Hey guys,
Ended up striking a great deal on an '01 fatboy, all stock except for SE slip ons.
I have access to a workshop that has a lot of take off heads from guys that have gone to stage IV kits at the dealerships and I know these later model heads come with beehive springs and flow better in stock form.
If I can find a nice set with low kms, what year heads (96" or 103") would be best for an 88 - 95"/97" build at 10-1 with wiseco / KB or even HD flat top pistons and a set of s&s 570 ez start cams? I don't need compression releases with the ez starts obviously. Hoping to find a clean enough set to just bolt them on rather than do any porting or headwork or even a valve job if I can get away with it.
Thanks for any advice.
The newer the better.
Are there any fitment problems with the 103 heads on the 88 jugs? Intake manifold? Different cyl head bolts or anything besides the ACRs.
Also, can I still use stock pushrods? Or do the larger heads change the valvetrain geometry?
Thanks
Intake flanges differ from 2005 and earlier, and 2006 and later. All other bolt patterns same, use stock push rods, head bolts. Exhaust port, guides & valves, springs different. ACRs can be used/activated if you have an 05 and newer ECM, otherwise simply block off.
The Stabilizer Mounts are different I believe. In 06 they changed to the front. But, I believe the rear Head did not change. IIRC
The front motor mount holes added, changed in 2009 on touring models. 6-8 were cable throttle iirc. The heads will still work on all models, just have the extra holes.
The holes were added in 08 first year when they went TBW.
Thanks for clarification.
Quote from: rigidthumper on February 17, 2021, 06:52:54 AM
Intake flanges differ from 2005 and earlier, and 2006 and later. All other bolt patterns same, use stock push rods, head bolts. Exhaust port, guides & valves, springs different. ACRs can be used/activated if you have an 05 and newer ECM, otherwise simply block off.
OK thanks, so does this mean that I will also need a later intake manifold? How do I accommodate the different intake flanges?
Thanks
the 06 and up heads use symmetrical INTAKE flange 26993-06 fits both front and rear heads,
whereas the 05 and earlier use asymmetric flanges 27009-86A and 27010-86A i.e. a Front one and a Rear one.
same intake manifold can be used, the 06 is slightly different but there's no evidence that I've seen to support it as an improvement, so use what you have
(http://i.imgur.com/hpgqFTp.png)
(http://i.imgur.com/clvhApU.png)
(http://i.imgur.com/EVtl1Xc.png)
(http://i.imgur.com/cuNY5zs.png)
Quote from: FSG on February 17, 2021, 04:35:07 PM
the 06 and up heads use symmetrical INTAKE flange 26993-06 fits both front and rear heads,
whereas the 05 and earlier use asymmetric flanges 27009-86A and 27010-86A i.e. a Front one and a Rear one.
same intake manifold can be used, the 06 is slightly different but there's no evidence that I've seen to support it as an improvement, so use what
Thanks FSG. a picture says a thousand words. 😁 Thanks for clarifying.
I ended up scoring a set of 2015 103" heads.. They were take off from s brand new bike that ended up stage IV... So they should hopefully be good to bolt straight on.
Just need to plug the ACR holes
Cheers 👍
Plug part number is 16648-08A.
Just to be sure- you got heads from an air cooled motor, not one from a water head bike?
I thought the 103 heads had bigger chambers-- more CCs
103 CVO heads had bigger chambers. IME, 96/103 heads measured ~86cc, and 88/95 heads ~85.
Always measure/adjust as appropriate.
Quote from: rigidthumper on February 18, 2021, 06:11:26 AM
103 CVO heads had bigger chambers. IME, 96/103 heads measured ~86cc, and 88/95 heads ~85.
Always measure/adjust as appropriate.
Thanks, that's good to know. Not much extra to get the heads cc'd to find out where I'm at.
Cheers :up:
Quote from: Adam76 on February 18, 2021, 02:43:07 PM
Quote from: rigidthumper on February 18, 2021, 06:11:26 AM
103 CVO heads had bigger chambers. IME, 96/103 heads measured ~86cc, and 88/95 heads ~85.
Always measure/adjust as appropriate.
Thanks, that's good to know. Not much extra to get the heads cc'd to find out where I'm at.
Cheers :up:
:up: Actually, a good idea when building an engine with balanced compression.