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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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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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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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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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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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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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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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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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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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Discussion Starter · #21 · (Edited)
I finished de-carboning the exhaust ports, am ready to start re-shaping things, do the "mild porting". I think anyone looking to port the KLR head, with a view towards improving performance, should give this a good careful read first - this Chris knows what he's doing.
He has a speed shop, Engine Logics, in Houston TX. Chris Kxxxxx... lots about him and his work in tuner forums BTW.

https://www.klrchris.com/klr650-small-port-head/

My takeaway, from reading that, and he emphasized this BTW in a call I had with him, is that the port volume of the stock head is near ideal for the stock piston. He actually saw improvement reducing port volume. My goal in "mild porting" therefore should be to smooth out irregularities, round areas with tight bends to improve flow, "de-restrict" without significantly increasing port volume... not remove too much materiel. Speaking of, IMO there is an element of risk in head porting - how thick is the casting in the area you're reshaping? Good question, isn't it? I had a head sectioned to get a better understanding of that very thing:





The answer is, the casting is not very thick in spots! Best not to get too carried away. I'll point out a few areas where, IMO the stock head porting can be improved upon... next post.
 

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Discussion Starter · #24 ·
Looks like I should be contacting Schnitz tomorrow! Re the valve seats, you'll see in the pics of the sectioned head, one half of a valve seat popped out. They are just pressed in. In one of the first set of pics I posted, there are on the bench the rotary cutter bits that I use with the Dremel flex tool. That works reasonably well. Maybe air powered works better, never tried it.

OK, I'll try to illustrate how I think the stock head can be improved upon. I had a good look at the porting on aftermarket automotive racing heads, pics I found online of other KLR head porting, researched it a bit before diving in.

The first and easiest thing to do is to grind off the head of the hold down stud that protrudes into the exhaust port:



I would be amiss if I didn't mention the benefit of grinding the adjacent wart of a weld off the inside of the stock exhaust header flange! I grind 'em down flush, have never had one crack or come apart (yet :^)



Here in this pic, I remove the splitters (circled), and bowl the area out, open it up around the valve guides, and blend and radius the transition around the valve guide transitioning into the port. I'll post a before & after pic too.

The red arrows point to where the machining stopped, leaving a ridge. I blend that away, widening the port slightly:



Bit of a crappy pic, but here from a previous head I'd done you can compare a finished intake port to stock:



Also on the intake side, there are these 4 casting bumps (circled) that intrude into the intake. I cut the bumps off using the rotary tool, blend that all smooth to make a straight curving path up into the intake bowl (nothing to trip the flow). Next to the center two "bumps", there are actually depressions - I don't trust JB-Weld to hold, or I'd just fill that. The red arrow points to where the port makes a jog intruding into the port, right where the head bolt runs through. I blend that away, so the port flows straight into the bowl (straight, or straighter shot) - I do same for all 4 spots in the ports that happens (head bolt locations):



Here on this exhaust port, around the sides of each valve guide (circled areas) I open it up a bit in order that the air has an easier path around the valve guides, smooth it, blend it. The red arrow points to another weird casting bump that I grind away, blend it all smooth:



On both the intake and exhaust ports (this is intake), the inner small radius (that the arrows are pointing to) makes a very tight bend, and the machining makes a sharp edge transition. I round that best I can, by hand with sandpaper, smoothly radiusing the curve, blending it nice and smoothly into the port:

 

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Discussion Starter · #26 ·
Here's a few more pics of heads I've ported previously.

A Gen 1 head:



A Gen 2 head. Note that Gen 2 heads don't have splitters in the intake to remove. The Gen 2 head does however have the port (hole) for the AIS, in one of the exhaust ports, which can't be improving flow! For this reason, I prefer Gen 1 heads.



Here's a finished intake side:



...and exhaust:

 

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Discussion Starter · #28 ·
Did you by any chance measure the widths of the 45 degree valve seat faces of either head before sending them to be re-cut & lapped?

The Gen 1 exhaust seats look almost 4mm wide on the pitted 45 degree cut & I see zero evidence of a 60 degree cutter to have ever been there!

The Gen 2 head looks to have had a 60 degree cutter on all 4 seats. Has possibly that engine been apart before or is that pic after returning from being freshly re-cut.
How wide/narrow does your machinist cut them for you?
Hi PD. I don't think I've ever taken a pic of the valve seats after they got re-cut. I'll try to do that this time. The seats looked factory new after re-cutting, quite narrow contact patches, nicely centered too. Very impressed by the job that tech did - he's the lead tech there at our local Kawi dealer (Headingly Sports), knows his stuff.

Neither of those heads had any attention prior. The Gen 2, believe it or not, only had 10,000 kms on it (6,000 miles). It was from a cheap ($600 Cdn) parts bike I bought, turned out to be stolen out of Calgary. As I was overhauling it, I noted that it had been repainted multiple times, went to my insurance broker, asked them to run the VIN, got a visit from the RCMP! It all worked out OK, got put in touch with original owner, paid him another $600, and I was free and clear of that mess. If it looks like too good of a deal to be true...

