Running lean, getting awful mileage; not sure how to fix. 1994 K75

Service guy said that it's done and that 5 valves needed to be adjusted (as expected). I think I will be doing my own adjustments from now on. I have the tools I just didn't have the time and rely on my K for daily driving so I didn't want to chance any more downtime.

toddlamp said:

That might be the issue. I had them done and the bike was running great for 99% of my trip. It was on the last day that I started to have issues. However, it's hard to narrow down my problems to just the valves since there were a few things that needed to be looked at. The bike is done and I'm just trying to get in touch with the service department to find out what their "recommendations" (as the voice message said) are.

The tech gave me the specs last time but I didn't think to look at them. I will ask for the same info this time and probably double check it myself. There is one tech at Bob's that primarily works on old K bikes. I have talked to him before and seems more than competent.

Lee: Just so I have it clear, tight = less valve clearance and loose = more valve clearance right?

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If the numbers you gave us are accurate for the current valve clearances, that WAS your problem. With .004" clearance on #3 exhaust, once the engine warms up, you have less than .000" clearance. That means that the exhaust valve is not fully closing. That will cause all kinds of problems including stalling when brought to idle.

If that valve had been set to around .007", it might run ok for a while. Tight exhaust clearances speed up valve recession (which is what happened. It went from barely ok to terrible in 9000 miles) because the valve doesn't have the dwell time on the seat to cool it. I know it doesn't sound like much, but that is how exhaust valves loose heat (through contact with the seat). Intake valves are cooled by the inrush of the incoming air/fuel charge. That's why the exhaust valves need to be set looser than the intakes.


If they did the previous valve adjustment, THEY SCREWED UP!

Yes. Tight = less clearance Loose = more clearance.

Thanks for the help and wealth of knowledge. I will be double checking their work to see where they shim it to.

The fact that they had to do 5 out of 6 valves PROVES that they were done wrong the first time.

And the fact that they are only doing 5 proves that they don't understand (or care?) what they are doing. Yes #2 intake is technically within spec. (.006-.008"). The fact that they have to change all the others but not that one means that they have a "close enough attitude". Tighter Intakes give you better performance and looser exhausts give you longer periods between adjustments.

It's a VERY good reason to do it yourself (Not counting the cost savings).

Doing a valve adjustment check is VERY easy and quick on a 2-valve K-bike.

You don't even have to remove the spark plugs as all the manuals recommend.

Engine MUST be cold (less than 92 degrees F.)

Remove valve cover.

One of the intakes and one of the exhausts (different cylinders) will be on the heel of the cam (the position for checking its clearance). Check those two and write them down.

Put bike in neutral, turn key and kill switch on. With your right thumb on the starter and your left hand on the kill switch, tap the starter and quickly kill the kill switch (don't want it starting with the valve cover off).

This will have bumped the engine over a little bit. It will almost always end up with two valves in position to check. Repeat until all valves have been checked. 2 bumps for K75. 3 for K100.

Replace valve cover and gaskets. Don't forget the grounding spring that goes on one of the cam journal caps.

Total time for K75 = less than 1/2 hour (unless one needs to be changed. Then add 10 min. per valve if you have the proper shims).

98lee said:

And the fact that they are only doing 5 proves that they don't understand (or care?) what they are doing. Yes #2 intake is technically within spec. (.006-.008"). The fact that they have to change all the others but not that one means that they have a "close enough attitude".

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You know I was just thinking about that. What I am worried about even more is that because that single valve was technically in spec they set all the other valves to the same spec leaving all the other valves right at the same "barely in spec" measurement.

I have the tools to do the swap but when I was looking at it last night I couldn't find any tutorials on how to do it and it didn't seem as intuitive as I had hoped. Hopefully the tech jotted down his measurements and the resulting shims that were used so I know exactly where they are now. Otherwise I will just go in and measure myself. Then I can at least have a running bike while I look into doing my own shim job to get them to the specs you suggested.

Ugh... this is the reason why you should do the maintenance yourself.

I got the bike back tonight and it is running ok. Here is the new specs of the valves (this is based off of the tech notes):

Cyl 1 Intake:
measured clearance: .25mm
old shim: 2.4mm
new shim: 2.35mm
new clearance: .30mm

Cyl 1 Exhaust:
measured clearance: .20mm
old shim: 2.5mm
new shim: 2.45mm
new clearance: .25mm

Cyl 2 Intake:
measured clearance: .20mm (in spec no adjustment)

Cyl 2 Exhaust:
measured clearance: .23mm
old shim: 2.4mm
new shim: 2.35mm
new clearance: .28mm

Cyl 3 Intake:
measured clearance: .25mm
old shim: 2.4mm
new shim: 2.35mm
new clearance: .30mm

Cyl 3 Exhaust:
measured clearance: .063mm
old shim: 2.40mm
new shim: 2.15mm
new clearance: .31mm

I have not confirmed this yet but I will check them tomorrow myself.

toddlamp said:

Ugh... this is the reason why you should do the maintenance yourself.

