I just completed a cursory search for failure info on the above-mentioned geared cam upgrade and can find very little on failures related to the gears (or anything else) attributed to excessive pinion shaft run out either at the time of installation or occurring afterward. There is very specific advice out there that the chain to geared cam conversion can only be performed if the pinion shaft run does not exceed .003" maximum (or in some cases the advice is .005" maximum depending on the source).

At the time, I seem to remember a mass rush to change to gear driven cams as the extent of the weakness of the OEM chain tensioning system became apparent. Statistically, there must have been many upgrades performed with significant pinion shaft run out...or at the least the dreaded pressed crank could be expected to "move" over time on some bikes sufficient to increase pinion shaft run out beyond the stated allowable. Yet the forums seem to be largely silent on such failures.

Was the upgrade just more robust and forgiving of run out than it was believed it would be? Were the geared cam manufacturers being conservative in their run out spec? Or were all the mechanics in the country just really disciplined about not installing geared cams in bikes with more than .003" of run out? In either case, the chronicling of geared cam failures (or related bearing or oil pump failures) traced back to run out problems seems scarce.

I'm more than casually interested as I upgraded my '03 TC-88 20,000 miles ago to a geared cam at the time I converted to a high compression 95" kit (120hp, 109 ft-lbs). I'm a backyard mechanic who did my own work...and made the geared cam conversion with .005" of pinion shaft run out. I'm made the call at the time to proceed even though the S&S kit said .003" maximum. I was feeling lucky, I guess but have not had a moment of problems since. I monitor the forums from time to time to see if there is a wave of failures from all those upgrades but haven't seen anything systemic yet.

Thoughts on the reliability of that upgrade and its sensitivity to run out (now in retrospect) would be appreciated. Thank you.

 

How many miles on the motor and how hard do you run it?

 

Many upgraded to the tapered Timken main bearing that came with the forged lower end in '99-'02 models to eliminate that worry.
I had an '00 FLHTC with a high compression 95" build with Baisley heads and S&S 575 Gear drives,put 100,000 miles on it with no cam train issues.
The bike had almost 100,000 miles on it when that build was done,at almost 200,000 a rod bearing went south so it became a 103" stroker,used the same cams that were in it again with a new cam plate oil pump and lifters,ran like a raped ape.

 

The SnS cams were either 585 or 570.. SnS don't make a 575.

 

44,000 miles total but just 20,000 since the upgrade that included the geared cams. Note, I upgraded the cam roller bearings too.

No burn outs or anything but I do enjoy acceleration. It pulls to 6000 rpm and I’ve shifted my shift point up a bit to take advantage of that fact. Overall, I have fun on it but not too radical. I never hang at high rpm’s, Riding speed naturally varies…I ride a mix of highway and city. On a scale of 1 to 10…10 being the hardest…I ride at a level 6.

 

The Timken conversion does absolutely nothing to improve or prevent crankshaft run out which is caused by the rods slipping on the wheels.
Truing/pinning/welding does. Or buying a better crank(S&S).

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So here is the thing. You can run 0.005 and not break gears, The 0.003 spec is to insulate SnS from any issues. One of the issues being simply gear noise.

I will say the running a bigger motor can have issues. 2000 fxdx, the right side crank bearing suffered some damage and the cam plate began to move on the crancases. A home built TC FXR had the right bearing walk out of the engine case and camplate move. It pushed an 0.030 snap ring out of it's groove.. I do know a guy that has been through 3-4 cranks, 2 sets of cases and a camplate or 2 and haven't busted a set of cam gears yet. He did wear them out some as the bike has close to 200K on it.. The ones where you see the gear break are typically over 0.010 IIRC.

 

Thank you all for your replies. The geared TC-88 cam upgrade must just be really robust and forgiving. More so than it was once believed it would be. I’ve again failed to come across any indications of systemic failures on this broadly applied upgrade.

 

I kind of regret not going to gear drive my self with my recent build and S&S crank.

 

This is great info. I always under the impression that the .003" runout was the deal breaker! Have an 04 Road King at 45K and about time to start looking at upgrades. Just checked the tensioners and appeared fine and did not have to be replaced, BUT, I hate the idea of having to take it all apart again in 10-20K to do the exact same inspection. I appreciate you all sharing your experiences!! Thanks