Flattops in a 61x

[D-Roc]

what would it take take switch to a flattop piston? i want to use a 82mm kawi small pin piston. If i cut the piston skirts to clear the cases and then deck the cylinder 4mm would that work?, or do i have to get flattop domes for my ada head so that the dome shape works with the flattop? i only heard of 85+ mm flattop motors,and i don't want to resleave, i just want to get a fresh bore and pistons and thought that using the flattops would be better. Let me know what you guys think good idea or bad idea.

 

[keefer]

I am no expert when it comes to the flat top setup, but I have heard it said many times that you have to have flat top domes cut to obtain the proper squish when running the flat top pistons. I am sure Jr, Supertune, or Tricky1 could tell you the proper way to get this setup to work.

 

[D-Roc]

yes i heard that too, obviously putting the flattops in would make a large squish so i could deck the top of the cylinder to get the proper squish but then the domes are still shaped for the stock yami domed pistons, i thought that in order for a flattop piston to work better it has to have the proper dome shape, am i on the right track here guys or way out.

 

[Matt_E]

Hence you'll need flat top domes.

 

[D-Roc]

so i should cut the ones i have, any flattop domes i've seen were for 84mm and bigger.

 

[sjetrider]

What kinda head you got? Have that co. cut you domes. You will need to deck the cylender the propper amount from top and bootom. You will also need to chamfer your transfer port where the KAWI piston ring gap is in the middle of a stock cyleber transfer port. And the Kawi piston skirts will need cuut as well to clear crank.

 

[Moondance]

What kinda head you got? Have that co. cut you domes. You will need to deck the cylender the propper amount from top and bootom. You will also need to chamfer your transfer port where the KAWI piston ring gap is in the middle of a stock cyleber transfer port. And the Kawi piston skirts will need cuut as well to clear crank.

:shrug: wtf did you just type

good thing you talk for a living:haha:

:kiss:

 

[egbrig]

There are other things to consider like: the port timing effect, the difference in pin to piston deck height.

 

[D-Roc]

would you deck the top of the cylinder the same amount as the bottom to get the port timing back to the same as it would be with domed pistons? Smitty has a 760 jug that is already decked for stock crank with flattops that he may sell me, it is ported for racing and would require total loss timing curve with race fuel, it has a scored sleeve, if i resleeved it, could it be reported for freestyle? my cases are opened up and have run that cylinder before. If that is the case then that maybe a better route for me to go.

 

[FL-cracker]

I have the motor In my Sig that I may be interested in selling for the right price. I havnt put it together yet, and the pistons are new. Maybe we can work something out. I have the head with the corrrect domes for 200psi. "JR" said the measurements were right on the money. I am just wondering if the motor is more then I need. The only thing that sucks is that the motor will need new sleeves once it needs bored again. The bottom of the sleeves were milled to fit none bored "stock cases" I paid $900 for the top end with head. Let me know if you may want to work something out. I would be interested in a ported cylinder if you wanted to do a trade deal.

Bronson

 

[D-Roc]

200 psi was a little higher then i wanted although i had been told that canadian fuels are of much better quality than in other places, i am not running any static timing on my msd enhancer so pump gas may just work with that combo. does anyone know for sure if a race ported jug can be converted back to pumpgas freestyle with a resleeve job? and if the jug is decked then the new sleeves will have to be shaved too.??? right now i am just reseaching into some of my options so if someone else wants your setup don't pass up on selling it. I will let you know if i do indeed want your motor.

 

[FL-cracker]

I think Im gona keep her....I keep hearing how bad arse it is.