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Discussion Starter #1
I would sincerely appreciate any help and elucidation on a few issues I'm having which are killing me


I have read and reread Snyder's 2nd ed, DucatiSuite's guide, and Haynes. Maybe I'm just retarded - that would make three of us at it today - but here are my questions, issues, etc:

1. Does each cylinder have to be @ TDC to take valve measurements for the respective cylinder?
- is the best way to verify TDC via ea cylinder's plug hole? Or is lining up the flywheel tic mark good, and if so is this procedure correct:
i.rotate the engine to line up the tic mark and (for argument sake) now the vertical cylinder is TDC. Take measurements etc ready to move the horizontal...
ii.rotate engine again until the tic is again lined up and now we're at TDC for horizontal cylinder?

2. Haynes does not mention loaded & unloaded gaps; they only say to measure between the opener rocker and the opener shim and that's your clearance. If I can make life easier via Haynes' method why would I do it via loaded and unloaded gaps/calculations/etc? (playing devil's advocate here)

3. If you will, please consider the following measurements, which I can not be confident are accurate despite my best efforts following the various guides. I know you can't either but was hoping you could provide ANY insight. These are from measuring loaded and unloaded gaps, but I feel like there's a third measurement I should be taking (as eluded to by one of the guides referenced):

Left Intake clearance betwn cam lobe/rocker .004"
Right intake cam lobe/rocker .003

Left Intake rocker/shim .003"
Right intake rocker/shim .004"

L Exhaust cam lobe/rocker .004"
R exhaust cam lobe/rocker .004"

L exhaust rocker/shim .008"
R exhaust rocker/shim .004"

Assuming those measurements (which are elaborated on to reflect loaded, unloaded measurements - I think!) are accurate what do I do with them? Are there calculations to be done now? Holy crap I'm getting stressed thinking about it all again
I tried calculations but they seem to give results that are all over the place.

I should note that when lifted upwards the Left (facing bike forward) Exhaust opening rocker had notable play such that an easily audible clicking could be heard (which I assume means the clearance is too large...?)

4. I know this depends on the degree of out-of-spec clearances but: assuming clearances were miscalculated and there were out of spec clearances is there a rough estimation of when consequences would manifest themselves, e.g. 3000K mi? 12K mi? And what would those manifestations be?

This ain't rocket surgery I know and I WILL figure this out (uh, hopefully with your help
)

TIA.

Modified by doocatiboy at 3:58 AM 3/27/2005


Modified by doocatiboy at 3:59 AM 3/27/2005
 
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Re: Valve clearance help (doocatiboy)

Pull the belts and remove the cams to check for rocker arm flaking, before you start to worrry about the clearances you have. I say this because if you have a flaker, (or potential flaker) you'll need to straighten that out first, which will throw the effected tolerances off. Also, leave the belts off to check the clearances, it's a bit easier.
Hope this helps a little!
 
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Re: Valve clearance help (Tornado-rider)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tornado-rider »</TD></TR><TR><TD CLASS="quote">Pull the belts and remove the cams to check for rocker arm flaking, before you start to worrry about the clearances you have. I say this because if you have a flaker, (or potential flaker) you'll need to straighten that out first, which will throw the effected tolerances off. Also, leave the belts off to check the clearances, it's a bit easier.
Hope this helps a little!
</TD></TR></TABLE>

good advice

I just pulled all my rockers and they all are strarting to fail
(no flake just turning grey)

also you will need 8 more measurements I am assuming that those are your opening rockers.

From some great help(thanks Art and Matt) I droped the motor for this and removed heads and split the cases. This allowed me to get the frame powdercoated
and learn a shit load about these beautifull(expensive) motors.

Haynes manual want you to get a measurement by attempting to cram a feeler in the closing rockers.


LT takes a different approach using the cam lobes for loaded and unloaded. Follow the chart in the manual if you have Excell on your pc use it and it will do the calculations for you.


We havent reinstalled everything(waiting on collets,rockers,stm adj pulleys) so thats as much as I know not much but Im sure others will chime in with a better explanation



Modified by brettmess24 at 8:58 PM 3/26/2005
 
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Re: Valve clearance help (doocatiboy)

I'm in the process of doing my 12k mile service and belt change on my 2000 996 right now. This is my first time but I think I'm pretty clear on the concept. I'll try to answer your questions and let others correct me as necessary. My reference is the Haynes manual, ducatitech.com and ducatisuite.com

1. Yes, each cylinder needs to be at TDC to measure that cylinder's valves. I did the horizontal first because it is most obvious when it is at TDC. First you have to pull the belt covers. You'll notice that there are marks on the pulleys and on the heads themselves. There are multiple marks on the flywheel (I think). Line up the tick mark on the flywheel WHERE ALL all of the marks on the pulleys line up with marks on both heads, horizontal and vertical. That is the TDC of the horizontal cylinder.