I think that bike got thrashed in the bush, seen some hillbilly style riding. The airbox had holes melted in both the front & rear plenums - looked like that poor engine was run for some time without filtration. Despite the low mileage, the valve seats had that terrible wear, and the valve stems actually had visible wear too - first & only time I've seen that. The valve guides actually weren't that badly worn - still easily passed the wobble test outlined in the book, and engine ran fine with a new piston in it, and the valve grind. I seem to recall replacing the valve stem seals as precautionary.

Daryl
 

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Discussion Starter · #29 ·
Got the intake side roughed out today. It doesn't look pretty at this point, as the rotary cutter chatters a bit, leaves a rough pebbly finish. From this point, I take and smooth and blend it nice with sandpaper... looks good (better) after it's sanded smooth, but probably does little or nothing for performance.





I apologize for the pic quality. It's hard to get decent pictures (am just using a smart phone).
 

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Discussion Starter · #31 ·
I wonder if schnitz was getting the valves cut to spec? Taking a oversize valve from another bike? We have donr this numerous times with ford valves?
No idea. With CNC machining, could even be small batch manufacturing from billet. I just stumbled across a YouTube video of a performance tuning shop getting an aluminum automotive intake manifold 3D printed!

One thing about these KLR heads - they ain't making 'em anymore, and they are basically a consumable wear item. And folks just keep running 'em low on oil, ruining the heads. Kawi will likely stock replacement valves for some time, but there is certainly room for a specialty shop to offer aftermarket valves & seats, headporting and the like.
 

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Discussion Starter · #33 · (Edited)
Well, the intent of this thread is to show that you can do this yourself, if you have the skills, and see some improvement. Sure, not flow or dyno tested (that always comes up, doesn't it), but I've seen the difference it makes compared to stock (better). I'm not particularly interested in going out of my way to get an engine I built dyno tested. For starters, I don't know of anywhere here that does that sort of thing!

Patman racing shows about a 2hp bump using a "big valve" head... I'm assuming with some porting done?

Patman's Kawasaki KLR650 KLR 650 Dyno Results

I actually just found the M-Tech webpage! Other (KLR Big Bore Kits, Etc.) - M Tech Motor Sports

Here, on the 60hp EFI project page, KLR Chris talks about "Flow ported cylinder head with 1 mm oversize intake and exhaust valves"... but no picture:

https://www.klrchris.com/60-hp-fuel-injected-klr-650/

Some time ago, I came across these KLR headporting pics, of a head supposedly done by KLR Cary:





I believe there was a fellow on .net that did headporting (WymanWin or something like that) but didn't like pictures getting posted?
 

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Discussion Starter · #35 ·
Carrying on porting today, started in to roughing out the exhaust ports, and saw something new (in a not good way):



If you follow the screwdriver tip up, you'll see a hairline crack! Betcha this head has been overheated. Might not affect anything (I guess we'll find out).

This exhaust port is a tad crooked, will benefit from a little port matching (brand new gasket in there to mark it out):



Longs ways to go on that. That's roughed out with a 1/4" ball cutter tip, switch to 1/8th ball, and then lots of hand sanding, fine tuning as I go.
 

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Discussion Starter · #37 ·
Any knowledge or evidence of ever having bent exhaust valve(s)? That would flex the valve stem in that direction.

Any damage around that tappet bucket from a misplace valve shim?
It was a runner when parked, but was using a lot of oil. The exhaust valves are caked. I popped off the valve cover, looked in that bucket bore to see if the crack progressed thru the casting. To inspect properly, I removed the oil seal off the valve guide, so I could remove the steel valve spring seat that protects the bottom of the bucket bore - all good in there. It would really suck if the head was unuseable. I just cleaned up the intake valves - they are actually still in good shape, can be re-used! I'm on the fence about buying new ones. No need really.
 

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Discussion Starter · #38 ·
I've been plugging away at porting the head, have it much closer to where it needs to be, thought I'd share some pics... that don't look much different than the others frankly. When you get 'em this smooth, the tiniest blemish really stands out! Many hours of hand sanding, and detail Dremel work to get to this point...

Intake, opened up, smoothed & blended:



One side of the exhaust port:



The other side of the exhaust:



Top view of course:



I would like to point out something - in the exhaust port, you can see an unsanded area where the casting mark is still visible. That is because the valve seat sticks out, leaving a lip overhanging the casting. Not a big deal on the exhaust, but can't be good on the intake side, where it catches and trips the airflow a little.



You can use a sanding cylinder attachment like this:



...to carefully taper and blend the seat into the casting - I've done that on the other heads pictured. Note however, that removing that lip would make it difficult to remove the seat. I'm waiting on exhaust valves from Schnitz (snagged the last 4 they had).
 
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