Motorcycle Repair: Twin Cam 88 Crankshaft Failures, twin cam 88, twin cams

Question
Hi again Mike, I can't find any previous Q&A on the following topic so thought I'd run it past you. My buddy likes his 20,000 mile 06 Ultra Classic but he's not satisfied with it's power. For some time now he's been shopping parts and has acquired enough to move forward with a 95" big bore using an 06 only Edelbrock Performer RPM kit he bought on closeout. It's a fairly stout package including heads, 10.25:1 pistons, cams and a good set of adjustable push rods. They advertise 103+HP and 97+FP torque on the dyno (I'm sure depending on their optimal setup.) We are both adequately capable to do the work and have or have access to the special tools. However, as I'm sure you know, twin cams have a rep for twisted cranks and excessive runout as a result that causes catastrophic related other parts damage when they fail. Some years & models are reported worse than others... We'll dial indicate the crank pinion shaft after disassembly of the cams chest and hopefully won't find more than .002"-.00025" runout. If it's good (and the rods side clearance wasn't set too tight at the MoCo), then we'll know we should have a good crank. And (finally) here is the question: If the crank checks out good, would you suggest or recommend that the crank be removed, welded and trued? Or just install the hi-po kit and button it back up? Seems the general consensus of the local engine guru's is it's not necessary to weld the crank at these power levels. I know my buddy is concerned about addl time & cost. But in my opinion it just makes sense get it welded for at least the peace of mind to avoid a possible crank failure down the road in the middle of the riding season. Especially given the known potential problem. What would you do in this situation? Thanks again in advance.

Answer
Anytime you are going over 100 horses you should weld to stop future problems. You dont want to do all this work only to have to do it all over at 10,000 miles.
Heres an artical you can check out
http://www.hotbikeweb.com/tech/0809_hbkp_building_a_stout_twin_cam_crank/modifyi...

Good luck and happy riding
Mike