Started disassembly for cam install on my 17 RGU this morning. Very disappointing to find nearly .005 run out on the crankshaft pinion. Did my 09 twin cam a few years back and thought .0035 was bad. What kind of run out are guys out there finding? Just curious to see if any are spot on like they should be. Thanks, Mike

 

.003. I did a thread on my build a couple months ago.

 

 

I measured mine at .001 when I did my cams recently. Spec is .012

 

​​​​​​. 001 ?!? Wow, that's really good. The moco spec of a max of .012 is ridiculous in my opinion. It is what it is I guess. Thanks for the replies....

 

.012" means other tolerances have to be loose to allow that much runout and not cause a problem. Crank runout on car engines I build get corrected if they're at .001". I understand the bearing setup isn't babbit but still that leaves a lot of room for improvement. Good ole tractor engine lives on in the 21st century!

 

I agree 100%. Not sure why they still run a 3 piece crankshaft in the first place. Even most, if not all tractors run a 1 piece crank! Lol

 

.005 is not all that bad is it? My Indy said .006 is the limit, he said a 7 or 8 could start to eat away at the oil pump. Harley spec at .012 is ridiculous, been that high since around 2002 or so. The Harley 3 pc crank has been a sore spot to me since they came out, I think it was around 2000 or 01.

 

The biggest issue is that its pressed together unlike the older engines, EVO and earlier. That and questionable QC.

 

In 2002 the spec was .003; the cranks were hot forged, not cast. 2003-2004 cranks were cold forged but had roller bearings on the drive side as opposed to Timkens. 2005 was the first year of cast cranks for the twin cam and there's your increase in run out spec. IMO, 1999-2002 were the best years overall for Harley engines but for the spring tensioners, as of this very moment, again IMO, Harley has yet to produce an engine with QC that high.

As mentioned above and in earlier posts, all the big twin cranks have been assembled from components, the Twin Cam was press fit vs the Evo being nutted. The M8 is a pressed together crank like the Twin Cam.