I got a wonderful valve compressor from Dave Plumb from this forum. I want to say a hearty 'thanks' because now I was able to get the valves out of my bike on Friday. So, examining the aftermath, it appears I'm going to have to cut a new seat for the exhaust valve by the looks of it. I've got a freind of a freind who is a retired machinist and has lots of experience with HD KR engines.
It appears the exhaust valve was open during its major period of dormant life and that it corroded. Fortnuately, the valve looks nice and sharp in the seat area after a wire brushing to remove the surface mung.
So my first question is, how much material is removable before it is necessary to change the spring on the valve? Are shims advisable to restore spring pressure?
Next issue... after removing the transmission and both footpeg brackets, I discovered that the footpeg roots were pushing on the crankcases. This can't be right. Should I remove some material from the footpeg castings to relieve this pressure from the crankcase? Seems to me the stress on the back of the lower crankcase can't be a good thing, yes?
Next, I've got loads of sludge in the oil tank. The paint on the whole bike is original REME BAOR, and I don't want to mess it up. So, how to clean the tank without distrubing the exterior paint? I'm thinking some mineral spirits, however, I don't want to take out the red lead lining. So, gasoline or kerosene? What say you folks?
Any and all advice and shared experience is appreciated.
thanks,
Kevin
hi kevin,that valve seat dosnt look too bad,it will prolly clean up with a few thou off. a local engine re manufacturer should be able to re cut your seats,and save the expense of buying the kit.its important to not remove too much material
so the valve doesn't become pocketed ie below the surface of the barrel.while its down ,an ideal chance to check the guides are ok.these will need to be within tolerance to ensure a good job
re seating.no need i think to shim there is enough spring in there to take up a few thou.
oil tank,kero and a few small nuts/washers,close the lid ,put fingers over the holes and give it a good shake (outside)
then a jet wash or hot water should shift it.hope this helps
cheers rick
email (option): richardholt@rocketmail.com
Hi Kevin...Jeffs advice is good on checking the valve stem to guide clearance and valve and stem condition before doing the seat(s).
Correct stem to guide clearance is .003"-.005" on both valves. I tend to go for the lower figure when fitting new guides. Inlet and exhaust guides are different lengths and the exhaust guide is counterbored at the upper end. The guides need to be fitted into the barrel the correct amount..this is measured from the top face of the barrel to the top of the guide when fitting. The measurements are...Inlet..1 1/8", Exhaust..15/16". Usually, the guides will need to be resized to the correct clearance after fitting to the barrel.
Valve springs are 2" plus or minus 1/64" when new..if they measure up at less than this and you don't know when they were last replaced, new ones would be a good idea.
On the exhaust valve there is a flat 'land' or 'lip' between the top of the valve head and the 'seat' of the valve. If the valve has to have the 'seat' ground to clean it up, or it has been previously ground, this 'lip' should not be less than .040" wide after completion of the work. If it is less than that figure the valve should be replaced.
The 'lip' provides sufficient material at this point for the valve to withstand the exhaust gas temperatures. If too thin exhaust valve failure (burning) is likely.
The seat in the barrel doesn't look too bad but if a heavy cut is required to clean it up the valve can become 'pocketed' or sat too low into the barrel. This effectively reduces valve lift as the valve opening is shrouded by the barrel casting, reducing its ability to flow the exhaust gasses.. If when the valve is dropped into the guide the head of a good valve (note my comments about the valve 'lip' here) is flush with, or below, the top surface of the barrel fitting of a hardened valve seat would then be recommended to return the valve to the correct position.
No shimming of valve springs etc. is necessary. However, another effect of dropping the exhaust valve too far is that you may have trouble (more than usual that is!) setting the valve lifter up..
Contact between the footrest support tube and the crankcase is quite common...many crankcases bear the mark that this contact produces. If there is sufficient material on the support tube, and there usually is, you can remove some to provide clearance...You should save that sludge from the oil tank in an old jam jar..it's original stuff..one day they'll be selling it on e bay...'Rare opportunity to buy some genuine oil tank sludge'
.....Ian
email (option): ian@wright52.plus.com
Yes, that's most important! If that spacer 66-4903 is too much compressed (or absent...) the outer primary cover will deform and the bowler hat of the clutch will touch and damage the outer cover; DAMHIK...
email (option): viaconsu # planet dot nl