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Discussion Starter #1 (Edited)
Hey guys it's been along time since I owned a banshee and I bought a 96 a couple days ago and have a few questions

it has toomey t5 pipes, vforce 4 reed valves, k&n pods with no airbox, pro designs cool head (don't know what domes it has) advanced timing plate set at plus 4, and Keihin 33mm pwk carbs. The cylinders are stock nonported and everything else is stock. I am right on sea level and I can't figure out why it's running so plugged up. It had 168 mains in it I ended up putting 158s in it, has 50 pilots, and air screw is 2 turns out. When driving down my drive way it seems like it's only running on one cylinder and when I slowly accelerate the other one kicks in. The carbs appear to be both synced, the slides open at the same time. I ordered uni foam pod filters and I have a custom aluminum airbox to put in. Right now I am in the process of taking the head off and cylinders to further inspect. I'm curious on what you sea level guys are jetted at with similar mods. And also what are some other things I should check? I ordered a seal kit and I plan on tearing down the engine to really check everything out and replace the shift shaft seal and the seal behind the counter shaft sprocket as they are leaking. Thanks for your time and it feels good to own another banshee.
 

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Check for leaks

One of the first things which a 2 stroke owner needs to do is a compression & leak down test. The very least is to spray the cylinders & top end with a lite mix of soap & water; look for bubbles & air leaks.
JT
:thumbsup:
 

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Discussion Starter #3 (Edited)
Update
I found it has 21cc domes
I probably should have waited two hours before I posted this. This morning I decided to pull the cylinders off and I found one piston had a one inch crack in it on the intake side. That most likely explains why she ran so rough. Bad compression. I'm glad I caught this before the piston broke down inside the cylinder while running. Thanks for the reply

I need to dig out my calipers to measure the piston and cylinder to see what bore I have. On top of the Pistons it is stamped I84C0

Any ideas off the top of your head what size that corresponds ?
 

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Hiroller; those aren’t Wiesco part numbers, probably an OEM number. At least you’re getting back into the 2-stroke frame of mind. A good dial bore Gage is available on ebay for a little over $60.00, check it out.
 

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It's good that you got the jugs pulled down in time so you didn't rip the cylinders up !
You could have destroyed the sleeves up and ended up having to resleeve!
 

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Discussion Starter #6 (Edited)
It's good that you got the jugs pulled down in time so you didn't rip the cylinders up !
You could have destroyed the sleeves up and ended up having to resleeve!


Exactly man I am so glad I decided to tear it down. Saved me a ton of money. The Pistons measured around 64.44 give or take I need to mic the cylinder to see what it reads but I'm guessing its stock bore. The cylinders are a little scratched up its not too bad tho I might just diamond hone it out lightly and call it good. I'm just going to go with new Pistons for now I really want to get the jugs ported but I have to wait till next year. I've been on fasts website every night drooling over a dune play port job. I have a kid due in February and I shouldn't be spending all my money on toys at this moment haha. After next summer tho I have big plans. Dune port and 4 mil stroker build. Hopefully next year I can find some good used elka shocks and a arms off this website the last banshee I had was A 4 mil and it had around 75 hp I had stock suspension on it and it was dangerous. Pogo stick on steroids
 

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Banshee cylinders don’t need a diamond hone; they’re just plain old cast iron unless somebody was stupid enough to get them plated.
:Cheers:
 

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Discussion Starter #8
Your saying to not hone the cylinders? I think it would be a good idea to run a home they them real quick
 

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Hone away; any hone will work on a banshee cylinder. Diamond hones are only needed on plated cylinders. It’s nice to keep things as correct as possible; every time I turn around somebody talks about a steel cylinder sleeve.
Cylinder sleeves were never made out of steel; cylinder sleeves are made out of cast iron, I’m sorry for the rant let’s keep things straight. (Keep your cylinders round & straight) LOL :Dope:
JT
 

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Discussion Starter #10
Hone away; any hone will work on a banshee cylinder. Diamond hones are only needed on plated cylinders. It’s nice to keep things as correct as possible; every time I turn around somebody talks about a steel cylinder sleeve.
Cylinder sleeves were never made out of steel; cylinder sleeves are made out of cast iron, I’m sorry for the rant let’s keep things straight. (Keep your cylinders round & straight) LOL :Dope:
JT

Yep roger that man. So the correct way to measure the cylinder is to measure off the bottom near the base of the cylinder correct ? You don't want to measure off the top of the cylinder ? One cylinder reads 64.57 the other reads 64.73 that seems like not much off but kind of a lot? What size Pistons should I order ?
 

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Hones & skirt clearance

The difference between the piston dia. & the bore diameter is normally the skirt clearance. In this case the difference will be the rattle clearance.
64.57 * .03937 = 2.5421 64.57 – 64.5 = .07mm .0028” rattle
64.73 * .03937 = 2.5484 64.73 – 64.5 = .23mm .0090” rattle

Normally the difference between the piston & the finish bore diameter is the skirt clearance. No magic, just the way it is. For the cylinder at hand a 65mm bore would be the next step; a 65.5mm piston would probably be a better choice if the mechanic expects the bore to clean up all the way.

