When i got mine it wouldn't rev past 6000 rpm, after much head scratching and advice dived into the tank and there was a shit load of crap blocking the bottom filter, cleaned it up and new fuel filter ( stamped 2001 ) it had not been changed since it's birth at bologna!!!! A very sound bit of advice, change the fuel filter! I have got an oberon slave on mine and an Electraeon fast throttle cam, http://www.electraeon.com/throttlecam.html makes a big difference on the wrist.
Reading the current thread about a forum shim exchange has got me started thinking on this ..... again . @Billywiztheelder wrote something that makes a lot of sense ..... to me , anyway ... A ball-bearing should make a very good substitute for the various problematic " measuring tools " .... or not ? 7mm / 8mm BB .... or maybe a smaller diameter ? I don't have any shims knocking around so I can't investigate . Any thoughts ?
I think that might not be as easy as you think, I'll and try and draw a sketch to show why, but as long as you have a known sized shim as a start it could be possible. The ball will need to be larger than the valve stem diameter but smaller than the well in the shim. The point of contact between the shim and the ball will depend on the diameter of the ball and it will not simply be a case of subtracting the diameter of the ball from the overall measurement. If you have a known sized shim and subtract its size from the overall measurement you will get the figure you need to subtract from each measurement using that ball but it won't be a simple round figure.
No is the short answer which I’m sure Derek will explain more fully. You need some thing with a flat base and top and for those two planes to be parallel.
Yes , I get what you're saying . It's been rattling around my head since I posted , and looking again at your drawing , it's that radius for the collet that seems to be the snag ( at least for the ebay tools that have disappointed people ) . @ben155 posted a pic of a socket he uses and the radius on the tip looks useful. Just out of curiosity , I've dug out the two smallest sockets that I can find ... 8BA and 10BA and measured the OD near the tip , which is 6.55mm and 6.12mm I'm fascinated now .... but not enough to yank a shim out of the engine ....
I have just looked again at Derek’s drawing of the closing shim and whilst the measurement we are all striving to measure is the distance between the two arrow heads my thoughts shifted to the overall shim height. After all the arrow heads gap is what varies. Therefore I would expect the the top of the shim down to the bottom of the recess to be a standard dimension, common to all closing shims (wouldn’t this make life simple). If I have any loose closers I will dig them out, measure and report back.
Off the top of my head I don't think the height is standard but has 2 or maybe 3 sizes depending on the thickness of the shim. Apart from that, if it was as simple as measuring the overall height would Ducati not mention it in their workshop manuals and there would be no need for them to make special tools.
Yes it would certainly make sense but I was thinking of how these things were made. Assuming that they were held somehow by the top whilst the bottom was ground to the required dim having regard to the relationship with the bottom of the recess.
The workshop manual for my 01 900SS mentions 2 ranges of opener shims (2 to 4.10mm in steps of 0.05mm and 4.20 to 4.70mm in steps of 0.10mm) but only one for closing shims (5 to 9.6mm steps not stated). This was in clarification of Derek’s thoughts on different shim ranges being available So I grabbed my box of bits in which there were 2 closing shims and measured the overall height and the shim thickness of each.The difference being what I thought might have been a standard dimension which would make our lives so much easier. Apologies for all of the following measurements being in thousandths of an inch but I think the concept will be easier to understand as they are, at most, to one decimal place (1 thou = 0.0254mm, you see what I mean?). The height was easy to measure and the range from a number of readings on each shim was within 0.4 thou on one and 0.2 thou on the other. The shim dimension takes some care to measure and if you look into the recess you can make out a very narrow band at the inner edge of the ledge on which the half ring collets are located. It is from this band to the bottom of the shim that needs to be measured. Because it’s so fiddly erroneous readings are easily taken, but they will always be on the high side. So I took 10 readings on each shim and settled for the median reading. The range of the two sets of readings was 1.3 and 2.1 thou. So bottom line, the 2 shims varied by 4 thou for the depth of the half ring collet recess. You might think that this is hardly worth worrying about. That is until you look at the acceptable range of clearances for both shims on both valves. Your minimum and maximum on all shims, all valves differ by 1 thou which I find incredible. I mentioned that it was fiddly measuring the closing shim with a micrometer and found that the best way to go about this is to slide the collet recess onto the anvil (fixed point) and as you get to the bottom of the recess you can feel it negotiate the curve at the bottom where the collet sits and ends up on that narrow inner band You can then wind the spindle in against the bottom of the shim. Finally, finally when I picked up my micrometer I zeroed it as usual. Because of the fiddly method of taking so many shim dimensions the heat from my hands had affected the absolute measurement of the instrument at zero by 0 827 thou, very nearly the allowable valve clearance margin.
I think the ball bearing idea is interesting. As Derek says the diameter would need to be between hole sizes and recess size. I would say for 8mm valve 9/9.5 having measured a shim. Calculation could be do with a bit of trig, but you would need an accurate measurement on the shim I.D. A most of mine were coming out at 7.99 but its a cheap digital vernier. Also measuring the overall height you have the ball on one side but a hole on the other. Putting something else there introduces another variable. I have measured my shims every which way and got a different result pretty much each time. I dont think you will ever measure a shim, order it, and it be right. I think you need to measure the best you can and try a few either side. I think this was demonstrated in "Brad The Bike Boy" video, he measured but had to try a few. This is were the DOC shim exchange could come in useful, If they can send a selection out, you just might have a chance. Just my 2ps worth I also tried measuring with an external mic like above photo, and with a depth mic from non recess end. Cheers Gaz
