jc2

That's beautiful. Very tasteful!

Yes, the DT2 crank is smaller diameter than the TY's

Many thanks fourex

That would be good if you could check it out Graham. cheers

Can anyone tell me if Italjet trials bikes had Mahle pistons as standard fitment?

On their later MX bikes it's on the steering tube but is very faintly stamped and is easy to miss especially if the frame has had a few coats of paint

Quite a bitza. Frame almost definitely DOT as mentioned above. Late 50's/early 60s? Rear frame loop bent up considerably looks non-standard Tank looks like Bantam Forks look early Montesa. Front wheel maybe too. Forks much longer than original DOT leading link forks, hence the raked out look. Have no idea about the triples/yokes or rear wheel That engine prefix is AJS Stormer MX engine. A bit frisky for trials but more modern design than 9E/32A/37A favoured for trials. Anything can be fixed with the right knowhow.

Many thanks for your responses. Yeh I've checked the cmsnl site and no-go there either. Many thanks for manuals Ian Dave, I haven't got the bike yet but I'm told the old piston is there. I have a feeling the TY-Z piston may go close.

Looking for a 240 piston. Tried David Silver without success Anyone know of another source? Or what piston from another make/model that fits?

Here's a few more

I have a keen interest in these too - in fact anything from the euro manufacturers that got little/no coverage in the UK press back in the day. Some fascinating machines Here's some pics to get you going: Franke again Sengfelder's bike Said to be Jacky Ickx's 1964 works 125 The other side of one above Another nice one And a Rickman Zundapp trials

Please do post some pics cheers

I could never understand why Bultaco didn't use/develop that engine more in their motocrossers, especially the big-bores, but I'm told it is a very heavy engine and that Pomeroy hated it. Apparently that meant end of story at the factory at the time, whereas the Brits (Malcolm Davis & Vic Allen) loved the last 400 prototype based on that engine. Seemed to me to be a much better design than the chain-drive engine. Anyone know the truth?

Some dealers back in the day took 125/175/250 Bultacos out to 325 using a new liner but it was a hec of a lot of work - press out the old liner, bore cylinder to take new 325 liner, open up the transfer ducts, split the cases to enlarge the crankcase 'mouth' for the new liner, machine head & combustion chamber adjusting dia & C.R. to suit larger capacity, then fit bushes on the 16mm gudgeon pin (of the smaller engines) to take the 325 piston (which used 20mm pin). Bert Flood sold the kits in Australia & a local rider had it done on his Sherpa S 125 by our local dealer. But it always seemed a somewhat less than satisfactory practice to me, especially bushing the 16mm pin to take the 83mm piston. And if you didn't get the transfer ducts and head mods right.... These days guys seem to prefer boring out the 250 to take 76mm GasGas piston, giving extra 28cc. Don't know if they just bore the std liner or make new one. The Bul 250 liners are 4mm thick so that would only leave a 2mm thick liner if they just bored the liner. For me that'd be right on the limit. Don't know if the deck ht is correct or if you need to run a reedvalve with the GG piston either (ie if there's holes in the skirt.) Another idea I've toyed with but never fully investigated is to use a 75mm KawJS550 watercraft piston, up to 1990 model which were pistonport engines (later models were reedvalve). Wiseco list them as having 16mm gudgeon, same as 250 Bul, but don't know if deck ht or ring locating pins are suitable. That'd give 21cc extra & more meat in the liner

For some reason that first website transposes "steep" to "spam", so whenever you see "spam", read it as "steep" or "steeper" to make proper sens of it.