Valve shim adjustment

[Dizzixx]

Options

So I played around with the measurements I have

and I got three options:

Option 1 -
The simplest option only requires buying/trading a single shim. The exhaust is left as is while the intake is loosened up by shifting shims around. Two valves slightly out of spec, one more than the other. The tight valve stays the tightest but moves to nominal.


Option 2 -
Very nearly .080 on all valves. Requires buying/trading 4 valves which are each an X size, meaning it is likely only possible if in stock with the shim club.


Option 3 -
This option opens everything up as I noticed a number of people in other posts saying you should aim for as high as .10mm, in particular on the exhaust. This involves buying/trading 4 shims but they are all standard sizes. Cylinders 2 and 3 end up more open than the outside cylinders not sure that it matters but I could see this being beneficial from a heat flow perspective though I really doubt it makes a difference if everything else is balanced like it should be.

I already bought the 4 shims from Z1 for option 3 because it covers both options 1 and 3 and was cheap enough that I thought I would try it. Worst case I end up with shims to trade more easily with the shim club. They should be here Friday. I am just wondering what everyone's thoughts are.

Also I am unsure if this makes much difference but the engine was rebuilt 6k miles ago and was bored to 850cc using a wiseco kit. At the time a number of valves seats were lapped and some valves were replaced etc. This was done by a professional mechanic. This is the second clearance check since the rebuild and the first one I am doing instead of a professional.

[Steve]

Numbers look good, your conclusions are sound, but you are using the metric approximations that are printed on the INCH feelers. That makes figuring a bit difficult.

Having the clearances on the looser side is good, but don't fret about them not all being the same.

.

[Dizzixx]

How loose is too loose? I know the spec says .08 but most people talk about going to .10 instead, or say .011 as in option 3, if that is even really what they are. There is also the issue of actually determining accurately the clearance based gauge drag. I have only ever done valves on my own and never had someone show me the correct amount of drag. But I imagine I err on the interference side of things, the idea being I should be closer to true clearance. This of course also means that inflating my clearances to .11 is potentially much different from someone who measures with very light drag on the gauge.

I noticed you made the same comment about inch to metric in another thread. I get that there is some rounding error (.038 is really .0381, .051 is really .0508, .063 is really .0635, etc.) but I imagine it is within their manufacturing tolerances anyways (cheap gauges), having said that I just bought a metric set of feeler gauges that go from .02 up to 1mm in increments of .01, I am going to use those next time after I check them with my caliper first. They were also cheap Chinese ones from Amazon.

[bwringer]

There are two tricks to know with the valve tool that everyone seems to miss. We need to sticky these or something... next time I do a valve check maybe I should get someone over here and make a video.

1) Make sure the "rib" that pushes on the valve bucket is clean and square. Many of these tools have a casting line on this rib, or are slightly uneven (thanks, Motion Pro...). Take two minutes with a vise and a file to dress the working surface of the tool.

2) As you insert the tool and push down, apply a little sideways pressure on the handle toward the bucket. DON'T just push straight down -- basically, push at a 45 degree angle. Once you understand this technique, it'll stay on the bucket and work correctly first time, every time.

Using the tool is a lot faster once you get the technique right. As Steve will note, there's a small risk of shattering a shim if the tool slips off, so if you're not confident in this then there's always the zip-tie method, which is pretty foolproof.

[BoCoMoMann]

God I love my FJ!





Tool in place -





Great bike to work on, I've kept it around longer than anything else, so far.

I thought for a little while a Honda XX would be it's replacement - but it's long gone and the FJ is still in the garage.....

That Blackbird was quick and fast!

[Dizzixx]

So long story short I didn't get the shim club shims until this weekend. I went with option 2 and have the following:

Intake Shim Clearance
1 265 .09 - .1
2 273 .09 - .1
3 272 .09 - .1
4 280 .08 - .09

Exhaust Shim Clearance
1 265 .08 - .09
2 263 .09 - .1
3 260 .07 - .08
4 257 .09 - .1

The clearance is go - no-go, so things are just a tad loose, but I am happy with where its at. After I synced the carbs with an ATF and plastic tube manometer and she runs like a top, start first time every time and pulls hard in every gear.

Thanks everyone for your help.