Need some serious advice/opinions here. My 2006 FXDBI, unbelievably, just grenaded on me for the third time - I've got a whopping 8100 miles on it. Same exact situation as the last - broke a tooth or 2 off the cam gear (gear drive, no chains). The first time it happened, it was at 95" with the gear drive. When it went down then, I went to a 103". Last time, I upgraded as many parts as I could, including a move to the Screamin Eagle crank set. All was previously warrantied, but I have a strong feeling I'm going to get pushback from the dealer on this one, as the original warranty is up. I only have 2500 miles on it since the last build, so I'm hoping they make me whole.

My worry is that they are obviously fixing the damage, and not the problem - always saying the crank run-out is the cause. I've never done a bottom end on a Harley. Does the crank ride on mains like a car motor? If so, do they/should they line bore/hoan this to ensure it is true? Could the main caps be flexing too much (110 LB/FT on the dyno)? If it has been bored twice, do I need a new bottom/main caps? What else could cause this? Amazingly, I wanted to go with an aftermarket cam plate last time, but they were adamantly opposed to it...

Any thoughts you have would be truly appreciated (keep me from driving this mother off a cliff)!!!

 

No caps, nothing like a car. Roller bearings. Does sound like too much crank runout, a chain drive setup will tolerate more than gears. The answer is to have the crank fixed,trued and welded so it can't slip so easy. Any oe crank will do this, even S/E ones. Mike

 

look at Dark Horse

 

Dumb question: What is Dark Horse?

 

Dark Horse is an engine shop that specializes in balacing, trueing, welding, and plugging cranks. They are pretty much the best.


http://www.darkhorsecrankworks.com/



Mike

 

wow....busted a gear i bet your oil pump aint far behind as well...

Here are some pics of a crank darkhorse fixed after they slipped.

 

Sorry to say but a lot of gear drives are made with pot metal and can't stand much sideways movement in the crank. Best thing to do is have a good mechanic shop....not your local HD shop...check for crank runout. For a gear drive to work well and stay together there has to be almost no movement.

 

Looks like a great option. Would be nice to save my SE crank...

 

Appreciate all the great advice, but I still have one burning question. What the Hell can cause this? Just ****ty parts and/or bad assembly on the dealer's part???

 

I can't believe someone didn't insist the crank had to be welded after you've had the same problem before.

I was talking to a machinist today that does custom headwork and has for many years. We were talking about my upcoming build and since I am only going for the 100 - 110 hp/tq #s he said there was no need to weld the crank but he would not build one @ the next level without it.

A Timken bearing, a welded & trued crank with <.002" runout will last forever.

The picture of the welded crank above is just what it should look like. When you start to weld a crank it will bend and then it must be welded on the opposite side to come back to true.

Gear drive cams are a bad recommendation for any build of '06 dyna and '07 above Twin cam engines that don't have the bottom end treated.