Ok, so I stopped by my local dealer and they were having a (very attractive) sale on 103" upgrade kits. I asked whether the kit would void my (very expensive) seven year warranty. I was told that the aftermarket warranty (after the 2 year factory warranty) would be voided. I asked, "what is the risk?"

I was told that changing the top end could cause problems in the bottom end. Specifically, there is this chain thingy (technical term) in the bottom end that, if strained to failure, could cause a catastrophic engine failure. One option, I was told, was to replace the chain thingy (in the bottom end) with a gear thingy (again, a very technical term) to avoid catastrophic engine failure. I decided to leave all my thingys alone, even though a 103" upgrade seemed like a nice, reliable upgrade.

On a recent business trip, I had the opportunity to stop by the dealership where I purchased my bike. I tend to trust these guys - they have never led me astray. They told me that the problems with the chain thingy had been resolved in 2007, with the installation of a new boot thingy. My bike - a 2008 FXDF - had the new boot thingy and would not have a catastrophic engine failure. They told me that changing over to gears would result in a constant gear whining sound. They also told me that a 103" upgrade (with or without cams - the cam upgrade also sounds sweet and reliable) would be covered by warranty if performed by a HD dealership. (BTW - the total cost quoted for 103" upgrade w/ upgraded cams and labor: a low, low price of $2000.00 OTD).

So what is the deal with this chain v. gear situation on 2007 and later bikes? What is the deal with a seven year warranty on a 103" upgrade with or without cams? Help!

 

chain drive was redesigned in 06 dynas only, then all 07's. The new roller chain has tension from hydraulics rather than spring. Alot better design. Gear driven cams are not loud at all, but wouldn't suggest em in 06 & up dynas without having the crank reworked, considering the run out factor!

 

Chad you may need to clarify for the gentlemen about crank runout. Especially since he was using the word "thingy" in a few places. lol

Crank runout is I undrstand correctly is the amount the crank moves back and forth in the crankcase. Right? If it moves too much, gear driven cams are not a good idea without trueing the crank.

 

With the absence of cam bearings in the cam support plate, what would the gear drive do to the cam support plate? One part of the big bore is pistons and cylinders, that gives you the horse power and the cams will bump up the torque. Torque gets you moving and horsepower is speed.

 

There are bearings in the cam plate for the cams.

 

Watch this youtube video....gear-driven cam swap.

http://www.youtube.com/watch?v=MPRbpbGq0-k

 

You can't do a gear drive conversion unless you check the runout, no matter what year. The max runout for gear drive is .003, period.
While for '07 and up chain drive it's a whopping .014. Runout is the up and down motion of the crankshaft measured at the back side of the cam plate. Personally, I think they should have stuck with .003. That big number is definitely not good for the cam plate and oil pump! Only a matter of time! Also, even if you're doing a chain drive cam swap, you might as well check the runout while you're there, good piece of mind. Look at the bearing in the cam plate too, if it's wearing funny, you can bet the crank is getting out of whack.

Now, so we don't worry about too many thingy's, the vast majority of stock cranks that have bad runout are from agressive driving. Jacking the gas on and off real fast, or dumping the clutch on engine decel. Anything that puts a hard and somewhat reverse load on the crank.

Confused yet?





Mike

 

So does my 06 dyna have the new cam chain tensioner setup?

 

Which is why we should all install the SE compensator sprocket....

 

Yes it has it, I mentioned earlier 06 dyna was the first!