New To The Market: Triumph T90 & 3TA Pistons

New To The Market: Triumph T90 & 3TA Pistons

Should you be rebuilding a vintage Triumph motorcycle, you might find that most parts are still available on the market today, whether new, used, or new old stock

If you are building (or rebuilding) a vintage Triumph 350 twin you might find that parts are harder to obtain as compared to its cousins the 500, 650 and 750 twin

Today we would like to introduce to you a new part for 2020 that will make rebuilding your little Triumph 350 much easier


Triumph 350 pistons

The Triumph 3TA or T90 models where the first unit construction twin to ever be designed and leave the Meriden factory back in 1957

It was a new design that paved the way for future engines from the TR6, T120, and T100

Although the Triumph 350 was made for about 10 years, there are a few parts that are extremely hard to find 

  • Piston assembly's (7.5:1 & 9:1)
  • Rings

Lucky for us, L.F. Harris in England has decided to take on the task of making new piston assembly's to fill this void 


The details 

Each piston is cast-aluminum and are made to the same specs as the originals

We currently have two types of piston assembly's in various sizes and compression ratios (7.5:1 & 9:1)

  • STD (Standard)
  • +.020
  • +.040
  • +.060

 L.F. Harris pistons are extremely high quality, in fact, when compared to original pistons, we have found that L.F. Harris pistons are more consistent than original Triumph pistons (weight, dimensions, material, etc) 

All piston assembly's come in there own convenient and protective box for added care upon delivery 

7.5:1 Piston assembly 

The 7.5:1 type piston was fitted to all Triumph T21 and 3TA models from 1957-1965

Features a shallow style dome but designed to make your engine more efficient, cooler and reliable

Gudgeon pins, clips and rings are all included 

Click here to view or purchase our 7.5:1 piston assembly


9:1 Piston assembly 

The 9:1 type piston was fitted to all Triumph T90 models from 1963-1968

Features a higher dome to achieve more compression, power and overall performance  

T90 pistons can also be used in T21 and 3TA motors as 350 cylinder heads are all interchangeable despite compression ratios 

enter photo

Gudgeon pins, clips and rings are all included 

Click here to view or purchase our 9:1 piston assembly

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  • Richard Wright

    To benefit from using the 9.1 pistons you should change the camshaft to t90 spec also.
    T90 also used a larger carb

  • Classic British Spares

    @Steve – I would imagine that you would see an increase. Running higher octane gas might be wise

  • steve

    Hi. I am going to fit new pistons in my 1964 triumph 3ta.
    If I were to use 9:1 pistons would I see any increased performance or would it be better to stay with standard 7.5:1 compression.
    Any help would be appreciated. Thanks.

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