Hey folks,


I just picked up an 81 flh. It has the typical leaks and needs a little tlc.


I am wondering if and should do any motor upgrades. Im going through it now and getting ccp and some other stuff to see if I can get an idea if it NEEDS anything vs just a valve job and a gasket kit.


If anything, I was thinking about just bumping up compression and MAYBE a cam.


My road king gives plenty of grunt and speed. Im not wanting a torque monster out of this 81. I would like it to perform on the highway on some out of state trips. For what its worth. It has the 4 speed trans in it.


Thanks everybody.


any suggestion's ?

 

I believe if it's not broke don't fix it.

 

1980 and 1981 in all the books for engine parts gives a warning about fits every harley known to man EXCEPT the 80 and 81 big twin - the MO CO desided to see how bad they could make the engine work - BUT in the after market those heads already may have been converted to the early or later style valve guides with more room, even on the chance they have not been done its not that big a deal when you are already doing a valve job

cam choices are slim and none are that great, its the design Andrews are the most used - A or BH - A2 or B2 are all choices with stock type hyd lifters and they have 450 lift the stock cam has 390 lift - if you add compression over 8 .5 to 1 you will be looking for trouble as it is a leaded fuel design from the very early 1960s And starting it up becomes an issue, and hearing the pinging accross the street will not maybe happen - it does

stroke the motor to 86 inches 4 1/4 stroke to 4 1/2 inch it gets better but no home run its just better

others will have a different opinion but this is mine as i do this every day in a shop

 

Sound like solid advise ! thank you. If I don't stroke it....I'll rebuild stock. It runs fine...just a lot of weeps and a few drips. Whoever had it before . already killed the oil lines to the primary chain oiler. and rear drive chain oiler. Oil cooler was also added. I'll find out what's inside this weekend. If I need any advise or questions. would you mind if I hit you up with a pm ?


thanks again guys !

 

even in my shop we no longer buy gasket kits as the stuff they are selling is the same junk you now have in the motor that Always leaks

its more expensive but you get the right stuff we use cometic 3 piece tin alloy tin head gasket - tin base gaskets and tin rockerbox gaskets - rocker shaft instead of the rubber O Ring we use the quad cut nylon seal and it never leaks - Moly piston rings are the deal try and get pistons with 1/16 - 1/16 - 3 /16 ring set pistons and NO did i say NO KB junk kieth black car pistons dont work in air cooled motors DONT care if someone has 1000,000 miles on them - in my world they dont - flea bay has a 4 1/2 japan made flywheel set with the correct rods - we have bought them and they are not in true nor are they balanced but for 550 bucks assembled you cant buy the parts for that BUT they have to pro fitted and balanced - its a cast wheel at stock weight so it will pull torque in a big way - you will need to jet the top end oil they sell a kit and an oil pump up grade is in the mix - black stainless valves and blue rubber seals are the deal - super E works well in this combo

 

I'm already a cometic gasket fan, there on the way. Where would I find quad cut nylon seals...they sound like they would be worth a shot.

 

Quad seals are a Later model [shovel] Harley Thing.
Any Indy will have them.

Edit; Good Excuse to get to Know your Indy...See if he is "all that"

 

I bumped up the compression to 8:1 and stuck in an Andrews A grind. The bottom end was really tight. So I didn't want to throw in a stroker at this point..


With a new valve job , new pistons with a little more compression to help that Andrews cam cometic and a new ignition, Im thinkin it should run fine. It won't keep up with my road king but then again, it doesn't have to.

 

A grind is an old tryed and true go to cam back in the day for a guy who wants just a bit most and no idle issues

the small increase in compression it will like it your good to go -- good luck with it