Thank You APE ! ! !

Just want to thank APE for doing an excellent job with my ported head I sent them to have rebuilt. It came on a GPz550 with a 615 kit, and Megacycle Cams I bought for $260.00 back in 2006.

THEN:


NOW:


Yea, I know, it was a great score!!!!

Anyhow, I sent it in to them to have rebuilt, and install a new set of RD Springs (stiffer for higher reving), and a set of Viton Valve Seals, along with a set of new Kawasaki Seals, and additional keepers. The Viton Valve Seals wouldn't work, so they used the other ones. APE knows I'm using this head for racing in AFM this year, so they sped up the rebuild process for me. They found out the valves in there were mushroomed, so I sent them another used set. They made a set of bronze valve guides to replace what was in there. Noticing the pitting on the head surface, they recommended surfacing the head till the marks were removed, and only removed what was necessary. I have about .006" remaining on the step, raising the compression about 1/4 percent Jay estimates. Bottom line, cleaned up, and not knowing the history of this head, and who did the work, I'm excited to get this engine together with the 615 kit and cylinders I had APE machine for me a few years ago.

Thinking of sending them a crank flywheel, and rods to lighten and balance, before I install all of this, doing it ones and doing it right, but it might go over my budget I thought I had when I started. I'll e-mail APE Monday.

I do not work for APE, and this is not a paid advertisement, but having sent them work in the past, and receiving great customer service then, I'll be continuing to send them work in the future. Having more than enough parts to build 6 GPz550s, and 7 GPz550 Engines, I'll have spares for a long time.

Thanks Jay, Jeff, and the whole APE Crew! You all know your stuff.

Corey,

The bike looks awesome!

Good luck with the racing. Nice to see those old 550's still out there.

Larry C

Thanks Larry. If I had a GPz750 turbo, I'd venture into the same performance upgrades you have.

Intake Port


Exhaust Port


Combustion Chamber


Head Surface Step

Your bike looks great Corey.
if u take a drumel to the air pasages around the ports and fins,to remove the factory slag, it will help to cool it better. It was also popular for the racers to drill 3/8" holes through the cooling fins.

Long time no see, Corey.

Looks like you've got a nice 550 going. How's the racin' going?

Mark,
Air passages around the port? Care to elaborate on that? I'll have to look into the drilling the fins mod too.

Thanks NONB,
I start racing next month with AFM, missing the first round at Buttonwillow this weekend, but I'll be spectating(crying). I hope to do the remaining 6 alternating rounds at Infineon(never had any wheels on that track), and Thunderhill. I have a lot to learn still, but am jumping in before I get too old. :blink:

Been busy Admining the GPz550 Site. I check in every once in a while.

CoreyClough wrote:

Head Surface Step

You see the little bit of slag around the chin well, just below the surface?
That is the stuff im talking about. it dosnt hurt in this area, but u want to look all over the head. any slag that will deter air flow, especially around the xht ports leading into the inner parts of the head, around the fins and plugs.
I'll see if i can find some pics of the fins drilled for u. this was common on the kz900/1000 race bikes. dont know about the 550's, but the principle is the same. it helps the air take the heat away from the fins faster.Pops yosh did it. he even drilled a bit of a hole into the top around the chamber, but i would not do that.he had a free supply of heads.u dont need to go crazy, unless u find u have a heat issue. with stock compression u will be fine.

I'd like to see that Mark. Thanks for the advice.

I have been getting oil in the pan temps around 240F with the stock oil cooler out on track. I posted about this here somewhere. I'm using a Daytona Digital Temperature Gauge. Eventually I'll instal a Zephyr ZR550 Oil Cooler I've had for a while. It's bigger and with a little frame modification(a few new holes) it should cool much better. Uses the same oil pan as the KZ and GPz550.

hi correy

some nice stuff in the pics, your bike is really inspiring.

Let us know what kind of HP you get with all that stuff thrown in. You started @ 55hp with not that much work right?

Cheers

TG