Kart exhausts: how to choose, and what 18 UK shops charge

We compared 927 kart exhausts listings across 18 UK shops. The typical cheapest price is £16.77, and the same part number can cost up to 41% more depending on where you buy it.

UK edition2026-11-016 min readData: PitHunt weekly scan

EditionEditions marked “guide” carry the advice without a price table — not enough shops in that region yet.

Key takeaways

18 UK shops list 927 parts in this category; 33 part numbers are stocked by more than one shop.
The typical cheapest price is £16.77; a tenth of parts cost £2.15 or less, a tenth £128.07 or more.
Biggest gap for one part number: £27.77 on Iame Water Swift Exhaust Restrictor 16mm Racing.
KKC Kart Components had the lowest listed price most often — 29 of the 33 part numbers stocked by several shops.

Shops: 18
Listings: 927
Typical cheapest: £16.77
Biggest gap: £27.77; 41% on one part

What a exhausts does

On a two-stroke kart engine the exhaust is part of the engine, not an accessory. The expansion chamber's shape times a pressure wave back to the cylinder that pushes fresh charge in and holds it there, so the pipe sets where the engine makes its power. Because of that every sealed-engine class fixes the exhaust: Rotax, IAME X30 and the KZ engines all run a specified or homologated pipe, and the silencer is a legal requirement as well as a courtesy.

Hot gas leaves the port into a header, expands in the chamber, and the chamber's cone reflects a wave back towards the port at a speed that depends on gas temperature — which is why a cold pipe feels flat and why pipe length matters. A perforated tube wrapped in an isolating mat forms the silencer; as the mat burns away the engine gets louder, loses performance and the silencer skin shows hot spots. Springs hold the pipe to the engine's exhaust socket and the silencer to the pipe so the joints can move with vibration; rubber mounts carry it on the chassis.

How to choose

1 · The class rule first
In a sealed-engine class the exhaust is specified, and a non-original one is an exclusion.
How to judge it: Rotax: the original Rotax system for the class is mandatory — Micro MAX part 273136, Mini MAX 273137 or 273138, Junior and Senior the EVO system — with 2 to 4 original Rotax springs at the socket and 2 to 4 at the silencer, and no safety wire. KZ and KZ2: only the exhaust homologated with the engine, and an FIA Karting homologated silencer. IAME X30: the one-piece pipe replaced the earlier flex-tuned pipe in the European package. Open and club classes are where a choice of pipe exists at all.
2 · Complete system, or the wear parts
Most of what an exhaust needs is cheap: springs, gaskets and matting.
How to judge it: A complete pipe is a large buy; the parts that actually wear are the isolating mat, springs, gaskets and rubber mounts. Flow Racers put the silencer matting's service life at 6 to 10 hours. Rotax allows the original mat to be replaced only with the Rotax mat for the class — 297982 for Micro, Junior and Senior, 297985 for Mini — and a steel isolation mat 297983 underneath it in Junior and Senior only.
3 · Repairs, and what is allowed
A cracked pipe can be legal to weld — within limits.
How to judge it: Under the Rotax rules welding is allowed only as a repair that returns the part to its original shape, to a maximum of 50% of the diameter on a round section and 150mm on any other, and a flange-end repair must be done by a JAG-authorised repairer who fits a JAG seal. Replacing the silencer end-cap rivets with 4mm screws and locking nuts is permitted; the perforated tube must be fully inserted and secured at 3 points. Adding extra silencing after the original silencer is allowed.

Compatibility. The pipe must match the engine and the class rulebook, not just the engine family: Micro and Mini Rotax share an exhaust body with different internal inserts, and Junior and Senior run the EVO system. Mounting position matters as well — Rotax requires the silencer outlet pointed so hot gas does not reach any chassis component. Springs, gaskets and mats are engine-specific parts, and under the Rotax rules must be the original items.

