Well hope you get it, if he wants more just pay more, heads & barrels alone are extremely sort after. particularly as both years are different heads & barrels.
good luck.
I am still looking for a JM22 (1938) M22 single port cylinder head with two holes per valve casting to attch the rocker box (later types have 3 holes).
hi all. will ask about other engines parts, he has just send me some pics of this m24 engine, it will need rebuilding and some alloy work,comes with a carb no mag, new piston and a gasket set. he's looking for 3k for it, which ok is a lot of money but, they dont come along every day, i did try and buy one last year on ebay, which went for 4600, which was not running, so could be in a deeper hole, i have checked on the m24 site, this engine is not listed on there.. heres some pics..please let me know what you think, warts and all.. cheers curt..
this is a reply back from him with other parts for sale....
" parts for sale, engine in bits # KB 26 771, engine # KB 24 1191,
engine # KB 461, engine # KB 21 696 only bottom half, ZB 31 23823 with ally
ZB 350 head and barrel, ZB 31 frame. some to think about."
Your tank might be OK for clearance i have a feeling that BSA made all the post war "M" tanks with clearance for OHV engines so may well be OK can't say definitely but try it first, the highest points are 2 bolts & the decompressor cable which are where the tunnel is anyway.
pics look fine nothing horrible .. typical rocker cover damage it must be where people don't slacken tappets off before removal etc because guess what.. mine have both also been welded there.
Piston needs identification (from number inside) as it looks low comp but prob makes it a good choice.
crankcases, cams, head, barrel all look correct for a KM24 (39)
Price is not greedy at all.
Exhaust downpipe shape is different to 38 also if he has one there, its flat at the front.
People wrongly point at the fins either side of the pushrod tunnel on mine assuming they are broken or modified.
All the "M" engines & frames widened 1939 onward so your engine will fit your M21 frame but you would actually have more trouble putting it in a 38 M24 frame.
Well i really like riding my 1938 engined bike .... its on a 45" straight through pipe so you can hear all the bangs
: D
Still amused that they produced an engine that you have to guess the tappet clearances on.
But even considering they had to add those two bolts either side of the pushrod tunnel as an afterthought i really do think the head & particularly the barrel on these engines are nothing short of a work of art.