New cylinder for my AT50

People from all over the world can present your mopeds here, or you can ask whatever you want to know about mopeds.
Odgovori
DiederikAT50
auspuh lager
Prispevkov: 5
Pridružen: To Feb 26, 2013 2:43 pm

New cylinder for my AT50

Odgovor Napisal/-a DiederikAT50 »

Hi everyone,

I'm a proud owner of a Tomos AT50 and I live in the Netherlands. I'm planning to do a full revision of my engine.

I would like to make it a BT50 and was wondering what options I have to buy a new cylinder for it.

The only one I found is this one:
http://www.trgovina.obnovi-si.si/index. ... uct_id=517

I have two questions:
  • - What is the difference between the original BT50 and the Junior cylinder?
  • - Are there other web shops I can order from?
Thanks in advance :)
Uporabniški avatar
macula
Mojster
Prispevkov: 2010
Pridružen: Ne Sep 12, 2010 8:05 pm
Kraj: Idrija

Re: New cylinder for my AT50

Odgovor Napisal/-a macula »

you have also this web page:
http://www.frcomoto.si/index.php?route= ... duct_id=17
cylinders are same, from same producer. Those are replicas not original. You have to correct porting a bit (to get junior porting) on those cyl and cut few mm on top (1-2mm).

There is a difference between BT, AT and Junior, BT has about 4kw,AT has 2kw and junior has about 5,5kw. It's a difference in porting of cyl. Ribs of BT are a bit smaller. Junior cyl head has smaller compression chamber. (you don't get cyl head together with this BT cyl).

To get BT cylinder from your AT cyl you can change porting on your AT but I think there is a lot of work.
"Everything seemed very much to the limit and very difficult to improve any more" -Jan Thiel

'Top speed is the most unimportant thing in racing. Keeping your minimum speed high is the most important'
DiederikAT50
auspuh lager
Prispevkov: 5
Pridružen: To Feb 26, 2013 2:43 pm

Re: New cylinder for my AT50

Odgovor Napisal/-a DiederikAT50 »

Thank you for answering my questions.

I want to keep my original cylinder as it is and it's a lot of work to make it perform better. So a new cylinder is what I want.

I don't have the original cylinder head, the person I bought it from had a Puch high compression cylinder head on it.

On the BT Junior replica cylinder is the piston size the default size 38MM ?
Uporabniški avatar
aljo69
el presidente
Prispevkov: 6810
Pridružen: Po Avg 10, 2009 1:53 pm
Kraj: Celje

Re: New cylinder for my AT50

Odgovor Napisal/-a aljo69 »

DiederikAT50 napisal/-a:Thank you for answering my questions.

I want to keep my original cylinder as it is and it's a lot of work to make it perform better. So a new cylinder is what I want.

I don't have the original cylinder head, the person I bought it from had a Puch high compression cylinder head on it.

On the BT Junior replica cylinder is the piston size the default size 38MM ?
yes it 38mm but when you buy the replica, you better check the piston tolerance if it's ok and you will have to correct portings and cut a bit from the top as @macula said. The replica cylinder also does NOT include piston or cylinder head and you also need to change your carburetor for 18mm or bigger (19mm or 21mm dell'orto) and buy better exhaust. It's quite a lot but in the end it will be worth it :)
DiederikAT50
auspuh lager
Prispevkov: 5
Pridružen: To Feb 26, 2013 2:43 pm

Re: New cylinder for my AT50

Odgovor Napisal/-a DiederikAT50 »

Thank you for your reply. I will make another topic with some pictures of my AT50 and ask you guys some more questions about it :D.
Odgovori