Sector Gear Hitting Cylinder

[S Porteous]

I’ve just taken my Double Bell 416 apart for the first time as I was planning to change the cylinder…  It’s a little noisy, so I was surprised to see it has bearings and not bushes.  Anyhow… when I took the cylinder out, I noticed a sharp nick in it:

View attachment 94463

And putting it back in, it lines up with the sector gear:

View attachment 94464

Trying to spin the gear with the gearbox closed confirms that it is hitting.

As I’m planning to replace this cylinder anyway, I was going to Dremel away a section from the cylinder until it no longer catches.

Has anyone had this issue before, and if so, how did they fix it? 

 

[S Porteous]

A little bit of Dremel action has given it the clearance it needs.

View attachment 94470

 

[Rogerborg]

Huh, no, that's a new one on me.  Was that all stock?

 

[S Porteous]

Huh, no, that's a new one on me.  Was that all stock?

Yes, all stock parts.

 

[-davo-]

If you have spare cylinder(s) or spare sector(s), i'd try if different ones have the same issue (in different combos with stock sector, and stock cylinder)

Possibly just badly machined from factory? (cylinder port looks a bit scraggly on photo) 
It's Double Bell, so makes sense 

Sounds liike a new one to me too, but you solved it yourself with a little mod
So, nice, good job

 

[S Porteous]

If you have spare cylinder(s) or spare sector(s), i'd try if different ones have the same issue (in different combos with stock sector, and stock cylinder)

I tried the new cylinder and that had the same problem, so it works suggest that the gears on the sector are a little proud. I don’t have a spare sectors great to try (without taking  something else apart), so will probably just modify the new cylinder after I’ve put it all together with the first cylinder and made sure everything works.

Possibly just badly machined from factory? (cylinder port looks a bit scraggly on photo) 
It's Double Bell, so makes sense 

Yeah, the edge of the port is a little sharp.   One of the reasons for  taking it apart was to just assess things and remove any sharp edges (the stock has sharp plastic edges that cut into the battery wires)

 

[Sneaky]

First time, I have ever seen that issue.  Hope you get it all sorted.