T5 top end

[H,POOL GADGE]

On behalf of a mate, long long nightmare cut short! Will a t5 standard top end run ok with a longstroke crank and 1.5mm packer???

[Jack221]

T5s have a 52mm crank so, if you mean a 60mm or a 57mm as a long stroke crank then......absolutely no way, not ever! Port timing don't work. If you mean a long stroke 54mm T5 crank, then that would be the best thing that ever happened to a standard T5!

[H,POOL GADGE]

Mmmm! Maybe their's light at the end of the tunnel, for the lad! Now that would explain why the piston hit the head, and with a 1.5mm packer he's now got clearance! He's gotta 54mm crank innit. Next question is... Why does the squish band area of cylinder head not go to the edge of the piston on a t5 centre plug head???

[225worb]

Hi
Is it definitely a standard 125 cylinder ?? not modified ??
How much area of the cylinder head touches the piston ?

[Yanker]

Malossi provide a head 'spacer' gasket with the 172 kit to allow you to use a standard un-modified head. This 'solution' is such a pile of shite (they don;t do it on any other of their geared Vespa kits). It is down to the lack of availability of T5 cylinder heads, and Malossi not wanting to make one coz the voluume of demand for them is too low. You need to get the head re-profiled to suit the kit to get things yo work properly. 65mm bore and 66mm head for a 172...

[ducksta]

T5s have a 52mm crank so, if you mean a 60mm or a 57mm as a long stroke crank then......absolutely no way, not ever! Port timing don't work. If you mean a long stroke 54mm T5 crank, then that would be the best thing that ever happened to a standard T5!

will tell you how my 60mm long stroke kawasaki kh 750 piston set gets on in the new year

[Morgan]

Hi Ducksta.

Will the kawasaki piston be standard or will you have to modify it (skirts/windows, etc) ?

Cheers for reply M8

[ducksta]

ime in the process of having it built by someone so not sat down and got the full spec but happy to share everything when built spec price etc

[roadrunnerian]

dusksta chiselspeed did one with the kawasaki as well as mbd

[fastfrog]

best choice for a standard barrel is 54mm stroke, no packing plate.If you put a 1,5 mm base gasket you'll have too much transfert timing ( imagine 2,5 mm of more port opening twice... and your squish with a 0,5 mm more clearance!). Check your squish clearance to get around 1mm no more. If necessary use the right head gasket to match . You'll get a space rocket....