Norton camshafts with lightweight BSA lifters for racing or street. Increase the RPM limit of your Norton and reduce the danger of valve float with BSA lifters that weigh less than 1/2 as much (35 grams) as the original Norton lifters (80 grams). These parts make your Norton more free reving while reducing stress, friction and overheating of the valve train. Superior to flat lifter cams in all respects. The radiused BSA lifters are much easier on the cam and wear is substantially reduced. Note the cam nose is broader (similar to a roller cam - see photo). This is to compensate for the radiused lifter and its the reason they last so much longer. Believe it or not, the cam in the photo above has one year of regular use on it. The durability and long life of these cams and lifters will save you money in the long run. Reducing the weight enables your valve train to operate more acurately and effeciently. Pushrods and rocker arms do not flex as much so you get the full lift your cam was deligned to deliver. You can use a more aggressive cam with steeper ramps to get more performance than you would get with cams designed for heavy inefficient stock Norton lifters. Energy saved on the valve train ends up going to the rear wheel. This technology was developed years ago when factory sponsored Nortons were winning US dirt track races. All cams hardface welded for the ultimate in reliability.
| DESCRIPTION OF NORTON CAM FOR BSA A65 RADIUSED LIFTERS (1-1/8” RADIUS) | CAM LOBE LIFT | VALVE LIFT | DURATION MEASURED AT .040” CHECKING CLEARANCE | LOBE CENTERS | SIMILAR IN PERFORMANCE TO FLAT LIFTER NORTON CAMHAFTS LISTED BELOW | VIEW CAM PROFILES |
| The perfect cam for stock Nortons and stock broad power band performance with a slight overall improvement, stock springs OK. Smooth idle with good low end torque. BSA A65 Spitfire intake lobe grind on intake and exhaust. | .345" | .390" | 262° | 104 | Performance close to Stock Norton Commando cam but with slightly more lift and duration. |  |
| 1st stage hot street and all around racing for 4 or 5 speeds with strong mid range, requires racing springs for track. Great for 750s. This is a copy of the famous Axtell #3 cam but for BSA lifters. Note that Ron Wood achieved 84 hsp with an Axtlell #3 cam in his 750 flat tracker. | .357" | .400" | 278° | 104 | Performance same as Axtell #3 and similar to Peter Williams PW3, Megacycle 560NR |  |
| 2nd stage full race cam with excellent mid & Hi RPM power for racers with 5 speeds and hot street 850s & 920s, requires racing springs. | .370" | .410" | 280° | 105 | Performance similar to Norton 4S, Steve Maney cam, Megacycle 560NSS, Norris RX, HPI #7 |  |
| 3rd stage cam for serious Hi RPM racing with 5 speed, Sifton 460 grind, requires strong racing springs. Used on factory sponsored Hi power US dirt track 750 short strokes. Lots of top end power. BSA lifters should be ground to 7/8" radius to avoid valve clash. | .400" | .450" | 283° with 7/8 radiused lifters | 106 | Performance similar to Megacycle 560-D+ (Norris D grind), OK for all out short strokes and large displacement racers |  |
Reconditioned/resurfaced BSA lifters are available in limited supply.
You must use radiused BSA A65 lifters with my radiused cams because stock flat lifters will tangle the valves. If you use raduised lifters on a cam designed for flat lifters you will lose duration and power.
Always look at cam lobe lift (not valve lift) when comparing BSA to Norton cams specs etc. Also make sure you use the same checking clearance (.040”) when comparing duration. If you check or "degree" your cam then I suggest using 104 Lobe center on the intake.
It will be necessary to grind chamfers on the outside corners of the BSA lifters to clear the pushrod tunnels as in photo below. These details are taken care of when you order a complete cam kit.
Mock up your motor with just one case half to check cam lobe clearances, lifter travel and determine vertical location of the lifter blocks - THIS IS VERY IMPORTANT. Be careful to compromise height about ½ way between the cam striking the lifter block and the lifter falling out of its channel. Provide at least .030” clearance between nose of cam and lifter blocks. Lifters should have at least .070” support from the lifter block tangs at 0 lift. Align the lifter block with the original small tabs that separate the original lifters - add a couple drops of high strength loctite where the lifter separators fit into their slots so the blocks won't slide downward if you happen to remove the locating pinchscrews. Be sure to lock the BSA lifter blocks in vertically with 10-32 allen screws through the front pushrod tunnels (about 7/8” above the bottom of the cylinders). Use a 3/16" drill bit to make a 1/16" deep divit in the bronze block for the set screw tip. Use high strength loctite on the threads of the set screws to prevent oil leaks. Check the tightness of the set screws after break in. Also check that the cam lobes are centered on the lifters and shim the cam on the inside of the case if necessary.
The left photo above shows the proximity of the cam nose to the brass lifter block. The right photo shows how much support the lifter has left in its channel at its lowest point (one lifter is removed for viewing). You must determine this compromise by adjusting the lifter block height with the pinch screws as mentioned above. This is a new cam and the Parkerized coating has not yet completely worn off. WARNING – high lift cams will not clear Atlas or early 750 (& possibly 850) camshaft tunnels and possibly lifter tunnel spigots, you will have to check and make clearance.
Location of divit and pinch screws for vertically locating the lifter blocks.
You must use shorter pushrods with the BSA lifters (approx 3/8"). The pushrods I sell are made of high strength aircraft quality aluminum to reduce flexing. They are superior and slightly lighter than stock push rods. They also have a higher buckling strength compared to steel pushrods of the same weight. I do not recommend steel pushrods because aluminum cylinders will expand when hot, causing the valve clearance to increase dramatically resulting in excessive valve tappet clearance, noise and loss of performance. Check to see if the tappet adjuster is generally centered on the valve tip throughout its travel. If the alignment isn't perfect then install hardened wear caps on the valve stems. The original BSA lifters are reliable (beware of low quality aftermarket lifters that come apart). Be sure to use stock 1-1/8” BSA lifter radius on BSA profile cams.
3/8" shorter pushrods for BSA lifters are available (see shopping cart).
A .050" clearance is required between the valves near piston top dead center. You take a risk when clearances get down to .040" or below and I have seen flat wear spots on valves at reduced clearances. Use a small light and a piece of bent wire inserted through the exhaust port to check clearance between the valves. You can file the wire down until it fits and then measure the wire. If clearances are too tight you can reduce the radius of the exhaust lifters from 1-1/8" down to 1" or 7/8" to reduce the duration.
Note that the Parkerised coating is just starting to wear off the new cam lobes after engine mock up.