Kawasaki KLR 650 Forum

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-   -   Valve shims (https://www.klrforum.com/klr-other-motorcycle-related-discussion/69867-valve-shims.html)

John93klr 09-30-2018 01:28 PM

Valve shims
 
I just bought my 93 klr with 27,000 miles and pulled the valve cover to check clearance. The intake valves are tight fits with a .15 and .18 mm gauge but the exhaust side does not fit even the thinnest feeler gauge I have. I dont have a torque wrench that measures in inch pounds so I havent pulled the can to see what shims I have but I'm curious if I should pull the head to see how the valves look. The bike seems to run great. Any insite would be appreciated. Also if theres any one in nw Washington it would be cool to know some people in my area

Voyager 09-30-2018 03:12 PM

Quote:

Originally Posted by John93klr (Post 672877)
I just bought my 93 klr with 27,000 miles and pulled the valve cover to check clearance. The intake valves are tight fits with a .15 and .18 mm gauge but the exhaust side does not fit even the thinnest feeler gauge I have. I dont have a torque wrench that measures in inch pounds so I havent pulled the can to see what shims I have but I'm curious if I should pull the head to see how the valves look. The bike seems to run great. Any insite would be appreciated. Also if theres any one in nw Washington it would be cool to know some people in my area

I would not pull the head unless I had a reason to such as low compression. I would adjust the valves before riding much more. Once the clearance is gone, particularly on the exhaust valves, the valve heads will run ever hotter until damage occurs. Most of the cooling of the valve comes through its contact with the valve seat. Once the clearance is gone, contact with the seat will get progressively worse causing the valve to run hotter.

killerkaw 09-30-2018 10:16 PM

X2....

Quote:

Originally Posted by Voyager (Post 672881)
Quote:

Originally Posted by John93klr (Post 672877)
I just bought my 93 klr with 27,000 miles and pulled the valve cover to check clearance. The intake valves are tight fits with a .15 and .18 mm gauge but the exhaust side does not fit even the thinnest feeler gauge I have. I dont have a torque wrench that measures in inch pounds so I havent pulled the can to see what shims I have but I'm curious if I should pull the head to see how the valves look. The bike seems to run great. Any insite would be appreciated. Also if theres any one in nw Washington it would be cool to know some people in my area

I would not pull the head unless I had a reason to such as low compression. I would adjust the valves before riding much more. Once the clearance is gone, particularly on the exhaust valves, the valve heads will run ever hotter until damage occurs. Most of the cooling of the valve comes through its contact with the valve seat. Once the clearance is gone, contact with the seat will get progressively worse causing the valve to run hotter.


pdwestman 10-03-2018 02:29 PM

John93klr,
Purchase a 1/4 drive torque wrench in about the 40-200 INCH Pound range (klr owners say Harbor Freight is plenty good).

My thin headed Snap-On wrench (Pricey) fits under the frame rail, most won't, so you may need to use a swivel joint & extension.

The lack of a properly small torque wrench or the mis-understanding of its proper use has caused much unneeded grief & dis-pare in motorcycle forums.

Go at-least 4 sizes thinner on the Exhaust tappets. this should get from your current near '0' to approximately .008 inches. Each shim is + or - .002inch (.051mm) from the previous shim. It is simpler & more accurate to just use INCH feeler numbers for valve tappet measurements. (I have never found a feeler gauge graduated in .025mm increments)

timberfoot 10-13-2018 03:38 AM

Valve Clearance
 
Hello all

I have an off topic question, but it does relate to this thread.

My question is about valve clearances.

I thought that valve clearances would increase over time because of wear. My logic being that wear usually makes things smaller, so the gaps between those things would increase.

I have learned from this forum that the clearances decrease over time. I do not understand what causes the clearances to decrease. Can anybody explain why they decrease to me?

Thanks in advance

Timberoot

Voyager 10-13-2018 08:38 AM

Quote:

Originally Posted by timberfoot (Post 673325)
Hello all

I have an off topic question, but it does relate to this thread.

My question is about valve clearances.

I thought that valve clearances would increase over time because of wear. My logic being that wear usually makes things smaller, so the gaps between those things would increase.

I have learned from this forum that the clearances decrease over time. I do not understand what causes the clearances to decrease. Can anybody explain why they decrease to me?

