

Difference between first and replacement was chalk and cheese, so much compression now its virtually impossible to pull over without the decompressor button in.   

[Stubby]

20 hours ago, slim reaper said:

Difference between first and replacement was chalk and cheese, so much compression now its virtually impossible to pull over without the decompressor button in.   

Their QC needs a kick up the tradesman's entrance .

[CallumA]

I bought a pop up piston kit for my 390 and this was the cylinder! To be fair I contacted supplier and they sent out a new kit FOC and didnt want the old kit back, so i now have a spare piston