Tighten and set the timing right
Let's start by replacing and torqueing down the head nuts. Be sure to keep the rags stuffed in the holes so you won't drop them into the engine case. Install them and tighten them all to 20 Nm to start. Be sure you tighten them in the proper order. Start with the 4 innermost ones than do the four outers in criss-cross fashion. After they are tight, then tighten again to 30 Nm. Finally, tighten them all an additional 90º in the same sequence.
Next you need to line up the timing marks so you can install the cams and gears. Look in the front of the rotor area, under the right hand engine cover (it is a wet cover, I thought it was dry and learned the hard way, oil will go everywhere once you pull it so be sure you have drained all your oil)
This next part is very important, as it's NOT in my manual, at least not the ones that were printed before 2005, The correct pictures and procedures are in the newest manuals with the Thruxtons in them.
You MUST line up the 2 lines correctly. There were 2 of them in the Speedmaster, the manual only lists one! you must set the little line marked "L" at the front of the rotor and in alignment with the line that is the case split line. At the same time the line marked "R" should be 90º behind it and straight up as shown in the picture. This is critical that you get this exact, NOT CLOSE, EXACT. Failure to do so can damage the motor seriously. Verify that the LEFT cylinder (also the #1 cylinder)is at Top Dead Center (TDC) by shining a flashlight into the left cylinder sparkplug hole. It should be right up to the hole really close. Pat yourself on the back.
When I did mine I did not have the correct manual pages and mistakenly lined up the "R" line to the front. This caused the valves and gears to be 90º lagging. I had to totally disassemble the entire thing again in order to correct this. DO NOT do it wrong!! Dumbass mistake #2
Be sure you take ALL the slack out of the FRONT (exhaust side)of the cam chain so that when you position it correctly the TOP mark is where it should be. Do not worry about a little slack in the rear, the cam chain tensioner will take care of this later, just be sure the FRONT is tight and there is no slack there at all. Now you can re-install the cam drive gear. Be sure the cam chain is still secure. Line up the marking on the top of the gear to match the fact that the left cylinder is at TDC. Slip the cam gear thrust retainer back into position taking extreme care to use the magnet tool to hold the washers so they do not fall into the motor.
Front of cam gear. Notice the TOP marking is aligned with the hole and is on the top and there is NO slack in the front of the camchain! Be sure it is EXACTLY like this or take it apart and do it again until it is.
Rear of cam gear.
Re-install the drive gear shaft retaining bolt and tighten to 10Nm. This comes in/out very hard and my need a slight persuasion with the LFH and a block of soft wood. Do not pound too hard as you may damage the threads, just enough to get it back into position.
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