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Discussion Starter · #1 ·
I thought maybe I could contribute some useful information regarding refreshing a head. I've had (I think) 6 heads apart, Gen 1 & Gen 2, have seen some pretty bad valve & valve seat wear, on engines that didn't have particularly high mileage on 'em. You can get a pretty good idea of how much valve & valve seat wear an engine has, by the shims required to get valve lash in spec. Each shim increment of adjustment, equates to approximately .002" the valve has recessed (worn) deeper into the head. Worn valves & valve seats affects compression (performance). So often I see guys addressing high oil consumption, replace the piston & rings, but don't refresh the head, only doing 1/2 the job IMO - most mid to high mileage engines could benefit from de-carboning, and at least lapping the valves to restore compression. The Eagle Mike head refurbishment program, at $190 USD, is a bargain IMO.

This is a head from an '01 Gen 1 that I took in trade (set a friend up with a 685 I built), and I think it had around 50,000 miles/80,000 kms (was a bad oil burner). This is, unfortunately, usually the condition I find heads in when I disassemble 'em.



The max width, as per the factory manual, for the valve contact patch on the valve seat, is 1.2mm, both intake and exhaust. The intakes are at max, and exhaust over 2mm. The valve seats are badly pitted, especially exhaust. This head requires valve seat regrinding, and two new exhaust valves.



Here's a few tools of the trade. I'll illustrate/document the process as I progress (if there's interest).

 

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Sounds good!

As I've mentioned, I'm currently going to be putting together my 685. The bike is a 2001 that doesn't burn any appreciable oil between changes and it has about 30,000 kms (19,000 miles) on it. I didn't follow my own advice and am installing the BB kit on a bike that ran just fine before! My plan was to do a solvent test to ensure the valves were sealing and that they and the seats are in good shape and then just doing a general de-carboning.
I'll follow you thread with interest.


Dave
 

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Discussion Starter · #4 ·
Will you be doing standard size valves?
Yes, I think so. I'll probably go with the Schnitz aftermarket valves on the exhaust. Regarding going 1mm oversize on the valves, where can you get that done nowadays? I notice the M-Tech KLR650 web page ( http://www.mtechmotorcycles.com/performance-projects-kawasaki-klr-685-705-kits.htm ) no longer works - have they closed?

I'm going to preface this "how-to" by saying, know your limits with respect to your personal capabilities. I personally think most people can accomplish amazing things, but these tasks (and that's how I view them) done improperly can ruin your head... the tolerances between the valve shim buckets & bores, and the valves & valve guides are very tight. If you nick (damage) a valve seat, that will require (expensive) re-grinding... not a DIY job.

You'll notice in previous pics, the combustion chamber was already de-carboned... with valves left in. I use a small screwdriver, on which I've taken like 400 grit sandpaper and radiused the edges slightly to reduce the possibility of gouging the soft aluminum. I use sandpaper, and 3M Scotchbrite pads to finish up. Don't remove any metal - enlarging the combustion chamber reduces compression ratio.

With the combustion chamber cleaned up, time to pop the valves out. The shim & buckets should come out easily - if not, you've likely got scratching in the bucket bores (carefully dress that out with 800 grit). With the buckets removed, use an automotive valve spring compressor tool ( https://www.princessauto.com/en/detail/valve-spring-compressor/A-p8003725e ) to compress the spring, and remove the locking collets. Be careful to keep each end of the tool centered - don't let the steel compressor end touch the (easily damaged) aluminum bucket bores!







Once you've popped the valves out, next step is to block off all areas you need to protect from crud - de-carboning and porting makes a mess, and you don't want that getting in the oil passages, valve guides, etc. I roll up pieces of paper towel, and wad it in the spots needing blocking off:



Don't forget to plug the oil line orifice, and remove the rubber intake boot. I install the valve cover back on, to keep debris outta there:



Ready for de-carboning... tomorrow. Ugly job that it is.
 

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I've found that the Thailand plant rarely cut the Most Important 60 degree angle on the exhaust valve seats to properly narrow the exhaust valve seat, seating surface for good sealing and long life.

Have you experienced the same fault?
 

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Discussion Starter · #6 ·
I've found that the Thailand plant rarely cut the Most Important 60 degree angle on the exhaust valve seats to properly narrow the exhaust valve seat, seating surface for good sealing and long life.

