Twin Cam Engine Fast Lane Head Work
New big end bearings New crank and plugs Power with confidence

Bulletproof Crankshafts

Not only is Fast Lane Head Work the only Harley head porting shop in the UK, now we are also the only Twin Cam crankshaft overhauling business in the UK! Another first!

Crankshaft Crankshaft Crankshaft

As I’m sure most of you reading this page will be aware, the crankshaft assembly is the heart of the engine.

With this in mind once performance has been increased by means of increased compression, more aggressive cam lobe profiles and stronger valve springs, it is inevitable that the stresses transmitted to the crankshaft are also increased. There are many theories out there behind the reasons for crankshaft failures. Some explanations are - over aggressive clutch disengagement at higher than required RPM, emergency stops without clutch engagement, hard acceleration, burnouts etc. While we may never establish a firm reason, the fact remains that they do fail. Usually the failure method involves the press fit between the crank pin and the flywheel being compromised. Once this occurs the assembly is rotating out of truth and the risk of catastrophic failure due to damage to the oil pump is high. This phenomenon is known as scissoring as one flywheel has moved forward or reverse in relation to the position of the opposing flywheel. The stock crankshaft in all Twin Cam models is pressed together at the factory and is intended to be replaced rather than serviced in the event of a failure. There are companies in the States that specialize in quality Twin Cam crank shaft overhauls but until now this service has only been available through the costly process of sending your failed crankshaft across the pond and back again. Here at Fast Lane I have been developing and testing overhaul procedures for the last couple of years and finally I am proud to announce the new exclusive ‘Bulletproof’ Twin Cam crankshaft rebuilding service.

How it works...

The service begins with the crank pin being pressed out of the flywheels for inspection. From here a new pin can be manufactured if required or the stock pin can be re used with new big end bearings and races. The rod races are also inspected at this point and are reground if required. Once the rods, pin and flywheels are assembled they are trued and a hardened steel plug is pressed into the pin recesses to increase the interference fit. The assembly is then TIG welded at two opposite points on each end of the crank pin so that the flywheel and the pin effectively become one unit and any chance of slippage is eliminated. You are then able to fully utilize the power your engine is capable of producing with the confidence of knowing that your flywheel assembly will never slip again. Once your crankshaft is running true you are then able to upgrade the camshaft drive system to gears which gives more accurate cam timing and a permanent problem free bottom end in your Twin Cam.

Price to true, plug and weld your crankshaft £500

Price to buy a complete overhauled unit £800

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This is not a Harley Davidson website, nor is it endorsed or sponsored by Harley Davidson. Fast Lane Head Work Limited is not affiliated with Harley Davidson in any way. Any use of the words Harley Davidson, Harley, Twin Cam or any other words registered by Harley Davidson are used here solely for reference.

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Registered Company Address: 8 Albert Place, Aberdeen, AB25 1RG (not the workshop address)