bholmes

Here's some useful links for all you banshee riders Banshee owners manual https://docs.google.com/fileview?id=0B0CQb1pV1ycgNTMwMDA1MGMtYzE5YS00NjM4LWJjYzEtYjRiMDhkZTU5NzAw&hl=en Banshee service manual https://docs.google.com/fileview?id=0B0CQb1pV1ycgMDQ3NjQ4ZTUtMjRlMC00Y2UwLTlkNzctNGY4ZGIxYjZhMDI1&hl=en Graham Bell two stroke performance tuning https://docs.google.com/fileview?id=0B0CQb1pV1ycgZTkzYzY5ZmYtMzc3MC00NGNiLWI0ZGEtOTg1MzMwMGMwY2Fi&hl=en Gordon Jennings two stroke handbook https://docs.google.com/fileview?id=0B0CQb1pV1ycgNTliNDYyZTctNDMzOC00ZjU3LWE4OTgtMDJlYTMzYjIzM2Jl&hl=en Good porting and performance info http://www.macdizzy.com/ Useful calculators for exhaust and port timing http://fpp.hamradio.si/roost/ Printable degree wheels http://mightymichaelis.com/pictures/fang/08.01.26_degree_wheel/degree_wheel_a.jpg http://www.jasonmcelroy.com/temp/free_degree_wheel.jpg If anyone else has any great links to share go for it!

Got the PM, good info, I really appreciate it. I also talked to Brandon at WildCard and he had alot of useful information. really for a 4mill and going with a trail type port all you need to do is raise the exhaust port up a bit, such that you're around 26.5mm ish below your TDC and the transfer ports are almost already where you want them. Brandon said that I could really just leave them alone and mod the ehxuast port and lower my port floors to meet the piston at BDC and wind up with a descent running machine. Of course be mindful of where your transfer ports are pointed, but nothing to suprising there. Aim the roof of the port upwards to allow a broader spread and leave the port walls alone. Then mill my head to clear the piston and I should be in buisness.

I spoke with a machinist that works on polaris and yamaha's (Rick Ritter of RCR) and he says on the stroker banshees that he does all I need to do is match my port bottoms to the top of the piston, and forget about the spacer plate (as i've been told before lol) and machine the head for piston clearance and he says the opening of the ports will be OK. He said that's more or less how he builds a stroker banshee with out major port mods. Sooooo no JB weld needed!

I'll be running LRD pipes and silencers, wiseco 759 pistons, 4mm stroker crank, i'm gonna go ahead and use the base plate despite ridicule to save on machine work, running stock carbs and a toomy 2 into 1 open air cleaner. stock reeds and cylinder heads. I'll be running a 13/41 sprocket set up and 20" tires out back. I ride primarily tight east coast type woods and do some nice hill climbs. But I really don't care if it's ported for max power or my particular riding. A stock banshee engine with those mods runs good, I just want it to run good with more torque than before, I'm not doing a max effort port job or anything. My trails are tight and don't allow you to really open it up for very long before shifting, turning, braking etc. I just want it run GOOD.

I emailed him, PM me if you want a copy, I have them on rapid share for some other guys on the forum, but it can only be downloaded 10 times before it expires or what ever.

AKheathen, Depending on what the forums policies are in regards to copywrited materials I have both Grahm Bell and Jennings books in PDF format and a Banshee service manual and owners manual. If you want any of them let me know.

Trust me, if I had the cash I'd be sending my cylinder out. I prob shoulda stuck with a reg stroke crank, but they were the same price soooo oh well. Hind site it 20/20. I'm very confident in my ability to port regardless. I ported my YZ490 and came up with a pretty good result, more top-end than previous. May not have been perfect, may not have run as good as if I'd had it professionally done. I'm just trying to see what experience there is out there I might be able to glean some information from.

I don't think I said i was going to use it on the exhaust port.....but even if I didn't say it you read my mind LOL. Where have you seen it used? On the transfer ports only or transfer and intake? I'll have to look more into the exhaust port and see what I'm up against there. I'm not sure that having it open a little longer will hurt unless it's sucking unburnt fuel charge out.....hmmm any insight?

The McDizzys site is a really good site and has some links to some math tools that are useful. I'm in the process of learning some of the basics of porting and expansion chambers. I *might* have some good readings in PDF format that would do you ALOT just send me a PM with your email and i'll shoot em your way. I'm working on a 4mil stroker, but I intend to keep essentially stock timing just scaled for a 4mil and a little freeing up here and there. But there's alot more to it than you'd think as far as the angles the tranfer ports shoot into the cylinder and stuff. Best of luck.

I'm wanting to fill my ports because my banshee has to much power and scares me. LOL not really. I want to fill the tops about 2mm (i gotta do final calculations once i get all my parts in) to retard my port timing and then take some out of the bottoms to get my proper duration because i'm going to be using a 4mm stroker crank. Basically I'm wanting to time it like stock for the 4mm crank and proportional port area/displacement to the best of my ability. I have found some liquid steel stuff they use at a local power plant a friend can get me that I think I will end up using. It is supposed to be good enough to use on heat exchangers so I think I'll be OK. Thanks for the help guys.

OOOook, I'm prob gonna get beat up for it....but has anyone used JB Weld on their ports? In my readings of either Grahm Bell or Jennings, I don't remeber which, but they talk about epoxying up your ports to lower/retard your port timing/opening. Any experience out there? My inclination is I wonder 1) the heat it sees and 2) how dissimilar are the thermal expansion rates of JB weld or epoxy and the aluminum of the cylinder.....any help out there?

Thanks for all the great information. I ran some numbers on my ports and could see alot of the issues with the stroker. The stock exhaust port would open at 90degrees and the stroker with base plate would open at 84 deg and with out the base plate would be 90 deg still. The Transfer ports would open at 143 deg stock, 133 with bast plate and 139 w/o base plate. ... so you can see the differences. I spose sticking close to stock would be the best idea. I'm actaully looking for more torque, but i'm sure the stroker will supply that, even if i port it proportionally as stock timing.

I see what you're saying about the spacer, I may end up just cutting the heads then... we'll see. I'm pretty confident in my porting abilities, I understand what I read and I just got a good 2 stroke calculator from that website that should help answer alot of my questions. My biggest deal is getting the crank installed and mapping my engine and going from there i think.

Good to know! I had hell with my brothers Buell over a coil. But they are notoriously weak.

Seeing as you have a new stator and CDI I'd check your coil, you can check it with an ohm meter. Or just replace it. I'd try a new coil, plug wires and plug. Often times coils when they start to go bad will be symptomatic at higher RPM. Is this a new problem for your machine? It could also be a jetting issue....

I have read alot about porting and read Grahm Bell's book on porting and the two-stroke tuning handbook by Gordon Jennings. So I have a pretty descent understanding of porting my engine but I am trying to get all the information I can before I cut into my engine. I'm doing a 4mil stroker and using a 2mil base plate and am running 115mil rods. I understand that I'm gaining 2mm at the top and 2mm at the botttom of my stroke, but I'm not really sure what this translates into for me as far as porting. I have yet to do my calculations for porting, but logically speaking my if I run long rod pistons that will take care of my +5mm at the top of the stroke due to the rods, then the +2mm spacer takes care of raising my ports and clearing my head from the piston. But what is unaccounted for is the 2mm at the bottom of my stroke. Would that mean that the only additional porting I would need to do is lower the ports or no? Also I have read that using a blaster piston with my long rod set up will work (http://www.macdizzy.com/1ban.htm) rather than buying long rod banshee pistons. I'm not sure there's much advantage one over the other, but I was just curious a bout experiences and input. Thanks.