I'm looking into doing my conversion with the new xb heads and a set of n-4 cams, and 10:1 pistons. What kind of hp/tq numbers should be looking for? Thks...Dan

Somewhere close to what the new 04s or the old 98-03 sports make..since that is pretty much what they have stock including the 10:1 stock on the 98-03 sports :)

Bigdan, If ya got an 04 or 05 I'd like your old 883 heads when your done. I'll pay for them of course if the price is right. :D

Mid 80s. :tour

That seems a bit high, do cams really kick it from low 70s to mid 80s..again the equipment he listed is basically what an 03 sport or 04 roadster already come with..and they are both around 70hp I guess if he revs it a good bit perhaps.

My guess with N4's will be 75-80Hp and 72-77ft lbs.

I assume you mean at the crank.

No. That should be rear wheel HP. My 04 did 75hp/77ft lbs at the wheel with just SE ac kit, slip-ons and jetted carb. The N4's should give him couple more HP but probably no more tq.

A 1200 Sport with cams (Stage II) is good for high 70s. Mine did 78 with modified CS mufflers and 81 with 30" drag pipes. I know of another that was over 80 with a SuperTrapp 2-1. I think it was an anomoly. A well tuned Thunderstorm set up is a low to mid 80s engine.

With the better XB heads, a 'real' 10:1, and cams, mid 80s should be a given. And that's rear wheel HP.

All I can state is what I have on my bike. Right now I have had the heads done, cycle shacks, N3's, jetted carb and a Twin Tech ignition and got 83HP and 81ft lbs and that is with the 04 1200 heads with .025 or so off them. With N2's I got 84HP and 79ft lbs. I'm not trying to start a pissing contest but that is what my bike put out. Without any head work I just don't think mid 80's is quite right. I may be wrong though.

From Nallins ( The XB and 2004 XL1200R heads are identical in every way except the finish and the breather holes, which are already drilled and tapped on the 1200R heads but not on the XB heads (the XB heads already have the boss, however).

Ya know, it's strange that there are so many folks getting lower than what I'd expect HP from XB headed bikes. I'm at a loss for ideas. But geeze, what's the good of these new heads if they can't do better than Thunderstorms?

Nallins makes a lot of power with em but they spin the bikes to 7000rpm's plus. The average guy can't afford to put that kind of money into bottom ends and stuff. I don't think my motor would last to long at those rpm's. The folks that did my heads said they are better than previous heads but the valves and ports are to big. He gets more power and torque out of the 883 heads. He has an 04 1200R with 04 883 heads, wiseco 9.5 to 1 and factory cams making more than 80ft lbs. Of cours it has no top end with the factory cams but I have a lot of work in to mine and just cracked 80ft lbs with custom made N3's. There is a good artical to read about his work here if you want to read it.

http://cycledoctor.com/JohnsonArticles/JET.html

and this one

http://cycledoctor.com/JohnsonArticles/Head.html

It makes sense and has worked well for him. He did a Dyna I had a few years ago and it made 100/100 at the wheel. 10 to 1, .010 over wiseco's, his heads, 560 cam, T-header and an S&S super E w/intake modified by him. And it made that HP at 6200rpm.

He won the HP shootout one year in Daytona with his 80 cu in FXR back in 85 or so. It made 114 Hp at the wheel. He let me ride it and it was a blast.

Barry ...

Very interesting reading!

i noticed that ...there hp dyno was at 7500 rpm. Some time this winter i will spin mine that high on the dyno, but not for real life. i will set the cieling at 6800 and the shift light at 6500. I am interestd in what it will pull that high...its doin 124 at 6500 some who knows....

I think the people who are getting mid 80s are likely on optomistic dynos.

Dyno's tell lies too...

I've had my '03 gsxr 1000 on a local dyno and it only showed 131.2.....

My mate on the same dyno won the day with a 135......

Now his bike had been dyno'd at 159.8 on another dyno.




I don't know what my sporty was puttin out BUT it ran high 11's all day in full street trim...changin at 6300....


I havn't seen a set of XB heads but I think some of the benefits are from a flat quench area....this is also possible with 883 heads...so it would explain the apparent lack of extra HP over good ported 883's

OK - here's my question, b/c this has been bugging me. Everyone refers to them as XL1200R heads. Does that mean that the XL1200C's don't have the same heads? I don't have a parts manual, so I can't confirm this for myself. It would seem silly to have 2 different parts for the 1200's - especially when they share with the XB's. So that leads me to believe that we're just calling them 1200R heads, when they're really 1200R/C heads.

Thanks
Speedy

No, they both have the same heads. 1200C and 1200R wear all the same parts just different colors, black or powdercoat.

They mean all 04-05 XL1200 heads. (Custom & Roadster)