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How do I set the spark timing on a 99 Honda VTR 1000

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First remove the valve cover and spark plugs and check your cam timing to confirm it's out before pulling anything else apart. Remove the ignition rotor cover so you can turn the engine over by hand. Turn the crankshaft clockwise(so that it is pulling down on the front run of the camchain) and you will feel through the spark plug hole the #1 piston moving up and down the cylinder. When the piston is at TDC you should have the timing mark on the ignition rotor lined up with the mark on the engine. The #1 cam lobes should be either pointing toward or away from each other depending on whether the engine is at TDC on the compression or the exhaust stroke. If it's on the exhaust stroke then the intake valve is about to open so turn the crank another 360 degrees. The valves should be closed and not about to be opened by the cam lobes as the engine turns over. You should now see the timing marks on the cam sprockets or on the end of the cam shafts. They should be aligned parallel with the top surface of the cylinder head.

If the cams are not correctly timed then you will need to remove the tensioner to get enough slack to adjust the chain. Do not move the crankshaft. I don't recall if the 900RR has sufficient room to allow the chain to skip a tooth so you may have to remove the sprocket bolts and pull the sprocket off to move the chain. Be _extremely_ careful not to drop the bolts or anything else down the camchain tunnel. I strongly recommend placing rags over the top of the engine and you must Loktite the sprocket bolts back in place.

If there is sufficient room to lift the chain off the sprocket then you can just turn the camshaft to where it needs to be and lay the chain over the sprocket again. Cams often have a hole through them or a cast hex so you can turn them but if yours don't then you can use a square-edged bar laid between the sprocket bolts. Be sure to keep tension on the front run of the chain and lay it over the exhaust sprocket. Do the same with the intake cam keeping tension on the chain back to the exhaust sprocket. When you have the cams in position check the crank has not moved. Then install the tensioner (with the spring held back). Hold the chain in place on the intake sprocket and release the tensioner spring. Then turn the engine over a few times by hand and check the timing is still correct.

It's probably worthwhile checking the valve clearances are still correct while you're in there again before putting the cover back on.


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