reboot

Hi guys, thanks for the info. I'm on a bit of a learning curve here. I made a mistake with the 21 bhp, it's for the rd 125 lc, 12 bhp for restricted model. Carb is 10v00. It appears the restricted model has a plate welded in the exhaust where it bolts to the engine. It needs painting so I'll check it out then, seems all I have to do is remove it, or would I have to rejet?

If it's straight forward to do - exhaust and jet - and only makes it the full power version, as Yamaha originally designed it, whats the downside? According to the Haynes manual the restricted version makes 12 bhp at 7500 rpm and the unrestricted makes 21 bhp at 9500 rpm. Thats going to make a big difference. Now I'm not sure if this applies to the Mk 1 but I hope so.

Thanks for replying Cynic. I just got the bike and I'm susing it out. It will do about 60 mph flat out in 5th but bogs down in 6th. From what I've read that indicates it's restricted. I'm only just getting back on the road due to back problems so need a light bike, the Guzzi's out of the question. A little bit more speed would help keeping up with traffic. I understood it was restricted only for the UK learner market. If the unrestricted 10v ( full power ? )version works OK and I can get it to that spec, why would that ruin it? From what I can gather so far the exhausts got a restrictor plate and I would need to increase the main jet. Any help gratefully received.

Hi, does anybody know how to derestrict a 12w 1982 DT 125 LC.