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valve clearance issue
Posted: Wed Nov 19, 2008 1:06 pm
by martym
Just measured the valve clearances prior to adjustment, and found that five are down to 1.5 thou seven are 2 thou eleven are 3 thou and 1 is 4 thou,I expected them to increase not decrease is this normal or have I got another problem. As far as I can tell the bike has only done 14000 miles and the cams don't seam to be worn, Could any body shed some light on this please
Posted: Wed Nov 19, 2008 1:12 pm
by alimey4u2
They "decrease" ( get tighter) as the valve impacts the seat on every closure.... Good question...
Posted: Wed Nov 19, 2008 1:56 pm
by EMS
alimey4u2 wrote:They "decrease" ( get tighter) as the valve impacts the seat on every closure.... Good question...
Larry has it down pat! The clearance gets less over time because of valve working against the seat. It is wise to set them on the larger end of tolerance when you adjust.
Posted: Wed Nov 19, 2008 2:07 pm
by Terry
Hmmm, its been about 20,000 miles since my last valve check...suppose I should......
Posted: Wed Nov 19, 2008 2:15 pm
by alimey4u2
EMS wrote:Larry has it down pat!
I'm bound to get lucky sooner or later Mike...
Posted: Wed Nov 19, 2008 6:05 pm
by martym
Thank for your replys, Would you recomend the full 0.005 inch to give a longer service interval as it's not a job you'd want to do too often?
Posted: Wed Nov 19, 2008 6:13 pm
by alimey4u2
Lots of differing theories on this, some well founded some...well maybe not so. I would go close to max limit on exhaust & in spec. on inlets. Not such a bad job really, just make sure you document it well so next time you have the right shims at the ready....
OH ! Never turn the engine with shims out, you'll shave the edges off the cam lobes...
Posted: Wed Nov 19, 2008 6:23 pm
by martym
Good tip thanks I'll have a go tomorow
Posted: Wed Nov 19, 2008 7:43 pm
by SteveG
Can I add my 2 cents (.01334 pound) worth?
When was the last valve adjustment done? With 14,000 miles, it was probably done once at the initial break in inspection (if ever even done).
Make sure to keep a record of what shims you end up putting in to get to the goal of .004-.005. Knowing what shims are currently being used will make the next adjustment much, much easier. You know you will be checking them again within the next couple of thousand miles just because you want to know what the clearances went to now
Do you have the chart to figure what new shims you will need?
I have a cheat sheet (excel spreadsheet) to figure out what shims will be needed if you want it.
Steve
Posted: Thu Nov 20, 2008 3:28 am
by alimey4u2
Excellent 0.01334 pounds worth Steve....