Wilsons Sandbox

> In a previous thread, some have suggested grinding the valve stems > for > proper/additional clearance. I'm curious if anyone has actually > done > this. The shop manual specifically states not to do it, but in > practice does it really happen? If not, how would you correct the > problem without replacing the entire cylinder head? > > From the Kawasaki repair manual: > "Do not grind the valve stem end to repair it or to permit > additional > valve clearance. If the valve end is ground, the lifter may contact > > the spring retainer and/or split keepers during operation allowing > the > keepers to loosen. Consequently, the valve may drop into the engine > > causing serious damage."

--- In DSN_KLR650@yahoogroups.com, Jeff Saline wrote: > > On Mon, 18 Aug 2008 17:32:22 -0000 "traderpro2003" > writes: > > In a previous thread, some have suggested grinding the valve stems > > for > > proper/additional clearance. I'm curious if anyone has actually > > done > > this. The shop manual specifically states not to do it, but in > > practice does it really happen? If not, how would you correct the > > problem without replacing the entire cylinder head? > > > > From the Kawasaki repair manual: > > "Do not grind the valve stem end to repair it or to permit > > additional > > valve clearance. If the valve end is ground, the lifter may contact > > > > the spring retainer and/or split keepers during operation allowing > > the > > keepers to loosen. Consequently, the valve may drop into the engine > > > > causing serious damage." > <><><><><><><><><><><> > <><><><><><><><><><><> > > Brian, > > Not all valves can safely be ground. Some contain sodium or are > aluminized. Some are also so worn that even if they are of a type that > can be ground they would be out of specs after grinding. > > There are a lot contact areas that must be considered in a valve system. > Contact area of the valve face is important for heat transfer. Changing > that changes how deep a valve sits in a head. On the other end the valve > stem will move out the deeper the valve is in the head. That removes > clearance between the end of the stem and the actuating mechanism. > Having a stem sit too high in the head will also change the spring height > as the keeper moves with the stem. This is going the opposite of having > tight valves which move the valve face too far from the valve seat > reducing heat transfer while extending the time the valve is open > (duration). > > Some valves can safely have the face ground or the end of the stem ground > to adjust to proper clearances. Shims can be placed under valve springs > to adjust spring height. But not on all applications. Valve seats in > the head can also be ground but only a small amount. Once they have > reached a limit they must be replaced either by replacing the seat if > possible or replacing the head. > > It looks like the KLR valves cannot safely be ground according to your > reference. > > Valve seats can usually be replaced if the machinist knows what they are > doing. New seats can return valve depth to the correct specifications > which will move the valve further out of the head. That in turn will > lower the stem height on the other side of the head again allowing proper > clearance (which is adjusted by shims in the KLR engine). > > So if your valve seats are too deep from excessive grinding they may need > to be replaced. But if the seat isn't replaced correctly it can work > loose and if a seat comes loose in operation it can allow the valve to > stick open contacting the piston (a bad thing) or break into pieces > damaging the piston, cylinder wall or head. Or maybe nothing worse > happens than the engine quits running and you have to get it replaced > again. Replacement seats must also be of the correct material for the > application. BMW Airheads in 1981-1984 had an incorrect material used > which caused premature valve failure. Once the correct valve seats are > installed the problem goes away. Some folks refuse to replace the valve > seats and instead end up replacing valves every 50,000 or so miles. > > This just barely touches the surface of valve info. If I had a head in > the shape that your's seems to be in I'd be calling Cary at Schnitz and > asking him if he could help me. > > Best, > > Jeff Saline > ABC # 4412 South Dakota Airmarshal > Airheads Beemer Club www.airheads.org > The Beautiful Black Hills of South Dakota > 75 R90/6, 03 KLR650, 79 R100RT > ____________________________________________________________ > Need cash? Click to get a cash advance. > http://thirdpartyoffers.juno.com/TGL2141/fc/Ioyw6i3mKetHZVlDUDiOpHlpc5 sXxKzSz9wJobUJFWyYZ5L9oD9WoU/ >

> > I made a mistake in my previous message. I am wondering if a 92 > KLR650 fuel tank will fit on the 88 KLR 650. > > Any idea? > > Kawasaki is giving me no help on this one. >