Valve Cover Gasket and Gauge Kit Fits Stihl BR800 BR800X

Valve cover gasket, valve clearance setting gauge and copper sealing ring that fit the Stihl BR800, BR800X and BR800 C-E backpack blowers. The gasket replaces 4283-029-0500, the gauge 4180-893-6400 and the 5 x 9 x 1mm sealing ring 9636-815-0270; together they make up the valve clearance setting kit 4283-007-1001. All three blowers use the same 79.9cc powerhead, 50mm bore by 40.7mm stroke, and the same valve cover. WHY A 'TWO-STROKE' BLOWER HAS VALVES. The engine is a true four-stroke with intake and exhaust valves, rocker arms and a camshaft, which is why there is a valve cover gasket and a valve clearance to set. It has no oil sump: it is lubricated by oil mixed into the fuel at 50:1, so it can run at any angle, and running it on straight gasoline will destroy it. WHEN TO ADJUST THE VALVES. Check the valve clearance if power is low or the starter rope becomes very hard to pull; clearance opening up with wear removes the decompression that normally makes the engine easy to pull over. A check around 135 hours is suggested. THE SPECIFICATION is 0.10mm, 0.004 inch, the same for intake and exhaust, and the gauge is cut to that figure. Adjust only with the engine COLD, using the gauge as a go/no-go check. Follow the service manual for the flywheel alignment: the mark lines up with the short arm of the ignition module and the rocker arms should not move.

• WHAT IS IN THE KIT - Valve cover gasket, 4283-029-0500. Valve clearance setting gauge, 4180-893-6400. Copper sealing ring, 5 by 9 by 1mm, 9636-815-0270. Together these replace the valve clearance setting kit 4283-007-1001.
• FITS STIHL BR800, BR800X AND BR800 C-E - All three share the same 79.9cc powerhead, the same valve train and the same valve cover. The differences are the starter and the controls, not the engine.
• YES, YOUR 'TWO-STROKE' HAS VALVES - This surprises people and it is why the part exists. The engine is a real four-stroke with intake and exhaust valves, rocker arms and a camshaft. What makes it behave like a two-stroke is lubrication: instead of an oil sump it runs on 50:1 premix, carried through the engine with the fuel.
• THE SYMPTOM THAT MEANS YOUR VALVES NEED ADJUSTING - The starter rope suddenly goes hard to pull. That is the one people misread, because it feels like a starter or compression fault. As clearance opens up with wear the effective valve timing changes and you lose the decompression that normally makes the engine easy to pull. Low power after break-in is the other sign.
• THE CLEARANCE IS 0.10mm - FOUR THOUSANDTHS OF AN INCH - The same on intake and exhaust, and the gauge in this kit is cut for it. Check and adjust only with the engine COLD. The gauge is used as a go/no-go against the minimum clearance rather than to set a range. Never run it on straight gasoline: the fuel mix is the only lubrication the engine gets.