oversize-valves-11-048-91-2463-691

Service-InformationM otorcycle BMW NA Service Department Group: 11 Engine June 1991 11 048 91 (2463) For USA Only Oversize Valves for BMWR8 0 and RlOOE ngines from 1985 > Information: If the valve guides are worn out, the possibility exists of reaming out the existing valve guide bores and fitting oversize valves with a stem diameter of 8.3 mm. For the 800cc and 1000cc boxer engines, the following valves with a stem diameter of 8.3 mm are available: Part No. 11 34 1 338 660 11 34 1 338 661 11 34 1 338 665 Valve Type & Size Inlet Exhaust Exhaust 42 mm 40 mm 38 mm Seat Angle 45 . ._./ ho 45 The following tool set must be used to fit the oversize valves: Part No. 88 88 6 004 600 – consists of the following: – 88 88 6 004 601 – Rough Cut Reamer Hunger 8.2 H7 – 88 88 6 004 602 – Finish Reamer Hunger 8. 3 H7 – 88 88 6 004 603 – Guide Block Item #1 ‘ ,-r..-_-_. -~ – see other side – Please initial and route to the following before filing Service I Parts j Sales I Warranty I Technicians Repair Procedure: – Secure the cylinder head with the combustion chamber upright in a vise with protective jaw coverings. The valve guide to be reamed should be positioned vertically. – Insert the top (tap wrench end) of the reamer into the guide block, then insert reamer into valve guide (reamer cut diameter is larger than guide block pilot hole, which is ground to match reamer shaft size). – Place the guide block, item #1, on the valve seat. This block guides the reamer. When reaming, press the guide block into the valve seat with two fingers. – Turn reamer with a tap wrench .. never use an electric drill! Powering the reamer with a drill will dull the reamer and create a larger hole than intended. Note: Start the reaming operation using reamer #004 601 (8.2 mm), item #2. Lubricate with thread-cutting oil only. – Turn reamer clockwise, never counterclockwise. – Clean reamer at frequent intervals, turning in cutting direction only. – When reaming is complete, remove the reamer downwards through the guide. Complete the reaming operation using the finish reamer – part #004 602 (8.3 mm). – After the valve guide has been finish-reamed, resurface the valve seat. Tool Note: 8.3 mm solid pilots for Neway valve seat cutting equipment can be purchased from The Carlson Companyb y calling 1-800-222-6199. Very truly yours, BMWof North America, Inc. Frank Stevens Richard Dampf National Service Manager National Technical M~nager FS:jel/41.1 ( (