Changing shims on ReSTored

[George]

Worked on ReSTored yesterday to get valve shims in spec. Only three were out, all tight, all on #3. Decided to bring #1 into mid-spec as well. Changed 7 of 8 shims, per the math calc. in the Honda manual. Put'er back together. Now 7 valves are WAY LOOSE!!! What did I do wrong? (gonna cross post this to ST1100 tech, too.)

Example: tight #3 rear exhaust, measure .008, shim is a 202. a=b-c+d.

b=.010
c=.008
d=............... Never mind, just got it. Shims are 1.2 to 2.8 mm, not .12 to .28 mm. I slipped the decimal point one space to the left. Start over on Monday I guess.

( replaced the 202 with a 155, should been a 198 (round down to 195 or up to 200?)

Thanks for listening.

 

[Mellow]

Yup... that darn decimal point will get you every time... they still put it in the wrong location for my paycheck... but they just don't listen to me anymore.

 

[freeSTyle]

Geo* Keep`practicing`til you get it right. I`ll be needing your help soon..........:>}

Don

 

[Byron]

Me and the metric system really don't get along well so I work in regular inch/thousandth measurements. My brain can't handle it.

 

[gryzz1325]

:banghead:

 

[George]

Me and the metric system really don't get along well so I work in regular inch/thousandth measurements. My brain can't handle it.

Byron, just stay with metric, it's much easier than inches (or parts of inches! Who ever decided 1/8, 1/16, 1/32, 1/64 was the way to go there!)

The problems usually come from converting back and forth. Just don't do that. The decimal point is missing from all the shims, I assumed (without thinking about it) that a 202 shim is a .202. so subtracted .54 instread of .054 (202 to 1.976) Lots of 198s in the kit 'cause I put'em in there from The Hulk (16 shims added.) D'Oh!

Ya get really confused, use a surveyors tape. Feet and inches but the inches are marked in tenths!

 

[Spotthegerbil]

Actually... 1/8, 1/16, 1/32, & 1/64 divisions make sense. It's all about halving.

Metric would be easy if we had to use it every day. Our old brains are just so used to SAE we need to mentally convert for it to make sense.

I always get tripped up when working with metric threads.

Actually...1mm, 0.1, 0.01, 0.001 & 0.0001mm divisions make sense. It's all about tenthing.

SAE (Imperial) would be easy if we had to use it every day. Our old brains are just so used to metric we need to mentally convert for it to make sense.

I always get tripped up when working with imperial threads.

As you can see, I've got a similar problem!

 

[Don B]

Changed 7 of 8 shims, per the math calc. in the Honda manual. Put'er back together. Now 7 valves are WAY LOOSE!!! What did I do wrong?

Thanks for listening.

George,
are you sure you didn't drop all yer shims on the garage floor somewhere along the way?

 

[George]

Actually...1mm, 0.1, 0.01, 0.001 & 0.0001mm divisions make sense. It's all about tenthing.

SAE (Imperial) would be easy if we had to use it every day. Our old brains are just so used to metric we need to mentally convert for it to make sense.

I always get tripped up when working with imperial threads.

As you can see, I've got a similar problem!

gerbil, you still got yur wentworth spanners?

 

[John OoSTerhuis]

George. This is simple. No need for any special, involved math/formula.

Measure in thousanths of an inch. For every thousandth of an inch that you want to change the clearance, go up or down one Honda shim size from the shim that's currently installed. It took me a while for this to sink in.

Remember, the Honda shims are in .025mm increments and .001" equals .0254mm. Virtually the same.

You can measure in millimeters and use the formulas and Dan Horton's spreadsheets, but unless you custom file a stock shim to a special thickness, you can't get any closer to the spec than the simple method of one shim size per thousandth of an inch clearance change desired. The spreadsheets and fancy math will all arrive at the same shim size as the simple method I've described.

HTH

John

 

[Spotthegerbil]

gerbil, you still got yur wentworth spanners?

Near enough! I had worked with my Dad on his cars from when I was old enough to walk. OK, work might have been stretching it when I was really young. Swept floors, cleaned muck off gearboxes etc. Almost typical of an apprenticeship. He had the range of tools that can only be obtained through a lifetime of farkling.

When he died and we cleared out his garage I got, amongst other things a full range of imperial sockets and spanners all the way up to about 1 1/2 inch, imperial micrometers, feeler guages (I had to buy a metric set when I got a bike), and a load of other stuff including the stripped remains of a gearbox drive shaft from an early seventies. He had recently spent some money so I've got a new set of valve spring compressors, a coil spring compressor and a tap and die set sitting unused.

