Cycle Playground Head Mod

[MJC]

About a month ago I sent the head off my 11xc 250 down to the guys at
http://cycleplayground.com/ to have them modify the head for more low torgue without sacrificing the topend and to reset the squish to 1.25mm. Now that I've had some time to evaluate the mod I can say for sure that they gave me exactly what I asked for. The bike now has more lowend torque and I'm able to keep the bike in 2nd and 3rd gear now going around tight corners. Where as before the head mod I would have to down shift before entering in order to pull through some of the really tight stuff. I would say the bike is now able to pull 1/2 gear higher in any given situation than it was before the head mod. This was achieved without the loss any topend over rev, just like I asked. I was very impressed. This mod alone has made a bigger diference than any pipe I've tried and is well worth the $60 it cost to have done. I'm very happy with this mod and they will be recieving the head off my 07' Honda cr125 soon. Here's a pic of my finished head.
Sorry about the size, but I don't know how to resize it.

[andoman]

Mike has a very, very good reputation over on the orange forum. Not only as a provider of excellent service, but also as a contributor with vast 2 stroke knowledge.

[GMP]

Yeah, he is an ECEA guy too. Looks good, just like my RBD modded heads that got the same results.

[Jakobi]

Looks very nice. Any chance you can find out what volume the new chamber is?

[Cruiser]

And he always has coffee on on saturday mornings too...

[MJC]

Originally Posted by Jakobi

Looks very nice. Any chance you can find out what volume the new chamber is?

I'll try and do it during the next rebuild.

[GMP]

Thats really irrelavant to the end user though, more of an in process tool for the tuner to tune the compression to the desired amount or match the original compression (by matching the end product to the original volume). The width of the squish band (MSV, or Mean Squish Volume) has much to do with the type of power. Assuming the correct clearance, the more MSV (wider squish band) the more low/mid focused power, less MSV more top. Whats important to understand though is that if the squish clearance is too large or unmatched, the effective MSV will be less than the width of the heads squish band would indicate. Without welding you are theoretically limited to what you can do as far as ultimate adjustment, but its not neccessary in practice. The end result in an RBD modded GG 250 head yeilds a slightly more narrow squish band than stock, but a higher MSV. This is good all around as many of us have found. The CP head shown here looks exactly the same and is what was asked for. I'm assuming its set up to run on pump gas, so guessing around 190-195 PSI compression.

[Jakobi]

Nice detailed response Glenn and right on the money. I do however see the chamber volume as some what a constant once the head is set up so it can be of some use. The trapped volume however plays a big part in the final CR and fuelling requirements.