Valve Adjustment

Valve adjustment seems like a daunting task, but with the right tools and instructions, it's merely time-consuming. This page does not attempt to replace a quality service manual. The authors recommend that you have a quality Triumph or Haynes service manual on-hand to reference for tolerances, procedures, and torque specifications.

Measurement:

Use a feeler gauge to measure the valve clearance (lash). Measure each valve when the piston is at TDC in firing position. To rotate the engine by hand, first remove the spark plugs and then either put the bike in 6th gear and rotate the rear wheel, or remove the right-side crankshaft cover and rotate the engine using a wrench. Do not rotate the engine backwards because this will put undue pressure on the timing chain tensioner mechanism. The crankshaft cover is a flush-mount cover and can often be broken free with a rubber mallet after the mounting bolts are removed. Intake valves should have between 0.10mm and 0.15mm of play. Exhaust valve lash should be between 0.15mm and 0.20mm.

Use a chart to record each valve mesaurement. Keep this chart with your maintenance documentation.

Adjustment: If you discover that any valve has less than the minimum tolerance, it's time to adjust valves. Triumph has a tool that can be used to remove shims from one cylinder at a time. This tool is reported to be somewhat complicated to use. If you need to change the shims on several valves, and especially if you do not have shim measurements, it would be a good idea to record the measurement of each shim. If you have the measurements recorded, then the next time you need to replace a shim, you will already know which size to order. Record the measurements of all shims before replacing any of them. This means that you will only need to order parts once. Some Triumph dealerships carry shims for these engines in-stock and can sell you the ones that you need during a quick visit.

The cam caps on older engines may have been in-place since the engine was originally assembled. Visually inspect the caps to determine if they were numbered at the factory. Most were. If the numbering cannot be determined, use a permanent marker to write the number of each cam cap on the cap. The cam caps must be reinstalled in the exact same orientation as they were removed. It might be a good idea to work on one cam at a time in order to avoid confusion. Some models use Torx bolts with a T-30 head and some use hex bolts with a 6 mm head.

When removing a Torx-head bolt, use a strong ratchet or break-over bar with the correct Torx bit, and use a snapping motion to break the bolt free. The Torx bolt heads aren't the hardest metal and it's possible to strip the insides out of a bolt head. This author was able to hammer a T-35 bit into two stripped bolt heads and successfully remove them. The cam caps were later re-mounted using 6mm hex-head bolts from a different engine (sourced from a local Triumph dealer). It's possible to access all of the shims without removing the cams. You should take the necessary steps to remove the cam chain tensioner ratchet and to block the tensioner slide in order to keep the chain from jumping teeth on either the cam sprockets or the crankshaft sprocket.

To access shims, lift the cam from the #1 cylinder end, or lift the cam vertically out of its journal and use a magnet to fish out the valve shim bucket. Do this one valve at a time. The shim should rotate freely in the bucket, but a thin film of oil between the shim surface and the bucket surfaces may keep the shim stuck. Use compressed air, a small screwdriver, or a dental pick to gently lift the shim enough to break the surface tension of the oil and then use your magnet to remove the shim from the bucket. Measure the shim with a micrometer if the shim's stamped measurement has worn off. Record the shim measurement and if necessary, calculate the size of shim to replace it with.

Coat the shim with oil and re-insert into the bucket. It should rotate

freely inside the bucket before the assembly is re-installed in the engine. The bucket should drop easily back into place and should rotate freely on the valve. Before buttoning up the engine, follow the maintenance procedure for measuring the cam chain tensioner spring and rotate the engine again by hand through several revolutions to ensure that at TDC on the #1 cylinder, the timing marks on both camshafts line up.