Scooterotica

My friend has put a hole in his Monza piston 69.5mm and slightly damaged the Nicasil bore.

He'd like to know if there are any suitable Jap pistons that can be used as a replacement?

He's in Thailand so is looking at Jap OEM or Pattern pistons. He thinks he could get away with the barrel as is, but is willing to bore it out and resleeve it if neccesary. He will even consider 18mm little end/gudgeon pin pistons. Looking for any options really. Ordering a new Monza piston is no go as 70% tax on Imports!

Any advice greatly appreciated

Cheers Stu

some yam yz have a 68mm bore so 69.5 is an oversize, has an 18mm pin, dont know if it will be suitable tho, most other stuff tends to be 70mm

the 70mm piston out of a Kx250 works when you use a Yamaha out board rod that 116mm long with a 18mm pin. The rod needs work to fit into the webs but if your friend has someone who's able to sleeve a barrel for him I'm sure getting the rod narrowed to fit the webs isn't that big of a deal.


Tim

mawso wrote:My friend has put a hole in his Monza piston 69.5mm and slightly damaged the Nicasil bore.

He'd like to know if there are any suitable Jap pistons that can be used as a replacement?

He's in Thailand so is looking at Jap OEM or Pattern pistons. He thinks he could get away with the barrel as is, but is willing to bore it out and resleeve it if neccesary. He will even consider 18mm little end/gudgeon pin pistons. Looking for any options really. Ordering a new Monza piston is no go as 70% tax on Imports!

Any advice greatly appreciated

Cheers Stu

Have a look here Stu.
http://scooterotica.org/forum/viewtopic.php?f=5&t=15941

Russ

Great info and help, cheers all!

Passed it on with the links...think rebore and resleeve is what he's planning. He has made his own 60 - 64mm cranks too in the past, so I think he'll like the 116 rod idea!

Thanks again

Stu

mitaka
cheap
superb jap piston made in taiwan
24.5% silicon so doesnt expand as much as others

Another option is a TS 250 piston, no need to sleeve, as 70mm plus 3 oversizes, Mitaka / Pro X quality and no doubt very good value out in Thailand. Will need to cut a reed window in, and use long rod with 18mm big end. Great piston for Rapido conversions by the way.
p.s If your mate by chance sources some genuine Honda MTX 200 pistons could he let us know?

Cheers, I passed on the further piston options. Doesn't look like anything 69.5mm about. The Nicasil is useable he thinks too now it's been cleaned up. Going to weigh up his options.

I asked him about MTX200 pistons too, he has a few Honda contacts he will ask about them.

I've got a new Mitaka PE250 piston, 60mm crank/116rod 18mm little end...no barrel or casing tho Anyone want to do some kind of Part ex with a damaged Imola barrel for a Rapido Classic 225 barrel?