I'm pretty sure there must be a post somewhere about this, but I'm starting my 1200 conversion with KB 9:1 dished pistons. I am planning to use some heads that I picked up, casting #'s 16663-86B Front & 16662-86B Rear. My bikes a 02 XLH 883 and FPM #'s are 16661-89B Front & 16660-89B Rear. Can I use these 86B heads? What are the differences? Something about Breather or Venting? Can't remember!?! :helpsign

Thanks, marco883 / maybe 1200?

So far I've found out that the earlier heads (pre-89) are not set up for venting crankcase pressure (no passage thru carb / intake mounting holes). There is supposed to be a vent fitting under the cam gear cover for crankcase breathing, but is it enough? Has anybody drilled the older style heads for the venting for the top end? I may have to use / machine my exhisting heads and wait to finish. A shame I took the week off to mess with the bike. Weather isn't too bad, guess I'll have to ride!!! YEE HAA

I seem to recall that in the late 90's - HD changed the oil breathers in the heads. Not sure what year - but '99 comes to mind, not sure if there where anyother changes or not.

Hate to say it, but if it was me - I'll hold tight and have my existing heads machined. At least you know they will fit.

gamhill,
Thanks for your thoughts. Went for a nice ride, and then thoughts of starting over corrupted my brain. I can still bore cylinders more, different pistons, New heads, N2 or N4 cams?!? OH NO!! ON THE FENCE AGAIN!!

I'm still trying to figure this out. The 86B heads have breather passages and have the hemi combustion chambers like the 89B's. I'm going to try and attach a pic out of my FSM that shows the breathers. Can somebody tell me if there are any differences between the 86B and 89B heads? If possible I'd like to use these on the conversion or at least pass them on with some info.
Thanks, Mark

If you use the newer heads you will need a newer style air cleaner to go with the vent system. When you remove the heads you should be able to compare combustion chambers but I do believe they are unchanged with the exception of the breather ports.

barry1967,
Thanks for the reply, the situation is that I have a 02 883 that I'm thinking of using these older heads for the 1200 conversion. I have the later style air intake and breather bolts, rocker cover, etc. My delima is that these older "86B" heads APPEAR to be the same as the "89B" heads used up to 03. I'm trying to find out IF THERE ARE any differences :o

If you have a set of 02 heads form your 02 bike, why would you digress to a set that is 15 years old? Kind of a step backwards. You would have to vent your engine somaplace else. The pre 89 or so bikes vented through the round section of the cam cover. You would have to do something similar.

The older heads ARE set-up for top breathing, and my 02 also HAS a crankcase breather fitting (pn#62375) in the aft end of cam cover, no problems breathing. The combustion chambers are the same. The heads are in PERFECT shape (fresh valve & seat grind, guides checked, new stem seals). I was trying to do the 883/1200 over my holiday break with parts already set-up. I didn't notice the casting # difference until I picked up my heads from the machine shop Thurs, The heads look identical to 89B's. Oh Well so much for my ignorance. That's why the XL Forum ROCKS!! because I keep finding out so much info and great input! Even though my bike is my commuter, it is a work in progress, always trying new things out. For now I was planning on doing the basic 1200 conversion w/9:1 KB272 pistons, stock cams, heads. Save my 02 take off heads, cylinders and trick em up, cams, ignition, carb, etc. So much for my best made plans. I appreciate ALL the input.

I thought you had the pre-vented heads. My mistake.

barry1967, no biggy. I'm just glad to see a reply!! This is getting to me cuz I was reading "101 HD Performance Projects" Love & Woodring. The 86 883 heads were a different casting than 87 and later. They state "somewherein the 1987 model run, the 883 got a different head casting with subtle changes to chambers and ports. Most folks agree that it slowed them down too. The 1986-model 883s are considered the best runners of the bunch." They don't elaborate on the "sublte changes" so if anyone knows, please enlighten? I'll probably have more hours researching this than what it will take to do the conv but it's all fun!! THANKS FOR ALL YOUR HELP