Thanks in advance

Timberoot

If the greatest wear was between the cam and the lifter, then the clearance would increase. However, with valves, the greatest wear is inside the combustion chamber as that is a much more hostile environment. It is hot, has high pressure and little lubrication. The cam and lifters live a charmed life in comparison. So, the main valve wear is where the valve head contacts the seat in the cylinder head. Both the valve and the seat will wear. This lets the valve sink deeper into the head when it closes and thus the valve stem moves outward towards the lifter pushing it closer to the cam and thus reducing the clearance.

Make sense?

pdwestman 10-13-2018 09:50 AM

+1, Voyagers explanation is perfectly 'spot on'.

Improper air filter servicing, ie lack of thoroughly re-oiling the foam after clean or allowing a bad exhaust mid-pipe gasket to burn a hole in the bottom of the air box or even a missing cap on the clean air side drain hose can all lead to dust ingestion which accelerates internal engine wear in descending degrees of severity.

If and when we ever rebuild the top end of any engine, we need to re-cut the valve seats, replace the valves, measure the protruding length of the valve stems and trim the tips to near minimum length to allow adjustments necessitated by the wear-down process all over again.

timberfoot 10-14-2018 04:28 AM

Thanks for the replies guys

Voyager that does make sense. Thanks for that, and thanks for your advice Mr. Westman.
When I service my air filter, I first wash it in kerosene. Then I wash it in warm water with a small amount of dishwashing liquid it. I use the water to clean the Kerosene out. Then I put a small amount of foam air filter oil on the filter and squeeze and squash it until the oil is evenly distributed throughout the filter, and it appears to be one, even colour. Would you say that is an effective way of servicing the filter?

On the topic of the air filter, I worry a bit about the hole in the middle where the bolt goes through. That hole seems to be a weak point in the filter's ability to filter. I have thought about putting a rubber washer over that hole to seal it a bit better. Do you have any thoughts about that?

Thanks again guys

Timberfoot

Voyager 10-14-2018 07:11 AM

Quote:

Originally Posted by timberfoot (Post 673351)
Thanks for the replies guys

Voyager that does make sense. Thanks for that, and thanks for your advice Mr. Westman.
When I service my air filter, I first wash it in kerosene. Then I wash it in warm water with a small amount of dishwashing liquid it. I use the water to clean the Kerosene out. Then I put a small amount of foam air filter oil on the filter and squeeze and squash it until the oil is evenly distributed throughout the filter, and it appears to be one, even colour. Would you say that is an effective way of servicing the filter?

On the topic of the air filter, I worry a bit about the hole in the middle where the bolt goes through. That hole seems to be a weak point in the filter's ability to filter. I have thought about putting a rubber washer over that hole to seal it a bit better. Do you have any thoughts about that?

Thanks again guys

Timberfoot

That is about how I do it also. The main difference is that I just use Dawn and hot water and skip the kerosene. If you press the foam between a few sheets of paper or shop towel, most of the excess oil will be extracted. Dawn does a great job on the residual oil. Just let it soak a couple hours after squishing it around in the hot Dawn water. If you think it needs it, a second wash with a clean batch of Dawn will be icing on the cake.

The key is to let it dry for 24 hours or so before oiling again. If not thoroughly dry, the water trapped in the foam will prevent the oil from fully coating the foam. The water then later dries out leaving dry spots in the foam.

This is why I much prefer modern paper element filters. They work great and when they no longer clean with compressed air, they arenít that expense to replace. And they save a ton of maintenance time.

pdwestman 10-14-2018 05:52 PM

timberfoot,
I'll suggest to not be so stingy with the air filter oil.

I use enough air filter oil that I can squeeze at least a few driplets back out between my fingers. If one can't squeeze some oil back out of the foam, some areas of the foam are not oiled well enough.
If you would care to use a dab of grease under a fair sized flat washer on the air filter center bolt, it would be like most real dirt bikes I've owned or serviced.

A thoroughly oil foam air filter is the absolute best defence against dust ingestion for an internal combustion engine. I doubt that one could find a single competition dirt bike in the current market place which comes from the OEM with any other type.

Voyager,
High pressure compressed air can actually open the pores of paper type air filters and then allow slightly larger particulates to pass thru. They are intended to be used once & then disposed of!
One can thump and bump and tap the worst of heavy deposits out of paper filters as a quick & dirty short term 'fix', but replacement is best.

OEM motorcycle paper disposable filters are always pricey, aftermarket brands are less expensive, but people still attempt to re-use. Not a good plan, in my opinion.


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