Stalling because I need to reshim?

My 77 650 was stalling at traffic lights after long rides last fall, just before I put it away for winter. This is what I found after checking my clearances today. Do you think that the clearances would be the primary factor inducing the stalling, if the other tune up variables are fine?

Intake:

.005/.127mm
.006/.152mm
.006/.152mm
.006/.152mm

Exhaust:

.008/.203mm
.003/.076mm
.005/.127mm
.005/.127mm

0.003 - 0.007 in.(0.08-0.18mm)

The clearance above is what a 650 needs, so it looks like you are fine, except one is at the low side at .076mm. I wouldn't say it's the clearance right now. Have you cleaned the air filter, and checked for air leaks on the air boots and intake manifolds? Is your cam chain adjusted?

Intake:

.005/.127mm
.006/.152mm
.006/.152mm
.006/.152mm

Exhaust:

.008/.203mm
.003/.076mm
.005/.127mm
.005/.127mm

I just lifted the exhaust cam and found these shims under the buckets.

.008/.203mm (250)
.003/.076mm (265)
.005/.127mm (260)
.005/.127mm (260)

I can NEVER keep this straight as all I see is imperial/metric/clearance fomulas. I just don't get it. Do I need to go up in the number on the shim to increase clearance? And, go down on the shim number to reduce clearance? What would you recommend for shims for my exhaust valves as they sit now? Any help is appreciated. Thanks.

old650 wrote:

Intake:

.005/.127mm
.006/.152mm
.006/.152mm
.006/.152mm

Exhaust:

.008/.203mm
.003/.076mm
.005/.127mm
.005/.127mm

I just lifted the exhaust cam and found these shims under the buckets.

.008/.203mm (250)
.003/.076mm (265)
.005/.127mm (260)
.005/.127mm (260)

I can NEVER keep this straight as all I see is imperial/metric/clearance fomulas. I just don't get it. Do I need to go up in the number on the shim to increase clearance? And, go down on the shim number to reduce clearance? What would you recommend for shims for my exhaust valves as they sit now? Any help is appreciated. Thanks.

As already mentioned your clearances are fine as is, but if you really want to you could decrease the first exhaust clearance (250) shim one size by putting a 255 in there. That would give you .15mm there, and increase the clearance on the second exhaust (265 shim) by putting a 260 in there. This is not going to make any difference though because your clearances are darn close if not perfect right now. Guys go a little overboard on this clearance thing.

The symptomes you describe are the classic symptoms of clearance being too small.

Aren't the exhaust clearances different from intake?
.003 seems awfully small for exhaust.

You'll want to print this out and have it handy.

#200 = 2.00mm = 0.0787in.
#205 = 2.05mm = 0.0807in.
#210 = 2.10mm = 0.0827in.
#215 = 2.15mm = 0.0846in.
#220 = 2.20mm = 0.0866in.
#225 = 2.25mm = 0.0886in.
#230 = 2.30mm = 0.0906in.
#235 = 2.35mm = 0.0925in.
#240 = 2.40mm = 0.0945in.
#245 = 2.45mm = 0.0965in.
#250 = 2.50mm = 0.0984in.
#255 = 2.55mm = 0.1004in.
#260 = 2.60mm = 0.1024in.
#265 = 2.65mm = 0.1043in.
#270 = 2.70mm = 0.1063in.
#275 = 2.75mm = 0.1083in.
#280 = 2.80mm = 0.1102in.
#285 = 2.85mm = 0.1122in.
#290 = 2.90mm = 0.1142in.
#295 = 2.95mm = 0.1161in.
#300 = 3.00mm = 0.1181in.

0.01mm = 0.0004in.
0.02mm = 0.0008in.
0.03mm = 0.0012in.
0.04mm = 0.0016in.
0.05mm = 0.0020in.
0.06mm = 0.0024in.
0.07mm = 0.0028in.
0.08mm = 0.0031in.
0.09mm = 0.0035in.
0.10mm = 0.0039in.
0.11mm = 0.0043in.
0.12mm = 0.0047in.
0.13mm = 0.0051in.
0.14mm = 0.0055in.
0.15mm = 0.0059in.
0.16mm = 0.0063in.
0.17mm = 0.0067in.
0.18mm = 0.0071in.
0.19mm = 0.0075in.
0.20mm = 0.0079in.
0.21mm = 0.0083in.
0.22mm = 0.0087in.
0.23mm = 0.0091in.
0.24mm = 0.0094in.
0.25mm = 0.0098in.
0.26mm = 0.0102in.
0.27mm = 0.0106in.
0.28mm = 0.0110in.
0.29mm = 0.0114in.
0.30mm = 0.0118in.
0.31mm = 0.0122in.
0.32mm = 0.0126in.
0.33mm = 0.0130in.
0.34mm = 0.0134in.
0.35mm = 0.0138in.
0.36mm = 0.0142in.
0.37mm = 0.0146in.
0.38mm = 0.0150in.
0.39mm = 0.0154in.
0.40mm = 0.0157in.
0.41mm = 0.0161in.
0.42mm = 0.0165in.
0.43mm = 0.0169in.
0.44mm = 0.0173in.
0.45mm = 0.0177in.
0.46mm = 0.0181in.
0.47mm = 0.0185in.
0.48mm = 0.0189in.
0.49mm = 0.0193in.
0.50mm = 0.0197in.


