Negative Clearance Confusion

[Moki of Rancho]

Went to check my valve clearances today with my fancy new metric feeler gauge, and the answer I got was "none". My question is, when I'm ordering a replacement shim, how much of a size difference do I go for when there isn't any clearance to start from? I was thinking 0.10mm smaller than whatever's currently in there. Thoughts?

P.S.

I used Bike/BassCliff's awesome tutorial because I'm a total newb.

[hampshirehog]

If you have no measurable clearance at all get hold of a very thin shim and use this as a checker. You should get a measurable gap and you can work out what you need from there.

[BassCliff]

Hi,

Take the shims out one at a time and see what size they are. Usually you can move some shims around to get some of your valves within spec, then order just what you need to complete the job.

On my first valve check (I don't think the PO ever checked) I had to go down two sizes (.10mm) on three of my valves. But you won't know what you need until you know what you have.

Thank you for your indulgence,

BassCliff

[BeerMonger]

All my shims were 1.50 to 1.65, so I went to my local bike shop and bought a 1.45. I moved this one from valve to valve to measure all the gaps, then I ordered what I needed online.

Email Steve for his valve shim spreadsheet too.

[Moki of Rancho]

Wow, I feel like an idiot. Couldn't figure out how to get the shims out, so I thought taking the camshafts out would make this job easier. (Hey, the timing and stuff was probably bad anyway! Right?) Anyway, back to shims. Here's my thinking... I know that the space between all the cam lobes and their shims are smaller than .03mm. From my understanding, that's exactly one size category. So if I bump up every shim by two sizes, that should put me within range, right?

[drejal]

Measure the clearances, get a digital micrometer or caliper on the shims and measure them. Put the values in Steve's valve adjustment spreadsheet, and it tells you all the answers!

[Nessism]

Anyway, back to shims. Here's my thinking... I know that the space between all the cam lobes and their shims are smaller than .03mm. From my understanding, that's exactly one size category. So if I bump up every shim by two sizes, that should put me within range, right?

This is the wrong approach. As someone already said, you need one thin shim so you can install one valve at a time and then determine what sizes you need. The service manual has a table to help you pick the proper shim size.

[Moki of Rancho]

This is the wrong approach. As someone already said, you need one thin shim so you can install one valve at a time and then determine what sizes you need. The service manual has a table to help you pick the proper shim size.

I guess that makes sense. Too bad I can't just waltz down to the 'local bike shop' and grab one. Yay ebay.

In other news, I've now landed myself in a much more irritating predicament- all the tension's gone out of my timing chain and I'm really not sure what to do about it. I, like an idiot, removed the cam chain idler, et cetera to get the camshafts out without any clue of what I was getting myself into. I've seen some guides floating around for complete rebuilds, but honestly I'm not really sure where to start.

[BassCliff]

Hi,

There's no need to remove the cams to change the shims on these motors. But I guess you know that now. There is a valve adjustment guide on my website that is pretty comprehensive. There's a special tool used to depress the buckets, then you use a pair of tweezers to get the shim out.

Z1Enterprises.com has the best price on shims, $5.28 each. There is also a Shim Club here in the forum. You might be able to trade for what you need.

You can put the cams and chain back together, just get the timing right.

Thank you for your indulgence,

BassCliff