No Gasket Required? - Seal It Up With Yamabond

No Gasket Required? - Seal It Up With Yamabond

British bikes have rightfully earned some popular nicknames, slogans and jokes throughout the decades that most can understand and relate too

Slogans like some of the following..

  • "Oil Bath"
  • "If its not leaking then theirs no oil in it"
  • "All British bikes mark there spot"

I'm sure theirs many others I missed but on a more serious note, I wanted to take the time today to talk a little bit about a sealer that we use here at the shop very frequently

This sealer is called Yamabond (#4) 

Over the years I have tried many brands of sealers, however, since using Yamabond #4 I have been getting positive and lasting results 

If you're unfamiliar with Yamabond #4, stick around and I'm sure by the end of this post, you may want some Yamabond #4 sealer in your workshop or next engine build 

Lets dive in

Getting to know "Yamabond"

Yamabond #4 Gasket Sealer

Below I will cover some info specifically on the Yamabond #4 sealer and also cover some points that make Yamabond my first choice 

Yamabond is a form of grey colored silicone manufactured by Yamaha used to dress engine cases, gear boxes and other surfaces that require sealing with no gasket

For example, if you happen to building a Triumph unit 650 motor, you would use Yamabond #4 on the crankcase halves, inner and outer gearbox cover and the timing cover where a gasket was not fitted with from the factory... 


Non-Setting Yamabond #4

    Most folks these days tend to run away from using silicone in an engine (especially in the classic British motorcycle community) however, Yamabond is "non-setting" 

    Non-setting is extremely important as the Yamabond sealer will not harden or set but will continue to seal and stay "soft" 

    Sealers that harden can break off and cause engine failure due to plugged oil ways, pumps, etc if used the incorrect way 

    Fills gaps

      Scratches & Grooves On Surface

      Should you have a flat surface with imperfections including dings, scratches or gouges, Yamabond will fill any void on surfaces up to .025" deep


      If you cant lap or mill your gasket surface, Yamabond is a great choice 

      Doesn't run  

      Grey Sealer

      Some sealers on the market today are often too thick and to runny - Yamabond is the perfect mix of thick and thin making the blend easy to work without making a mess all over your parts

      Easy to apply and can be done so in a quick manner 

      Dries in a reasonable time 

      When applying Yamabond you will have enough time to do your entire part and not have to worry about it setting only to find that your job is half done 

      With Yamabond you can take your time to ensure the job is sealed correctly 

      Takes approx 1 hour for the sealer to be used and 24-hours for the sealer to cure 

      Easy to remove 

      Removing Yamabomd

      If you want to know how good (or bad) a sealer is, see how easy / hard it is to remove once the sealer has cured 

      Yamabond #4 can be removed very easily

      Just a small amount of Aceton or simply "rub" the sealer off with your index finger or finger nail 

      Oil friendly 

      We have found that Yamabond works great even when surfaces are not perfectly cleaned or prepped 

      Sometimes when your working on an engine and time is limited, we have found that Yamabond stills seal well under conditions where oil or residue is still present on the mating surfaces 


        How to properly use Yamabond 

        The key to a successful seal and bond that will prevent future leaks or weeps is all in the preparation  

        I will cover the steps that Kyle and Malcolm like to perform in the workshop when applying Yamabond 

        How To Apply Yamabond #4

        1. Make sure all surfaces are flat and clean (use acetone or alcohol to clean surfaces)
        2. Apply a conservative amount of sealer on both surfaces (thin amount)
        3. Wait approx 1 minute to allow both surfaces to become "tacky" 
        4. Join both surfaces together using hardware to secure  
        5. Allow parts to cure to for at least 1 hour before use 
        6. Clean up any residue left behind 


        Ready to seal the deal?

        Want to give Yamabond #4 a try on your next engine build?

        Click on the link below to purchase your new genuine Yamabond #4 gasket sealer today

         Brand Gasket Type Sealer Color Specs Link
        Yamabond RTV Gasket Sealer Grey Semi-Drying Click here


        Thanks for reading today 

        Thank you for reading today's post 

        Should you have any questions please drop us a comment using the section below 

        Click here for more blogs, tech and other useful information and tips

        Ride safe! 


        • Delbert

          Been using Yamabond for years, very good stuff.
          Thanks for confirming my use of the sealer.

        • Classic British Spares

          @Geoff – I think they are!! – Thanks for the kind words!

        • Geoff Ahrens

          Good stuff also. I have also had good results with Permatex Gray.
          Thanks for the tech tips and your support of the Brit/Bike industry!!!

        • Rob McGoff

          I got a tube years ago and I swear by this stuff. I’ve done 7 bikes with it. Worth every dime.

        • Dan

          Thanks for the tech tips. Here is a spelling tip:
          What are they doing to that Triumph over there? They’re putting Yamabond on the sealing surface. Why are they doing that? They don’t want their bike to leak oil. Love the tech tips. Keep ’em coming.

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