Harley Davidson
Forum F.A.Q Page Calendar Photo Gallery Sponsors Contact Us

Delete all board cookies

All times are UTC - 8 hours

one two


three four
one two
three four
one two
three four

1 2

Chrome Sposnors


3 4
Home Page Home Page  [ 1 post ] 
  Print view
Previous topic | Next topic 
Author Message
 Post subject: Twin cam power builds vs plunging reliablity
PostPosted: Wed Oct 20, 2021 9:10 am 

Joined: Wed Oct 20, 2021 8:19 am
Posts: 1
FXDX Rider. Live on the edge of Texas. 60's. Love the bike as a comfortable responsive and so far reliable tourer and play-bike.
My riding area is Southeast Texas up to Texarkana, over to Tennessee and up to Kentucky and or Illinois and down to the middle of Florida and back to Texas. I have to ride a ways to find interesting riding terrain. It's all flat and grids around my home.
My Dyna is pretty much stock excepting Stage one -exhaust. Have a K&N RK 3909 Air cleaner. The cam chest hardware and cams are swapped out for the 2007 cam plate and oil pump.
Just put a series volt regulator in, tired of replacing the stock Harley unit and spending a 100 for new battery as well, each time one fails. Never been stranded by it though.
With Sundowner seat and bags, tours two up pretty good. The FXDX differs from other dynas in having adjustable suspension front and rear and frame mounted rear pegs which I swapped for old FXR rear foot boards.
Started riding in the 70s. 1st was a 250 Triumph thumper (mini thumper?). Followed by Xt-500 Thumper, GT500 Suzuki Titan 2 stroke, Ducati 750 GT, and various other bikes. Got the FXDX in 2003.
The TC has come and gone. Do we know now what power level it takes without grenadeing?
> Apparently Harley mostly admits to designing a TC engine that was reliable (skipping the cam chest f up) in stock form but iffy for more power.
Later the factory upped the displacement without fixing the plain crank bearing or the press fit flywheel and other issues. In 2006/7 they at last fixed the cam chest, or pushed the maintenance interval/nightmare twice as far away and tossed in a better oil pump.
Always confusing (to me) as to what power level the Twin Cam engine could be expected to live long and prosper with!
So, with the Twin cam having come and gone, surely there's solid knowledge now on the effects on reliability for upping power output?
Anyone know of or have a chart for power / reliability? Torque /HP on one side and mean failure rate say, on the other?
I've an FXDX with 40K and am thinking of upping the power but mindful of my crippled Plain Bearing Crank End (2003 year) and other weak points. Seems the 95" kit was a safe deal, with factory 96's and all, but what about 98" kits? Not so much worried bout the shortcomings of the myriad kits out there as the cost of successfully upping power vis the life of the lower end.
I understand there are builds that will get your HP matching your displacement and even (claiming)100 hp out of 98". Never any mention of additional engine mods to safely handle the strains though.
At the close of the TC era do we know the incidence of flywheel shift and crank /crankshaft bearing fails with each increase in engine strain?
Thanks to anyone who can point at an authoritative chart power up / reliability down, and /or recommended additional mods for every 10 HP gain to maintain solid reliability.

Profile My Photo Gallery Send private message E-mail
Display posts from previous:  Sort by  
Home Page Home Page  [ 1 post ] 

All times are UTC - 8 hours

Who is online

Users browsing this forum: No registered users and 3 guests

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum
Jump to:  
Welcome To The Harley Riders Forum The Ultimate Harley Davidson Enthusiasts Website!                Click Here For J&P Cycle's Big Sale!                Click Here For S&S Cycle's High Performance Parts!                Click Here For Harley Davidson Motorcycles


© Harley Riders Forum - ABS Enterprises All rights reserved.   Harley Riders Forum is not affiliated, owned or operated by Harley Davidson, Inc.