I got the bike back tonight and it is running ok. Here is the new specs of the valves (this is based off of the tech notes):

Cyl 1 Intake:
measured clearance: .25mm
old shim: 2.4mm
new shim: 2.35mm
new clearance: .30mm

Cyl 1 Exhaust:
measured clearance: .20mm
old shim: 2.5mm
new shim: 2.45mm
new clearance: .25mm

Cyl 2 Intake:
measured clearance: .20mm (in spec no adjustment)

Cyl 2 Exhaust:
measured clearance: .23mm
old shim: 2.4mm
new shim: 2.35mm
new clearance: .28mm

Cyl 3 Intake:
measured clearance: .25mm
old shim: 2.4mm
new shim: 2.35mm
new clearance: .30mm

Cyl 3 Exhaust:
measured clearance: .063mm
old shim: 2.40mm
new shim: 2.15mm
new clearance: .31mm

I have not confirmed this yet but I will check them tomorrow myself.

Click to expand...

Whoops! If correct, not right!

That's not even in spec. for the intakes let alone the desirable setting.

It's very obvious they have some issues with their technicians (and I use the term loosely). They can't even read the manual let alone set the valves to the optimum setting.

That's pretty bad since they knew they screwed up the first time to screw it up again. That's attention to detail for you!!!!

I sure hope they didn't charge you for doing it wrong----AGAIN!!!

98lee said:

That's not even in spec. for the intakes let alone the desirable setting.

It's very obvious they have some issues with their technicians (and I use the term loosely). They can't even read the manual let alone set the valves to the optimum setting.

That's pretty bad since they knew they screwed up the first time to screw it up again. That's attention to detail for you!!!!

I sure hope they didn't charge you for doing it wrong----AGAIN!!!

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They don't know about it yet. I picked up the bike after hours so it was already paid for. Oh and the service dept is closed tomorrow, Sat, Sun, and Mon!!

I will be calling them first thing Tuesday to have a word with the service guys. I also don't like that they charged me $4.59 for each of the 5 shims and didn't return my old ones!!

In the interests of inches and millimeters, the Haynes says (cold):

Intake - 0.15 - 0.20 mm / 0.006" - 0.008"
Exhaust - 0.25 - 0.30 mm / 0.010" - 0.012"

98lee said:

That's not even in spec. for the intakes let alone the desirable setting.

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I am pretty sure that it was just a calculation error. The tech has 2.40mm as the shim thickness and then writes 2.45mm but crosses it out and writes 2.35mm. My guess is that he confused himself. That's said because he also wrote .15-.20 at the top indicating that he knew the specs.

As I said before I need to verify this for myself before I start making calls.

My earlier assumptions were right. I just test the clearances.

Cyl 1
In: .33mm
Ex: .25mm

Cyl 2
In: .178mm
Ex: .275mm

Cyl 3
In: .305mm
Ex: .275mm

Looks like Bob owes you a couple of free shims

Ted said:

Looks like Bob owes you a couple of free shims

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And a refund for BOTH valve adjustment labor charges!!!!

Plus the shims they removed. They charged you list +10% for the ones they put in. In most states you are entitled to the parts they take off.


That is pathetic, especially since they knew there was a problem from before! I thought Bob's was supposed to be one of the good dealerships.


IF the measurements you got are accurate AND the measurements of the shims that they put in are accurate:

Put a 2.50 shim in the #1 Intake

Put a 2.40 shim in the #1 Exhaust

Put a 2.50 shim in the #3 Intake

The rest are as close as you can get them to what you want.


If they give you the shims that they removed (and charged you for) in the first and second valve adjustments,you will have a small selection that you might be able to use the next time you do your own valve adjustment.

The MAJOR problem was the #3 Exhaust (it usually is). They could have caused a burnt valve from the way they adjusted it the first time. Check the compression (especially #3). If the compression is good, I bet all your drivability problems are gone, even with the intakes being so far off.






.

How many miles are on this bike?

lostboy said:

how many miles are on this bike?

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38,300

That's not many miles.

I shimmed 5 valves on my '94 K75RT this week at 59000 miles. I've had the bike since it had about 8000 miles on it and this is the first time I've had to make any adjustment.

Jordan

98lee said:

The MAJOR problem was the #3 Exhaust (it usually is).

.

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Any particular reason why #3 exhaust is susceptible?

mljordan said:

That's not many miles.

I shimmed 5 valves on my '94 K75RT this week at 59000 miles. I've had the bike since it had about 8000 miles on it and this is the first time I've had to make any adjustment.

Jordan

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This is the second valve job i've had done in the 29,000 miles that i've owned it.

toddlamp said:

Any particular reason why #3 exhaust is susceptible?

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It develops the most heat. Even though they are water cooled, #3 seems to run slightly hotter because it has less air flow helping to cool it.