KEL800 Valve Clearance - Inspection & Adjustment (DS800X Rally)

The KEL800 (Loncin factory code LX284MW) is the 798 cc DOHC 8-valve parallel twin powering the DS800X Rally. Like the larger DS900X engine, it uses shim-over-bucket valve adjustment with shims available in 0.01 mm increments. Procedure is straightforward to inspect but requires partial top-end disassembly to adjust - budget half a day if a shim swap is needed.

Per the official service schedule, valve clearance is inspected at 24,000 km (then again every 24,000 km). It’s a relatively infrequent but high-stakes job - get it wrong and the symptoms range from rough running and lost power to dropped valves.

Specifications

Item	Value
Intake valve clearance (cold)	0.15 - 0.20 mm
Exhaust valve clearance (cold)	0.20 - 0.25 mm
Engine temperature for measurement	Below 35 deg C (cold)
Intake midpoint (target after adjustment)	0.175 mm
Exhaust midpoint (target after adjustment)	0.225 mm
Shim thickness range available	1.72 - 2.60 mm
Shim thickness increments	0.01 mm (89 different shims)
Cylinder count	2 (parallel twin, 270 deg crank, 19 deg cylinder offset)
Total valves to check	8 (4 per cylinder: 2 intake + 2 exhaust)

The engine must be cold - under 35 deg C. If you ride to the workshop, leave the bike overnight before measuring. Hot-engine measurements give false-tight readings because aluminium expands more than the steel valve train.

Note: the KEL800 has tighter exhaust clearances than its larger sibling KEL895 in the DS900X (0.20-0.25 vs 0.26-0.35 mm). Don’t substitute one bike’s spec for the other.

Tools needed

• Crankshaft turning tool - the LX284MW has a different access path than the LX286MX; consult the service manual for the exact tool size on your bike
• Feeler gauge set (0.05 - 0.50 mm range)
• Magnetic pickup tool / tweezers for extracting shims
• Micrometer for verifying shim thickness
• Torque wrench in 5-25 N.m range
• New cylinder head cover gasket and seal ring (always replace)
• New view hole cap o-ring
• New flat washers for swinging arm shaft screws (Voge specifies replacement)
• Engine oil (for re-assembly lubrication)

Procedure - Inspection only

1. Prep

Park the bike upright on level ground. Confirm engine temperature is below 35 deg C. Remove:

• Fuel tank (refer to chassis service manual)
• Air filter and any cosmetic parts sheltering the cylinder head cover
• Cylinder head cover, gasket, and seal ring (the corner-place o-ring)
• Left decorative cover, view hole cap, and o-ring

2. Set timing - find the basic circle position

Turn the crankshaft counter-clockwise until the basic circle (heel) of both intake and exhaust camshafts on the left cylinder is aligned with the swinging arm of the valves. This places left cylinder valves on their fully-closed position.

When correct, the cam lobes both point away from the valves on the left cylinder.

3. Measure left cylinder

With the feeler gauge, measure the clearance between the camshaft basic circle (or protrusion) and the swinging arm tappet for all four valves on the left cylinder - 2 intake + 2 exhaust.

Record each value in a labeled table (L-IN-1, L-IN-2, L-EX-1, L-EX-2). Acceptable ranges:

• Intake: 0.15 - 0.20 mm
• Exhaust: 0.20 - 0.25 mm

4. Set timing - right cylinder

Continue turning the crankshaft until the basic circles of both intake and exhaust camshafts for the right cylinder are aligned with the valve swinging arms.

5. Measure right cylinder

Repeat the measurement procedure for all four right-cylinder valves. Same specs.

6. Decide

If all 8 valves are within spec, you’re done - re-assemble per the assembly section below.

If any are out of spec, proceed to adjustment.

Procedure - Adjustment (if needed)

1. Set timing precisely with the TL alignment

Turn the crankshaft clockwise until the scale line “TL” on the magneto rotor aligns with the timing mark “IN” on the timing driven gear of the intake camshaft, and “EX” on the timing driven gear of the exhaust camshaft. The mark “IN” must point at the intake side and “EX” must point at the exhaust side, parallel to the cylinder head surface.

If the timing marks aren’t in this position, rotate the crankshaft another full 360 deg counter-clockwise and check again. The KEL800 is a 4-stroke so each valve event happens once per two crank rotations - one of two positions will be wrong.

2. Remove tensioner

Remove the tensioner base tail bolt (16 N.m, with o-ring), the installation bolts on both sides of the tensioner base, the tensioner base, the seal ring of the base, and finally the tensioner itself. (Service manual Chapter 5 has the detailed step-by-step.)

3. Remove camshaft bracket and camshafts

Loosen and remove the camshaft bracket bolts in the numbered sequence printed on the bracket itself (Ref. No. 1-12 on the camshaft bracket). Don’t deviate from this sequence - improper loosening can warp the bracket or stress the cylinder head.

Do NOT remove the installation bolt on the timing driven gear of the camshaft. That’s a different fastener and removing it disrupts cam timing.

Lift out the camshaft bracket, then carefully lift each camshaft out of its journal seat.

4. Extract shims

Open the relevant valve swinging arm to access the shim. Use a magnetic pickup tool to lift the adjustment shim out of its seat in the bucket / tappet.

Shop discipline matters here:

• Don’t drop shims into the crankcase or spark plug hole. Cover the spark plug holes with rags before opening swinging arms.
• Mark each removed shim with its valve location (e.g., “L-IN-1”, “L-IN-2”, “L-EX-1”, “L-EX-2”, and same for R). You need to know which shim came from which valve to do the calculation.
• Measure each removed shim with a micrometer to get its actual thickness. Don’t trust the printed value - wear and carbon buildup can change effective thickness.

