Rd350 YPVS F1 Exhaust puzzle and front disc plea

[skidlid]

Evening gents

Just started to refurb the the exhaust that were fitted on the bike when I bought it. 
The part numbers on them are:
R/H 31K-14721
L/H 31K-14711
Can someone confirm these are correct because the parts manual I have states 14710 R/H and 14720 L/H also the L/H pipe has a reducing ring fitted. Can I remove this or are the internal baffles reduced as well or do I need to buy a correct numbered pipe. 

Also has anyone got a decent unwanted r/h front disc going spare?

cheers
chris

[Yogi]

RD350N/RD350F
59HP
'85
31K - 14711

31K - 14721

Pipes look right to me

[midlifecrisisrd]

They had a ring in the header as if to locate onto the gasket. They tend to come off so just remove the other to match

The only early ypvs pipes with restrictor were marked 31w and it was just a reducing cone at the header so again easily removed

Steve