Alternative Cam-chain roller

It fits, it works and they are considerably le$$.  Just saying !
=24.0ptFor Kawasaki KZ900 KZ1000A Z1 Z1R Timing Camshaft CAM Chain Tension Roller Guide=12.0ptP.O.M.=12.0pt stands for Polyoxymethylene (often called acetal or polyacetal). It is a highly durable engineering thermoplastic known as the "plastic that acts like metal". Engineers choose POM for precision parts that require high stiffness, low friction, and excellent resistance to wear and moisture. [ 1 , 2 , 3 , 4 ]=15.0ptKey Characteristics

• =12.0ptHigh Strength & Rigidity:=12.0pt POM retains its shape and offers high tensile strength even under repeated stress or at temperatures ranging from -40°C to 120°C.
• =12.0ptLow Friction & Self-Lubricating:=12.0pt It has a naturally slippery surface, making it excellent for moving parts.
• =12.0ptLow Moisture Absorption:=12.0pt It does not readily absorb water, meaning it maintains its dimensions and won't swell in wet environments.
• =12.0ptChemical & Wear Resistance:=12.0pt It is highly resilient against many solvents, industrial chemicals, and physical friction. [ 1 , 2 , 3 , 4 , 5 ]

=15.0ptCommon Applications=12.0ptBecause of its durability and precision, POM is widely used across multiple industries: url=https://www.ensingerplastics.com/en-us/thermoplastic-materials/pom-acetal][color=blue]1[/color][/url

• =12.0ptAutomotive:=12.0pt Fuel system components, door locks, and interior mechanical linkages.
• =12.0ptMechanical & Industrial:=12.0pt Gears, bearings, bushings, rollers, and conveyor systems.
• =12.0ptConsumer Goods:=12.0pt Zippers, toys, and pen mechanisms.
• =12.0ptPlumbing:=12.0pt Valves and specialized pipe fittings. [ 1 , 2 , 3 , 4 , 5 ]

=15.0ptThe Two Main Types=12.0ptPOM is available in two main chemical formulas, each with slight advantages: url=https://salesplastics.com/pom-material/][color=blue]1[/color][/url], [url=https://langhe-industry.com/what-is-pom/][color=blue]2[/color][/url

1. =12.0ptPOM-H (Homopolymer Acetal):=12.0pt Often known by the trademark name Delrin. It offers maximum mechanical strength, higher density, and slightly better stiffness.
2. =12.0ptPOM-C (Copolymer Acetal):=12.0pt Known for better chemical and heat resistance, as well as easier processing during manufacturing. [ 1 , 2 , 3 , 4 ]

=15.0ptCommon Trade Names=12.0ptDepending on the manufacturer, you may see POM material referred to under different brand names: url=https://www.ensingerplastics.com/en-us/thermoplastic-materials/pom-acetal][color=blue]1[/color][/url], [url=https://yumoparts.com/en/resources/blog/what-is-pom][color=blue]2[/color][/url

• =12.0ptDelrin®=12.0pt (DuPont/Delrin USA LLC)
• =12.0ptTECAFORM®=12.0pt (Ensinger)
• =12.0ptDuracon®=12.0pt (Polyplastics)

   

How to remove the "center rib"
I had a valve stem from a house hold shut-off
 
Requires very little material to be removed from the thread to get a perfect snug fit into the needle bearing.  Did this on the drill-press using a fine file.
The rest should be self explanatory