Jap Speedway Engines

[marcusthepom 7]

whilst in the uk this year i purchased a 5 stud jap engine in a erskine frame,the idea was to restore this bike once it arrived back in australia.the bike arrived last week after a short boat trip from england.the first thing i wanted to see was the engine number,well i have been over the engine with a fine tooth combe and cannot find a number.can anybody offer a reason why this engine wouldnt have an engine number.i have aged the motor between the mid 1930s to around 1948.but would love to pin point the engines year of manufacture.on the pushrod side of the engine on the timing case there is a decompression outlet which has been pluged,you would think that might put the engine in the late 30s not late 40s.can anybody offer some help please.there are no numbers,stamps or letters anywhere on this engine.

[colin 0]

whilst in the uk this year i purchased a 5 stud jap engine in a erskine frame,the idea was to restore this bike once it arrived back in australia.the bike arrived last week after a short boat trip from england.the first thing i wanted to see was the engine number,well i have been over the engine with a fine tooth combe and cannot find a number.can anybody offer a reason why this engine wouldnt have an engine number.i have aged the motor between the mid 1930s to around 1948.but would love to pin point the engines year of manufacture.on the pushrod side of the engine on the timing case there is a decompression outlet which has been pluged,you would think that might put the engine in the late 30s not late 40s.can anybody offer some help please.there are no numbers,stamps or letters anywhere on this engine.

<{POST_SNAPBACK}>

 

On my Jap the engine No (it dates it at 1958) is on the timing side crankcase at the very front, but the cases are not a pair, both seem to be different materials, however on a pair of (matched) cankcases that I have, the engine no is on the drive side side case and is in a different (bigger) form of type face.

Perhaps a case has been replaced (probably) at some time.

I have a copy of the J.A.P by Jeff Clew which has engine No. details, if you need the info I can write it out for you.

 

Sorry not very helpful.

Colin

[marcusthepom 7]

On my Jap the engine No (it dates it at 1958) is on the timing side crankcase at the very front, but the cases are not a pair, both seem to be different materials, however on a pair of (matched) cankcases that I have, the engine no is on the drive side side case and is in a different (bigger) form of type face.

Perhaps a case has been replaced (probably) at some time.

I have a copy of the J.A.P by Jeff Clew which has engine No. details, if you need the info I can write it out for you.

 

Sorry not very helpful.

Colin

<{POST_SNAPBACK}>

hello colin thanks for that,my first idea was perhaps the cases were new but the decompression plug dates the cases early.i have been told but im not sure weather this is correct but even new cases had engine numbers stamped on them.i have engines (japs) dating from 1938 thru to 1964 there have been a few little changes to webs and fins etc on the cases,these cases on this engine seem to be dated late 30s till late 40s.i just cant find a letter,number etc on the outside of the engine or on the inside,im stumpped