4stroker Posted October 22, 2007 Author Report Share Posted October 22, 2007 ok well now youre not making any sense. if you have to run a 1mm spacer plate anyway then why not run a thicker one to accommodate the 10mm crank? thats just stupid not to. crank prices are the same as well as trenching. with either motor you really need to be running at least 39mm carbs, straight cut gears, lockup, big air filters and a good solid clutch. it doesnt make any sense to build a 7mm at this point. there have been many guys that built 10mm out of stock cylinders than ran very well.. honestly, i dont think you have any clue as to what youre doing is you think you cant build a 10mm. the spacer plate will raise the cylinders back up to get your port timing back to where you need it. if i run a spacer and bump the height of the barrels up to suit a 10mm crank, the roof of the transfer ports will end up too high without even grinding them... how do you suggest i "lower" the transfer port roofs without making a custom sleeve for some standard cyls?? you may very well be able to use a 10mm crank with banshee cyls, as they prolly have less transfer timing than an RZ... i cant check that at the moment though as my banshee cyls are at the machine shop. RZbansheeman thanks for the offer but i have downloaded a bunch of port maps and i have mapped these new barrels myself to check that they were standard and yeah, a 10mm def cant be done, might not even be able to do a 7mm but im def gonna try everything before i bite the bullet and buy a 4mm instead! i think i do know what im talking about... Quote Link to comment Share on other sites More sharing options...
blowit Posted October 22, 2007 Report Share Posted October 22, 2007 if i run a spacer and bump the height of the barrels up to suit a 10mm crank, the roof of the transfer ports will end up too high without even grinding them... how do you suggest i "lower" the transfer port roofs without making a custom sleeve for some standard cyls?? you may very well be able to use a 10mm crank with banshee cyls, as they prolly have less transfer timing than an RZ... i cant check that at the moment though as my banshee cyls are at the machine shop. RZbansheeman thanks for the offer but i have downloaded a bunch of port maps and i have mapped these new barrels myself to check that they were standard and yeah, a 10mm def cant be done, might not even be able to do a 7mm but im def gonna try everything before i bite the bullet and buy a 4mm instead! i think i do know what im talking about... If you have a bunch of maps for the RZ, could you float those over to us? We never did really document the different maps relative to the castings. Thanks Brandon Quote Link to comment Share on other sites More sharing options...
4stroker Posted October 22, 2007 Author Report Share Posted October 22, 2007 And I think you missed the day that they taught port timing 101. Raising the cylinders will increase port timing thus make things worse. He has a very valid reason for considering 7mm vs 10mm. You are obviously bogging on someone that has sense enough to "check" port timing and verify that indeed, target numbers are out the window and optimal flow will not be seen. There are a bunch of banshees that run big cranks but many have "stroker" sleeves that have a taller barrel that the head locks in to and have relocated ports for the big stroke. A big waste of time compared to a PV cheetah though. 4stroker, yes the 4mm is as big as you can go with optimal port timing. The 7mm can be done but you have to stack base gaskets and further increase timing to get it done. Worth it though but I would not even do a 10mm on a stock cylinder anymore. Just not enough blow down and not worth it. Brandon ha yeah man i havent even run the numbers for a 10mm crank but im guessing transfer duration would be like 140 degrees! anything below 8000rpm and the mixture would prolly blow right out the exhaust! can anyone tell me how far it is from the top of the barrel to the top of the transfers on a standard banshee cyl? thanks, mark Quote Link to comment Share on other sites More sharing options...
4stroker Posted October 22, 2007 Author Report Share Posted October 22, 2007 If you have a bunch of maps for the RZ, could you float those over to us? We never did really document the different maps relative to the castings. Thanks Brandon no problem they are at work, pm your email and i will pass them on actually hit rzbanshman up for them, they have blocked me from the hq at work lol so i might not get them to you until tonight (my time) Quote Link to comment Share on other sites More sharing options...