Types, and the trade-offs

Type	For	Against	Best for
Rotax EVO / class-specific system	Mandatory, so there is no decision; parts and mats are everywhere.	Expensive as a complete unit; repairs restricted.	Every Rotax class — it is the only legal option.
IAME X30 one-piece pipe	No flex to break or leak; current spec.	No length tuning.	X30 Junior and Senior.
KZ homologated pipe + homologated silencer	Matched to the engine's homologation.	Must be the one homologated with that engine; a different maker's pipe is not legal.	KZ and KZ2.
Open-class or club pipes	The one place pipe choice tunes the engine.	A pipe tuned for peak power can cost mid-range on a tight club track.	Non-homologated club classes and rental-style engines.

Expansion chamber: The bulge in the pipe whose cones reflect pressure waves back to the port.; Matters when: Always — it is the tuning. In a sealed class it is fixed; a dent changes it.
Isolating mat / matting: The packing around the perforated tube that does the silencing.; Matters when: Every 6 to 10 hours; louder, slower and hot spots on the silencer mean it has gone.
Flex: A braided flexible section between header and chamber on older pipes, used to adjust length.; Matters when: The X30's old pipe; the one-piece replacement ended the mess and the broken flexes, and racers on the thread found the flex tuning gave little real gain.
Exhaust springs: The coil springs that hold the joints together and let them move.; Matters when: Carry spares; Rotax requires 2 to 4 original springs at each joint.
Noise: Drive-by testing under Motorsport UK K.146 to K.148.; Matters when: A 2026 club regulation quotes the K.148 limit as 103 dBA at 3.6 metres, with exclusion for exceeding it; a burnt-out mat is the usual cause.

What it costs across UK shops

Cheapest listing per part number£0.00 → £128.07+

£2.15

a tenth cost this or less

£16.77

typical

£128.07

a tenth cost this or more

Part	Cheapest	Dearest	Gap
Iame Water Swift Exhaust Restrictor 16mm Racing cheapest at KKC Kart Components · 2 shops	£67.18	£94.95	£27.7741%
Kart Republic - Exhaust Support Complete Rotax cheapest at KKC Kart Components · 2 shops	£108.95	£128.00	£19.0517%
Iame X30 Exhaust End Can cheapest at KKC Kart Components · 2 shops	£37.98	£53.95	£15.9742%
Synergy Envy 950 Rotax Exhaust Bracket Chromed cheapest at KKC Kart Components · 2 shops	£27.12	£38.95	£11.8344%
Rotax Genuine Exhaust Restrictor Micro/Intermax/Junior/Senior cheapest at KKC Kart Components · 2 shops	£25.99	£36.95	£10.9642%
Iame X30 Exhaust & Senior Manifold With End Can Grade A Karting cheapest at KKC Kart Components · 2 shops	£19.97	£28.95	£8.9845%
Righetti Ridolfi Chrome Exhaust Bracket cheapest at KKC Kart Components · 2 shops	£12.95	£18.95	£6.0046%
Flat Exhaust Support Bar cheapest at KKC Kart Components · 2 shops	£10.59	£15.95	£5.3651%
Rotax Evo Exhaust Retaining Plate Mount cheapest at KKC Kart Components · 2 shops	£22.32	£27.43	£5.1123%
OTK Mini Rookie Exhaust Support Bracket (old Cadet style) cheapest at KKC Kart Components · 2 shops	£18.95	£22.95	£4.0021%

Same part number at every shop in the row. Parts listed at £10.00 or more; ranked by the gap in money, not percent.

Cheapest most often

Of the 33 part numbers stocked by more than one shop — a count of wins, not a verdict.

KKC Kart Components29 of 33
Strawberry Racing2 of 33
Precision Kart1 of 33
ZipNorth1 of 33

What this covers

This is a snapshot of kart exhausts as listed by UK kart shops on 2026-11-01. PitHunt indexed 927 listings from 18 shops, covering 872 distinct part numbers. Of those, 33 are stocked by more than one shop, which is where a price comparison means something: the same manufacturer part number, different tills.

Prices are the shops' own listed prices in their own currency, captured by PitHunt's weekly scan. They are not quotes, they move, and the cheapest shop for one part is not the cheapest for every part. Each one links to the shop's own page so you can check before you buy.

