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first banshee- low compression :(


slothman

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Average cost to hone cylinders / $10.00 each.

Average cost to bore cylinders / $40-45 each.

Where are you located. I'm sure you can call your local cycle shop and ask who does Machine work locally.

 

 

Good luck,

Troy

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Ok guys pulled the jugs...not really sure what the think from looking at everything. What are your thoughts? By looking at the pistons, it seems like there is a gap between the piston and the jug.

 

Time for a bore maybe? How do I know if these are the original pistons ?

 

23u38s5.jpg

 

 

velq1v.jpg

 

 

wurl1z.jpg

 

 

33xa83k.jpg

 

 

2you2ci.jpg

 

 

(looks like pitting but it's accidental coolant spill)

swg45s.jpg

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Your into it now Slothman !

 

That little gap your talking about doesn't mean you need a Bore job neccesarily. I forgot exactly how to tell if your pistons are stock bore. I'm pretty sure there is part #'s on top of the pistons that you can google and it will tell you what you got. You will have to get the black of the crowns of the pistons to see this # if I remember correctly. Aslo You will see an arrow and when you put your new pistons back together make sure that arrow is facing toward the front of the bike (toward the Radiator).

 

I hope you have a Clymer's manual and if you don't get one and read everything when putting your top end back together.

 

Here is a video I posted before I had my cylinder's bored by Jeff at FAST.

 

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Your into it now Slothman !

 

That little gap your talking about doesn't mean you need a Bore job neccesarily. I forgot exactly how to tell if your pistons are stock bore. I'm pretty sure there is part #'s on top of the pistons that you can google and it will tell you what you got. You will have to get the black of the crowns of the pistons to see this # if I remember correctly. Aslo You will see an arrow and when you put your new pistons back together make sure that arrow is facing toward the front of the bike (toward the Radiator).

 

I hope you have a Clymer's manual and if you don't get one and read everything when putting your top end back together.

 

Here is a video I posted before I had my cylinder's bored by Jeff at FAST.

 

 

Ya I actually watched your video earlier today. Looks we are in the same boat lol.

 

Tomorrow I will scrub off the black carbon from the pistons and see if I can find the mfg and piston type.

 

I'll be calling around my area to see what reputable shops work on banshee jugs.

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are those cylinders ported? Looks like there has been some exhaust port work done on them. You can easily rebuild for 300, most shops will inspect your cylinders for free, mic them and tell you what you are looking at. They may say they are in spec, and you just need a hone.

 

There is a Service manual in my Sig!

 

Adam

 

Welcome to the banshee world

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are those cylinders ported? Looks like there has been some exhaust port work done on them. You can easily rebuild for 300, most shops will inspect your cylinders for free, mic them and tell you what you are looking at. They may say they are in spec, and you just need a hone.

 

There is a Service manual in my Sig!

 

Adam

 

Welcome to the banshee world

 

Good point ticktock,

 

Wouldn't that be nice if everything mic'd out good for him and he good get away with a hone, rings, cir clips. Shoot I'd be tempted to buy the hone tool just to have. I think that tool is like $45.00

Y buy piston's if you don't need to.

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Good point ticktock,

 

Wouldn't that be nice if everything mic'd out good for him and he good get away with a hone, rings, cir clips. Shoot I'd be tempted to buy the hone tool just to have. I think that tool is like $45.00

Y buy piston's if you don't need to.

 

Well, I'd rather have forged Wiseco pistons rather than cast shitty ones lol

 

I'm just trying to figure out why she had low compression.....pistons don't look too bad, cylinder walls look pretty clean...rings look ok ?

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I know my ring's looked good when I took them off of my old pistons too but there is no getting around you definately need rings. And it might be that your pistons don't mic properly at all six points. A good machinist should be able to tell you the deal.

 

When I sent my pistons to Jeff he thought we could get away with boring my cylinders .010 and after doing that thing's where better but needed more boring. After he bored them .020 things mid'd and measured great and I havn't checked my compression since the work. No need to the banshee is running great. Lot's more power. :bolt:

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Spoke with Larry at Fireball Racing (central CA sponsor) and he seems like a cool guy. He made a valid point:

If the exhaust side has in fact been ported and the head is stock, the compression will be lower. Which might be giving me 80 psi in each cylinder.

