Hi all, when re-assembling my cams after a rebuild i've come across a slight timing issue and need some clarification on the correct tecnique of timing them? I have read and read all over these forums but cannot find a solution to my problem which is:- after setting TDC using the alignment mark on the crank whilst the tensioner is slackened off, i can't for the life of me manage to get the timing marks on the inlet cam to stay at 3 o'clock, inline with the rim of the head as it's pictured in the manual. when i release the tensioner, it will pull the inlet cam slightly clockwise, retarding the timing? I have tried and tried several times but no matter which method i use, (cam chain on the exhaust cam first; chain on inlet cam first; set chain 1 tooth off so when tensioner is released it should tighten it into alignment; no matter which way i try i can't get it to stay at the correct timing so that i have 9-12-3 both cams and H "I" aligned perfectly? I am beginning to wonder if my chain is stretched and in need of a replacement? i hope not, as i priced up a flywheel puller from Yamaha today and they want over £120 for one! mental prices or what for a tool that'll be used maybe once a year! (Unless any of you guys know of an alternative one i could buy? i've had a look at car ones but they seem way too large?) anyway, back to my chain issue.... it does stand to reason that if the cams were aligned with a slackened chain, then surely when tension was applied to it, it would move in a clockwise direction against the tensioner subsequently setting the camshafts out of their correct timing, granted, only a little, but at high revs this could possibly upset the tuning? Am i being overly cautious here and just set them as close to alignment as possible or is there a problem with a slack chain, which i don't imagine would cause this as a new chain would be "pulled" offline just the same once tension was applied to it, surely? any ideas anyone? i'd greatly appreciate any tips on where i can get a suitable flywheel puller as i'd prefer to put a new chain/guides on while the engines stripped, even though they seem ok? coz it's a right B@#t@#d fitting the chain over the cogs on the cams, so it don't feel like it's overly stretched? I know about the 13=WR, 12=YZ links timing thing too, which i'll get around to once i am clear on this alignment issue?