210psi compression. wtf.need opinions

[LCW]

Hard to say since they are big bore. What pistons are in it at the moment? Usually have a part numbers on the crown of the pistons. I see the crank is stock stroke and rod length. Probably have to run a blaster piston and have domes cut for them. Then of course the jugs need ported to match the stroke.

[gonzodesign]

I think your gonna need some stroker domes and alot more CC's

[blowit]

You need to send the cylinders to someone competent to tell you what will work with them.  You don't just "bolt up" another crank.  Port timing will be radically affected.  That is what makes turd bikes.  You need to know what you have. 

 

If it was trenched, it might be setup for a 10mm, you don;t know. 

 

As far as compression, again, cranking compression does not mean a thing!!!!  I have some of my MX motors out there with 250psi of cranking compression!!

[bansheerider313]

3057j 8964 69.42mm - pistons. I have built a 4mm before withthe 795 pistons and spacer plate.im just unsure about thebig bore cylinder bullshit

[sleeper06]

Unless you can degree the motor yourself and take critical measurements dont fuck with it is there something wrong with it that u wanna change besides compression why throw parts at it if its ported for the bore already

[bansheerider313]

im going to go see k&t this weekend. See what they have to sya and what theyll do for me

[sheerider11]

I believe there is a 60% balance factor on all these Banshee cranks, when you start to get compression over 170 I think its time to change it, or do people just say screw it and run it until it blows up?

where do you come up with this?!

[gonzodesign]

I traveled to a crank manufacturer in Taiwan awhile back, I seen a cranksworks crank and seen the added weight at the bottom of the crank and was interested in their formula

[bansheerider313]

ktperf said I can buy 70mm 5mm long rod pistons and a 4mm crank and take it to them and he will put it all together for me and port it case matched and he said he'll check true and weld on crank.he said I should do a lock up clutch and a transmission mod.

[registered user]

As far as compression, again, cranking compression does not mean a thing!!!!  I have some of my MX motors out there with 250psi of cranking compression!!

im with this guy. could give a shit less about kickin compression

[gonzodesign]

I am curious to the fuel? what dome design? what RPM does it run? what timing?

[Nightmare]

Elevation?

 

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[gonzodesign]

I did alot of research today and was laughed at! I was told noone should be running a Banshee or actually his quote was a "twin" with 250 PSI and this is per Yamaha Motor, the efficiency is lost after 180 PSI, a banshee will stop making any more torque after 180 so why do it? I was also told Dynoedge I believe was the name used in Michigan did excessive tests and started actually raising the head at 200 PSI just because the 8mm studs could not hold that amount of pressure! now this was from a very knowledgeable individual that has a vast amount of information but he may be wrong,

[sstaton1983]

I did alot of research today and was laughed at! I was told noone should be running a Banshee or actually his quote was a "twin" with 250 PSI and this is per Yamaha Motor, the efficiency is lost after 180 PSI, a banshee will stop making any more torque after 180 so why do it? I was also told Dynoedge I believe was the name used in Michigan did excessive tests and started actually raising the head at 200 PSI just because the 8mm studs could not hold that amount of pressure! now this was from a very knowledgeable individual that has a vast amount of information but he may be wrong,

. And this is all based on CRANKING compression.....Who gives a shit about building a motor around the cranking compression, port timing can alter the compression and there are a lot of variables to total tourqe output. Edited April 25, 2014 by sstaton1983

[gonzodesign]

after he altered it he had 250 thats the point..and after 180 you will gain zero in the torque dept. and this will start to hold back HP