250-500cc GasGas piston in WR 300

it´s time for me to change piston, and i decided to use the gasGas piston for better performance as many recommend it. Does anyone of you guys use it, and if so, what´s your opinion? Does anyone know what increase in compression i will recieve? What´s the torque of the cylinder head and cylinder? Anything special to think about when i take it apart?

Johnny:sweden:

I emailed Vertex asking about the Gas Gas 300 piston as their website did not show anything for that bike. The rep replied back advising they do not make a GG300 piston.I guess that MXA article was wrong as they clearly stated it was a Vertex piston. Or quite possibly the rep is wrong.

Not sure how much of a compression bump you'll get, especially if you're using the stock head without having it cut. I would do the solder test to measure the squish before I even attempted to start it. If its way off then you will need the head cut.

Cylinder nuts = 21.6 - 24.5Nm or 15.9 - 18.1ft/lb
Head nuts = 17.6 - 19.6Nm or 13.0 - 14.5ft/lb

PM me your email address and I can send you a sheet for all torque values.

Here´s the link to the Vertex parts catalog.
Let us know how it went Jonnymannen.

http://hosting.candlcompanies.com/VP_ ITALY_2010_Vertex_Parts_EuroPriceList.pdf

Thanks!

I can get the Wiseco equivalent of that piston for $160 w/ rings, pin and bearing. I wonder why the Vertex is so expensive... that MXA article stated it was $250.95.

Does anyone know if all GG 300 pistons are domed or is that an option they can choose to do like us Husky owners can too?

Update: The Wiseco crossover part # is 850M07200. It is a 72mm domed piston and can be found for around $165 shipped here in the states.

The Wossner and Vertex pistons are both cast as where the Wiseco is forged. I've had great luck with Wiseco's in the past, so I'm happy they make an affordable alternative.

Got one on the way. Will post back in a week or two after I've had a chance to play.

What are the benefits of the domed piston?

Is the head OK with the stock WR300?

When i ordered my Wössner piston we checked in the computer and GasGas pistons are the same between year 2003-2010. Mine is 71,95mm diameter. Should also be lighter then standard they say at Wössner. Who knows. I will weigh it when i pick it up just of curiousityrofessor:

Johnny

Higher compression and better squisharea that gives better burning=more power!

Johnny

Many of the newer Vertex pistons are forged. The 144 piston I source from Vertex is forged and a bit lighter than the Wiseco. It also has a slightly raised flat dome that brought my squish more into line with optimal but still slightly wide. My compression is 180#'s so I don't think I want to raise it much and risk detonation with pump gas when I go down in elevation during the winter.

Walt

Wiseco and Vertex forged pistons are about the same price at OEMCylce. I pay $108 for the 144 piston kit.

Domed pistons tend to make more low end torque and flat tops lean toward top end HP, due to different savaging effects.

Also, depending on the squish angle cut into the stock head it might optimize squish velocity for better low rpm performance.

Then, there's the obvious, more compression.

If guys are able to run a domed piston with the stock head cut, then compression and squish velocity must be on the detuned side from the factory. That would also explain why PC was able to get so much more power from the motor.

The main thing to consider when looking at a piston swap is the height of the timing edge from the wrist pin and that the exhaust skirt doesn't uncover the exhaust port at TDC.

On a reed motor the intake skirt isn't that big a deal, unless it's WAY short. A piston port motor will know the difference.

The piston shipped today, so I should have it later this week and my motor guy is awaiting the head. I emailed him and he said the head was designed for a domed piston and he was surprised Husky did not supply the bike with one. Kinda odd...

I'll bring him the OEM piston, the GG piston as well as the cylinder to ensure the GG piston does not throw off the port timing. Not a problem for Pro Circuit who can correct this on the fly, but it'll be a problem for me.

Should have the piston in and head modded next week. Will report back then!

Yep.
He does all my work.

Sheesh you guys like doing things the hard way don't you!!
Just drop that gas gas piston inside a nice gas gas and you'll be good to go!!

Oh look, we got a funny guy here.

I think it´s better if you put a huskypiston in the gasgas and then you change the rest of the parts on the bike instead!