5. Calculate new shim thickness

Use the formula:

A = (B - C) + D

where:

• A = thickness of new shim (what you need to install)
• B = measured valve clearance (the value you wrote down in step 3 / 5 of inspection)
• C = midpoint of clearance spec (0.175 mm for intake, 0.225 mm for exhaust)
• D = measured thickness of the removed shim (from your micrometer reading)

Worked examples:

Intake valve, measured clearance 0.27 mm (too large), removed shim 1.85 mm: A = (0.27 - 0.175) + 1.85 = 1.945 mm -> install nearest available shim, 1.94 or 1.95 mm.

Exhaust valve, measured clearance 0.16 mm (too small), removed shim 2.10 mm: A = (0.16 - 0.225) + 2.10 = 2.035 mm -> install nearest available, 2.03 or 2.04 mm.

The shim selection range is 1.72-2.60 mm in 0.01 mm increments (89 distinct thicknesses), so you should always be able to find a match within +/- 0.005 mm of the calculated value.

6. Install new shim

• Coat the end part of the valve rod with engine oil.
• Drop the new shim into its seat at the original position on the valve spring base.
• Close the swinging arm.

7. Re-assemble camshafts

Coat the camshaft journals with clean engine oil (10W-40, API SL+, JASO MA - same spec as engine oil) before installation.

Re-confirm crankshaft position (TL alignment from step 1).

Hang the timing chain on the timing driven gear, assemble the intake and exhaust camshafts, ensuring the timing mark “IN” on the intake driven gear is parallel to the cylinder head surface and faces the intake side, and the mark “EX” on the exhaust driven gear is parallel to the cylinder head surface and faces the exhaust side.

Replace the camshaft bracket bolts, washers, and seal rings with new ones (Voge specifies replacement). Install the camshaft bracket.

Tighten the bracket bolts in two stages, in the numbered sequence on the bracket (Ref. No. 1-12):

• First pass: 5 N.m in numbered sequence
• Final pass: 15 N.m in numbered sequence

12 bolts total (6 per camshaft bracket).

8. Restore tensioner

Re-fit the tensioner and base, then release the tensioner per the service manual procedure.

9. Verify

Slowly turn the crankshaft counter-clockwise by two full rotations by hand. Listen and feel for any binding. If the engine binds at any point, stop immediately and re-check timing - a bent valve from incorrect re-installation will fight you here.

Re-set timing to TL alignment and measure all valve clearances again. If still out of spec, the calculation was off - re-check shim thicknesses and recalculate.

10. Final assembly

• Re-fit the cylinder head cover with new gasket and seal ring. Bolt torque: 12 N.m x 5 (M6).
• Re-fit the view hole cap with new o-ring. Torque: 7 N.m.
• Re-fit the left decorative cover with new seal ring. Torque: 10 N.m.
• Re-fit air filter, cosmetic shrouds, and fuel tank.

Run the engine briefly and check for oil leaks at the cylinder head cover gasket and view hole cap.

Common pitfalls

• Measuring on a hot engine gives false-tight clearances. The 35 deg C cap is real; ignore it and you’ll over-shim and end up with too-tight valves on the next cold start.
• Mixing up shim positions - always mark shims by valve location. Two shims that look identical may be 0.05 mm different and rotating them between positions just shifts the problem around.
• Not following the numbered sequence on the camshaft bracket when loosening or torquing the bracket bolts. Loncin prints those numbers for a reason - skipping the sequence stresses the head and can crack a camshaft journal.
• Re-using the cylinder head cover gasket or seal rings - Voge specifies replacement. The compressed gasket / o-ring won’t seal properly on second use; you’ll get oil leaks or coolant ingress within a few rides.
• Wrong oil grade for journal coating - the KEL800 spec is 10W-40 SL+ JASO MA (different from the KEL895’s 5W-40 MA2 in the DS900X). Always use the correct grade for the actual engine.

Cross-reference

The KEL800 / LX284MW engine is not the same engine as the KEL895 / LX286MX in the DS900X. They share architecture (parallel twin, DOHC 8-valve, shim-over-bucket valve adjustment, similar crankcase design), but specifications differ:

Spec	KEL800 (DS800X Rally)	KEL895 (DS900X)
Displacement	798 cc	895 cc
Bore x Stroke	84 x 72 mm	86 x 77 mm
Compression	12:1	13.1:1
Cylinder offset	19 deg	15 deg
Spark plug	NGK LMAR8J-9E	NGK LMAR9J-9E
Spark plug torque	17 N.m	12 N.m
Intake valve clearance	0.15-0.20 mm	0.11-0.20 mm
Exhaust valve clearance	0.20-0.25 mm	0.26-0.35 mm
Engine oil grade	SL+ 10W-40 JASO MA	SL+ 5W-40 JASO MA2

Don’t substitute KEL895 specs for KEL800 work or vice versa. Different shim sizes, different torque values, different oil grades.

Sources

• Voge DS800X Rally Engine Service Manual (English) - pages 18-22 cover the valve clearance procedure and pages 12-13 cover the cylinder head torque tables. This guide is condensed and reorganised from those pages.
• Voge DS800X Rally Owner’s Manual - confirms the 24,000 km inspection interval.
• DS800X Rally torque specifications - full torque table for cross-reference.

If you’ve performed this procedure on your own DS800X Rally - particularly any field notes about access to the camshaft bracket, the timing alignment marks visibility, or shim sourcing - send us your notes and we’ll fold them into the guide.

Disclaimer: Valve clearance is engine-critical work. The values and procedure here are sourced from the official Voge engine service manual, but motorcycle work involves judgment that documentation alone cannot fully convey. If you are not confident in your ability to track timing alignment, manage shim selection, and torque-sequence camshaft brackets correctly, this is a job worth handing to a Voge dealer or experienced motorcycle technician.