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Hello to all. Just came over to the dark side of metrics after doing Brit bike restorations with a 1970 Jupiter 450 (springer head). The valve set up is so very different from the Triumphs and Nortons I know, soI need advice. There is zero clearance on both rockers.... so do I understand correctly that there is no adjustment other than to get shorter caps or file them down? I read in an old postthat the repair manuals settings of .003 and .005 are incorrect. Also, that the way to adjust is to pull the rocker pivot shaft. I found that I can lever the spring down with a screwdriver and remove the cap. Questions
1. Am I misunderstanding something here?
2. What is the correct valve clearance?
3. What is the acceptable cylinder compression range?
Thanks for sharing your knowledge.

Hi Eddie and welcome to the Forum.

1. Correct. Valve clearance is done by changing the shims. You CAN'T file them - that is no where near accurate enuf . You can reduce them using a carpenter's oil stone, but it takes time. Or, if you're good, on a bench grinder. Or simpy replace them. Once set, the clearances don't go out unless something else is going wrong.

2. Clearances are beween 0.05 and 0.10mm, both valves. This is from the owner's handbook, btw. Naturally, you can trend towards the higher side on the exhaust.

3. As you've discovered, you can release the shims by pressing down on the springs with a screwdriver. Just be careful: if the tip of the screwdriver isn't fully in or if it slips, you can chip the head .

4. Sorry, I can't now recall what compression reading I get on my 450 SCR. If I find it in my records, I'll post it on here.

But an absolute value doesn't tell you much, really. What you should be interested in is any variation either over time - so not your case. Or if, for example, you get a different reading when you put some oil down the bore ...

HTH

Craig

Craig: Thanks for the reply. Appreciate the help. Eddie