The XS650 performance Camshaft and Valve Springs Kit ( 05-0025 ) is designed as a drop-in cam if being timed to OEM positioned timing marks ( stock ). This is a direct replacement for all 1974 – 1984 XS650’s with 447 / 533 type engines. The camshaft has a removable 36-tooth drive sprocket, requiring timing-to-stock marks to install. This kit includes premium valve stem seals, high-performance valve springs and clearance caps. No valve guide modifications are necessary.
These camshafts are machined from new billets (no “re-grinds” or “hard-welds” here) and internal bushings are pre-installed.
Please note : A new camshaft should NOT be used with damaged rocker arms. Inspect your rocker arms for wear and replace them if there is damage to the hard-facing. Valve adjustment screws should also be inspected and replaced if any pitting, galling, or any other damage exists.
Installation
- Closely inspect your new camshaft for any defect.
2. Lubricate the new camshaft before assembly.
3. Align the camshaft to OEM timing marks OR degree in the camshaft with a dial indicator on the valve collar and a degree wheel on the crankshaft. Seek a professional mechanic if you do not have this expertise.
4. Now, the valve-to-piston clearance should be checked. The XS Performance Camshaft is fully functional with the stock Yamaha pistons, with 0.060″ minimum clearance from the valve face to the pistons. “Claying” the piston is the safest way to check valve-to-piston clearance and is essential if the timing is varied from stock or if you have aftermarket pistons with higher compression and/or modified domes.
5. This kit has been designed to have sufficient valve cap to valve stem clearance but note that our premium valve stem seals ( provided with the kit ) must ALWAYS be used. If you chose to not use the provided stem seals, always check this clearance, as the valve guide height may have to be reduced (cut down).
6. Cam sprockets are secured with special 7mm bolts. If these are loosened and/or removed, they must be secured with Locktite when reinstalled. We recommend using Locktite primer, making sure the hole and bolt threads are clean and free of oil and debris. Failure to do this may cause extensive engine damage if the bolts become loose while the engine is operating.
We recommend a good petroleum-based 20W/50 Grade oil be used (such as Valvoline Racing).
Disclaimer: MikesXS is not responsible for any damage that occurs during installation. Any variation of this installation is the sole responsibility of the purchaser.
Timing Specifications
Timing is to be checked with zero clearance. Running clearance (lash) can be seen below.
Timing is shown at 0.040″ lift at the valves.
OPEN: Intake: 26 degrees BTC Exhaust: 60 degrees BBC
CLOSE: Intake: 66 degrees ABC Exhaust: 32 degrees ATC
VALVE LIFT: Intake: 0.420″ Exhaust: 0.420″
DURATION: Intake: 272 degrees Exhaust: 272 degrees
LOBE CENTER: Intake: 110 degrees Exhaust: 104 degrees
RUNNING CLEARANCE (LASH) is 0.006″ for both intake and exhaust valves
You have now installed your XS Performance Camshaft and Valve Springs Kit.
For tech support, please contact customerservice@mikesxs.net