0.001in. = 0.025mm
0.002in. = 0.051mm
0.003in. = 0.076mm
0.004in. = 0.102mm
0.005in. = 0.127mm
0.006in. = 0.152mm
0.007in. = 0.178mm
0.008in. = 0.203mm
0.009in. = 0.229mm
0.010in. = 0.254mm
0.011in. = 0.279mm
0.012in. = 0.305mm
0.013in. = 0.330mm
0.014in. = 0.356mm
0.015in. = 0.381mm
0.016in. = 0.406mm
0.017in. = 0.432mm
0.018in. = 0.457mm
0.019in. = 0.483mm

Different publications had different recommended clearances. The original owners manual specified .15mm which is about .006" on both intake and exhaust. A friend of mine who was a factory Kawasaki (not dealer) mechanic told me for all intensive purposes if throughout the entire rotation of the cam if a .05mm (.002") feeler could be inserted and a .20mm (.008") feeler could not, the clearance was whithin range that swapping shims was not necessary. Everyone has different ideas on the subject. I try to do what he said but up the lower by .05mm, so if a .10mm can be inserted and a .20mm cannot throughout the entire rotation of the cam then clearance is A-OK. Over the years I've read different and have tried tightening or loosening the clearances to a more precise .05mm to .10mm to .15mm and came to the conclusion he was right in his original idea. No noticable difference in valve clatter or performance by tightening or loosening whithin this range that I could tell at least.

Thanks for the info guys.

I had the same problem you do 2 years ago.The engine would run great when it was cool out and just cruisng around town.I made a couple hard long runs in the hot weather and as I came to a stop the engine would die.Beleive me I pulled my hair out for 2 months trying to find the problem went through the carbs multipul times as it seemed to be running out of fuel when hot at a light.I found my exhaust clearances were a little tight on 2 cylinders.I went through and reshimed the clearances at .006" on the intake and.008" on the exhaust.I rode all year in 80+ degrees after the reshim and had no problems. Good Luck

Basically, the hotter you run it, the more cold-clearance you will need.

Bikes with barely under-size clearances will run absolutely fine in every aspect, until you do a high-speed, hot-weather, highway run for 20 minutes. Then they sputter or die when you come suddenly to idle. A few seconds or a minute later they will be back to running just fine. (A compression test takes too long and will only show a shim problem if the clearance is near zero).


The 550's call for pretty large cold-clearances, so .003" just looks small to me.

Like Ron said, I've never noticed much, if any, difference in valve noise after a shim job.

I appreciate all the insight/info and effort that you guys gave. But, I have one last question in regard to reshimming. What are incremental shim values moving sequentialy, say 250/255/260 etc.? Am I moving two thousandths with each shim? ex. .002/.004/.006 ? I asume that each shim is moving sequentialy in 5mm in crements 250/255/260. Putting 5mm into conversion software gave me .196, or two thousandths. So I'm guessing that shims move up or down in .002 increments. Is this right or wrong ?

I understand the concept of the metric system, it moves in units of ten. Deci/centi/milli, but I lose it when I mix it with imperial. I tend to use imperial because I "get it" instantly.

old650 wrote:

I appreciate all the insight/info and effort that you guys gave. But, I have one last question in regard to reshimming. What are incremental shim values moving sequentialy, say 250/255/260 etc.? Am I moving two thousandths with each shim? ex. .002/.004/.006 ? I asume that each shim is moving sequentialy in 5mm in crements 250/255/260. Putting 5mm into conversion software gave me .196, or two thousandths. So I'm guessing that shims move up or down in .002 increments. Is this right or wrong ?

I understand the concept of the metric system, it moves in units of ten. Deci/centi/milli, but I lose it when I mix it with imperial. I tend to use imperial because I "get it" instantly.

Each shim size moves in .05mm increments (not 5mm).
.05mm is about .00197".
So yes, it's about 2 thousandths of an inch from one shim size to the next.

Post edited by: loudhvx, at: 2007/03/19 19:44

loudhvx wrote:

old650 wrote:

I appreciate all the insight/info and effort that you guys gave. But, I have one last question in regard to reshimming. What are incremental shim values moving sequentialy, say 250/255/260 etc.? Am I moving two thousandths with each shim? ex. .002/.004/.006 ? I asume that each shim is moving sequentialy in 5mm in crements 250/255/260. Putting 5mm into conversion software gave me .196, or two thousandths. So I'm guessing that shims move up or down in .002 increments. Is this right or wrong ?

I understand the concept of the metric system, it moves in units of ten. Deci/centi/milli, but I lose it when I mix it with imperial. I tend to use imperial because I "get it" instantly.

Each shim size moves in .05mm increments (not 5mm).
.05mm is about .00197".
So yes, it's about 2 thousandths of an inch from one shim size to the next.<br><br>Post edited by: loudhvx, at: 2007/03/19 19:44

Riiiiiiiiiiiiight. Now Dr. Evil can get precise with those nasty exhaust valves ! Bwoooo haaa haaaa.:evil: