Super loose exhaust clearance?

floatingLomas · February 17, 2015, 01:41:54 PM

I finally braved checking my valve clearance last night - my feeler gage sucks though, and only has (in millimeters) 0.051, 0.076, 0.102, 0.152, 0.203, etc - and most were ok:

0.051 < right intake < 0.076 - 0.051 was snug (2.62 measured)
0.051 < left intake < 0.076 - 0.051 was snug (2.65 marked)
0.102 < right exhaust < 0.152 - 0.102 had a touch of resistance (2.70 marked and measured)

BUT: the left exhaust was somewhere between 0.152 and 0.203, and probably closer to the top (2.65 marked and measured). I find it hard to imagine that someone would do that on purpose, but it looks like they've been checked fairly recently, so maybe?

Should I not ride the bike until I bring down that clearance, or is it ok to ride while I wait for the new shim?

Malfruen · February 17, 2015, 01:54:17 PM

Someone with more experience will jump in shortly, but I think at that clearance you could run the risk of the shim being dislodged and being chucked up into your top end at higher rpms. Not fun. I personally wouldn't risk it.

The_Paragon · February 17, 2015, 02:02:58 PM

These meaurements are in mm right?

twocool · February 17, 2015, 02:17:46 PM

I personally wouldn't go that loose on exhaust...somebody already replied the chance of throwing a shim. Also it is just too fare out of tune...

You might want to get some better feelers?? With all the sizes.... .03 .04 .05 .06 .07 .08 .09 .10

I think you could actually do your valves with only one.... that .102

Here's how....if the .102 is a"go"....then put one size bigger shim...then check again...if the .102 is still a "go"...put yet one bigger...etc...

Once the .102 is a no go...you're in spec....

Any clearance where the .102 is a "no go" from the start, put a smaller shim in...try again...repeat until the first shim where the .102 is a go...then put next bigger shim...

Of course that method will drive you batty and there's a lot of shim changes...so best to buy a good feeler set...

Cookie

Quote from: floatingLomas on February 17, 2015, 01:41:54 PM
I finally braved checking my valve clearance last night - my feeler gage sucks though, and only has 0.051, 0.076, 0.102, 0.152, 0.203, etc - and most were ok:

0.051 < right intake < 0.076 - 0.051 was snug (2.62 measured)
0.051 < left intake < 0.076 - 0.051 was snug (2.65 marked)
0.102 < right exhaust < 0.152 - 0.102 had a touch of resistance (2.70 marked and measured)

BUT: the left exhaust was somewhere between 0.152 and 0.203, and probably closer to the top (2.65 marked and measured). I find it hard to imagine that someone would do that on purpose, but it looks like they've been checked fairly recently, so maybe?

Should I not ride the bike until I bring down that clearance, or is it ok to ride while I wait for the new shim?

gsJack · February 17, 2015, 04:27:53 PM

Looks like you have an inch type feeler gauge with the .007" blade missing? That's the only kind I've used for 180,000 GS500 miles. You have all the sizes I've ever used for my GSs; .002, .003, .004, .005, and .006". The .006" (.152mm) is my no-go feeler for exhaust valves.

The .001-.003" Suzuki spec is good for the intakes but too tight for exhausts. I set my exhausts to a .003-.005" spec. The .006-.008" left exhaust is too loose for spirited riding. If I had (or wanted) to run it before I got a larger shim in there I'd keep it below 7k or so rpm until it's changed. Your bike, your decision, just saying what I'd do.

floatingLomas · February 17, 2015, 06:03:02 PM

Thanks, all. Yes, mm - edited original. I wondered if I was running the risk of chucking a shim, so I'll park her until I can get a new shim for the LE.

Quote from: gsJack on February 17, 2015, 04:27:53 PM
Looks like you have an inch type feeler gauge with the .007" blade missing? That's the only kind I've used for 180,000 GS500 miles. You have all the sizes I've ever used for my GSs; .002, .003, .004, .005, and .006". The .006" (.152mm) is my no-go feeler for exhaust valv
The .001-.003" Suzuki spec is good for the intakes but too tight for exhausts. I set my exhausts to a .003-.005" spec. The .006-.008" left exhaust is too loose for spirited riding. If I had (or wanted) to run it before I got a larger shim in there I'd keep it below 7k or so rpm until it's changed. Your bike, your decision, just saying what I'd do.

Thanks, Jack. So based on what you're saying here: my intakes are in spec (being within .002-.003"), and my right exhaust is probably in spec (being at the low end of .004-.006"), but my left exhaust is buggered

(being over the no-go of .006")? Also, given that my right exhaust is probably not much above the 0.102mm gauge, I probably should just leave that guy alone, right?

My plan at this point is to pick up a 2.70mm shim which should bring the LE into the 0.102-0.152mm (.004-.006") range, and when I do that, I'll check the two exhausts against .005" (which I just realized is just the .002" & .003" gauges stacked; I wish I'd thought of this last night

), and if they are over, I'll pick up 2.75's - seem reasonable?

gsJack · February 17, 2015, 07:40:47 PM

RT EX should be .004-.005" now within the .003-.005" range and a .005" (2+3) feeler should confirm. With LT EX between .006-.007" now one shim size (.002) larger should do it. Might be good to check it with a .007" (3+4) feeler before getting new shim.

floatingLomas · February 17, 2015, 08:07:07 PM

Awesome.

You know, except for the part where you want me to tear it all open again.

gsJack · February 17, 2015, 08:42:41 PM

When I got my first GS years ago I checked the valves one morning, closed it back up, rode out to a dealer 35 mi away to get shims, and put it/them in the next morning. Always got 2 or 3 shims, one the size I thought I needed and a couple more smaller. Sometimes you need one smaller than you figured after putting one in and rechecking it. Exhaust valve gaps always got smaller, never larger.

floatingLomas · February 22, 2015, 03:27:01 PM

Ok, replaced the 2.65 exhaust shim with a 2.70 and now it's within 0.004-0.005". Awesome.

floatingLomas · February 26, 2015, 10:50:56 PM

Hey gsJack, I forgot to ask: do you have any concerns about the wider exhaust spec (0.003-0.005") chucking shims with 'spirited riding?'

gsJack · February 27, 2015, 07:09:03 AM

I don't have any concern setting my exhaust valves at a .003-.005" gap on my stock GS. A stock GS's HP peaks at 8500 rpm and takes a nosedive after that, there's no point in going past 9k and I've run it for hours at 7-9k rpm in the mountains back when I was a kid of 70.

Back in Apr 02 doing a valve check preparing for a trip to the mountains I had an exhaust valve that was receeding rapidly that I then set at .005" on my 97 GS. Turned out that was the only time I ever opened up a GS hitting 110 mph indicated, probably an honest 100 mph. There was much very spirited riding on that trip that resulted in a couple online friends who came on big cruisers to change their riding habits. He has a couple 600cc sportbikes (road and track) and she is riding her 2nd Ducati now.

I used to warn riders who redline their GSs to keep the exhaust valves down closer to the .003" end of the range but have dropped that warning over the 10 years since I and many others started using the wider setting. My valve log:

http://img.photobucket.com/albums/v443/jcp8832/GSvalvelogs_zps55f27f5e.jpg

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Super loose exhaust clearance?