The price range

Taking the cheapest listing for each part number, a tenth of them cost £2.15 or less, the middle of the range sits at £16.77, and a tenth cost £128.07 or more. The spread is wide because the category mixes small hardware with complete components, so the useful comparison is always like for like — the same part number across shops.

The widest gaps for the same part

The comparison ranks part numbers by the difference between shops in money, among parts listed at £10.00 or more — a big percentage on a tiny part is arithmetic, not a saving.

The largest gap in money is on Iame Water Swift Exhaust Restrictor 16mm Racing: £67.18 at KKC Kart Components against £94.95 at the dearest of its two shops — £27.77, or 41%, for the same part number. The full list is in the comparison table above, ranked the same way.

A gap like that is not a judgement on either shop. Listed prices reflect stock bought at different times, different suppliers, and whether a shop is clearing a line. What it tells you is simply that for this part number, on this date, checking a second shop was worth the minute it took.

Which shops were cheapest most often

Across the 33 part numbers stocked by more than one shop, KKC Kart Components had the lowest listed price for 29 of them, followed by Strawberry Racing with 2. That is a count of wins, not a verdict: a shop that is cheapest on the parts you actually need matters more than one that is cheapest on average.

The honest way to use this is the boring way. Find your exact part number, look at every shop that lists it, and let the number decide. Name the part, and PitHunt lines every shop up cheapest-first.

Before you buy — the checklist

Buying used, check

☐Cracks: look at the chamber, the silencer, the mounting brackets, every weld and the engine outlet connection — the places Flow Racers list — with the pipe clean, because dirt hides them.
☐Repairs: any weld must be a like-for-like repair within the limits, and a Rotax flange-end repair must carry the JAG seal.
☐Dents in the chamber: the shape is the tuning, and a dented chamber is a different pipe.
☐Silencer: hot spots on the skin, a loose or protruding perforated tube, missing rivets or screws — expect to repack it.
☐Fit: the correct part number for the class, the right inserts on Micro and Mini, and the original springs and gaskets.

Mistakes to avoid

✕Running the pipe with a burnt-out mat: the engine gets louder and slower, the silencer skin shows hot spots, and a drive-by noise test can exclude the kart.
✕Fixing the exhaust with safety wire instead of springs — it is specifically forbidden in the Rotax rules, and a rigid fixing cracks the pipe.
✕Welding a repair beyond what the rules allow, or having the flange end repaired by anyone but an authorised repairer; the pipe then fails scrutineering.
✕Buying a non-original or 'tuned' pipe for a sealed class because it is cheaper or promises power; it is an exclusion.

Questions

›How often does the silencer need repacking?

Flow Racers give the matting a 6 to 10 hour service life. Louder, slower and hot spots on the silencer say it is due.

›Can I weld a cracked Rotax pipe?

Only as a repair returning it to its original shape, up to 50% of the diameter on a round section and 150mm elsewhere; a flange-end repair must be done by a JAG-authorised repairer and sealed.

›Is an aftermarket pipe legal in X30 or Rotax?

No. Both classes fix the exhaust to the original system for the class; KZ fixes it to the pipe homologated with the engine.

›Where do these prices come from?

From the shops' own websites, collected by PitHunt's weekly scan of UK kart retailers. Each figure is the price the shop listed on the date above, in the shop's own currency, before delivery.

›Why would the same part cost more at one shop?

Stock bought at different times, different supplier terms, and clearance decisions. None of that is visible from the price alone, which is why comparing the same part number across shops is the only fair comparison.

Sources for the buying advice

Reviewed 2026-11-01. Buying advice comes only from these sources; prices come only from PitHunt’s own scan.

How this was built

Every number on this page was computed from PitHunt’s weekly scan of kart shops’ own listed prices, in the shop’s own currency, captured on 2026-11-01. The text was then checked against that data: any figure not in it fails the article. Prices move after we scan them, and exclude delivery — always confirm on the shop’s page.

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