Seal, large Mag, Viton, MB


A high quality large magneto or inner flywheel seal.

Fits all Series 2 and 3 magneto housings but not Series 1 models.

It's worth changing the small seal while your engine is apart.

Made from Viton to resist modern fuels.

Another MRB Race-Tour product.

TOP TIP, Always make sure the mag housing fits freely into the engine casing, make sure the seal and flywheel side shoulder are greased and oiled and spin the crank as the mag housing is fitted.


Seal, large Mag, Viton, MB
  • Seal, large Mag, Viton, MB
  • Seal, large Mag, Viton, MB
  • Seal, large Mag, Viton, MB
  • Seal, large Mag, Viton, MB
  • Seal, large Mag, Viton, MB

£ 5.47
Price: £ 4.56 Ex Vat

Related Items (2)


  • Viton brown rubber separates it from normal black and blue nitrile seals.
  • Two seals available, Drive side and Large mag seal.
  • Marked with the quality MRB Race-Tour branding.


  • Made from special higher wearing Viton rubber.
  • Doesn't break down with unleaded fuels.

Development History

  • After manufacturing, designing and testing hundreds of performance MRB engines, Mark found when stripping these engines after many miles the only thing in common with each engine was the seals were worn out whilst all the performance parts were perfectly alright.
  • This minor failure of seals over many miles lead us to develop these new MRB Viton seals.

Reasons to Buy

  • Longer lasting.
  • Harder wearing.
  • MRB quality.


  • Fit the seal dry on outer edges.
  • Grease or oil inner seal faces before fitting.
  • Oil seal surfaces on crankshaft.
  • Use a crankshaft puller to fit the crankshaft.
  • Spin the crankshaft when drawing into place.

Fitted Pictures ( 1 )

Reviews ( 1 )


5 star 1. Spursy 16 Mar 2012 

quality item

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