Now for vertical TDC. This was more confusing to me but it turns out my pulleys were marked for VTDC, as well. I rotated the engine until the next tick mark on the flywheel which also happened to match up to marks on the vertical cylinder's pulleys on my bike. Sorry I can't be of more help there.

2. I think you may be over thinking the measurements required using the loaded/unloaded method. You should be taking two different (usually) measurements from the same place. I'll explain more below.

3. I'm having a hard time making sense of what of your measurements so I'll try to explain what I did. I apologize if I'm telling you stuff you already know.

First you take the opening measurement by placing the feeler gauge between the opening shim (perched on top of the valve) and the cam lobe. Note that number. Let's say it is .004" Now you use something (I used a plastic bicycle tire "iron") to push down on the closing rocker (the forked thing wrapped half way around the valve) and take a measurement from the same place as the opening measurement, between the opening shim and the cam lobe. These will generally be slightly different. Let's say this one is .006". The difference between the opening (.004) and closing (.006) is .002". That is your closing measurement. If anything is out of spec, pull and measure the corresponding shim and figure out how much larger or smaller it needs to be to bring that valve back in spec. That's it.

4. I don't have a definitive answer for you but if you follow what all the books and helpful websites say, there isn't really a reason to doubt your measurements.

Also, I'd like to echo what tornado said. Pull the cams and check for flaking rockers. If you've torn the bike down to the point of measuring valves, it's really no big deal to pull the cams. Just make sure you have all the new o-rings and gaskets required. Those necessary are noted in the Haynes manual. Also, if you're pulling the cams you're pulling the belts which means you're removing the tensioner pulley's lock nut. Replace that nut with a new one.
 
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Re: Valve clearance help (brettmess24)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by brettmess24 »</TD></TR><TR><TD CLASS="quote">

also you will need 8 more measurements I am assuming that those are your opening rockers. </TD></TR></TABLE>

Right, we had to pack it up for the day after doing the vertical cylinder. But...uh...where do I take closer measurements or is does the calculation yield that?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by brettmess24 »</TD></TR><TR><TD CLASS="quote">
Haynes manual want you to get a measurement by attempting to cram a feeler in the closing rockers.
LT takes a different approach using the cam lobes for loaded and unloaded. Follow the chart in the manual if you have Excell on your pc use it and it will do the calculations for you.
</TD></TR></TABLE>

Right - but why is that less desirable than the unloaded/loaded gap method? Less accurate? What Excel doc are you referring to? Is there a program floating around someone created in Excel that has the calcs in it (if so, where?)?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jasont_ot »</TD></TR><TR><TD CLASS="quote">
3. I'm having a hard time making sense of what of your measurements so I'll try to explain what I did. I apologize if I'm telling you stuff you already know.
</TD></TR></TABLE>

I just labeled them differently; they're loaded and unloaded (just labeled as to demonstrate where the measurements were taken to show loaded, unloaded) and we did as the manuals (I used the same ones) and you describe.

Thanks for the replies.

 
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Re: Valve clearance help (doocatiboy)

LT's manual is great.I did my 996 last month.simply subtract the unloaded from the loaded and,voila,your closing clearance.Excell,what? I used my AutoCad drafting software to make this template,you could use any old piece of scrap paper.I didn't complete the chart because my numbers were consistent and didn't need shim adjustment




Modified by ducxl at 4:44 PM 3/27/2005
 
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Re: Valve clearance help (ducxl)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ducxl »</TD></TR><TR><TD CLASS="quote"> simply subtract the unloaded from the loaded and,voila,your closing clearance.Excell,what? I used my AutoCad drafting software to make this template,</TD></TR></TABLE>

Yup, that's what I was doing in this case but my buddy wasn't confident for some reason (I think b/c we were unsure if TDC was necessary, which we were at).
Do you have that CAD file you can email me doocatiboy @ yahoo com? I'm running 04. While I know it's not a complicated form it'd be nice to have typed out rather than scribbled.

Thanks!




Modified by doocatiboy at 3:28 AM 3/28/2005
 
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Re: Valve clearance help (doocatiboy)

get a degree wheel.TDC compression stroke,yeah.My Duc wheel was like$300. I'll try to E-mail that template but,have had probs. trying. shoot me an E-mail and I'll snail mail you one through the US postmail.
 
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