When we measure a cylinder we measure it all over, preferably in the area of highest wear. In a 2 stroke the areas of highest wear are around the exhaust port & just below the area of the intake ports. While honing, I’d slide the bore gauge back & forth in each area so as not to start to hone a taper anywhere in the cylinder.

The illustration is a Blaster cylinder which is very close to a Banshee cylinder in bore diameters.
For rough honing & heavy stock removal we use the vertical hone with a Sunnen AN hone head.





For fine finish honing we use a double stone 3 point Sunnen head on the Sunnen Rod hone

This Sunnen finish mandrel assures that this cylinder is round & straight.

As I think you are noticing; boring your cylinder & fitting a piston is a very tricky business. Using a set of feeler gauges & a Dingle Berry hone is a Slip Shod way at best; although many cycle shops get away with it for many years.

Lastly the ports are champhered & a plateau hone is finished off.
Brush hones work nicely for this operation.


Ball hones also work nicely for a plateau finish

Ball & brush hones are only named this way as a convieance since neither is a hone; each is only used for that final deburr & cross hatch finish.

I only charge $55.00 per hole to bore cylinders here at Small Engines; As you all are aware this price is pure charity. Blind bores & outboard cylinders are a special situation which is completely different.

In closing; know & trust the people who are doing your machine work. Your cylinder is the heart of your engine & doing a CRAPPY job is a FOOLISH move.
JT
:Cheers:
 

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Discussion Starter #12
The difference between the piston dia. & the bore diameter is normally the skirt clearance. In this case the difference will be the rattle clearance.
64.57 * .03937 = 2.5421 64.57 – 64.5 = .07mm .0028” rattle
64.73 * .03937 = 2.5484 64.73 – 64.5 = .23mm .0090” rattle

Normally the difference between the piston & the finish bore diameter is the skirt clearance. No magic, just the way it is. For the cylinder at hand a 65mm bore would be the next step; a 65.5mm piston would probably be a better choice if the mechanic expects the bore to clean up all the way.

When we measure a cylinder we measure it all over, preferably in the area of highest wear. In a 2 stroke the areas of highest wear are around the exhaust port & just below the area of the intake ports. While honing, I’d slide the bore gauge back & forth in each area so as not to start to hone a taper anywhere in the cylinder.

The illustration is a Blaster cylinder which is very close to a Banshee cylinder in bore diameters.
For rough honing & heavy stock removal we use the vertical hone with a Sunnen AN hone head.





For fine finish honing we use a double stone 3 point Sunnen head on the Sunnen Rod hone

This Sunnen finish mandrel assures that this cylinder is round & straight.

As I think you are noticing; boring your cylinder & fitting a piston is a very tricky business. Using a set of feeler gauges & a Dingle Berry hone is a Slip Shod way at best; although many cycle shops get away with it for many years.

Lastly the ports are champhered & a plateau hone is finished off.
Brush hones work nicely for this operation.


Ball hones also work nicely for a plateau finish

Ball & brush hones are only named this way as a convieance since neither is a hone; each is only used for that final deburr & cross hatch finish.

I only charge $55.00 per hole to bore cylinders here at Small Engines; As you all are aware this price is pure charity. Blind bores & outboard cylinders are a special situation which is completely different.

In closing; know & trust the people who are doing your machine work. Your cylinder is the heart of your engine & doing a CRAPPY job is a FOOLISH move.
JT
:Cheers:
Absolutely. You said it well and thanks for the information, sounds like you have worked on a cylinder or two. After sleeping on it I am for sure going to just send off the cylinder and have it bored for a set of Pistons. The scratches are not what worries me it's just the different measurements I got measuring the bore in several different spots. I emailed Kevin and HJR asking a few questions about port jobs and when he gets back to me I am most likely going to send them off to him, I'm not sure the difference between a dune play port and the dune hill shoot port I'm leaning towards whichever one of those suits me best. I'm also very tempted to go the 4 mil route.
 

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If the cylinders need a bore, then take them to 65.00. The numbers you posted sound to me like its on the stock bore, maybe run hot and possibly egg shaped the sleeve. You really need to check the cylinders inside the wear area of the piston rings. The rings never make it fully to the top or bottom of the sleeve.
 

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Discussion Starter #14
I measured the top and bottoms of Bo cylinder walls. I used digital calipers and that is all I could measure with what I had. My guess is this engine has never been rebuilt before. It has oem pistons in it. And stock bore. I would imagine the cylinders are well used and abused. There isn't much scuffing and scratches in the cylinders which surprises me.

I am going to send them out to get bored and while they are out of my hands I might as well get them ported. I haven't been able to get in touch with her jugs racing and I have read a lot of great reviews and posts on redline racing, I think I am going to give them my money. The prices on their website are cheaper than anyone else's too. I really want to go the 4 mil route, but I'm going to have to wait until next summer. I have a kid due in February so to get me rolling for the winter season I'm just going to go the inexpensive route. Thanks for the replies everyone, a lot of good advice and knowledge on this website, and most of all more friendly people. I appreciate it
 
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