S3 Heads
 

Hey guys, I will be installing S3 heads on my EC300 later this week and would love to hear your feedback on which dome worked best for you?

[IMG]http://i772.photobucket.com/albums/y..._R/S3Heads.jpg[/IMG]

Rod, check through this thread http://www.gasgasrider.org/forum/showthread.php?t=11970
Jakobi did a very thorough write up, in the end- no matter the insert you use, you'll still need to machine the head for proper squish. I actually think he came to the conclusion that just doing the stock head a better value but the S3 head certainly adds looks to the equation

Unless you like running race gas, get the stock head modded. My buddy ran an S3 head this weekend in TN and his bike knocked so bad he quit after the 4th test. He was afraid he was going to bang a hole in the top of his piston.

Roger that. Each insert is similar to shaving a the head without doing any other work. Volume of the chambers remain the same.

So if you can get the black insert with a squish around that 1-1.3mm range, you'd better have some really good fuels available. Not to mention the effect all that comp has on top end/over rev.

On the 300 I found the black insert had an acceptable UCCR, but had to use 1.3mm to time the ports for top, which gave 1.9mm squish clearance.

You should see if the factory can do up various chamber volumes!

I just received my S3 head.
It is like a piece of jewelry.:D
The machined surfaces won't inhibit coolant flow like the cast OEM head.

I think I will try the silver insert first.

So if you don't want to machine the stock head and have the S3 on the shelf, get the port timing right with base gaskets, see which insert gives you 1.1 - 1.3mm squish, then have that insert machined for proper volume so as not to have excessive compression. I have the 2011 Nambo with the silver insert installed (not pulled so I don't know what the squish or port clearance is) and have the S3 kit for my 2011 6 days, not installed. Previous owner of my 6 days had the RB designs mod done on the head and carb, it's strong but not like the nambo. Both running Sunoco 98 octane GT260 and jetted well.

I think the Nambos have something different. Never worked out what, but its more than the head. Maybe crank case volume?

You also assume you can get the port timing right with the S3 insert. IE my 300 with ports timed where I wanted and the HIGH HIGH insert gave me a minimum clearance of 1.9mm still. Granted 1.3mm of it was gaskets which could be removed, but they would have altered port timing.

The process you described however, is exactly what I did with my S3 250 Cylinder to get 1.25mm squish, then had the head machined back to 14:1UCCR.

I have a gold one, and a red one. Well aware how good they look, but as for being functional/practical.. not so much. $$$ bling!

I have the S3 on the shelf..... In truth, the 6D bike is about perfect for HS racing in Va woods as it is. When I get the nambo suspension back (parts on back order from Sweden) I'll rethink the S3 option. Can't risk tinkering yet.

This thread is interesting to read. I have always thought how cool to have that nice looking S3 head (bling-bling). But now glad I have not got it. And not knocking the ones who did because I know you have made it work and does an awesome job. Currently my OEM head is down at RB Designs getting machined. Should have it back this week and back installed. I also had my cylinder jug fresh air ports cleaned up (ported - not polished) by removing the factory casting burs and any imperfections.