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1988 Paso Valve Clearances

Posted: Fri Mar 19, 2021 1:10 am
by murphus
I've searched the forum for a possible answer to this question, but maybe I'm using the wrong key words as I've come up empty. The question isn't what are the specified clearances, it's what, in the experience of those, well, more experienced, is too tight? Just checked the valves, and all of the opening shim clearances were what I'd call a very loose .003in, almost .004in, which is spec. I used the unload method for checking the closing shims and they're all in spec at .001in, with one being tight, perhaps on the order of .0008in. The shim caps all spin easily when I unload the closing rocker arm. Are my opening clearances acceptable against a recommended .004in? Is the one slightly tight closing clearance cause for concern?

This is my first Ducati, so my operating knowledge is limited. At present, I don't even know if the engine runs. I'm working through it slowly with the aim of ensuring it actually runs before I commit substantial time/money. OK, I know it'll take plenty of time, but ...

Thanks in advance for any insight.

Re: 1988 Paso Valve Clearances

Posted: Fri Mar 19, 2021 10:35 am
by Derek
I'd be happy with those clearances. I'm not sure about the 750 engines but for the 904 at one time Ducati specified .003" inlet and .004" exh for openers, that was later changed to .004" and .005".
Even if you can't measure the gap, as long as all the closers can spin when you press down on the closing rocker arm they are good

Re: 1988 Paso Valve Clearances

Posted: Fri Mar 19, 2021 8:12 pm
by murphus
Thanks for the input. Based on experience with other engines the numbers I got didn't seem far enough off to warrant a readjust, but not really knowing these engines or how tolerant they are I was interested in experienced opinions. From what I've learned, a previous owner sent the heads out to a shop in Chicago. This likely would have been in the mid- to late-90s. He apparently didn't feel confident attempting adjustment and didn't have access to shims, so he removed the heads and sent them out. I have no idea what shop, but assuming it was someone familiar with belt-drive Ducs.