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Tripp
| Posted on Sunday, December 09, 2007 - 10:34 pm: |
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would there be a benefit to using screaming eagle heads vs. xb/xl heads(i have a carb). the se heads are already decked out with valves and beehive springs. i really want to do a head swap, i already have the xb rocker set-up which should work on the se heads too. |
Buellistic
| Posted on Monday, December 10, 2007 - 12:14 am: |
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Your 99 M2 already has THUNDERSTORM heads ... The ports are a little better and you get a lighter valve train with the XB heads ... |
Tripp
| Posted on Monday, December 10, 2007 - 08:10 am: |
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screaming eagle heads are just t-storm heads? wow, i figured they had to be a step-up. i guess i'll just do the xb heads then, or new xl heads(i have carb), is it the 03 or 04 heads i'm looking for? |
Loki
| Posted on Monday, December 10, 2007 - 11:17 am: |
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one thing to remember...... The XB heads are not drilled to be able to hang a carb off of them. Easy enuff fix though. The sporty head will be drilled. |
Djkaplan
| Posted on Monday, December 10, 2007 - 04:48 pm: |
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You'll need a special front mount to use XB heads on a tuber. Al has them at American Sport Bike, and there are other sources as well. |
Lucas70374
| Posted on Monday, December 10, 2007 - 11:04 pm: |
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what pistons and cylinders are recommended with xl heads |
Buellistic
| Posted on Tuesday, December 11, 2007 - 08:00 am: |
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if you use XB9 pistons you get a higher compression ratio than with the XB12 pistons ... |
Lucas70374
| Posted on Tuesday, December 11, 2007 - 10:11 am: |
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what about a top end off the xl 1200 |
Hurricaneleah
| Posted on Tuesday, December 11, 2007 - 01:59 pm: |
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Done this swap many times...using the xb9 piston puts you at 11.7:1 (stock head, no decking). The xb12 piston puts you at nominally 10:1. a 2004 and up XL1200 piston (true flat top) is nominally 9.5:1. We run the 9 piston in the road race and drag bikes. The XB12 piston would be a good compromise for knock resistance. The 2004 and up xl1200 head is essentially an xb head with drillings for the side vent breather system. Still needs the new mount though.Watch out for 2004 and up 883 heads, completely different ports/combustion chamber/valve size. |
Tripp
| Posted on Wednesday, December 12, 2007 - 07:52 am: |
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i'd like to use the pistons i already have, nrhs hurricane, bumped compression to 10.5 with my stock heads, would that make it 11.0 with the xb(xl) heads? |
Hurricaneleah
| Posted on Wednesday, December 12, 2007 - 09:07 am: |
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Tripp, I'm not familiar with that piston, but the XB/XL head is a bathtub/squish design that requires a flat squish band on the sides. Essentially the sides of an XB piston are flat, like a flat top. The dome of the XB9 is essentially an upside down bathtub. The thunderstorm combustion chambers were more of a semi-hemi design (actually based on the 883 chamber), so to get 10.5: 1 compression with that style head, the entire piston is 'domed'. I suspect you would have interference issues, but i don't know as i am not familiar with that piston. I think NHRS does machine XB head combustion chambers in a thunderstorm style combustion chamber, but again I am not sure of the compatibility with your pistons. To get 11:1 using all h-d parts, I would get the XB12 piston and run xb/xl heads that have been decked.....have notes back in the shop how much decking that requires. will shoot another note this evening. |
Buellistic
| Posted on Wednesday, December 12, 2007 - 09:43 am: |
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being an old H-D mechanic/parts man "i" do like Lead does ... Retro fitting across unit platforms makes it a easier task as you know what you have to work with ... |
Tripp
| Posted on Wednesday, December 12, 2007 - 10:07 am: |
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good point, i do have 1250 jugs, it seems i'll have to go to the after-market for the pistons, sounds like flat top is the way to go? i'll do some snooping in the kv and see what some of these guys have done with the 1250 kit and xb heads. thanks for the good info guys! i know i need the new bracket, al has a nice one from nhrs i'll pick up after christmas. |
Hurricaneleah
| Posted on Wednesday, December 12, 2007 - 02:56 pm: |
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tripp, you may want to try wiseco for pistons (wiseco.com) for your 1250, they make XB pistons in a variety of oversizes. The XB12 piston would put you in the 10.5:1 neighborhood. these are forged aluminum pistons and I have had great luck with them. They measure .0008 to .001 small, so they are a bit noisier than cast pistons when cold, but no complaints on power or durability. |
Tripp
| Posted on Wednesday, December 12, 2007 - 05:22 pm: |
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thanks leah! |
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