900SS Valve Adjustment Question

abmartin · Post by **abmartin** » Mon Aug 08, 2011 3:25 pm

I'm confused by information I've read on valve adjustment. Should the clearance for the closing shims be measured with the valve fully open or fully closed?

Bruce

gioto3 · Post by **gioto3** » Mon Aug 08, 2011 10:08 pm

fully closed
Ciao
Giovanni

Lumpy · Post by **Lumpy** » Tue Aug 09, 2011 12:04 am

Not sure how your going about checking your valve clearances but I made up a very simple tool that incorporates a dial indicator for the closing rocker. I found feeler gauges to be fiddly and not that accurate. The tool is basically a bit of flat bar, the dial fits onto a smal spigot and it srews down onto the rocker cover face with one of the screws that hold down the rocker cover. The dial bears on one side of the closing fork and a screw goes to the other to wind down finger tight and over come the hair spring. I have always been of the mind set that closing clearance is best set when the head is in place and torqued down. The tool and the small dial I have can be used to do all valves with engine in place and only seat and tank removed. The tool is very simple and I constructed it at home using only a pedistal drill and an oxy to weld the spigot for the dial to the flat bar. Been meaning to take some photo`s and post them on here next time I do the valves but with the advent of my Beemer 1150GS the poor old Duc`s are only getting sunny Sunday workouits and not racking up many k`s...........................I can hear the wolves baying already.................

gioto3 · Post by **gioto3** » Tue Aug 09, 2011 3:59 am

Very interesting, if you can post a picture of the tool itself, it should be great.
I just measure the closing shim clearance over the opening shim, depressing the closing spring and subtracting the fitting feeler gauge value from that with the spring not depressed, but I'm interested to check if this way of operating is really correct and your tool seems to suit for that.
Please don't leave the old Ducs in the garage, let they Conti still bark!!

abmartin · Post by **abmartin** » Tue Aug 09, 2011 4:56 pm

Photos of your set-up would be good. I'm doing it the low tech way, trying to insert a feeler gauge between the rocker and the shim while pressing down to overcome the spring. Two of mine seem good - the shims can be turned without any up and down movement of the rockers. The other two seem quite loose.

One of the opening rockers is also out so perhaps thats why the bike won't idle properly. Serves me right for neglecting the job. I'm changing all the collets first to see if that makes a difference.

Bruce

johnnyb · Post by **johnnyb** » Thu Aug 11, 2011 5:50 am

I find it very hard to measure the gap directly between the closing shim and the closing rocker. Its hard get a feeler gauge in and I find its not very accurate.

This is the way I measure/calculate the closing shim gap.
- ensure the valve is fully closed
- measure the opening shim gap
- make note of the gap (A)
- use a piece of wood to push open the closing rocker. you have to push it hard enough to over come the closing spring
- remeasure the opening shim gap
- make note of the gap - should be larger if there is some closing shim gap. If the is no change there is no gap so all is good/in spec. (B)
- subtract the 2 measurements and you will have the closing sim gap (B)-(A)=closing sim gap

Once you fit new closing shim to have close to 0 clearance (almost impossible to get 0 clearance) ensure you check there is no binding around the whole rocker i.e. not just one point on the cam. Better be safe than sorry.

Hope it makes sense.

abmartin · Post by **abmartin** » Thu Aug 11, 2011 5:05 pm

Makes sense to me. Thanks for this.

Bruce

in-two · Post by **in-two** » Mon Aug 15, 2011 8:44 am

Just a quick addition to this good advice, I was taught to do my valves by Giuliano, one of the works Ducati mechanics helping Steve Wynn/Mike Hailwood in the Isle of Man after clattering into the Castle Mona hotel carpark following a brisk lap. He didn't measure the gap, just whipped out the closing shim, chucked away the collets, measured the old shim, got out the next size up and some new collets, put it together and rotated the shim. If it was tight anywhere on the cam he whipped it out and rubbed it (the shim...) on a coarse carborundum stone until he could easily rotate the shim with fingers at any point on the cam. Took him about 10 mins! Naturally this only works if you have a drawer full of shims and havn't left it too long. Lumpy's approach seems the way to go if you have to order shims, but on an optimistic note, Giuliano's parting shot was "ees good when make de noise" I think meaning that loose is better than tight!
Cheers

gioto3 · Post by **gioto3** » Mon Aug 15, 2011 10:10 am

Hi in-two
thanks for sharing with us this remarkable experience.
Ciao
Giovanni