Bikesure_adrianflux

Valve Shims

  • Thread starter Thread starter analogue_rogue
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If you're familiar with the use of a micrometer it is possible to measure them without the adaptor, but it requires a good engineering "feel" or else its easy to get it wrong. The problem is that you need to measure from the broad flat face that the closing rocker bears on, to the shoulder in the bore (that holds the wire collets). BUT I believe this shoulder is NOT FLAT, but radiused to match the cross section of the wire collets. This makes it easy to get a high reading. The true reading is between the innermost corners of the face and the shoulder, where they meet with the bore of the shim. In practice this boils down to being the smallest reading you can get before the anvils of the micrometer slip off into the bore. .....Anyway, the adaptor eliminates this problem ...it fits against the radiused shoulder sort of like a spacer, and you measure across both, then subtract the length of the spacer. Brancato Engineering OX44 7RW, 01865 891203 make one (they call it a button) £23.50 (see Classic Bike apr '08). I've not tried one. Any such device has to be trusted to be accurate, until you've bought a shim of known thickness to check it against, that is. Some shims have thickness marked on them anyway. And a word of caution.... I've seen respected Ducati mechanics measure shims wrongly using Ducati workshop tools. Set the closers even slightly too tight and it all goes crunch, so with belts off and opening rocker disengaged, check that the cam rotates by hand with no tight spot. AND FINALLY, the wire collets bed in to something like the difference between one shim size and the next, so fitting new ones can restore valve clearances on their own (for a while)....or just confuse the issue. They also bed in one way, so if you put the old ones back in upside down (cos they fit either way) they act like new ones and change the clearances by maybe one shim size. And you need a lens to spot the wear marks, and then its not easy. My advice would be ..measure up, take notes, leave collets in situ, work it all out but don't change anything unless it needs at least two shim sizes, and maybe then just go one size with new collets. Or even try just new collets first....they only cost pence but shims are pricier. Check the videos...the guy from california..excellent. And do use the trick method of measuring the closing clearances via the opening shims...much easier, more accurate and doesn't chew your feeler gauges. Btw, those red kites round your way are stunning, aren't they?
 
If you're familiar with the use of a micrometer it is possible to measure them without the adaptor, but it requires a good engineering "feel" or else its easy to get it wrong. The problem is that you need to measure from the broad flat face that the closing rocker bears on, to the shoulder in the bore (that holds the wire collets). BUT I believe this shoulder is NOT FLAT, but radiused to match the cross section of the wire collets. This makes it easy to get a high reading. The true reading is between the innermost corners of the face and the shoulder, where they meet with the bore of the shim. In practice this boils down to being the smallest reading you can get before the anvils of the micrometer slip off into the bore. .....Anyway, the adaptor eliminates this problem ...it fits against the radiused shoulder sort of like a spacer, and you measure across both, then subtract the length of the spacer. Brancato Engineering OX44 7RW, 01865 891203 make one (they call it a button) £23.50 (see Classic Bike apr '08). I've not tried one. Any such device has to be trusted to be accurate, until you've bought a shim of known thickness to check it against, that is. Some shims have thickness marked on them anyway. And a word of caution.... I've seen respected Ducati mechanics measure shims wrongly using Ducati workshop tools. Set the closers even slightly too tight and it all goes crunch, so with belts off and opening rocker disengaged, check that the cam rotates by hand with no tight spot. AND FINALLY, the wire collets bed in to something like the difference between one shim size and the next, so fitting new ones can restore valve clearances on their own (for a while)....or just confuse the issue. They also bed in one way, so if you put the old ones back in upside down (cos they fit either way) they act like new ones and change the clearances by maybe one shim size. And you need a lens to spot the wear marks, and then its not easy. My advice would be ..measure up, take notes, leave collets in situ, work it all out but don't change anything unless it needs at least two shim sizes, and maybe then just go one size with new collets. Or even try just new collets first....they only cost pence but shims are pricier. Check the videos...the guy from california..excellent. And do use the trick method of measuring the closing clearances via the opening shims...much easier, more accurate and doesn't chew your feeler gauges. Btw, those red kites round your way are stunning, aren't they?

Excellent description. Worthy of a sticky IMO.
 
The red ktes are where im from but im now up in the midlands near wolverhampton... but i cant change my location! :(
 
So if you're in wolverhampton, you're not far away from me in Leicester. I'd be happy to measure your shims for you if you can get them here. I've got a spare micrometer that you could borrow too, although its an imperial (inches) one, so you'd have to convert to mm.
 
i wont be doing the tappets till the winter season hits as i use the bike daily at the minute. but my plan is to remove engine and strip for painting then on reassembly put new shims in to stop the ticking from the valves... if you fancy a visit with tools closer to the time i have tea and coffee and biscuits... lol
 
Let me know when you're doing it. I have family in shrops, so could maybe call in en route. Where exactly are you?
 
sorry for late reply. .....Newport is just a few miles north of you, on the A41, t'other side of the A5. And Muxton is sort of similar, but smaller. I lived around there for 20 years. Now back in my hometown of leicester, but have an ex, and 4 kids over there, so I'm often about. Should be no prob to arrange a meetup, and I can def lend you a mic if you like. I've got 3. Happy to pass on what I've learn't from doing mine. And would be nice to meet a stranger, as t'were. I seem to remember a cafe near the base...something about spiders...? I know where that is.. Just off the A41. Let me know when you're doing it and we can maybe sort something.
 
yeah spiders web cafe.. im in quarters here. its where im stationed..
 
just to revive this thread as the monister is coming off the road at the end of the month... for stripping and spraying of the engine!!! and some help with the valve shims?
 
Only just spotted your last post. Offer still stands for borrow of micrometer. I've got a spare closing shim that you could practice on too. Will bring them if/when I'm over that way in the near future, or you could collect if you're in the Leicester area.
 
no rush.. the bike isnt sorn until end of oct... but to be honest could do with your help if you have done it before.. so once i have the bike strippd and the heads off then i can give you a shout if you pm me your number? prob wont be until mid nov though...
 
Happy to help. I've only done it once before, but went VERY slowly, the main aim being to learn all the angles and pitfalls for future reference (cos I'm NEVER going to sell this bike), so I reckon I've got a pretty good handle on it now. Remind me via pm when you're ready and we can take it from there.
By the way, you mention taking the heads off.....No need for that. Just raise the tank, release the oil cooler fixings (leaving the pipes connected) and remove the rocker covers.
I'm assuming that you have a rear paddock stand so the engine can be turned over via the rear wheel...?
 
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