Gas Gas 125 power valves

[geoffg]

Hi
I am after some power valves to fit a spare 2004 125 cylinder.
Researching the parts books, I find a number of part numbers.

ME720001208 (2010)
ME720101209

ME120516016 (2005)
ME120516014

ME120416016 (2004)
ME120416014

ME120216016 (2003)
ME120216014

Does anyone know if they are interchangable and which are the most durable. I have read somewhere that some are steel and some aluminium.

The plan is to use my spare cylinder as part of a 144cc project. They are fairly expensive so I want to get the most durable ones.

 

[GMP]

I don't know the part #s off hand but they did go from the original small dia guide aluminum valves, to larger dia alumimum valves, back to smaller dia steel valves. The aluminum valves were breaking on the earlier 125s. I updated an '01 XC125 with the steel valves. I have no idea what the '10 parts may be, but all previous should be compatible you just need the proper ID guides as well.

I would not be surprised if Yamaha PV parts would work, as the cylinder is VERY close in design. Would be interestig to check and Yamaha parts are cheap.

 

[geoffg]

Thanks Glen

The Yamaha Power valves are $190 US each!! I think I will stick with the Gas Gas ones.
I will have the cylinder off my 2005 MC125 on the weekend and see if they are steel or aluminum. It should have the original valves in it.

 

[GMP]

$190 That sounds awefully high, most Yamaha parts are reasonable here.

From what I was told in the course of dealing with this problem, was that the valves were breaking on the SM and MC 125s that saw a lot more sustained high RPMs, so those bikes got the steel valves before the ECs. My parts were ordered by now gone Smackover Motorsports as SM125 parts.

 

[fastfilli]

I have 2009 valves in my 2001 ec straight swap and much better design!
Not cheap

 

[geoffg]

Hi

I got around my problem by buying a damaged cylinder that had the valves included.

How are the 2009 valves different to the older ones?

 

[fastfilli]

The shaft is a bigger diameter on the valve.
And the steel collet that the valve slides in has a smaller inner diameter.

On my 2001 EC125 the original power valves snapped on the shaft then dropped in to the piston causing lots of damage.

My friend had a 1989 Yamaha back in the day and said this was a common problem with the engine. The EC 125 engine seems to be based on the 1989 Yamaha engine.

 

[GMP]

fastfilli,

Can you tell me if the older 125 cyls would work on the '09 cases? I assume so if the PVs can be swapped, and I don't think the cases were ever changed. 125 knowledge base is much more limited! Thanks.

 

[fastfilli]

I have no experience with the new engine.

But I have studyed the parts manuals online from GasGas.es and the engine does not look any different.