Have you experienced the same fault?
Hi PD. Can't say I've noticed that specifically, but I would say I noticed a difference in the shims that Gen 2s come out of the factory with. There appears to be thinner shims than what used to come with Gen 1s - when performing valve adjustments, on lower mileage Gen 1s, I found it not uncommon to find 275 or 280 shims... Gen 2s I'm finding 260, 265 factory installed. This means they are (needlessly?) removing more materiel during grinding & lapping, recessing the valves deeper. Seems a shame, as you'll run out of adjustment shim sizes sooner.

What I see though, is by the time exhaust valves require 225 or 230 shim size, that contact patch is very wide, like 2.5 to 3mm... i.e. re-grind is required before running out of shim sizes. The crazy thing, is they seem to still run OK like that, with badly pitted worn valves and valve seats. The power goes soft tho, as the compression fades. Around here, they use crushed limestone for gravel, and that dust is, I suspect, very abrasive. No air filter is 100% efficient (there's always some particulate getting thru), and I suspect wear rates correspond to what's seen in the way of exposure... and air filter maintenance!

Related... just like on the head I've got here/am working on now, on most of the previous heads that I've had apart, I generally see exhaust seats wearing way faster than intake. I suspect that's carbon bits getting caught between the seat & valve on the way out, causing pitting.

Thoughts? See the same?
 

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Yes, I think so. I'll probably go with the Schnitz aftermarket valves on the exhaust. Regarding going 1mm oversize on the valves, where can you get that done nowadays?

No where unfortunately. I bought the last three 1mm oversize valves from Schnitz Racing. M-Tech didn’t have any in stock and said they’d order them, but I haven’t heard anything back from them. Schnitz Raving is no longer making them. If you find a 1mm oversize intake please let me know.

In the meantime I’m looking at a quad ported head where you use stock and oversize valves.
 

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Discussion Starter · #8 · (Edited)
No where unfortunately. I bought the last three 1mm oversize valves from Schnitz Racing. M-Tech didn’t have any in stock and said they’d order them, but I haven’t heard anything back from them. Schnitz Raving is no longer making them. If you find a 1mm oversize intake please let me know.

In the meantime I’m looking at a quad ported head where you use stock and oversize valves.
That's too bad. For the larger displacement big bore kits, I think those oversize valves would make a difference. I see in the KLR Chris 60 hp EFI project bike, that he used a 1mm oversize valve head - I wonder who did that for him?

One thing about it, if you stick with stock size valves, you can get the valves re-ground at a dealer. I sent one head to E-M for refurbishment, and have had the local Kawi dealer re-cut the valve seats on two or three heads. The lead tech there does a fantastic job grinding & lapping valves, but it costs me dearly to get it done there.
 

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That's too bad. For the larger displacement big bore kits, I think those oversize valves would make a difference. I see in the KLR Chris 60 hp EFI project bike, that he used a 1mm oversize valve head - I wonder who did that for him?

I believe KLRChris did it himself. I too think the larger valves would be of benefit. My cylinder is in EM’s hands now getting the 719cc BBK installed. I’m going to be sending my crankshaft out to Crank Works Inc. to be modified as a stroker. If I can get a quad port head maybe it’ll be an even better engine for my needs. I have an ongoing thread on it now.
 

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Discussion Starter · #10 ·
I believe KLRChris did it himself. I too think the larger valves would be of benefit. My cylinder is in EM’s hands now getting the 719cc BBK installed. I’m going to be sending my crankshaft out to Crank Works Inc. to be modified as a stroker. If I can get a quad port head maybe it’ll be an even better engine for my needs. I have an ongoing thread on it now.
I'll check out your thread. Maybe give Chris a call - he's very helpful.
 

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I've found that the Thailand plant rarely cut the Most Important 60 degree angle on the exhaust valve seats to properly narrow the exhaust valve seat, seating surface for good sealing and long life.

Have you experienced the same fault?
I wonder if that wide seat was purposely cut that way?

A wider seat will transfer more heat from the valve to the head compared to a narrower seat, albeit at the expense of some loss of sealing ability.

Also, when folks grind the valve seats is there concern about sinking the valve too deep in the head? And what about valve stem length; is it/can it be trimmed accordingly?

