Rebuilding a new set of George's "REBUILT" Carburetors

[Guest]

Keith, you really have me confused now. "OldVet66, your valve clearances are too tight. .002 isn't acceptable. .003 is the minimum." The Suzuki manual states 0.03mm-0.08mm (0.001in-0.003in). that puts me at .0508mm clearance on all valves except #3 & #4 intake with .0762mm clearance. I was shooting for the middle of the scale, and got it on all but two. Some of the shims had the size facing up, and rubbed off, so I got to play the shim game until I finally found the right size. At least I have something I can work with now. Hopefully you confused my measurements. I Had ordered a gauge from Z1 that is marked .05 .002 on one end and .08 .003 on the other end. I am assuming this gauge is from the middle to the end of the allowable scale. in both millimeter and inch scales. I used another much longer set of feeler gauges when I was adjusting and had .001, .002, .003 and .004 out so I didn't get anything too tight or loose. What clearance should I be adjusting to? Statements in the Suzuki manual lead me to believe they meant the middle of the scale. My name is Roger, by the way. The OldVet66 comes from what happened after I graduated High School in 1966. I'm retiring the bike tomorrow until the motor is swapped, adjustments properly made and new Avon tires to replace my new Metezler tires that are cracking along the sidewalls again.

 

[Steve]

OldVet66, your valve clearances are too tight. .002 isn't acceptable. .003 is the minimum. Get the right shims. There are also "fat" shims available that allow much finer adjustments than just every .005 They are designated by an "X" in front of the thickness number. They are great when you have a borderline .008 but the next thinner shim somehow results in a tight .003. Always error on the loose side. Much better to have a .008 which is the maximium acceptable clearance than making a change that results in anything less than .003 Be sure they are Suzuki shims, not Kawasaki (different diameter/common mistake believe it or not).

Keith, you really have me confused now. "OldVet66, your valve clearances are too tight. .002 isn't acceptable. .003 is the minimum." ... I Had ordered a gauge from Z1 that is marked .05 .002 on one end and .08 .003 on the other end. I am assuming this gauge is from the middle to the end of the allowable scale. in both millimeter and inch scales. I used another much longer set of feeler gauges when I was adjusting and had .001, .002, .003 and .004 out so I didn't get anything too tight or loose. What clearance should I be adjusting to? ...

This just illustrates the FUN of having the same number show up in two different measuring systems.

Keith, you are confusing inches and millimeters. The proper clearance is 0.03mm to 0.08mm, NOT 0.003 to 0.008. See the extra zero? Makes a BIG difference. OldVet66 appeared to be giving dimensions in INCHES (although he did not really say so), so 0.002 INCHES is a proper clearance. The range in inches is 0.0012" to 0.0031". Most INCH feeler gauges only go down to 0.0015", so take that as your minimum. If that does not fit, go to the next smaller shim.

This is the perfect illustration for why you should really use METRIC feeler gauges for your valve adjustments. Since the shims are sized with metric numbers, it is so much easier to understand what you need.

OldVet, did you use the spreadsheet I sent you last month? That should have eased your mind about your clearances and shim sizes. With the spreadsheet, though, it does not really matter whether you use inches or millimeters to check your clearance, it will handle them both with equal ease.

If you have questions about it, please let me know.

Now to address Keith's comment about Kawasaki shims:
Unless you have calipers with you, it can be difficult to tell the difference. The Kawasaki (and Yamaha) shims are 29.0mm in diameter, the Suzuki shims are 29.5mm. Yes, that silly 0.5mm makes a difference. One thing to watch for, if you get your shims at a shop that sells multiple brands, make sure you got the right ones. Because I used to have a Kawasaki and my son currently has a Yamaha, I have a box of 29mm shims, VERY CLEARLY LABELED. I have another, very similar box of 29.5mm shims for our Suzukis, VERY CLEARLY LABELED. I try to not get both boxes off the shelf at the same time, just to minimize the possibility of cross-contamination.

.

 

[Guest]

Sorry for the confusion, I was using what was at hand. I'll be getting metric gauges as soon as possible. If I bring #3 and #4 intake down to 0.002 in, will this be where I want to be, or should I get back into the shim box and go in another direction? The manual states " too small a tappet clearance may reduce engine power; too large a tappet clearance increases valve noise and hastens valve and seat wear." That's why I shot for the middle of the range. I used WD 40 for a temp. lube. A .2.5 in. long 0.001 gauge is mighty thin. I thought I would get more accurate readings without the shim floating on a thicker oil. I was going to go back through and coat them with engine oil once I was sure I had things right. I need to go back through and check them again in pairs as the manual states. I did check each one individually in both positions ( in most cases many times), so I'm close.

