750871 Thundermax Cams Von FÜR

Converting from the stock chain driven cams to gear driven cams improves valve timing accuracy by eliminating timing chain lash. Another advantage is that you loose the chain tensioner shoes that wear out or even fail. Bolt-in cams do not require head work.
Easy Start cams start any engine regardless of displacement or compression ratio, using your stock starter. Consequently, they save your starter and battery. They work automatic, no buttons to push. The two exhaust cam lobes are equipped with a spring loaded compression release lobe on the "heel" of the cam at the point where the valve would normally be fully closed. The lobe holds the exhaust valve open slightly at cranking speed. This releases some of the compression, making the engine much easier to crank. Once the engine starts, and rpm increases, the compression release lobe is centrifugally retracted and the engine runs normally, with full compression, and without any loss in performance. Easy Start cams have been tested for 100,000 accumulative starts and over 150,000 road miles without breakage or compression release failure.
Complete S&S gear drive camshaft kits contain front and rear cam, all gears, gear cover gasket, bearings, retaining ring, o-ring, thread lock and instructions. For those who have already converted gear drive and just want to change to Easy Start cams and/or valve timing we also have cams with just the inner gears available.

Notes: Stock valve springs in 1999 thru 2004 Twin Cams can handle cams with valve lifts as high as .515". Stock valve springs in 2005 thru 2017 Twin Cams can accommodate valve lifts up to .590". The OES and 557 grind cams can be installed using the stock pushrods. However, we recommend S&S Quickee Adjustable pushrods ZPN 752108 for easy installation of all S&S cams.

OES grind: Original Equipment Specification (OES) A bolt-in replacement cam with stock cam timing is designed for riders with stock engines. Does not require tuning. Bolt-in stock. Equivalent to OEM A-Grind

509 grind: Designed as a bolt-in, high torque cam for 1999-'06 models. 180 psi cranking compression, no need for compression releases. For 88 CID engines with stock compression ratio. Idle-4500 rpm. Bolt-in torque.

510 grind: Designed as a bolt-in cam for 88, 95, and 96 CID engines with compression ratios below 9.7:1, stock, un-ported heads and stock valve springs or performance valve springs with less than 160lb. of seat pressure. 3000-5500 rpm. Bolt-in.

551 grind: Designed for engines with 96 to 106 CID and 9:1 to 9.9:1 compression, this is a bolt-in cam set designed for stock or mildly modified touring bikes. Not recommended for compression ratios of 10:1 or greater. Greatly improves low-end and midrange torque, strongest from idle-4000rpm. Bolt-in torque.

557 grind: Designed for 2009 to present Tri Glide models, this bolt-in cam, with its short duration, produces lots of usable torque. Has stock base circle that permits the use of stock pushrods. Bolt-in.

570 grind: Designed for 88 to 103 CID engines with compression ratios between 9:1 and 10:1, this bolt-in cam will provide a nice power increase across the entire power band. 3200-5700 rpm. Excellent bolt-in for overall power on 103". Bolt-in.

583 grind: Optimized for use in Softails and Dynas, this bolt-in cam makes horsepower and torque that you can feel all the way through the rpm range, making the most power right where you need it:1500-5000rpm. Bolt-in.

585 grind: Designed for 88 to 106 CI engines with compression ratios from 9.7:1 to 10.5:1 and 106 to 124 CI engines from 9:1 to 10:1 compression. This bolt-in cam provides massive horsepower and torque increases starting at 3000rpm and holds steady all the way to redline. 3500-6000 rpm for 88" - 103" engines and 2500-5500 for larger engines.

625 grind: Cam set designed for 95" or larger engines with compression ratios between 10.0 and 10.75:1. 3000-6000 rpm.

640 grind: Used in S&S T124 engines, this cam makes horsepower! Intended for engines of 95 CID or more w/ compression ratios between 10.5:1 and 11.5:1. 3000-6000 rpm.

675 grind: A high lift monster, this cam set is designed for 120" or larger engines with at least 11:1 compression ratio. 4500-6500 rpm.

MR103 grind: Designed as bolt-in cams for stock 2012 and later 103 CI engines with stock 9.7:1 compression ratio up to 10.5:1. Works well with stock, un-ported heads, but is great for ported heads. More power across the rpm range best results from 2500-5500 rpm. Bolt-in.

HP103 grind: Designed as bolt in cams for stock 2012 and later 103 CI engines with stock 9.7:1 compression ratio up to 10.5:1. Works well with stock, unported heads, but is great for ported heads. Ideal for lighter bikes and racing applications where getting the most horsepower from a stock engine is imperative. Best power in the higher rpm range, 3000-6000 rpm. Bolt-in.

635HO grind: High lift cam for modified engines with 106" or greater displacement and compression ratios between 10.0:1 and 11.0:1. Works well with stock, un-ported heads, but ported heads are recommended. Best power from 3000-6000 rpm. This is not a bolt-in cam set. High-lift springs and clearance checks are required.