Jason
 

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Also, when folks grind the valve seats is there concern about sinking the valve too deep in the head? And what about valve stem length; is it/can it be trimmed accordingly?

I know that stems can be trimmed. It’s going to happen on my build. Which brings up another question though ...

Valve seats are generally cast right into the head from what I’ve seen. I’ve also seen steel, copper, or alloy valve seats put in or added as a replacement. So, the question is ... which is best?

I mean copper is soft but absorbs heat well, but wears quickly. Steel is harder and lasts longer. Got no idea on the benefits of an alloy valve seat.
 

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Discussion Starter · #14 · (Edited)
There are instructions in the factory manual on re-cutting the valve seats, and that guidance didn't change between Gen 1 & 2. They don't really discuss how far the valves can be recessed into the head, but IMO you've really probably got only 1 valve grind you can do before you run out of room. Regarding tipping the valve stems, I do that, but it's not mentioned in the factory manual. By tipping the valve stems the proper amount, you can bring the shim needed (when performing valve adjustment) back in to the middle of the shim size range.

For example, let's say the head was removed for a valve grind, at the point where 240 shim size was installed. Grinding the seats enough to remove the pitting, might remove .010" to .020" materiel, recessing the valve that much deeper into the head. There are only 8 thinner shims (235, 230, 225, 220, 215, 210, 205 & 200) you can get for adjustment, and each shim adjustment is approx .002". Regrinding could result in the required shim being something like 210. You'd have two adjustments left! This is why "tipping" the valve stem becomes necessary. You can calculate how much to "tip" the valve stem to start over with shims in the 260 to 280 range.

One point - when tipping the valves, it's important to leave a non-abrasive surface. I saw in the forum threads somewhere, a picture of a tipped valve (refurbished at E-M) which had ground it's way a bit into the underside of the bucket. I radius the edges of the stem end slightly after tipping, with 400 grit, maybe finish up with 600 or 800.



Here's your inspection wear limits:



My understanding is the cutter tools are pretty expensive:

 

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I wonder if that wide seat was purposely cut that way?

A wider seat will transfer more heat from the valve to the head compared to a narrower seat, albeit at the expense of some loss of sealing ability.

Also, when folks grind the valve seats is there concern about sinking the valve too deep in the head? And what about valve stem length; is it/can it be trimmed accordingly?

Jason
I personally believe that the skipped step of 60 degree inside cut is/was just another short-cut by that 3rd world plant!
Just like only using the large bushing sized drill bit (instead of 2 sizes of bits) on the alternator case which resulted in the overly 'Deep Hole' for the starter reduction gear shaft.
Who's gonna' miss another HP or two this old tractor engine?

I have to suggest that there is a BIG difference between the service spec Maximum of 1.2mm wide valve seat surface and the 2.5 - 3.0mm wide seats that I found on the three 2009 oil burners that I installed 685's into. Like GWN suggested, it unnecessarily consumed available future maintenance opportunities.
Extremely too wide of seating surfaces do Not seal as well because of too much surface area to achieve high enough PSI of contact pressure. Therefore the 2 involved surfaces both wear/erode faster.

I've used hand held Neway valve seat cutters on a total of 5 KLR heads. I aim for a .9 - 1.0mm cut seat width. I used new valves (in the 2 OLDER KLRs) to ensure the most available future shim selection, and lapped them in.
The finished seat pattern will show 1.0 - 1.1mm wide on the face of the valve. The 3 '09 oil burners and the 2 older bikes all had the valve stem tips trimmed 0.3 - 0.4mm (.012 - .016inches).
Very time consuming hand work, using dial caliper, Magic Marker, spark plug gap wire gauge & magnifying glass.

One should Not trim/tip the valve stems more than 0.4 - 0.45mm (.016 - .018inches), IMO. Due to possible contact between spring retainer & tappet bucket.
 

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Discussion Starter · #16 ·
I personally believe that the skipped step of 60 degree inside cut is/was just another short-cut by that 3rd world plant!
Just like only using the large bushing sized drill bit (instead of 2 sizes of bits) on the alternator case which resulted in the overly 'Deep Hole' for the starter reduction gear shaft.
Who's gonna' miss another HP or two this old tractor engine?

