medley Posted December 25, 2011 Report Share Posted December 25, 2011 what all needs to be done to the motor for a 4mill? i dont want to run the base plate for it because i have heard thats not the right way too do it. i have to split the case because the seal went bad on the right side and smoking bad out of the right side. a guy i know said he will trade me a vito's 4mill crank for my weisco crank. will 28mm keihin pwk flatslides be big enough? i plan on getting a dune port or agressive dune port for it. thanks for any help Quote Link to comment Share on other sites More sharing options...
Nieskes Posted December 25, 2011 Report Share Posted December 25, 2011 Looks like you already know what you need, only thing I would add is cut domes. Your porting, riding, and compression might help determine what size carbs you want/need. Quote Link to comment Share on other sites More sharing options...
medley Posted December 25, 2011 Author Report Share Posted December 25, 2011 (edited) i have a cool head with 21cc domes right now. do i need to get my domes sent off to be cut? my compression is at 160 each cylinder. do i have to have the cases cut or is that just for 7mil and up? Edited December 25, 2011 by medley Quote Link to comment Share on other sites More sharing options...
ticktock Posted December 25, 2011 Report Share Posted December 25, 2011 I have questions about this also. I would like to up from the stock motor to something in the 70-80 Hp range on Pump Gas. What is the best way to get in this range? There is a lot of stuff out there that I just do not know about even though I am very handy with a wrench. Are you using Stock Cylinders or are you going with aftermarket? I have seen a lot of posts about the Dune/Play porting being the most versatile. I also read that Aggressive porting will reduce you to mostly dragging, is this fact? 4mil Cranks do not require case trenching from everything that I have seen. Let me know if you have any more information that will help with my goals. Thanks, Adam Quote Link to comment Share on other sites More sharing options...
medley Posted December 25, 2011 Author Report Share Posted December 25, 2011 thats the same power i am trying to make. i am using stock cyliders. my top end and bottom end might have 8hrs on it so i am going to try and reuse my piston and maybe rings. i dont want to loose all my bottom end so i will probably go with dune port and inframe cpi's unless the agressive dune port wont be a big noticeable loss of bottom end. i still like to trail ride and climb dirt hills so i need some bottom end. Quote Link to comment Share on other sites More sharing options...
toytech Posted December 25, 2011 Report Share Posted December 25, 2011 hit up Jeff at fast racing! he will hook you up. I had him do a agressive dune port for a 4mill , I run rocket r2 pipes 35mm carbs, it's a power house you'll love it. Quote Link to comment Share on other sites More sharing options...
Nieskes Posted December 25, 2011 Report Share Posted December 25, 2011 Yes, you have to send your domes to get cut or buy some that are cut. I would call up a site sponsor such as f.a.s.t. Quote Link to comment Share on other sites More sharing options...
guns4children Posted December 25, 2011 Report Share Posted December 25, 2011 your also going to need new pistions for the 4mil. im not sure if you can get around it by using the 110 rod, but i do know you will need them with the long rods. Quote Link to comment Share on other sites More sharing options...
CFH87 Posted December 25, 2011 Report Share Posted December 25, 2011 http://www.herrjugsracing.com/Yamaha_Banshee.html 4mil kit for a little over 1000$ get it! Quote Link to comment Share on other sites More sharing options...
Jereme6655 Posted December 25, 2011 Report Share Posted December 25, 2011 th epistons you'll need are depicted by what length rod you get on the crank. you can get a 110 rod which is the stock length or you can get a 115 rod. the longer rod allows the rod to have less side angle and allows the piston to go up and down without as much side load onto the side of the cylinder. If your gonna run wiseco (which i and just about everyone here will suggest) you are going to need a 513 series piston for the 110 length rod and a 795 (i believe its a blaster piston) for the 115 length rod. you can order off the shelf domes from any site sponsor or you can have custom cut domes made for your bike by most of the sponsors. Your carbs will be fine as the stock sized carbs are usually good until about 70hp. Porting is not specifically for drag racing......there are various different ports that you can have done to your cylinders that will allow for the powerband to be modified for any specific area that you would want........best bet is to call a site sponsor such as Jeff at FAST racing and talk with him....just tell him what your looking for the bike to do and he will be able to tell you what kind of port job is perfect for you. Kevin at HJR is also said to be a great motor guy but i have only dealt with Jeff. only +7mm and larger cranks will need trenching.....but during assembly it only takes a second to look and spin the crank to check for any binding. just pay attention to see if the connecting rod just barely touches the case holes cut into the top of it....its rare that they do but it has happened.......so before you get the head on just spin the motor over by hand and pay attentino to any binding. and the best way to attain 70-80 hp while still being able to run pump gas to make those numbers is going to be to order a serval kit from our site sponsors. it is said to have lots of low end power and able to hit that high hp mark without the need to run race fuel or a mix to keep the detonating down... Quote Link to comment Share on other sites More sharing options...
sprinklerman Posted December 25, 2011 Report Share Posted December 25, 2011 Heres what i'd recommend > http://bansheehq.com/forums/index.php?showtopic=148961 Call Cam up and be prepared for top-notch service and no BS . Has everything you need and the dyno chart speaks for itself. Quote Link to comment Share on other sites More sharing options...
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