Power Valve definatly adjustable !!!

[101racing]

I was looking at gasgas.com parts break downs on some random models and it seems that GG has retained the same Pv spring for 200-250-300 for many years. Thats not saying that they didn't change the spring deminsions or rate and retained the part number. The only different part number on my random search is the 125's. I'm not sure whether it would be stronger or weaker or if they would fit in the other bigger bikes. That would be opening a can of worms as far as expirementing. The stock spring could be rated and measured and possibly there are springs available somewhere with different rates. The stock spring apparently has a leverage ratio that is low tolerant because of the super thin shims that are installed to affect rate. On the other hand there is an extreme difference in the KTM springs supplied with the newer bikes. The red spring is the weakest and can be compressed easily by hand. The green spring is very stiff and the yellow in between. The difference in the power delivery is very noticable. The green spring makes the power very mild and in my opinion is only good for extreem tight slimmy conditions.The leverage ratio on the PV spring I believe is way different from GG to KTM. That said , I think a little bit will go a long way on the GG. JMHO

[GMP]

I would not bet the farm on the GG part#s and the springs being the same, especially on the earlier bikes, but its possible. There is also no specific quantity of shims listed for each year. Its also possible that the governer is set in a fixture at the factory and force at a certain dimmension is adjusted with the shims, but I'm just guessing here.

Thanks for contributing.

[socalscott]

Way back, I woke up an KDX via softening the PV spring. I purchased a few springs and then ground the O.D. to varying degrees. I checked full range tension with a weight scale.

Added shimming to my KTM200. For sure, avoid washers. This would be overkill and the intersection(timing) between the bhp and hp will be to far off.

[moto9]

We played around with this on the older hondas.
But found that it was a little too violent for trail riding, unless there was optimal traction, on the MX track it worked great.
I think the area in which the bike is ridden should be considered before attempting this mod.
I live in an area that is very rooty and greasy...basically a pre-greased rain forest, I don't think this mod would work well here...in fact I might benefit more by adding a couple of shims. (IMHO)
I found that the melloness of the stock power makes the bike faster, I can navigate thru the nasty stuff, up greasy hills, where "for instance" my buddy on his tricked out YZ 250 gets stuck and is forced to slow because he's always breaking traction.
Just my 2 cents worth