I have to suggest that there is a BIG difference between the service spec Maximum of 1.2mm wide valve seat surface and the 2.5 - 3.0mm wide seats that I found on the three 2009 oil burners that I installed 685's into. Like GWN suggested, it unnecessarily consumed available future maintenance opportunities.
Extremely too wide of seating surfaces do Not seal as well because of too much surface area to achieve high enough PSI of contact pressure. Therefore the 2 involved surfaces both wear/erode faster.

I've used hand held Neway valve seat cutters on a total of 5 KLR heads. I aim for a .9 - 1.0mm cut seat width. I used new valves (in the 2 OLDER KLRs) to ensure the most available future shim selection, and lapped them in.
The finished seat pattern will show 1.0 - 1.1mm wide on the face of the valve. The 3 '09 oil burners and the 2 older bikes all had the valve stem tips trimmed 0.3 - 0.4mm (.012 - .016inches).
Very time consuming hand work, using dial caliper, Magic Marker, spark plug gap wire gauge & magnifying glass.

One should Not trim/tip the valve stems more than 0.4 - 0.45mm (.016 - .018inches), IMO. Due to possible contact between spring retainer & tappet bucket.
Thnx for sharing that - that info is pure gold. Feel free to add pics, etc. How much would it cost do you think, to buy the tooling to regrind? I don't do this as a business, just a hobby, and this could be the last head I get done. I was intending to just bring the head to the dealer after porting it a little (what I've been doing).
 

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The reason I asked about tipping the valve stems is that some valves are only surface hardened and tipping to any degree exposes the soft "under-belly". I seem to recall that the valves on my old KZ1000 could be tipped without worry but have no idea about the KLR valves.

Jason
 

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Discussion Starter · #18 ·
The reason I asked about tipping the valve stems is that some valves are only surface hardened and tipping to any degree exposes the soft "under-belly". I seem to recall that the valves on my old KZ1000 could be tipped without worry but have no idea about the KLR valves.

Jason
Jason, I'd read that too, about some valves being surface hardened. That head I sent to E-M for refurbishment, I took it apart when I got it back, had a good look at what was done. I found sanding marks on the stem ends, identical to what you'd get using a bench sander disk. I rotate the valve as I "tip" it, and carefully hand sand the end smooth after, with very fine sandpaper, chamfering it too. No problems noted in service (and that's what matters :^)

Like I'd mentioned at the beginning, I've done quite a few heads, that've gone on engines in different bikes, sold 3 KLRs and a spare engine that've been refreshed and mild ported... no issues with reliability or longevity that I'm aware of. If I sell a bike to a friend, I joke it comes with an extended warranty.

Daryl
 

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Daryl,

Do you ever replace a valve seat?

As I mentioned previously, I know it gets done from time to time, but not always why. Other than the valve seat area is so worn it has to be replaced with a pressed in seat or toss the head away.

Oh, spoke with KLRChris. My cylinder head goes out to him on Friday. He or his buddy he’s been teaching will do the quad port upgrade. Another item off my bucket list. If I can split the case and pack up my crankshaft that will be the last major component of the build sent out.
 

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Discussion Starter · #20 · (Edited)
Daryl,

Do you ever replace a valve seat?

As I mentioned previously, I know it gets done from time to time, but not always why. Other than the valve seat area is so worn it has to be replaced with a pressed in seat or toss the head away.

Oh, spoke with KLRChris. My cylinder head goes out to him on Friday. He or his buddy he’s been teaching will do the quad port upgrade. Another item off my bucket list. If I can split the case and pack up my crankshaft that will be the last major component of the build sent out.
No, I haven't (replaced a valve seat). Kawi doesn't sell 'em, Schnitz neither. BTW, I emailed Don at Universal Cycle in Calgary (he's a bit of a KLR guru over there) about buying a set of Schnitz SS valves... none in stock ATM. He thinks you can still order 'em (oversize). The website still shows 'em as orderable:

https://store.schnitzracing.com/schnitz-stainless-steel-exhaust-valve-kawasaki-klr650/

Just picked up on something looking at that - those valves are .5mm oversize, probably fit in the stock seat. For some reason I thought they were 1mm OS. Wasn't that what M-Tech was offering?

Edit - I ordered a set of those .5mm OS SS Schnitz exhaust valves... and a 685 piston kit. Expensive night.
 
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