Marston Sunbeam Lion 500cc engine for mid 1930’s motorcycle

Marston Sunbeam Lion 500cc engine for mid 1930’s motorcycle


Marston Sunbeam Lion Longstroke Model 6B 492cc side valve engine for mid 1930’s motorcycle. I believe this is a 1934 motor.

This is a very good start for someone who needs a Lion engine for their Sunbeam project. It turns over and the valves work. So, it has the cams and pushrods. You can see from the images, that there is nothing inside the timing chain cover. However, it does have the oil pump fitted. The head has some chipped fins (see images) but overall it’s a good engine. It is missing a few of the bolts / studs / screws. For example, the timing cover is missing a few.

The engine number begins with 6B.490.1.2XX if you want to check on the age.

Other Sunbeam parts: I have some. Please get in touch.




  • International shipping available. Please ask.
  • Combined shipping available if you buy other parts. 
  • I usually ship to most destinations. If you don’t see a price, please ask. Shipping is in addition to the listed price for the item.

Viewing: Please come and check it over before you buy. It is at PE28, near St Ives in Cambridgeshire.

Collection: If you don’t want it shipped, I have plenty of space. If you can’t collect for a while, it’s not a problem. However, I will need to be paid very soon after the sale. Thanks.

Payment: This site has a facility to pay online. Good old fashioned money on collection is preferred. I can accept payment through PayPal or by bank transfer as well.

Import Taxes: Please note that IMPORT DUTIES are not something I can control. If you are buying from outside the UK, there is a chance that you will have to pay import taxes. Import taxes vary from country to country. If there are charges to pay, it is the buyer’s responsibility to research the cost and pay the duties. The price that you see on my advert is for the item and not the item plus whatever taxes might be due.

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