SLORYDER

Ok here are my latest and greatest numbers I used This program to determine durations, using 185.5/ 118, which are very close to accurate when factoring in the .020" base gasket. http://www.nclra.org/Programs/PortTiming.php?GO=1&Stroke=54&RodLength=110&PortHeight=24.5&PortTiming=125.57&Deg=Calc+Duration Stock---------------------------------------------------------------------183.5/ 118 29bd Stock +.060" base gasket--------------------------------------------------188/ 124 32bd Stock + 2mm base gasket---------------------------------------------------192/ 129 31.5bd 4mm crank no spacer .080" head gasket-------------------------------------185/ 125 30bd 4mm crank .060" base gasket .040" head gasket-----------------------------189/130 29.5bd 4mm crank 2mm spacer stock head gasket------------------------------------192/135 27.5bd These blowdown numbers are within 1 degree

I agree. Which is why it is easy to make power with a 4mil crank. You don't have to worry about touching the transfer roofs at all. You can reach your time area numbers by LOWERING he port floors which is foolproof. And I'm sure just about everyone knows that increasing your transfer time area and opening the exhaust port are the 2 biggest factors in porting a banshee once you get your timings correct. I love how you guys come on here like you're trying to be so helpful, when in fact you are not trying to help anyone. If you know better, why don't you post some numbers guys, huh? I can guarantee you 4mm crank +2mm head gasket +raising the exhaust port 2mm and widening 3mm will make a really strong all around engine. Probably in the 60-65 hp range w/ supporting mods. Another 1-2mm wide and 1-2mm up and you will have a more top end biased engine. You guys can stop with the act

Like I said, the numbers are close enough for practical reasons.

If you look at the numbers you can see how easy it would be to simply drop in the 4mm crank and hot dune/ drag port the cylinders yourself. All you would have to do is lower the intake ports 2mm, the exhaust port 2mm, widen the exhaust port by about 4mm and raise it 3mm. Then install a thicker head gasket to fix your squish and you'd have a 70hp bike for the cost of the crank and a new head gasket if you already have a dremel and some bits.

Ok so I did some math and figured what the port timings would be like if you installed different cranks and spacer plates. This pertains to BASE PLATE spacers. When I mention 1 or 2mm spacer I am talking about the COMBINED thickness of the extra gasket plus the spacer.Also I used .020" for the deck height due to the base gasket; this will be apparent in all calculations. 4mm crank results are using a 115mm "long rod" I am fairly certain that these durations are within 2 degrees;however I am not an engineer nor have I calculated these durations with a scientiffic calculator. Which I would recommend doing if you are considering a build based on these numbers 1. Bone stock cylinders: 183.5 exhaust 118 transfers 2. Bone stock cylinders plus 2mm spacer: 190 exhaust 130 transfers 30 blowdown 3. 4mil crank no spacer: 182.5 exhaust 127.5 transfers 26.5 blowdown 4. 4mm crank 1mm spacer: 187 exhaust 130 transfer 27.5 blowdown 5. 4mm crank 2mm spacer: 193.5 exhaust 137 transfer 27.75 blowdown It seems like for a do it yourselfer with limited tools and knowledge you could get some big gains for cheap if you know what you are doing. Obviously there are other factors involved and simply installing the spacer may do more harm than good. Note that obtaining these durations using a spacer would obviously not yield the same hp numbers as if you had it ported properly; however the "bang for your buck" factor would be high.

Don't forget about compression. the banshee is designed to run on the lowest grade of gasoline. THEN there are variances in manufacturing meaning the tolerances are looser still than what the manufacturer's compression golas were to be safe on regular unleaded. What this means is that there is a LOT of room to improve your combustion chamber efficiency. If you want to stay on pump gas, mill your head .025" If you want to run 50/50 race fuel of avgas, you can shave .030" off the head. This will give you a nice gain across the powerband. Like I said, timing too, you can buy a plate for 30 bucks or mod yours for free. Then the pipes. It will be a totally different machine after you do this. RB racing does a reallly good port job as well and his services I believe are the best porting bang for your buck. For $600 dollars you can go from 35 ish hp to about 60

Shave head .025" Timing (you can mod yours for free Used Pipes fmf fatty pro circuit toomey t-5 Under 300 dollars and you will be real impressed

Ok let me try to chime in here with some logic. OP, you can totally make your banshee WITH stock pipes A LOT faster than it is now. I guarantee you that you can port that sucker to have 50 wheel horsepower Clean up port/ open up the intakes/ add boysen reeds/ K&N filter/ some porting and you will be spanking bolt on 450's all day long guaranteed. You just have to port to the pipe; don't do much raising on the exhaust, widen it a good 3 millimeters and raise 2 or so. Square it off a little. I am about to go this route with my stock piped blaster. I can't wait to see the kids faces on their piped blasters when I smoke them.

