Spark Exhaust Stainless Steel Tube Ø 52 × 1.0 mm 500 mm Universal G9013

Fifty-two millimetres. Two more than the standard size — which is exactly what makes it useful.

Key Features

• Straight exhaust tube, AISI 304 stainless steel.
• Ø 52 mm outside, 1.0 mm wall thickness.
• 500 mm long.
• Slips over 50 mm tube as a sleeve.
• Spark part number G9013, made in Mantova, Italy.

The Sleeve Size for 50

Fifty-two outside with a one millimetre wall gives fifty inside. A 50 mm tube slides into it without machining, expanding or swaging — which turns a butt weld into a slip joint and a permanent system into a serviceable one.

A single 500 mm length yields half a dozen sleeves. On a build using 50 mm tube throughout, it is the cheapest useful article on the page.

Crevice Corrosion

The one drawback of a slip joint is that it creates a gap where moisture and salt can sit. On a road bike, that gap is where a stainless system will corrode first, long before any of the exposed surface does.

Assembling with exhaust paste and making sure the joint drains rather than collects handles it. Do not seal a joint that has to slide.

As a Run in Its Own Right

Fifty-two also works as the main section on a large-capacity twin or a four with a generous collector. At this diameter gas speed is low at small throttle openings, so it belongs on engines that spend their time above half revs.

Fitting Over a Bend

A sleeve will not slide onto the flattened section of a poorly made bend. If you are joining to a home-bent piece, check the ovality at the end before cutting a sleeve to length — it is easier to round the tube end than to open the sleeve.

A Rack Item

Workshops that build more than one system keep a length of this diameter on the rack permanently. It is the article that turns a mistake into a repair: a butt weld that came out crooked can be cut back and sleeved instead of scrapped.

Cutting Sleeves to Length

A sleeve wants between one and one and a half tube diameters of overlap — sixty to eighty millimetres at this size. Shorter and the joint can cock and leak; longer adds weight and makes the assembly harder to separate once carbon has built up inside it.

Ordering

One 500 mm length per article.