Mrs Gerbil and I are planning on doing up a Mini (a real one, not that German pile of ***) so we are fully equipped. Cheers Dad!

 

[Mr. BR]

This is simple. No need for any special, involved math/formula. Measure in thousanths of an inch.

At least when it comes to valve adjustments, I still think in inches too. Just did my '95 and an exh valve on #3 was at .008" (a thou under min.) with a #208 shim which measured .081" thick. Simply used my caliper and found a shim that was ~.079 to give me another 2 thou of clearance and voila! Clearance at 0.010" (right in the middle of the 9 to 11 thou spec).

Btw, for the actual clearance check, I rotated the engine via the front crank bolt and put the cam lobes pointing up directly away from the bucket, and then checked the clearance. Is that what most folks do?

Brendan

 

[Blrfl]

I do mine in cubic hectares.

--Mark

 

[GitSum]

Brendan - there is an actual procedure in the service manual that involves rotating the crank to a certain position, aligning some marks on the cams and then checking certain valves

Take a look at this - you may find it helpfull

https://www.st-owners.com/forums/showthread.php?t=75926

 

[John OoSTerhuis]

At least when it comes to valve adjustments, I still think in inches too. Just did my '95 and an exh valve on #3 was at .008" (a thou under min.) with a #208 shim which measured .081" thick. Simply used my caliper and found a shim that was ~.079 to give me another 2 thou of clearance and voila! Clearance at 0.010" (right in the middle of the 9 to 11 thou spec).

Brendan,

Honda marks/stamps their shims with a three digit number (see the list below). Note that all the n.n75mm shims' markings are rounded up to nn8 and all the n.n25mm shims are rounded down to nn2

In the example of the 208 shim, it's 2.075mm (.08169") thick. To increase the valve clearance two thousandths to the desired .010", simply select a shim two increments (2 x .0.025mm = 0.050mm) thinner = a shim 2.025mm (.07972") thick (marked '202'). You don't even have to do the math, just look at the shim list.

edit: remember - each shim increment of .025mm equates to a valve clearance change of one thousandth of an inch (.001").

