Phathead Racing High Compression Cyl. Head

[monkeyonahill]

Alright, i was looking through my TWMX magazine a few months ago, just before winter started. and i usually start looking through the adds in the back to find some good sites for parts, services, ect. and i found Phathead Racing's ad, and it was one of the only adds i found that have specific parts for 2-strokes! so i looked into it and found their billet cylinder heads and high compression domes. only $171 with shipping for the head, 2 domes, o-rings, washers, and acorn nuts. So i ordered them last monday and they came in on friday!
So.. here's the layout..

What
Phathead Racing Billet Aluminum Cylinder Head (red) and H12/H14 (7.6cc / 5.8cc) High Compression Domes. For Honda, Yamaha, Suzuki, Kawasaki, and KTM 125 + 250 2-stroke bikes. Most years available.

Installation
Installation was very simple. Drained the coolant, removed the gas tank, removed the old cylinder head and cylinder head gasket. (Cyl. Head requires assembly) Installed Phathead cylinder head.
-- To assemble the cylinder head you pick which compression dome you're going to run and install a small o-ring, included in the kit, to help seal it, then you slide the dome in the cylnder. Then you use a light film of grease and put it on the other 2 sizes of o-rings and slide them in place in the grooves on the bottom ends of the cylinder head and dome. (on Honda and Kawasaki bikes you REPLACE your head gasket with the o-rings)

Price
$159.00 for 125's
$179.00 for 250's

Options

125's
Billet Aluminum Cylinder Head
-Anodized Red, Gold, Black, Blue
-Billet Aluminum

High Compression Domes
-H12 (closest to stock, 7.6cc)
-H13 (6.7cc)
-H14 (5.8cc)
-H15 (5.0cc)

250's
Billet Aluminum Cylinder Head
-Anodized Red, Gold, Black, Blue
-Billet Aluminum

High Compression Domes
-H21 (17.6cc)
-H22 (16.4cc)
-H23 (15.5cc)
-H24 (14.4cc)
-H25 (13.3cc)

Where can buy one
[Only registered and activated users can see links. ]

Impressions
It seems like a very nice part to raise your compression so you can get more out of your higher octane gas, on their site it says their high compression heads with a +2mm big bore makes killer power and high octane gas (which i might try to attempt). I haven't ridden on it yet, i installed it friday but went snowmobiling saturday. i will be heading out on Saturday to Horn Rapids ORV for sure to test out the H12 dome on 93 octane with Champion octane booster (4oz/5gal. of 93 octane). And i may get a chance to test it on friday in the dunes.

I also had a few questions about the higher compression dome, the H14 (5.8cc dome). what octane of gas do i need to run to avoid detenation? 105? 110? tryin to keep my engine safe but not lighten up my wallet too much ($10/gal for 110 leaded )

Here's a pic of the full kit for my '01 CR 125:

[ossagp1]

I have seen the Phathead. It is a quality item and when you think about what it takes to make one, the price is pretty good. In my case though, accessory heads have never made sense. I can get a head machined the way I want it for for far less. Two piece heads sound "handy", but after seeing the Phathead, I can change a complete head and be running again faster by swapping entire heads rather than change a dome. Though I doubt that you would ever have a leak with the Phathead assuming you are careful on assembling it if you decide to change the dome, it is just one more step, one more place to leak, and a little added weight.

Oh, I am not one to ever announce that my engine is not stock either, so maybe I am not the one to listen to.

[Henry]

hey andrew, why dont ya post some pics of it on the bike so everyone can see...

man, man i dont have ANY patience whatsoever...

[monkeyonahill]

ill try to snap a few tomorrow before i head out to work after school, if i can! i kinda ran into a problem when i started it up tho... i think my float went is waaay off now... i never really had it set. but when i turn on the gas and twist the throttle gas just poors out of the tubes... time to get that carb off and set the float to about 7mm...

but it did sound a bit different when i started it up... is this normal when u switch to a higher compression head? it was only a 7.6cc dome, so its close to stock. but the kit does remove the head gasket. just made my bike sound a bit lower-toned, maybe louder? idk, didnt want to rev it up too loud and get the neighbors pissed (one of my neighbors is a Cpt. in the local police dept!).

But the overflow problem would be the float correct? it's letting WAY too much gas into the carb... gas will just poor out of the tubes, not drip or drizzle, but poor. and i didnt touch the carb in the installation of the head. i think it was bound to happen... but it wasnt doing that last Saturday at the track?... hm, ill try to get the carb off this week and fixed by thurs/fri.! But there's no coolant leaks, inside o-ring seems to be sealing good, i didnt smell any coolant being burnt!

So i give it a on sealing and i got it in 2nd gear in my driveway and i think i felt a lil bit more power. not a HUGE difference. but a bit. should be fun to try to 5.8cc dome with 105 unleaded or 110 leaded (im not expecting a major difference, but somewhat of one).

[Henry]

my float got out of measurement when i was just working on my clutch, once too. the bike was laying on its side for close the 1h 30min, and i guess the float didn't like that.

your float could just be stuck, mine was a little and i also had to re adjust it. take the butt end of a screw driver PLASTIC or softer and LIGHTLY tap the bowl of the carb 2 or 3 times(while it is still one the bike), your float may just be stuck, if it still is pouring so not tap any more and take the carb apart. when mine did the same thing yours did i tapped the bowl and it lessened the gas coming out but i still had to adjust the float. good luck! and i look foward to the pics!

[ossagp1]

I would take the carburetor "down" and set it to specs (the float) and clean it. Henry is right though about a quick fix on what might just be a stuck float.

Oh,,, you will notice a difference with the highest compression dome. I think you will like it too. Just be really attentive to the carburetion needs of it until you are sure your fuel and your jetting won't let you down.

[monkeyonahill]

now that i think of it i was actually only in first. and the throttle seemed a bit more crisp and snappy. i like

I think my float may be stuck. ill give it some light taps and see if that wont fix it. if it does ill prolly take off the float bowl and clean the jets anyways.

[monkeyonahill]

float was stuck, a few light taps from a hammer on the floatbowl fixed the problem! thanks guys!

[Henry]

Originally Posted by monkeyonahill

float was stuck, a few light taps from a hammer on the floatbowl fixed the problem! thanks guys!

no problem bro!

now how about those

uh o, more lack of patience...

[monkeyonahill]

lol! ill try tonight, idk, life is kinda hecktic... plus my bad memory! ill try to have pics by tonight... cuz tonight i get in some new gear from Motosport! (2007 Thor Statics jersey/pants/gloves and 2007 Dragon MDX Nate Adams Sig. goggles)

[Henry]

Originally Posted by monkeyonahill

lol! ill try tonight, idk, life is kinda hecktic... plus my bad memory! ill try to have pics by tonight... cuz tonight i get in some new gear from Motosport! (2007 Thor Statics jersey/pants/gloves and 2007 Dragon MDX Nate Adams Sig. goggles)

how about some pics of the new gear too!

[monkeyonahill]

lol, patience henry! ill go snap some shots of it right now. its still loaded on the trailer from my ride yesterday (check out the ride report on Horn Rapids ORV). and ill try to snap some pics of my new gear too!

[monkeyonahill]

Alright, here's the pics of everything! haha, this is what you've been waiting for Henry!

(more pics to come, lol, have to go to church now but around 1:30 or 2 ill have all the pics posted)

[Henry]

SWEETNESS!! how did it work out for ya monkey?