 

I'm going to have him look at the jugs today to measure them.

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Got the jugs checked out- they were @ 64mm- I'm going to have it bored .020 over with 64.5 Wiseco Prolites.

 

I'm going to pull the carbs and check out the jets. The p/o had a k&n filter installed with some pipes (which I don't have) so I'm wondering if he leaned it out too much causing the low compression/worn motor.

 

What carb rebuild kits do you guys recommend ? Also, should I get some aftermarket reeds? Do the reeds really make a difference?

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Got the jugs checked out- they were @ 64mm- I'm going to have it bored .020 over with 64.5 Wiseco Prolites.

 

I'm going to pull the carbs and check out the jets. The p/o had a k&n filter installed with some pipes (which I don't have) so I'm wondering if he leaned it out too much causing the low compression/worn motor.

 

What carb rebuild kits do you guys recommend ? Also, should I get some aftermarket reeds? Do the reeds really make a difference?

 

 

I don't have much time to respond right now so I'm hurrying.

 

I bought a jet kit through Vito's. Just make sure to tell him that you want jet sizes 270 - 320. Also make sure you have 2 27.5 pilot jet's. If not get those from Vito too. Also if you order from him it never hurts to get a spare set of bowl gaskets. If you don't specifically tell him what size mains you want in the kit your going to get 300 - 340 which I didn't need at all. I'm running 290's.

 

I got the same Bore and the same pistons. I Love them.

 

Also I had boyeson carbon fiber reeds and honestly they worked great but I went ahead and got the VForce 3 system and honestly they are incredibly better than the boyeson's. Big difference, Very snappy throttle. Don't know if I'm aloud to say this but I got them through amazon $225.00 Shipped.

 

 

Sorry, Gotta run, Later !

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I don't have much time to respond right now so I'm hurrying.

 

I bought a jet kit through Vito's. Just make sure to tell him that you want jet sizes 270 - 320. Also make sure you have 2 27.5 pilot jet's. If not get those from Vito too. Also if you order from him it never hurts to get a spare set of bowl gaskets. If you don't specifically tell him what size mains you want in the kit your going to get 300 - 340 which I didn't need at all. I'm running 290's.

 

I got the same Bore and the same pistons. I Love them.

 

Also I had boyeson carbon fiber reeds and honestly they worked great but I went ahead and got the VForce 3 system and honestly they are incredibly better than the boyeson's. Big difference, Very snappy throttle. Don't know if I'm aloud to say this but I got them through amazon $225.00 Shipped.

 

 

Sorry, Gotta run, Later !

I know it will be tough finding the correct air/fuel ratio and the correct jetting, but in a nut shell, exactly how will I KNOW the jetting is fine ? I would rather run rich than run lean and blow the motor.

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I know it will be tough finding the correct air/fuel ratio and the correct jetting, but in a nut shell, exactly how will I KNOW the jetting is fine ? I would rather run rich than run lean and blow the motor.

 

 

There is a thread in this forum about what jet's different people are running on there Banshee's based on what mod's they have and at what elevation they are at. You will have to do a search to find it but it is definatley here.

 

Also look up and read about jetting more. Your going to need to do a plug chop and instead of me explaining it to you it is explained in great detail in another thread on this forum but to answer your question on how you will know when your jetting is correct is by doing a plug chop. At least that will tell you if the mains are at the right number.

 

If you do none of what I just said, if you have pipes, and a k&n filter without the snorkle and +4 timing start with your mains at 280. That would be pretty safe but do what I said and find the threads I've mentioned.

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  • 2 weeks later...

bad news- finally rebuilt the top end today- and now it won't fukin start.

 

On top of it all- did a compression test with the same guage, and I'm STILL getting 80 psi after the rebuild. I hope my gauge is just a POS ....

 

Also- I kicked it over with the start plug grounded to the pipe, and I'm not seeing spark. WTF could have happened?

 

Tomorrow I'm going to dig into it- plugs seemed bone dry as well (like they weren't getting fuel) ...

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