 

[Guest]

I also had a lot of problems with George's carb, I in fact never got them to work. He took like 6 months to get them done in the first place. On the upside I have a nice heavy paperweight.

 

[Guest]

Well, what goes around comes around. just make sure you have the nice heavy paperweight properly aligned when that door smacks him in the ass.

 

[Guest]

I rechecked the valve clearances again using the procedure in the Suzuki manual, and there was quite a bit of difference in my readings. I also used a gauge that I has gotten from Z1, with an angled .05mm on one end and .08mm on the other end (.002in-.003in). Very easy to use compared to the longer gauges. three valves were correct at .05mm. I had enough shims in the kit to check each bucket with a shim smaller and larger than what was in there. I ended up with 5 valves that the next larger shim did not provide enough clearance for the .05mm gauge, but the next smaller shim allowed a snug fit for the .08mm, so it looks like all 5 are sizes in between standard shim sizes. I need a 2-50x, 2-55x, two 2-60x and a 2-65x.

 

[KEITH KRAUSE]

Roger, sorry about the confusion on measuring. As Steve said, I looked at the numbers wrong. Somehow I looked at your posted numbers as ".02" in mm, and looked at it as .002 mm. At least the error appears to have led you back to measure them again using the factory procedure. Now that you got different measurements I assume you took the first reads using another method. So I'm glad it worked out for the better.

Steve, thanks for backing me up about the differences between Kaw' and Suz' shims. Many dealers sell both brands and you can be sold the wrong shim. I'm pretty sure the type of print used for the stamped number by Kaw' is a little different too. If you have both you can see the difference. But obviously, the different diameters is what matters.

 

[KEITH KRAUSE]

Also, I'd use only motor oil on the shims as part of making an accurate measurement. Not sure how different the results would be compared to using WD40 but it's best to do what the factory manual says.
I'd bathe them all in oil and cycle the motor a few times and then take measurements. Gotta use the right thickness gauge that goes down to .03mm too.

 

[Guest]

Keith, I've got the hang of the factory procedure now. I've rechecked it 4 times and am sure of my measurements. I don't like what I am seeing. The last time through with a complete factory shim kit except 2.50mm, I was only able to get six valves in spec. Three were .05mm and the other three were .08mm., mixed intake and exhaust. One of the others might be in spec with, You guessed it, a 2.50mm shim, the only one missing in the factory kit. The other one is out of spec both ways and needs a 2.55 x. I know they make them because I have 5 X shims in the box, but in the 2.80mm and 2.90mm range. I can't find a source of X shims. I gave up in frustration and pulled the 3,800 (original mile) motor from my '79GS1000E parts bike today. I will start checks on it as soon as I can get it over to the GS Motorcycle Shop under the O'Unison's Pub. Chris has 4 GS bikes down there, two 750E's and two Gs 1000's, one an original S model, and my motor, soon to be motors. The engine paint under the grunge is almost perfect except a few corrosion bubbles. Is there a match to that paint that you know of? This motor looks too nice not to go the whole way with it. I hope the inside is as nice as the outside. I'll let you know soon. You wouldn't know of a source for X shims would you? I understand some of the British cars used the same diameter shim. I'm trying to track them down, hoping their thickness is in between our sizes.

 

[Steve]

I'm pretty sure the type of print used for the stamped number by Kaw' is a little different too. If you have both you can see the difference. But obviously, the different diameters is what matters.

Since I had both, a Kaw and a Yamaha, the shims got intertwined in that box, not sure I could tell the difference between them. Yes, the print that they use is different than what Suzuki uses, but then so are the shims you get from Z1 for your Suzuki, so you can't just use the font to tell what you have.

The other one is out of spec both ways and needs a 2.55 x. I know they make them because I have 5 X shims in the box, but in the 2.80mm and 2.90mm range. I can't find a source of X shims. ... You wouldn't know of a source for X shims would you? I understand some of the British cars used the same diameter shim. I'm trying to track them down, hoping their thickness is in between our sizes.

As far as I know, your only source for X shims is to luck into them. There is no place where you can order them, with the possible exception of the "shim club" here on GSR. I have never used them, I don't know what's available.

What is the obsession with having to use the X shims? Your clearance can go all the way down to 0.03mm, not the 0.05 that you are using. The entire range of allowable clearances will take you from one shim size to the next. Yeah, the X shims let you split the difference, but there is no real need.

Depending on your comfort zone, you can also set your clearances a bit larger, to 0.09 or 0.10mm. The valves will not make any more noise, you may lose a bit of horsepower at the top of the rpm range, but will gain a bit or torque in the middle, which is better for street riding, and it will be longer before your next valve adjustment.

