Repairing Yamaha Rd500 Power Valves ?

[rd84]

Hi,

I'm re-building a Yamaha RD500 engine and have found the bearing surfaces of all the power valves badly scratched. Does anyone know of a company capable of fixing them ? - I assume metal spraying and machining might be the technique required ? - I suppose a machined collar might also be possible ? - at least a better material could be used in this case ?

Thanks.

Cheers

Paul

[Tom Mac]

have you seen the CNC machined replacements on ebay?

http://www.ebay.co.uk/itm/Yamaha-RD500-YPVS-NEW-Billet-Powervalves-Rzv500-CNC-Machined-/261312989672?pt=UK_Motorcycle_Parts_13&hash=item3cd777c9e8

[rd84]

Hi Tom,

Thanks for the info - I've ordered a set of those - however I still want to repair my old ones if possible - for one thing I've noticed my Yamaha power valves are blended to the exhaust ports and also I wanted a working Yamaha set to keep as near original as possible - looking inside the engine I can see that it has had some porting done - however I won't know the extent of this until I can get it on a dyno.

Cheers

Paul

[Guest]

I'd have thought that was fairly standard fare for any reasonably well equipped shop? Actually turning them down and fitting a phosphor bronze bush might be a good way?

I'd call in a local place and support the local industry.

[rd84]

Hi Barry, BSBRacer,

I was wondering about a bush since the PV holder is brass - seems strange to have a hard metal and a soft metal together ? Fortunately I'm local to SEP so I'll give them a call.

Many thanks.

Cheers

Paul