Checking Valves for the first time.

[mrhedges]

Hello, as part of my rebuild project I decided to check my valves. All the intake valves are in spec but two of the exhaust valves are out of spec. I was able to get the one all the way to the right (if your sitting on the bike) which I think is #4? then use the manual to figure out the size I needed. I then tried to use the same with #3 which is the one just to the left and the tool kept snapping back. I can't get it in the right position to hold the valve down to get the shim out. It's extremely tight, like I couldn't get the smallest feeler gauge into there. Hopefully I didn't mess anything up.

here is a pic shared via google https://photos.app.goo.gl/ZGYDHrFwemQBGgpB8

here is a video https://photos.app.goo.gl/CDt3CUCmoEBs9RF37

am I doingt something wrong here? It took me a while to figure out how to get the other one out but once I got it in the right place it came out pretty easy but I am stumped on this one and don't understand why it's not working.

The other exhaust valve (the one got the shim out off) was over spec, I think the measurement was .107 and spec is .04-.08 while this one is super super tight, is this normal? I would think they would all be similar or at-least out of spec tight over loose? I think I read here somewhere that exhaust valves tighten up over time?

Here is my history with the bike. I bought it in 2017. It developed an oil leak from the base gasket so I decided to have the engine rebuilt by a friend who was started a shop specializing in vintage bikes. Ran it stock and it ran amazing for years. I rode it all over the country 4 times. Got stolen in 2020 recovered in 2021 pretty trashed (there's a thread about it here somewhere) The thief put pod filters on it and I decided to go with it (perhaps a mistake) so I had a different friend who is great with vintage Japanese carbs rejet the bike and with minimal work I ripped around town on it for a couple months. It developed some other issues so I decided to take it off the road and considering my busy life I don't have as much time to wrench as I'd like so I'm slowly going through it trying to make it a reliable around town bike for fun commuting.

[Rich82GS750TZ]

Yes, we always number the carbs and cylinders 1234 - Left to right as you sit on the bike.

Full Disclosure: I do not have nor have I ever done this, as I don't have an 8-valve engine. But I have read about it. On BikeCliff's Website - link in my signature - there is a Valve adjustment guide for the 8-valve engines and a Zip-tie method supplement. both linked below. Many members report less frustration using the zip-tie method rather than the bucket depressing tool that seems to be the issue. Check it out.

Valve adjustment:

https://gsarchive.bwringer.com/bikecliff/images/gs850valve_adjust.pdf

Zip-Tie Method:

https://gsarchive.bwringer.com/bikecliff/images/valve_tool_zip_tie.pdf

If you would like Steve's Excel Spreadsheet to help you with the math, send me a PM with your email address and I'll email it back to you.

[Nessism]

I use a small screwdriver alongside the shim tool, to keep it from jumping out. It takes some practice to learn the technique, but it works pretty well once you get the hang of it.

[mrhedges]

I use a small screwdriver alongside the shim tool, to keep it from jumping out. It takes some practice to learn the technique, but it works pretty well once you get the hang of it.

I'll have to try that one. The zip tie method looks interesting but I'm afraid of dropping the zip tie into the engine or messing something up, I'm a bit of a klutz.

[unfocused]

I've had the same issue and if you hold your tongue just right it can be done. Keep it as close to the lobe as possible. Big PITA...

[Burque73]

I'll have to try that one. The zip tie method looks interesting but I'm afraid of dropping the zip tie into the engine or messing something up, I'm a bit of a klutz.

Try it and you'll see how much easier it is. I have the tool, but prefer the zip tie.

If your readings are too loose I'd suspect the position of the cam lobes when measuring. For example, when checking exhaust valves for cylinders one and two, one lobe is level with the edge of the head and the other points away from the shim. In other words, neither of those two are pushing down on the shim. Same for the other side of the cam chain on exhaust three and four. If you are checking one at a time and rotating the crank after each one you may have inaccurate measurements. Also, if you swap a shim make sure to rotate the cam to squish out any oil under it before taking another measurements on that shim.

Hope that makes sense.

[Who Dat?]

I'll have to try that one. The zip tie method looks interesting but I'm afraid of dropping the zip tie into the engine or messing something up, I'm a bit of a klutz.

Ever since I have discovered the zip-tie method, that's all I use. I have the proper tool, but find it way too frustrating.

There is actually very little chance of losing the zip-tie if you do it correctly. First, get one that's at least 11 inches or so long. Fold it in half, use pliers to make a crisp fold. Use tape or some shrink-wrap to hold the ends together. Finally, make another fold, this one is about 1/2" from the folded end, and only bent to about a 45° angle.

When you rotate the cam (using the crank, of course), you can see the valve through the spark plug hole. Insert the zip-tie under the edge of the valve, rotate the crank until the cam is pointing away from the valve. It will now be VERY easy to remove the shim. To remove the zip-tie, simply turn the crank to open the valve to slide it out.

Another advantage of folding the zip-tie: If you are frugal, and hang on to the zip-tie for many (many) sessions, it will eventually get damaged enough to get cut. Since only one of the thicknesses will be cut, there will be no pieces falling into the cylinder. I have use the zip-tie method for about 15 years, and have only seen two of them get cut. Each of them had gone through about 20 valve adjustment sessions. Yeah, I work on a few bikes.

[salty_monk]

Yeah usually they should be tight. Also make sure they are "overnight" cold when you measure. You can't come in from a ride & jump straight in. if they are loose they've either been set wrong by a previous owner or something else funky is going on.....
Exhausts close up quicker than ignition but none of them are "quick". I would expect most bikes could be set on Top Tolerance after a few thousand miles & almost never need touching again... One "X" half step in Shims works out about 15k in my experience.

[mrhedges]

[QUOTE=Who Dat?;n1736746]

Ever since I have discovered the zip-tie method, that's all I use. I have the proper tool, but find it way too frustrating.

I agree. I took me about 10 minutes to figure out and I finally got it out. Thanks for the advice guys!

[mrhedges]

Yeah usually they should be tight. Also make sure they are "overnight" cold when you measure. You can't come in from a ride & jump straight in. if they are loose they've either been set wrong by a previous owner or something else funky is going on.....
Exhausts close up quicker than ignition but none of them are "quick". I would expect most bikes could be set on Top Tolerance after a few thousand miles & almost never need touching again... One "X" half step in Shims works out about 15k in my experience.

I always thought it was strange that the manual suggests valve checks every 3k miles.

[Datsa Noydb]

It's good to have them checked at the first scheduled service (usually 600 miles), then maybe again at 3k, but it takes a few measurements to establish a trend. After you see that they are not changing, you can extend the interval. My bikes are all well over 50k, so I only check them once a year, regardless of miles.