I'm currently (5 hours into the job so far) in the process of doing my valve clearances (most fun job i've done in ages) and the noticed that the Haynes manual says that you must replace both gaskets. Is this a must?

Its looking like i've got at least 10 shims to replace as it is so 2 more items to the repair bill won't hurt i suppose but i'd rather know if i have to before buying them.

Are you talking about the rubber gaskets? In short, that answer is no, you don't have to replace them. Check them thuroughly though as if they are starting to crack or perish then it's best to replace it now rather than in 6/12 months time.

With regards to the shims, will none of the 10 needing replaced not fit in somewhere else? ie if you need a 1.25 shim from one place and you've got a 1.26 lying spare from somewhere else, just used that one. Remember though, it's better to have a bigger clearance than a smaller one.

Yes i did mean the rubber gaskets. Thanks for the info on that.

With regards to the shims i'll go through the calculations again this evening as i was getting tired last night but initial thoughts were that nothing was close enough to get me in the range needed. I'll pop my results on here later and see what you all think also.

I'm glad i'm doing it though as some of the measurements were quite shocking whilst others weren't too bad.

The bike hasn't been running too badly but i've always thought she's been running a little on the rich side as the engine would never get really warm even in the summer. Upon taking the carbs apart it would seem that i have 122s in the front and 124s in the back. The bike has got a half system and a normal airbox and filter so i'm going to put 118s and 120s in and see what its like.

I've also added Rick O's fork upgrade kit and got a new chain and sprockets to go on.

I'm hoping the bike will be noticably better after doing all this work to it!