Author |
Message |
Jmartz
| Posted on Friday, April 02, 2004 - 08:10 am: |
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AAron: Will a 3.5 stroke use a 6.770 rod? |
Aaron
| Posted on Friday, April 02, 2004 - 09:10 am: |
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Well, if you shorten the stroke by .3125 and you want to keep the piston's pin height the same, you'd have to make the rod .3125/2 = .1563 longer ... 6.926 + .1563 = 7.082". But that's a custom. I'd suggest a 7.113 rod (available off the shelf from S&S or Carillo) and adding an extra base gasket or two, that'd be the simplest way. |
Sarodude
| Posted on Friday, April 02, 2004 - 10:34 am: |
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Anyone know the rod lengths / strokes of various 1 litre twins out there? RC51? 999? TL? It'd be an interesting comparison with the short stroke Buell. -Saro |
Jmartz
| Posted on Friday, April 02, 2004 - 10:40 am: |
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Thanks Aron, I went the opposite way in my calculation. |
Jmartz
| Posted on Friday, April 02, 2004 - 10:41 am: |
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Another alternative for an off the shelf rod length is to have the stroke adjusted accordingly since it has to be done anyway. |
Jmartz
| Posted on Friday, April 02, 2004 - 10:44 am: |
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A 7.113 would have a 3.44 stroke if my calculations are correct this time. |
Jmartz
| Posted on Friday, April 02, 2004 - 10:46 am: |
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Or have AAC mill the jugs a little less for more length. |
Jmartz
| Posted on Friday, April 02, 2004 - 10:47 am: |
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Raising the top end might will be additional trouble though with front mount, exhaust and manifold fitment. |
Aaron
| Posted on Friday, April 02, 2004 - 11:08 am: |
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You worry too much. These height differences are in the noise. People move things more than that all the time by just changing gasket thicknesses. My guess is you'll get to zero deck height with just one additional .018 base gasket. You'll be using a head gasket that's at least that much thinner to get your squish right anyway. So that combination overall is gonna come in right about stock height. It's not unusual at all for people to do combinations of milling & gasket thicknesses that drop the top end .040, .050, .060, or more. Sometimes you've gotta narrow the manifold a little, as well as use short (or adjustable) pushrods. We even sell a set of .040 shorter than stock non-adjustable pushrods for exactly this reason. But it's not an issue for the motor mounting, it can tolerate quite a bit more variation. Hell, I use a stock motor mount with my 100" motor, and it's a quarter inch taller than a stocker. |
Shotgun
| Posted on Friday, April 02, 2004 - 09:19 pm: |
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Dyno'd my 9 today, don't have a scanner. 85 hp, 68 pounds torque. Big dip 2400 to 2800 then pulls nice to the top. Mechanic tried to trim the dip with the Power Commander but couldn't. 10.50 Kit, Aaron's Stage III heads, Force exhaust, 12 airbox. Motor "snarls" nicely except at that dipsite. |
Blake
| Posted on Friday, April 02, 2004 - 11:06 pm: |
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Can you post the chart?... On the Dyno Chart page in the Knowledge Vault? Please? |
Blake
| Posted on Friday, April 02, 2004 - 11:12 pm: |
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If you have a digital camera, snap a pic and post it. |
Bigj
| Posted on Saturday, April 03, 2004 - 01:35 am: |
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Speaking of that, Jim A. overlaid the hp curve of the XB12 against the new literbikes' curves over at www.sacborg.com pretty interesting. |
Airbox
| Posted on Saturday, April 03, 2004 - 07:22 am: |
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had my 12s dynoed at about 1500 miles, completely standard and made 93.0 hp at the wheel which I thought was pretty good. The guy who dynoed it for me said to expect a few more bhp as more miles go on it. So with a decent can. chip and filter it should see 100hp I reckon. He didn't do a torque graph as apparently it takes longer to set the machine up and it was on an dealers open day and freee dyno runs. Great bike, really pleased with it except for one thing, that f***ing exhaust is a heap of shite. Why make it out of mild steel. I have had the bike for 5 1/2 months, done 2100 miles never let it get dirty, don't take it out in the wet and it is already rusty. They do salt the roads in the UK but as I said I only really use it in the dry. It spoils what is otherwise a great bike. |
Dyna
| Posted on Saturday, April 03, 2004 - 09:51 am: |
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Blake
| Posted on Sunday, April 04, 2004 - 12:44 am: |
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Interesting. An XB12R spinning to 8,300 rpm. Whoever did that graph got it wrong. |
Reepicheep
| Posted on Sunday, April 04, 2004 - 09:04 am: |
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You can spin an XB12 to 8300 rpm... Once |
Dyna
| Posted on Sunday, April 04, 2004 - 10:00 am: |
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Jim overlaid it on there. If you look at the max hp it says 6600 rpms. Obviously he just started the graph in the same place as the 4 other bikes. |
M1combat
| Posted on Sunday, April 04, 2004 - 03:18 pm: |
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It's way off dude... |
Opto
| Posted on Monday, April 05, 2004 - 05:07 am: |
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So are you saying the Buell's making 22HP at 500rpm? sorry just had to throw that in! |
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