Pair of M6×85mm zinc-plated hex flange bolts for QMB139 GY50 50cc scooter engine – showing hex flange head and threaded shaft Pair of M6×85mm zinc-plated hex flange bolts for QMB139 GY50 50cc scooter engine – showing hex flange head and threaded shaft
M6×85mm QMB139 flange bolt pair – alternate angle showing threaded tip and full bolt length M6×85mm QMB139 flange bolt pair – alternate angle showing threaded tip and full bolt length
Pair of M6×85mm zinc-plated hex flange bolts for QMB139 GY50 50cc scooter engine – showing hex flange head and threaded shaft
M6×85mm QMB139 flange bolt pair – alternate angle showing threaded tip and full bolt length

Scooterworks USA, LLC

M6x85 Flange Bolt Pair – 139QMB GY50 50cc Engine

SKU 1100-1334
$4.40
Shipping calculated at checkout.
Description

Long 7mm double-ended cylinder stud for securing the cylinder head and cylinder to the engine case on most vintage Vespa Largeframe and Smallframe scooters from the 1960s and 70s. Threaded on both ends with a smooth shank in the center. You’ll need four studs per engine, plus 7mm nuts and washers to complete the job.

Does NOT fit GS, SS, handlebar-style Rally, or P200 models — those require 8mm studs.

Features

  • Long double-ended stud, threaded on both ends
  • 7mm diameter — correct for Largeframe and Primavera/ET3 engines
  • Secures cylinder head and cylinder to engine case
  • Sold individually — four required per engine
  • Use with matching 7mm nuts and washers (sold separately)

Specifications

  • Thread diameter: 7mm
  • Length: ~4.75"
  • Configuration: Double-ended stud (threaded both ends)
  • Material: Steel
  • Sold: Individually (4 required per set)

Compatibility

Series Models
Vespa Largeframe (1960s–70s) VBA, VBB, VBC 150 Super, VNA, VNB, VNC 125 Super, VLA GL150, VNL GT/GTR, VLB Sprint, V9B 100 Sport
Vespa Smallframe VMA Primavera, VMB ET3 125
Vespa P/PX Series VLX P/PX 150, VNX P/PX 125


Product Diagrams
Features
  • M6 × 85mm flange bolt with integrated hex flange head
  • Flange distributes clamping load — no separate washer needed
  • Zinc-plated steel for corrosion resistance
  • Fits QMB139 (GY50) 50cc 4-stroke engines in a wide range of Chinese scooters
  • Sold as a pair (2 bolts)
Specifications

Thread: M6 | Length: 85mm | Head type: Hex flange | Finish: Zinc-plated steel | Qty: 2 (pair) | Engine: QMB139 / GY50 50cc 4T
Model Fitments

EngineDisplacementNotes
QMB139 (GY50)50cc 4-strokeWide range of Chinese 50cc scooters
  • Same day shipping for orders placed before 2PM (CST) M-F
  • 30-day return period on eligible items
  • Flat-rate shipping for orders shipped to the 48 Contiguous United States.
Since 1989

Supplying parts and accessories for vintage and modern scooters since 1989 – Over Half a Million Served and Counting!

Comprehensive Resource

From wear-and-tear items like tires and oil filters to aftermarket parts from industry-leading brands.

Dealer Focused

With a committed team of dealer-focused sales reps and streamlined pricing and shipping processes, we are dedicated to supporting your business.

Innovative

Our team constantly strives to develop and source the best new products for your scooter.