Valve adjustment and cam removal: check it before I wreck it.

[Sol]

I would like to check myself here before I do something entirely avoidable in retrospect

I just got done playing with my feelers and ---
(For Ref: My gauges are the standard&metric that for mm go: .1, .13, .15, .18, .2 Also the bike is a 1980 LG aka MNS so I-speck= .11 to .15 & E-speck=.21 to .24)

I1: .1 no contact, .13light contact, .15 overshoot
I2: .8 no contact, .1 very light contact, .13 overshoot
I3: .13 no contact, .15 extreamly light contact, .18 overshoot
I4: .8 no contact, .1 very light contact, .13 overshoot

E1: .15 no contact, .18 contact
E2: .15 no contact, .18 extreamly light contact, .2 overshoot
E3 .13 no contact, .15 my imagination? , .18 medium contact
E4 .13 no contact, .15 my imagination?, .18 overshoot

So I figure I=.13 and E=.23 are ideals to shoot for (tighter better for perf that I probly would not feel, best to keep it in center of spec range otherwise is assumtion)

now these shims come in .005mm which would not register on my scale: should I try playing between the cracks to estimate as close as possible or would at or around these following numbers be just fine as long as I get it in the median:

I1: 0 adjustment
I2: .03 smaller then existing shim
I3: .02 larger then existing shim
I4: .03 smaller then existing shim

E 1,2,3,&4: .05 smaller then existing shim across the board.

The next step is to find out my existing shim sizes but the tool I don't have is not reported to work that well. That leaves pulling the cams.

First question: my dots and arrows line up spot on, but on the "F". The book says this should happen on the "T". Whats up with that? It seems to me that chain ware would make the dots wander apart rather then in the same direction, and if my box c miles are anywhere near right I have only around 12K mi on this thing - not in chain replacement mileage range. Possible mix up at sometime? my chain does seem to have a master link which I have read is not stock? or would this possibly be a case of set right with poor marking accuracy from the factory? confusing.

Second question: In the books process of removal it states (with the motor at TDC) to remove the reachable cam sprocket bolts (1 each) then rotate the engine 180 with out moving the cams to get at the other bolts. I think I am missing something basic here, but I don't understand how that would be possible. if we leave the chain in place to move the sprockets when we move the motor 180 and the sprocket is still attached to the cams due to the bolts we wish to remove, then would this not move the cams? like I said I am failing to understand something. I would normally just take it apart to better understand it, but in this case learning by discovery may not be smart . This is the greater good all those gagets died to teach me as a little kid: If you plan on reassembly - take it apart right!

If you are still with me, I thank you!
what are your thoughts?

[Sol]

I think I learned something

going through more posts, it seems I may be off 1 tooth/link on the cam sprockets and chain. how why and since when, well if the PO knew he would not have done it, right? oddly it seemed to run just dandy.

I also on the sprocket removal, and I should have seen this coming:
Rather then try to make the book right - do it bassakward!:
Don't start at TDC but take it 180 out then remove the bolts, bring it back to TDC get the last 2 bolts.

If this is incorrect please let me know!

Thanks!

[petejw]

hi sol,

im not understanding the measurement u wrote to clearly,

i know the book states metric and i was brought up with metric,
but for ease i use thou to measure the valve clearances,
intake 4 - 6 thou
exhaust 8 - 10 thou
each half mm shim adjustment is equivalent to 2 thou,
makes checking the valves so much easier.

depending on how many shims u need to replace, u dont need to remove the cams, do one cam at a time and loosen the cam nuts this will raise the cam at an angle and raise it enuff that u can get in an replace a shim, i also dont loosen the cam chain tensioner, this way u dont run the risk of the chain slipping, but after adj of the valves have been made it is best to retension the cam chain.

[TopCatGr58]

Hey Sol,

Too much math there for me right now! Yes, erring in middle range is safer, but erring on wider range is more safer, because when these bikes wear, the clearances get smaller/closer due to the valve seats getting hammered into the head, and if the clearances get too tight, burned valves can occur. Setting them to the wider spec will get you LONGER TIME before you may have to redo the shims.

Also, the "tool" does work, I got it with the shim library a year or so ago when I worked on an XJ, so..you could TRY the tool first, and if you get it to work, then that will save you time removing the cams. HOWEVER, if you cams ARE 1 full tooth off position, then yes, you'll need to at least remove the sprockets to reposition the cams, and YES, doing the 180 degrees away bolts FIRST is the way, then rotating the engine/cams back up to TDC="T" mark to get the remaining sprocket bolts, then the sprockets can be slid off the cam shoulders, slipped the 1 tooth, then the cams slightly rotated with a wrench as necessary to be able to realign the sprocket holes to get the first bolt back IN!

Once you have the first bolt back in on each sprocket, snugged, then you can rotate the engine a few turns and bring it back to "T" First to verify that the dots do line up before putting in the last sprocket bolts.

To get a little more slack in the cam chain, you can loosen the tensioner lock bolt, but once you get the sprockets/cams/chain back in primary dot aligned position, RELOCK the tensioner bolt before rotating engine!

T.C.

[Sol]

don't worry about the math

that is what I should be using Excel for rather then long handing it in my notebook. If I make a functional valve.xls I will find a way to share it.
Thanks TC for the correction about preferable setting ranges. It looks like I will be needing to get at least most of the 8 valve shims as swapping them wont do the trick on this one. I'll post the numbers after I make the .xls but I have pulled the cams to get the shims. I zip-tied the chain to the sprockets and have the timing set at TDC. I can recreate the way everything was when I started; then worry about why stuff did not line up to begin with.
Thanks!