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  Topic Review (Newest First)
10-15-2018 03:17 PM
Voyager
Quote:
Originally Posted by pdwestman View Post
Voyager, One test of automotive air filters vs 48 years of work experience on motorcycles with all different types & brands of air filters is not enough to change my opinion when it comes to motorcycle air filters.

Have you also noticed that Uni-Filter brand is the most open pore design of all major brand of oiled foam air filters which I am aware of?

I actually prefer the finer pore OEM or TwinAir or similar which work Very Well with SAE 40 or even 10W40. (Yes, I know the engine oils migrate inside of the air box, but easier clean-out than sticky stuff.)

I really like the Kawasaki road bike & atv fine pored oiled foam filters which have 1/8th inch tall Yellow Hair on their exterior. They should have used that material for all Kawasaki product, IMHO. The Hair reduces plugging of the foam pores, which allows easier air flow and longer service interval. And works very well with engine oils.
I am also using 49 years of experience with motorcycles, chainsaws, lawn equipment, heavy machinery, and two engineering degrees. And this is one test of many. I have never seen a single test where a foam filter captured particulates better than a paper element. If you are aware of such a test, I’d appreciate a reference. The main drawbacks of paper element filters are cost and lack of water resistance, however, some synthetic media now is pretty good in the latter regard.

You mainly find foam on small engines that will not see the hours or miles of most larger vehicle engines. Or as a prefilter before a paper element to catch the larger debris and extend the life of the paper element. The reality is that most off-road motorcycles will not see 30,000 miles and most lawnmowers similarly wont see 1,000 hours of operation. In those scenarios, the extra dirt passed by the foam filters won’t make much difference. It probably takes 50,000 miles or 2,000 hours before the lesser wear from the better filtration of a paper element begins to make a practical difference.

However, we each get to make our own decision in many cases. If an engine comes with foam, I stick with that. If an engine comes with paper, I stick with that. I will never switch from paper to a K&N foam filter. Some engines, like the Kawasaki’s in my John Deere’s, have the best of both worlds: A paper main element with rubber gaskets to provided excellent particulate trapping and a foam pre-filter to catch large stuff like bugs and grass and any water that may be ingested.
10-15-2018 11:08 AM
pdwestman Voyager, One test of automotive air filters vs 48 years of work experience on motorcycles with all different types & brands of air filters is not enough to change my opinion when it comes to motorcycle air filters.

Have you also noticed that Uni-Filter brand is the most open pore design of all major brand of oiled foam air filters which I am aware of?

I actually prefer the finer pore OEM or TwinAir or similar which work Very Well with SAE 40 or even 10W40. (Yes, I know the engine oils migrate inside of the air box, but easier clean-out than sticky stuff.)

I really like the Kawasaki road bike & atv fine pored oiled foam filters which have 1/8th inch tall Yellow Hair on their exterior. They should have used that material for all Kawasaki product, IMHO. The Hair reduces plugging of the foam pores, which allows easier air flow and longer service interval. And works very well with engine oils.
10-15-2018 07:15 AM
Voyager
Quote:
Originally Posted by timberfoot View Post
Thank you again for your advice and knowledge sharing guys.

PD Westman, I like the grease and washer idea, i will do that. I always seal around the base of the filter with grease before I put it bag in the air box.

I have to admit that I have never let my filter dry for as long as 24 hours. I usually put it in the sun for about three or four hours. it has seemed to be dry to me, but I will make extra sure that it is completely dry from now on.

Thanks guys

Timberfoot
Good foam takes a surprisingly long time to dry all the way through.
10-15-2018 02:00 AM
timberfoot Thank you again for your advice and knowledge sharing guys.

PD Westman, I like the grease and washer idea, i will do that. I always seal around the base of the filter with grease before I put it bag in the air box.

I have to admit that I have never let my filter dry for as long as 24 hours. I usually put it in the sun for about three or four hours. it has seemed to be dry to me, but I will make extra sure that it is completely dry from now on.

Thanks guys

Timberfoot
10-14-2018 08:24 PM
Voyager
Quote:
Originally Posted by pdwestman View Post
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.
Certainly you have to be careful using compressed air to clean a paper element. If you keep the nozzle 6” or so away from the paper, you will remove the loose dust on the external part of the filter and extend its life a fair bit with no damage to the filter. I have done this for 40 years without issues and most paper element manufacturers allow it.

I have to disagree that an oiled foam element is the “absolute best defence” against dust ingestion. Many tests have shown just the opposite. Oiled foam is the worst element at catching dust. It has less restriction so provides more performance and will withstand getting wet, but it is a much poorer filter of particulates. Here is just one test that shows this quite clearly.
ISO 5011 Duramax Air Filter Test Report

If you race and thus value performance over engine life, then oiled foam is the way to go. Similarly, if you ride or drive where the engine may ingest water, then foam is better. However, under all other conditions, a good paper element is the best dust and dirt filter you can get for a car or bike.
10-14-2018 05:52 PM
pdwestman 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.
10-14-2018 07:11 AM
Voyager
Quote:
Originally Posted by timberfoot View Post
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 aren’t that expense to replace. And they save a ton of maintenance time.
10-14-2018 04:28 AM
timberfoot 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
10-13-2018 09:50 AM
pdwestman +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.
10-13-2018 08:38 AM
Voyager
Quote:
Originally Posted by timberfoot View Post
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?
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