DD50 corsa

Downsouthdio · Post by **Downsouthdio** » Thu Jul 12, 2012 9:16 pm

Thats crazy high comp.. You may end up with 3 gaskets. I have 2 to get mine at 125

veedubh20 · Post by **veedubh20** » Fri Jul 13, 2012 12:59 am

well, I dont have trouble using polini gasket base and oring head gasket.

I dont play on compression ratio gaskets.

Downsouthdio · Post by **Downsouthdio** » Fri Jul 13, 2012 7:33 am

Well i dont wana fry my engine either , i can pull more power out of it

kauaianman · Post by **kauaianman** » Fri Jul 13, 2012 10:31 pm

added head gasket again. compression now 120-125.

motor still running hot.

I have since put hondabon with the base gasket to ensure no leaks.

I'm starting to think it's the cylinder.....

like i said the piston sits a good 1mm below the exhaust port on the bottom stroke. maybe when the exhaust port is all the way open the 1mm bottom lip is causing bad airflow out of the exhaust.

this is the first cylinder that i put in that sits below the exhaust port.. they are all usually dead flush with the bottom of the exhaust port.

I seem to have tried everything with this block. don't know what to do next.

going back to stock carb and mani. soon. just to try

kauaianman · Post by **kauaianman** » Fri Jul 13, 2012 10:36 pm

kingkamehameha wrote:Crank needs to be taken out anytime that you do port work. If your compression is at 155 you will blow a hole in your piston with the pump gas

only did very minor port work and only on upper portion of boost port. i just soaked some rags with oil stuffed them in the crank area, flipped the block upsidedown, and used a small file and very frequently wiped out all the filings as much as possible.

Corsa boost port not much bigger than stock so not much to clear.

tru72 · Post by **tru72** » Sat Jul 14, 2012 12:22 am

kauaianman wrote:
kingkamehameha wrote:Crank needs to be taken out anytime that you do port work. If your compression is at 155 you will blow a hole in your piston with the pump gas

only did very minor port work and only on upper portion of boost port. i just soaked some rags with oil stuffed them in the crank area, flipped the block upsidedown, and used a small file and very frequently wiped out all the filings as much as possible.

Corsa boost port not much bigger than stock so not much to clear.

thats not porting ...
boost port helps in cooling the motor as well...

kingkamehameha · Post by **kingkamehameha** » Sat Jul 14, 2012 12:57 am

Boost port needs to go straight down thats why the case needs to be separated an crank taken out. I doubt your getting hot because of that. You need to do a correct pressure test on your motor and then get back to us

kauaianman · Post by **kauaianman** » Sat Jul 14, 2012 1:43 am

thanks for the advise.

i usually cutr the boost port straight down. i was lazy and just wanted to clean up the top a little.

still working on making a pressure tester.

i dont think an intake leak is causing the heat because wheni soak the intake (the entire intake) with carb cleaner i get no change in idle at all.

i would think a manifold leak big enough to run the bike lean would be found with some carb cleaner.

and the weird thing is the plug shows no signs of running lean.

kauaianman · Post by **kauaianman** » Sat Jul 14, 2012 1:45 am

the other day that minor leak on the boost port was bothering me so i pulled the head and put hondabon on with the aluminum base gasket.

sopme pics

kauaianman · Post by **kauaianman** » Sat Jul 14, 2012 1:47 am

made sure hondabon was even all around.

kauaianman · Post by **kauaianman** » Sat Jul 14, 2012 1:50 am

after putting the hondabon i used only original corsa O-ring head gasket and got 150psi compression

: 2012-07-12_16-58-41_423.jpg (28.35 KiB) Viewed 5292 times

tried it out and ran hot so i pulled the head again and used a regular size head gasket with the corsa O-ring and compression came down to 120.

: 2012-07-12_17-08-30_80.jpg (26.79 KiB) Viewed 5292 times

still running hot.

no leaks comming from base of cylinder at all.

kauaianman · Post by **kauaianman** » Sat Jul 14, 2012 1:55 am

tru72 wrote:
kauaianman wrote:
kingkamehameha wrote:Crank needs to be taken out anytime that you do port work. If your compression is at 155 you will blow a hole in your piston with the pump gas

only did very minor port work and only on upper portion of boost port. i just soaked some rags with oil stuffed them in the crank area, flipped the block upsidedown, and used a small file and very frequently wiped out all the filings as much as possible.

Corsa boost port not much bigger than stock so not much to clear.

thats not porting ...
boost port helps in cooling the motor as well...

yeah i kno.... sad for me to call that porting at all... more like minor clean up. i though maybe it would help a little.

my friend running same setup with no porting at all on hisd dd50 block and bike run good. 250-270 degrees cruzing under 35mph. all bolt on no adjusting/tweaking anything.

veedubh20 · Post by **veedubh20** » Sat Jul 14, 2012 2:10 am

what oil did you use and gas?

Downsouthdio · Post by **Downsouthdio** » Sat Jul 14, 2012 8:08 am

Check your shrouds, make sure they are snapped together, you running the plug that came with the corsa?

kauaianman · Post by **kauaianman** » Sat Jul 14, 2012 3:27 pm

using shell V-power gas. redline oil. premix 3.5oz per gal.

all cooling/engine shrouds are good and tight. i use NGK B8hs plug.

pulled the manifold last night and found leak at base of manifold.

tested base of manifold and it doesn't sit perfectly flush with the block. I gotta find a belt sander and try to get the CT back as flat as possible so there is good contact between the manifold and the block.

any good ways to do this?

i cant imagine that i have the only CT manifold with this casting issue.

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