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stock head displacement?


Valin

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Guys, what size are the domes on a stock shee head? I've been searching, but I cannot find the answer.

 

Also, would 20cc domes be too small on a shee on 91 octane, with +4 timing at 1000 feet elevation, or would 21's be better?

 

Thanks for the help.

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Guys, what size are the domes on a stock shee head? I've been searching, but I cannot find the answer.

 

Also, would 20cc domes be too small on a shee on 91 octane, with +4 timing at 1000 feet elevation, or would 21's be better?

 

Thanks for the help.

From what I understand it depends on the manufacture of the head. Not all stock heads were the same. I thought there was a serial number on the head that may corrolate to the cc size of the dome. Best course maybe to actually measure the volume of the dome itself.

 

SP

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valin, i see your on here now too......LOL. i never knew that you had a banshee. is your shee ported?....the exhaust port modified? on stock OEM porting, IMO the 20cc domes would be a little tight. i would stick to the 21cc domes. i have a stock "2guy-2" head that i can cc the dome here if you like.

 

valin, what is the casting # on the top of your stock head? the "1guy" heads were larger in cc size than the "2guy" heads.

Edited by mopar1rules
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valin, i see your on here now too......LOL. i never knew that you had a banshee. is your shee ported?....the exhaust port modified? on stock OEM porting, IMO the 20cc domes would be a little tight. i would stick to the 21cc domes. i have a stock head that i can cc the dome here if you like.

 

Haha, I am everywhere! I am just in the process of picking up a Shee.....I'll have it next week. I haven't had one since 2004. This one is a ground up resto. I'm getting the entire bike for $600, and everything is nice and straight. It's all stock, but won't be for long, as i'm sure you could imagine. I haven't decided yet if i'm going to go with cub cylinders, or just port the stock jugs. It will have a 4mm crank, coolhead, timing, and t-5's. It won't be anything too crazy, since it's going to be on pump fuel.

 

I am only asking what the stock head displacement is just for knowledge sake. I am guessing it's in the 22-23 cc range. I would have just measured it, but I don't have the bike yet :) I kinda figured 21cc domes would be the better choice. What is the ratio with 21's?

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the trapped comp ratio or full stroke comp ratio, w/the 21's?

 

also, i seen your thread about not being able to view others posts, and i had the same problem. i just needed to delete the cookies, then restart the computer and BINGO!

 

 

Full stroke, uncorrected CR willl do.

 

I'll delete the cookies and give it a whirl. Thanks for the tip!

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valin, i'll go out to the shop and cc up that head for you. then i'll hop onto my TSR and see what the full stroke comp is. i do know that yamaha says the OEM trapped comp ratio is 6.6:1. oh, what year is the shee you're getting?

 

glad the cookie deleting worked for you. :thumbsup:

Edited by mopar1rules
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valin, i'll go out to the shop and cc up that head for you. then i'll hop onto my TSR and see what the full stroke comp is. i do know that yamaha says the OEM trapped comp ratio is 6.6:1. oh, what year is the shee you're getting?

 

glad the cookie deleting worked for you. :thumbsup:

 

The shee is a '97. Don't worry about running the numbers on the TSR. Corrected is just fine, and thanks. Would you also happen to know the carb center to center spacing? I'd like to slap a rack of 33 flatslides on there, if there are any with close CC spacing.

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ok, stock "2GUY" head....

 

15* band angle

.042"-.045" step cut

24.3cc volume, w/spark plug

 

TSR says @ 6.5:1 ratio (which yamaha claims is what a stock banshee is) is a 10.9:1 full stroke ratio

 

don't know off hand what the center to center is of the intake boots. i've always thought myself of choping up a rack of srx carbs and bolting them on. sounds like you got the idea that i was thinking last year......LOL.

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ok, stock "2GUY" head....

 

15* band angle

.042"-.045" step cut

24.3cc volume, w/spark plug

 

TSR says @ 6.5:1 ratio (which yamaha claims is what a stock banshee is) is a 10.9:1 full stroke ratio

 

don't know off hand what the center to center is of the intake boots. i've always thought myself of choping up a rack of srx carbs and bolting them on. sounds like you got the idea that i was thinking last year......LOL.

 

 

Thanks alot Mopar. That info is very useful. 10.9:1 is too damn safe :)

 

Yes, I have far too many sets of SRX carbs laying around. I think i'll have to do it.

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if i remember correctly, it's exactly 4" (100mm) :biggrin:

 

now, i'll have to go out and measure up one of my extra racks of srx/viper carbs and see it they would work. now that i think of it, i think we'll need to run fuel pumps tho, cause our sleds w/these carbs use fuel pumps......huh.

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Thanks alot Mopar. That info is very useful. 10.9:1 is too damn safe :)

 

Yes, I have far too many sets of SRX carbs laying around. I think i'll have to do it.

 

no problem. now, if i have some sled questions in the future, maybe you can help me out then?? 10.9:1 is too safe IMO too. that's why i had to shave off .030".....LOL. also, i forgot to say, that w/OEM head and OEM gaskets, your squish will be .080". i cut .030" off the stock head to get .050" squish. if i remember right, my squish velocity is @ like 29 meters per sec now.

Edited by mopar1rules
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no problem. now, if i have some sled questions in the future, maybe you can help me out then?? 10.9:1 is too safe IMO too. that's why i had to shave off .030".....LOL. also, i forgot to say, that w/OEM head and OEM gaskets, your squish will be .080". i cut .030" off the stock head to get .050" squish. if i remember right, my squish velocity is @ like 29 meters per sec now.

 

 

Wow. 24.3cc's and 10.9 CR after cutting 30 thou. That's rediculous.

 

As far as having to run fuel pumps, that might not be necessary since it looks like there are members on here running 34's and bigger off gravity feed. We'd have to turn the fuel inlet spigots upwards, but not a big deal. Then again, running a pulse line for a fuel pump into the crankcase is very easy to do also.

 

If you ever need any info or help with the sled, let me know.

 

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