SOLD – J.A.P. Twin Port 350cc OHV single cylinder engine from 1931

SOLD – J.A.P. Twin Port 350cc OHV single cylinder engine from 1931


J.A.P. 350cc OHV single cylinder Twin Port engine from 1931.

Almost complete 1931 JAP OHV motorcycle engine that might have been built with some race specification. I mention that at the engine numbers read: IOZ/H. (H = 1931) but it’s the letters that come after the unique number oblique that are of interest: “BS”. I think B is for “modified gear cover and exhaust valve lifter” and S is “Double row roller big-end bearing (250cc and 350cc OHV racing engines) ”

I’m sure that there is a specialist on JAP motors out there who will confirm, or deny, this. They seemed to make significant changes to their engine identification after 1926.

The engine: Overall, it’s in good condition. The fins are actually very nice. Importantly, it still has the original paired engine cases as the numbers match. It retains the JAP oil pump cover. I have shown a picture of how it looks inside. This is a very good start for a nice project.

Condition remarks: There is a slight nick / cut out of the magneto platform mount. It’s shown in the images. I’m sure that a competent engineer will be able to add some weld at that point, if only for cosmetic reasons. There is no timing cover. But these are readily available. The engine does not turn by hand. This is probably just because it has stood for a while. It is missing the cam wheel inside the timing cover. I have shown a picture of what is available.

International shipping available. Please ask.

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

Shipping: I usually ship to most destinations. If you don’t see a price, please ask. Thanks. International shipping available.

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: 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.





,ref: 2210-B473-923e

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