Scooterotica

J1MS you may not get a pic till the weekend as cryogenic works away all week and doesn't have internet access.
This is actually a motor I built so is a little close to my heart. I have actually fitted the expander ring on my own GT which has so far done in excess of 3000 miles and also two other customer engines which are so far haven't had the problem(although I don't know what milages they have done).
Must admit I'm a little worried now and wasn't aware these caused problems untill now. My thinking was if it goes in a RD350 ypvs reving 12000 rpm plus it'll be alright in a Lammy pulling 7000 rpm tops.

Maybe interesting ?.......

http://www.125ccsportsbikes.com/forums/ ... opic=53510

Diablo wrote:J1MS you may not get a pic till the weekend as cryogenic works away all week and doesn't have internet access.This is actually a motor I built so is a little close to my heart. I have actually fitted the expander ring on my own GT which has so far done in excess of 3000 miles and also two other customer engines which are so far haven't had the problem(although I don't know what milages they have done). Must admit I'm a little worried now and wasn't aware these caused problems untill now. My thinking was if it goes in a RD350 ypvs reving 12000 rpm plus it'll be alright in a Lammy pulling 7000 rpm tops.

Same thinking here If its good enough for an RD its going to be good enough on a Lambretta, reving out at about 8000 rpm. In my opinion, I think theres a couple of possabilities... its either been a dodgy ring peg or the expander ring has been hardened and not properly tempered or maybe ring groove was incorrectly machined.... Mitaka pitons are better than people give credit for... The rings as mentioned are not of the same quality as the OE ones (which I think were ART pistons  having high quality drawn wire rings fitted ) but are more than up to the job . I dont believe it has anything to do with how it was put together, and may just be a one off.... but as you say there are a few out there with these rings fitted which was why I kept an interest on this post... couldnt you get a picture off Cryogenic (Via his phone) and post it for him....???

Picture for you guys at last Please note that this engine ran fine it stayed with a TS1 no probs to and from Brid in 2007 and just shows that even with this amount of damage it still ran
http://i593.photobucket.com/albums/tt18 ... 032009.jpg

Just trying to see if i can get image up on page without link

http://s593.photobucket.com/albums/tt18 ... 032009.jpg

Guys take a nosey at the Ring peg it is still in but may have come out to create the cross across the ring groove. what ever has happened is a bit of a mystery