Here's the list of Honda shims (also attached below) which can also be seen in the ST1100 Archive Of Wisdom - Valve Adjustment Tips ( ST1100 ) :

~~~~~ ST1100_Valve_Shim_PNs.txt ~~~~~

Compiled by John OoSTerhuis, STOC 1058

HONDA ST1100 VALVE SHIM LIST

......Honda...... ..Noun-Nomenclature..
..Part Number.. ...(thickness in mm)... Stamped
-------------- --------------------- -----
14901-KT7-013 SHIM, TAPPET (1.200) 120
14902-KT7-013 SHIM, TAPPET (1.225) 122
14903-KT7-013 SHIM, TAPPET (1.250) 125
14904-KT7-013 SHIM, TAPPET (1.275) 128
14905-KT7-013 SHIM, TAPPET (1.300) 130
14906-KT7-013 SHIM, TAPPET (1.325) 132
14907-KT7-013 SHIM, TAPPET (1.350) 135
14908-KT7-013 SHIM, TAPPET (1.375) 138
14909-KT7-013 SHIM, TAPPET (1.400) 140
14910-KT7-013 SHIM, TAPPET (1.425) 142
14911-KT7-013 SHIM, TAPPET (1.450) 145
14912-KT7-013 SHIM, TAPPET (1.475) 148
14913-KT7-013 SHIM, TAPPET (1.500) 150
14914-KT7-013 SHIM, TAPPET (1.525) 152
14915-KT7-013 SHIM, TAPPET (1.550) 155
14916-KT7-013 SHIM, TAPPET (1.575) 158
14917-KT7-013 SHIM, TAPPET (1.600) 160
14918-KT7-013 SHIM, TAPPET (1.625) 162
14919-KT7-013 SHIM, TAPPET (1.650) 165
14920-KT7-013 SHIM, TAPPET (1.675) 168
14921-KT7-013 SHIM, TAPPET (1.700) 170
14922-KT7-013 SHIM, TAPPET (1.725) 172
14923-KT7-013 SHIM, TAPPET (1.750) 175
14924-KT7-013 SHIM, TAPPET (1.775) 178
14925-KT7-013 SHIM, TAPPET (1.800) 180
14926-KT7-013 SHIM, TAPPET (1.825) 182
14927-KT7-013 SHIM, TAPPET (1.850) 185
14928-KT7-013 SHIM, TAPPET (1.875) 188
14929-KT7-013 SHIM, TAPPET (1.900) 190
14930-KT7-013 SHIM, TAPPET (1.925) 192
14931-KT7-013 SHIM, TAPPET (1.950) 195
14932-KT7-013 SHIM, TAPPET (1.975) 198
14933-KT7-013 SHIM, TAPPET (2.000) 200
14934-KT7-013 SHIM, TAPPET (2.025) 202
14935-KT7-013 SHIM, TAPPET (2.050) 205
14936-KT7-013 SHIM, TAPPET (2.075) 208
14937-KT7-013 SHIM, TAPPET (2.100) 210
14938-KT7-013 SHIM, TAPPET (2.125) 212
14939-KT7-013 SHIM, TAPPET (2.150) 215
14940-KT7-013 SHIM, TAPPET (2.175) 218
14941-KT7-013 SHIM, TAPPET (2.200) 220
14942-KT7-013 SHIM, TAPPET (2.225) 222
14943-KT7-013 SHIM, TAPPET (2.250) 225
14944-KT7-013 SHIM, TAPPET (2.275) 228
14945-KT7-013 SHIM, TAPPET (2.300) 230
14946-KT7-013 SHIM, TAPPET (2.325) 232
14947-KT7-013 SHIM, TAPPET (2.350) 235
14948-KT7-013 SHIM, TAPPET (2.375) 238
14949-KT7-013 SHIM, TAPPET (2.400) 240
14950-KT7-013 SHIM, TAPPET (2.425) 242
14951-KT7-013 SHIM, TAPPET (2.450) 245
14952-KT7-013 SHIM, TAPPET (2.475) 248
14953-KT7-013 SHIM, TAPPET (2.500) 250
14954-KT7-013 SHIM, TAPPET (2.525) 252
14955-KT7-013 SHIM, TAPPET (2.550) 255
14956-KT7-013 SHIM, TAPPET (2.575) 258
14957-KT7-013 SHIM, TAPPET (2.600) 260
14958-KT7-013 SHIM, TAPPET (2.625) 262
14959-KT7-013 SHIM, TAPPET (2.650) 265
14960-KT7-013 SHIM, TAPPET (2.675) 268
14961-KT7-013 SHIM, TAPPET (2.700) 270
14962-KT7-013 SHIM, TAPPET (2.725) 272
14963-KT7-013 SHIM, TAPPET (2.750) 275
14964-KT7-013 SHIM, TAPPET (2.775) 278
14965-KT7-013 SHIM, TAPPET (2.800) 280
14966-KT7-013 SHIM, TAPPET (2.825) 282
14967-KT7-013 SHIM, TAPPET (2.850) 285
14968-KT7-013 SHIM, TAPPET (2.875) 288
14969-KT7-013 SHIM, TAPPET (2.900) 290

[total shims available : 69]

~~~~~~~~~~ end of file ~~~~~~~~~~~~~~

HTH

Regards, John

View attachment ST1100 Valve Shim PNs.txt

 

[jaysponger]

How do you know you need to replace your shims?

 

[Mellow]

How do you know you need to replace your shims?

There is a gap that you check. You have a +/- tolerance from the center gap so it can be off a little each way but once you are past that tolerance, they definitely need to be adjusted. That means putting a thicker or thinner shim in place to make that gap bigger or smaller.

 

[John OoSTerhuis]

Here's another, previous discussion on this subject that should be of interest to all the folks still following this thread:
https://www.st-owners.com/forums/showthread.php?t=34494

For those who still want to do the math, post 15 (linky) in that thread includes an excellent valve shim calculation spreadsheet by Dan Horton, STOC 1256, that you can download and simply plug in your own numbers.

The beauty of this Excel file is that the math is done for you and will always be correct. Dan's file has both metric and SAE input sections, your choice.

HTH If you find any of this helpful, click the icon please.

Regards, John

 

[George]

John, that's the perfect example. My problem was letting the decimal point slip one while not paying close enuff attention. All is good now, thanks for the input.

Folks, I've owned one or more STs for 16 years. This is the first time I've changed any shims. Says sumpin' 'bout the reliability of the bikes or my slack maintenance technique.

 

[sundesj]

george - thank you for adding neededoPoST1: humor