GPZ750/810 racer running....

will post some pics form the race in a separate thread,

back to some stuff just before closing the engine

big believer in good squsih, so here i am about to check it in a few points

that's how the plasticine looks after squishing and cutting in the middle.

After welding the tapered area in the head, the wiseco piston has now a nice 1/4" wide squish area that should actually do something

put the plasticine bit in the fridge so it gets hard for measuring

030" was at the low end of what i wanted as squish, would have gone with 035" , so a bit risky even but I run out of time to procure a thicker gasket!

another last trick is something i've picked form Yoshimura who used to drill the head and block in strategic places to avoid pockets of hot dead air = improves cooling

from another angle

through some side fins too

fitting the CR29's was a bit tricky, found that stock KZ1000 rubber matched my carb stubs but the between the holes distance was 58 against 54 in the head! damn

crafted this simple screw adapter in delrin with offset holes, the countersunk screws bolt to the head, the black holes have M6 thread to take the boot screws

the starter mounting bolts were good to hold the cam timing pointer!

next day i was at the dyno...

The fuchs dyno at Superbike Milano is pretty cool, it has built in fan and extractors, so you can run even an aircooled motor as long as you want wihtout overheating or having to rest.

quite better than the old dynojet in the shop that i used to work with.

the guy made quite a few pulls to seat the rings

and at the end guy run out of ink in the printer, so took a shot of the screen

88.7rwhp @ 9500 was pretty nice but after the run plugs were VERY VERY dark with 125 mains. should make it into the 90's with 120-115's, we just run out of time to check!

We also discovered that for the time being the motor likes stock heat grade plugs (BR9ES)
i tried cooler BR10ES and it fouled one or two.

last worrying bit was the the gear change felt super stiff but there wasnt a lot i could do about it until i got on the track. the guy wouldnt let me run a test to feel how the lever...

DPR9EIX-9 NGK Iridium Spark Plugs is what I run. Work great for me.

My GPz550 Cylinders come with the holes in them as you have shown, but not as many.

I have seen a bike using a heat barrier material between the engine and carbs, keeping the heat from getting sucked in:


Thanks for the pictures, and descriptions.

Now I'm off to look for that other thread with the pictures...

yep, thats one solution, Yoshi used to do that, Schwantz's early 750 GSX's and GSXR's had that kind of carb heat shielding.

My plan is to go beyond that and build an actual airbox so that carbs not only suck non-heated air but also air that is still and non-turbulent.

Get the airbox and runner volume right and you can even get a boost from that too. Open carbs are very old school today....motogp and WSBK run airboxes.

I am just at the beginning of the development process for my racer, have plenty of plans and areas for improvement, hei! havent even ported the head yet

just taking some time off being in the garage every night. will pick up development again in the two month break i have mid season.