I had rb do a blaster jug for me and I beat 2 ported blasters BADLY. My only mods were pro circuit pipe k&n and porting. One of the blasters had a 240 kit as well as an extended swingarm

Brandon, I'm almost 101% sure the pistons fall .017" to .029" short of reaching the deck...

Perhaps your high exhaust port is the culprit. Having an aggressively ported cylinder willl cause your cranking compression to be low

It depends on your budget Here is what you need to blow a pipes 450/ 700 out of the water, for the cheapest. 1. Used set of pipes: $300 IMO you will be very pleased with either pro circuit, toomey t5, fmf fatty, or cpi, which is more of a drag pipe 2. Shave your stock head .025"- $50 3. Buy a timing plate of mod yours $35 That should put you running neck and neck with them. If you have some extra cash and really want to blow them out of the water, a $300 dune port from HJR or another sponsor will have you dominating 9/10 450's, 700's. Don't waste your money on a cool head at this point.

up....

BTW I have a 51mm wiseco like new if anyone wants it. It is in the non banshee for sale section

I've heard good things about the tdr's...

This. Porting the cages and adding boysens is a great alternative to VF3 reeds. Might not get every last fraction of a horsepower, but the cagea, after ported allow almost 150% of the flow of the stockers. If increasing flow is a waste of time, why do people buy aftermarket reeds??? For a bone stock engine with just pipes and filter, there may not be much to gain, but once you start adding porting/ bigger carbs it is well worth the time spent.

Yes, here is a like new wiseco piston for the LT80/ KFX80 It is a 51mm piston it comes with rings and one circlip. You will have to buy the other; any suzuki dealer will have them for .98 $45 shipped

Cheap ghetto power, my speciality, hehe. 1. Mod your stock timing plate to get +4 timing. 2. Shave your head .025" if it has never been shaved. 3. While you have the head off, get a scribe and, with the piston halfway up the exhaust port make two notches on the piston top denoting the width of the exhaust port. Now pull the cylinders off and grind a 1mm deep groove into the crown of the pistons from scribe line to scribe line with a dremel or a file would work, but be time consuming. This groove should extend from the edge of the piston to about 1/4" back; like the vitos superstock piston.Clean the piston off and re-install. 4. Look into the exhaust port, and grind the metal sleeve even with the aluminum cylinder. Just #1 and 2 will probably allow you to beat him; likely a 6-8 hp bump Add 3 and 4 and you'll probably get close to double that if I had to guesstimate

Yes, I can fully understand this. Would it be possible to alleviate this problem by going up on your slow jet and maybe on your needle?

So learn not to floor it and you're good!? Haha I don't know. The velocity thing didn't make sense to me and my OCD would not let me have peace. I wish I could ride my shee I'm in Colorado for another 2 months and my baby is in Louisiana. I have, however bought "the wife" a blaster and the boy an lt80 since I've been here to get a little fix here and there. I do, however have her jugs and head and by the time I get home she will have a serious port job going.

But what you aren't taking into consideration is the fact that at lower RPM's, there is not a difference in the size of the "piping" due to the fact that the slide is restricting the throat of the carb. Doesn't matter if it's a 10mm carb wide open or a 35mm carb barely cracked open, you are still getting the same amount of flow through there. Perhaps the problem lies when putting down the trail, and you suddenly crack the throttle wide open, I could see where the large bore of the carb may have trouble "keeping up" with the relatively weak vacuum of the cylinder..... IMO this condition could be remedied by not going full throttle from a near standstill.. Learning how to ride with the new carbs. Is this making sense to anyone?

I know it might seem like I'm being hard headed, but just saying that the velocity is too low on a bigger carb isn't enough for me. I would actually like to get a grasp on what's going on here, but I can't do so unless I can actually visualize what the mechanism is that is affecting the power. Maybe I'm wrong, but I would be willing to bet that if a bigger carb does cause a loss of bottom end, it has nothing to do with the velocity of the air fuel mixture into the cylinder, like most people are inclined to believe. If velocity did play a role in this, to me it would be insufficient velocity through the carb bore to pull the correct amount of fuel out of the slow jet. If this were the culprit I believe that it could be corrected with jetting.

I think you should fine tune your jetting before you do anything else. I am under the impression that those big carbs come set up for a cylinder much larger than 175cc, as far as the low to mid circuits. It appears they work well for topend. Not saying the 2:1 won't help, because it seems like most people notice an increase in performance in the bottom end after going 2:1, but I really think that on a cylinder smaller than 250cc or so the stock jeting on those carbs is way off on the pilot and needle circuits..

Well then explain to me how velocity through the intake affects the power on a banshee.