Tappet gaps Hi, could you tell me please what the inlet and outlet gaps are for the Tappets, 250 AN W reg. Many thanks Michelle

They should be hydraulic tappets and are self adjusting. If you have a noise check the wear of the rocker bushes and rocker shaft.

Tappets......... perhaps is what your friend said. The tappets are part of the engine inlet and exhaust valve set up. Most tappets are self adjusting in modern motors, (Hydraulic).
The old fashioned tappets are manually adjusted during regular car servicing. This happens at set intervals, for instance every 20,000 miles.
Inlet valves allow air and fuel into the engine and exhaust valves let the burnt fuel and air out.
Tappets are fitted between the inlet and exhaust valves, they ensure that the valves open on time and more importantly close properly. If the tappet happened to be badly adjusted and did not let the valve close properly then damage to the valve and cylinder head can happen by burning.
If you have a significant power loss I would be surprised to find that the just tappets/valves were to blame.

12th inlet 14 exhaust for the valve clearances ,adjust by the rule of nine that is number one down adjust number 8 -----number 2 down adjust number 7 ---and so so so every adjustment adds up to 9 ,simple when you know how isnt it

I am not 100% but I think the answer is both right!!

They are hydraulic but can be shimmed

Option 1: Go to mechanic

Option 2: Adjust the tappets. If you have never adjusted tappets or worked with engines before it is better to have someone experienced with you. The following is the procedure I use.

1: Carefully remove side panels.
2: Close fuel tap and disconnect pipe.
3: Carefully remove fuel tank. (undo the bolt under the seat and slide the tank 2 inches back, then lift it upwards)
4: Undo the bolts of the cylinder head cover (3 bolts with 12mm head, one of them also holds a small bracket for the throttle cable or ignition wire, I can't remember).
5: Remove the cylinder head cover. If you find this difficult put the bike in 5th gear and rotate the engine (by rotating the rear wheel) to the "inlet valve open" position so that the cover clears the "inlet valve rocker". Be careful that you do not damage the top cover gasket (made of rubber) or you will have an oil leak and no lubrication to the rockers.
6: Rotate the engine to a position with both valves closed, as close as possible to "top dead centre of compression/power strokes". There is a notch on the flywheel indicating top dead centre - you see this by opening the cap on the top of the flywheel cover on the left side of the bike. (do not stay at "top dead centre of exhaust/intake strokes")
7: Check the free play of the rockers on the valves. The service manual recommends a clearance between the valve and the rocker of 0.08mm with the engine cold (left to cool overnight). Maximum acceptable is 0.10mm and minimum is 0.06mm. The gap is checked using a feeler gauge (you know that you have a gap of 0.08mm by sliding a feeler that is 0.08mm thick and there is just a little friction slowing you down - if the feeler is hard to pull the gap is less than 0.08 and if the feeler passes with nothing resisting it then the gap is larger than 0.08mm).
8: If the tappets are knocking then the gap is too large. Undo the locknut on the tappet adjuster (10mm nut at the end of the rocker) just enough to let you turn the tappet adjuster. Then rotate the tappet adjuster until you get the right gap and tighten the locknut. Be sure to hold the tappet adjuster with pliers or something else while tightening the locknut so that the adjuster does not rotate.
9: Check and re-check that the gap between the adjuster and the valve is as specified. Incorrectly adjusted tappets are very bad for the engine, especially "tight" tappets with no gap between adjuster screw and valve. The first time you adjust tappets you might have to repeat from step 7 several times until you get used to it.
10: Assemble everything in the reverse order of disassembly. You might have to rotate the engine to "intake valve open" position again to place the cylinder head cover easily. During assembly be careful the the rubber gasket of the cover is not damaged or out of place. There is an oil path from the head to a nozzle above the rockers and the gasket must seal this well.
10: Once you assemble everything start the engine and once it is hot enjoy a more silent bike. It is normal on these engines to have some tappet noise when cold, but if the tappets are adjusted right they are nearly silent when hot.

Always refer to an expert when you are not sure. Maybe the first time it is safer to watch your trusted mechanic do this work.

I have a Robin but they all are pretty much the same for plug gap and tappets. I worked in a lawnmower small engine repair shop for many years in San Diego
I set them all the same and never had one return. I just did mine a couple of months ago and hand lapped the intake and exhaust valve seats. Starts first time everytime like the 7.5 year old unit is new!!!

Plug gap 0.19

Tappets

Intake .005 cold
Exhaust .006 cold.

Hi,
The method of adjusting the tappets is the same on most engines that don't have hydraulic tappets.
The gap between rocker arm pad and the top of the valve stem is important for several reasons - to allow for expansion of the metal, to ensure that the valve is fully closed when needed, and to ensure the smooth running/timing of the engine.


The rocker cover gasket or oil filler cap leak eventually over a period of time and the top of the engine gets in a right mess, like the one shown here.
Remove the filler (series have a 7/16" bolt in the side of the cover to retain the filler)
The heater hoses are held by one of the three acorn nuts that hold the rocker cover on. Remove the center nut, and then slacken the 10mm pinch bolt enough for the pipe support to be removed.
Remove the other two acorn nuts and alloy washers, then the rocker cover will lift away.
Each tappet should have a locknut and slotted thread - you will need a 13mm ring spanner and blade screwdriver.
Starting at the front of the engine - turn the crankshaft by way of the crank bolt until No2 valve is open. The camshaft lobe for No1 is now out of the way and the tappet for it can be adjusted. Undo the locknut a couple of turns - if the threaded part turns as well, then keep it still with a screwdriver.
Insert the right thickness blade in the gap between the rocker pad and top of the valve stem and turn the tappet thread until the blade is slightly pinched. Keep the screwdriver dead still and tighten the locknut.
You may find that the tappet gap will close too much when you tighten the locknut. If that happens, then re-set the gap, allowing for this. Work through all 8-tappets, making sure that you set the correct gap for the valve - inlet or exhaust. Once done - clean around the top of the head, the gasket faces, and the rocker cover inside and out. Sticky gaskets are very handy.
Refit the cover, use new alloy washers on the three studs, and re-attach the heater hose clamp.
For pictures you can refer to: http://forums.lr4x4.com/index.php?showtopic=8023

Thank You for contacting Fixya.com

adjustment of valve reasonably simple, remove tappet covers, remove small bung from mag cover top and rotate engine until you are able to see a capital T on the flywheel, providing whist you rotated engine it was on the correct stroke the inlet valve should have just closed when you saw the T. this is the correct stroke. loosen tappets lock nuts, adjust the tappets so you can just move it with your fingers, if your want to get technical the clearances between tappet and valve should be about .05mm

for single cylinder dirt bikes that age go with 4 thou inlet and 6 thou exhuast