RZBansheeMan Posted October 22, 2007 Report Share Posted October 22, 2007 Hopefully this will help you some Brandon. Quote Link to comment Share on other sites More sharing options...
blowit Posted October 23, 2007 Report Share Posted October 23, 2007 Hopefully this will help you some Brandon. Thanks for the pics. I will put that in the file. The stock banshee is about 44mm or 114 degrees but factory chamfer varies greatly and will affect timing. Hope that helps. Brandon Quote Link to comment Share on other sites More sharing options...
locogato11283 Posted October 23, 2007 Report Share Posted October 23, 2007 ok, so if the 10mm isnt worth it with the RZ jugs because the port timing wont work like you need it to, then why run these jugs at all? wouldnt it be smarter to just run stock banshee cylinders and do the 10mm as opposed to running rz jugs and doing the 7mm?? are the rz jugs supposed to make a lot more power or what? i understand you have the PV's for the extra bottom end but i guess i cant just see the point of swapping to the rz cylinders unless youre gonna make a lot more power with the 7mm rz as opposed to a 10mm stock.. i personally wouldnt go any bigger than 4mm on stock cylinders as my last 2 motors have been a 4mm and 10mm cub.. ok so you got me on the port timings.. i dont know much about that. i would just think there would be a crank/rod/piston/spacer combo that would accomodate doing the 10mm.. just trying to offer some ideas here. carry on! :beer: Quote Link to comment Share on other sites More sharing options...
blowit Posted October 23, 2007 Report Share Posted October 23, 2007 ha yeah man i havent even run the numbers for a 10mm crank but im guessing transfer duration would be like 140 degrees! anything below 8000rpm and the mixture would prolly blow right out the exhaust! can anyone tell me how far it is from the top of the barrel to the top of the transfers on a standard banshee cyl? thanks, mark A 10 mill crank with stock rod and 2mm correction factor for cylinder lift is around 140 degrees. I would not bring the piston out more than 3mm. This was assuming stock port timing. The 7mm crank puts you at around 130 with only .5mm correction which is more livable as long as other ports carry suit to allow proper blowdown. Brandon Quote Link to comment Share on other sites More sharing options...
4stroker Posted October 23, 2007 Author Report Share Posted October 23, 2007 I figure if I try to use a 10mm crank and a spacer that allows the pistons to only pop 2mm out the top (like a 4mm with no spacer Quote Link to comment Share on other sites More sharing options...
RZBansheeMan Posted October 23, 2007 Report Share Posted October 23, 2007 I know that somebody makes a stroker sleeve for stock cylinders, but it is Banshee cylinder based. It may sound ludacris, but it might be possible to modify and stuff those sleeves in some RZ jugs. I think the only area of the sleeve that might need to be modified is the area around the top of the exhaust port where the valve rotates, but I don't know for sure. Might be something worth checking into if you are after a 10 mil stroker, or maybe modified replacement Banshee sleeves could be used for the 7 mil stroker and then reported to the correct durations required. Just a thought. Mike Quote Link to comment Share on other sites More sharing options...
blowit Posted October 23, 2007 Report Share Posted October 23, 2007 I figure if I try to use a 10mm crank and a spacer that allows the pistons to only pop 2mm out the top (like a 4mm with no spacer Quote Link to comment Share on other sites More sharing options...
4stroker Posted October 23, 2007 Author Report Share Posted October 23, 2007 I think you will find that there are plenty of good pipes out there without having to make a custom set. Thing is, the dims of the pipe are largely dependent on the stroke of the engine. IE, you may be able to use the bigbore shearer or CPI inframe and hit the sweet spot. You may also find it MUCH easier to buy a set of say CPIs and chop the belly in half or modify the diverging cone to get what you want as opposed to starting from scratch. It's one thing to design a pipe on paper, but a whole other stack of apples to get it to fit in the frame without compromising the dims of the pipe. Brandon i thought about all those things too. will have to have a chat to some pipe builders and go from there, apparently MOTA (the tuning software i want to buy) is pretty good at pipe design and facilitates all the bends you could ever want without compromising the specific dimensions of the pipe Quote Link to comment Share on other sites More sharing options...
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