I have also heard about a car maker using 29.5mm shims, but never heard which one. Chances are, though, that they would use the same .05mm increments, so good luck with that. If you find out which car, please let us know.

.

 

[Guest]

The one that needs the X shim is too tight with a 2.60mm shim, yes it might just make the .03mm, it's too loose with the 2.55, (.10mm). These adjustments are all over the board and will not get close with any combination I have tried. If I had all the sizes, I could dial them all in to a specific value within the acceptable range and I would feel comfortable with that. This motor is an unknown, from Ebay. I don't understand the erratic wear on this motor. I suspect I will see a more even wear pattern on the motor I pulled today. If that is the case, the Ebay motor may have been a Frankenstein assembly of odds and ends from other motors, explaining the strange wear pattern. This is the first one I have tried, and I don't know what is normal or not. I would think all values within the specs. should be adjusted to be the same, or is that an impossible task with these motors.

 

[Steve]

The one that needs the X shim is too tight with a 2.60mm shim, yes it might just make the .03mm, it's too loose with the 2.55, (.10mm). ...

If a 2.55 shim makes it .10mm clearance, a 2.60 should make it .05mm. :-k

If it was my engine, I would run the 2.55.

.

 

[Guest]

It should, but it doesn't. I've even had my friend set it up to avoid me making the same stupid mistake every time, and it's too tight for the .05mm gauge with a 2.60 shim in there. Tried several different 2.60 shims, and will be ordering another gauge from trying to make it do what it's supposed to do. .10mm was an easy fit with a long feeler gauge, apposed to the easier to use angled gauges (can see why they sell them in cards of 6). The gap could have been a little wider.

 

[KEITH KRAUSE]

You have to use the correct feeler gauge or it complicates things. Using a gauge that doesn't go down to .03 just makes it more difficult. I know it doesn't make much sense but I too have often found that even a "wide" .08 measurement that should become a .03 when the next thinner shim is used just won't allow the gauge to slip in. I've cycled the motor to "set" the new shim if you will and still get a read that contradicts what should be. I always go with the .08 in this case.
I wouldn't go outside the factory range of .03 to .08. Guess I've been lucky. I found X shims locally years ago. Only needed a couple. Typically, a 2.55 X shim is really 2.57 or at the most and less frequently 2.58. Same difference for all the sizes. They come in very handy and can help you fine tune the clearances and avoid being right at the minimum or maximum clearance.
What's exactly happening in your case I'm not sure, especially when you say you've tried several shims stamped the same thickness. What I said above about it not making sense is just the way it is and using that .05 gauge is adding to that. If you're sure you're taking the measurement correctly (factory procedure and oiled shim) I'd measure the 2.60 shim with calipers or verniers to verify. Then verify the 2.55. If both are correct, then you can be sure the .10 clearance will become .05 or very close (certainly not less than .03) when you swap the 2.55 for the 2.60. If you were using the right thickness gauge you wouldn't be having this issue.

 

[Guest]

I'm pretty sure of those measurements. I do have a gauge that goes to .03mm, but it's not like the nice angled one from Z1. I suppose I will have to sacrifice a standard set and make one so I can accurately check all possibilities. Using the proper type of gauge makes all the difference in the world. I might be able to check the '79 motor tonight, but I have a leaking hot water heater that needs immediate replacing before we have a real mess.

 

[Guest]

It seems that things are finally looking up for a change. I got a look at the motor on the '79 today. Absolutely no sign of wear on the cams. All the valves are in spec., .05mm and .08mm. The bike this motor came from had 3,802 miles on it. Either the first valve adjustment was done just before it was parked, or it didn't need one. The motor had been fogged down before storage. I will swap motors this weekend and run a compression test. I'll go back through the carburetors and check the floats and do a proper bench sync. We have a Color Tune, but it might be several weeks before I can order the Morgan Carb Tune manometer. Finally moving forward.

 

[KEITH KRAUSE]

Good deal. Let us know if you need help.

 

[Guest]

Had a bit of a long day today. Spread the tarps out in the driveway parked the bike to one side, hauled the new motor up beside it and proceeded to change the motor. got properly sunburned in the process. I don't have a timing light yet, so I scribed around the washers on the plate for my Dyna S ignition, so I could get it close. fast forward to the end of the day with everything assembled, primed the carbs gave it a little choke, and it fired immediately. This motor is sweet. I installed my new carb boots, used Rotella T 15W40. The front sprocket on this motor has 14 teeth apposed to the 16 teeth on the other motor. It has lots more low end power, hope it doesn't effect mileage too much, I'm liking it. Next stage is to sync the carbs. I still have to order the Morgan Carb Tune, so It will be a little while until I'm ready to sync it.