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Discussion Starter · #1 ·
Hello everyone,

i have a 1989 KLR 250 with 5000 miles on it. I have owned the bike for about 5 years and put nearly all of the miles on it. It is ridden relatively hard but is also well taken care of it. It’s a pretty clean bike and I like to keep up on my stuff. Over the past year or so, the valves have needed increasingly frequent adjustment (I like to adjust themto about the middle of the tolerance, as looser they seem to have a little noise which I don’t care for). The last time I adjusted the valves, they only stayed in tolerance for a weekend worth of gravel road riding. By the end the bike would only start on a bump start (when adjusted, the bike is a first kick start). It also burns about a half quart of oil every other tank of gas. Is it time for a new top end? Anyone have an opinion on this issue? Any information is much appreciated!
 

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It sounds to me like your bike has been ridden most of those 5000 miles with a Dry foam air filter which allows most of the dust to simply pass thru it.

Or it may have some other fairly major air filtration issue.
Either of which severely wears the valves, valve seats, piston, rings & cylinder walls.
Burns 1/2 quart of oil per 3-4 gallons of gas & valves receding into the valve seats rapidly.
Yes I'd say it needs a top end rebuilding.

All dirt & dual purpose bikes should come with a Big Orange label on the air filter box.
CAUTION! Foam air filter MUST BE THOROUGHLY OILED After Cleaning. (See Owners Manual)
 

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Discussion Starter · #3 ·
Pdwestman,

Thanks for your response. The bike has always received an oiled dual stage Uni filter, but the klr250 air box and flat style filler is an optimistic contraption, and I am skeptical about the effectiveness of the seal and filtration.

Will a new piston/ring assembly be enough or would you imagine it needing new valves? Is there a way to check valves for excessive wear? In the past when I have been in the head, it has looked good with minimal signs of wear.

Thanks
 

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If you have been having to re-adjust them often I'll suggest they have been wearing rapidly enough that they need replacing. Once they have been dusted (by previous owner?) the embedded dust in the seats & valve faces continue to wear on each other.

The valve seats need to be properly Narrowed (.5 - 1.0mm or .020 - .040inches) & the 45* seating area just lightly touched up. The higher contact pressure on the properly narrow seats will seal tighter & therefore wear slower.
(Provided that its never dusted again.)

New valves & stem seals, new 1st over-sized piston & rings. Do a 100% job once or a 50% job twice, your choice.
 
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Discussion Starter · #5 ·
Hey PD,

I had a chance to open up the head this afternoon and found heavy carbon buildup at the top of the piston and at the valves. Blowby past the rings appears minimal and not much in the way of scoring on the cylinder walls or around the cam shaft. I am curious what you think of this wear. Here are some pictures:

Drinkware Serveware Cup Drink Ingredient

Automotive tire Wood Rim Gas Automotive wheel system

Automotive tire Audio equipment Gas Automotive wheel system Loudspeaker

Automotive tire Wood Cookware and bakeware Gas Auto part

Wood Metal Fashion accessory Automotive lighting Cookware and bakeware

Motor vehicle Automotive tire Hood Rim Automotive exterior
 

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As I understand the I.C.E. theory, your oil Consumption is Washing off the carbon from the piston crown & cylinder head combustion chamber.
The vertical scratches are only part of the reason for its massive oil consumption. An over-bore & proper hone pattern with an over-sized piston & ring set, along with 'zero' future dusty air ingestion is the only way to eliminate its current oil appetite.

Excessive oil consumption can easily lead to too little volume of oil in the engine, which will DESTROY the cylinder head camshaft bearings first. Furthest bearings in the lubrication system!

Looks like your intake valves have worn into the valve seats quite a bit! The exhaust valves are quite a bit harder, on purpose. But I'll bet they have a distinct scallop on their 45* faces.
 

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Discussion Starter · #7 ·
Hey PD,

Well, I was about to report back to you with many thanks… after working with a local machine shop and getting the parts back, I finally had a chance to do the install Friday and Saturday. Everything went smoothly and Saturday afternoon she fired up third kick (significantly more compression, idled smoothly at atouch below 1000rpm, and sounded excellent I must say). I let it idle for 15 minutes a few times yesterday, and this morning did the same. However, it didn’t want to sit so comfortably at a low idle. In the end, it sputtered out and spit a cup of milky oil out of the crank overflow. The oil contained coolant. Do you have a prognosis on this? Surprisingly little information for the 250 on this, more so on the 650. People talk of bad head gasket, cracked heads, and water pump seal. Guess the feather in my cap can be removed. I was feeling most proud! It was running strong!
 

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Welcome to the "did it twice club." There's only one interface where water can get across into the oil, and that's the head gasket. Did you use a new head gasket? I'm not a 250 expert, but I'll guess that the case design is similar to the 650. On the 650, there is a space between the water pump and the left engine case, so water will drip out of a weep hole if the water pump seal is bad. Make sure the weep hole between the water pump and the left engine case is not clogged. Otherwise, the head has to come off. Of course, carefully inspect the cylinder while the head is off, but if you didn't get coolant in the oil before you removed the head for service, I can't see why you would have a crack in the cylinder or the head after you replaced the head.
 

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I sure hope you installed new 'valve stem seals'. Judging by the pattern of the oil in the chamber itself the intake valve stem seals were definitely leaking. It also sounds from your description that you improperly installed the head gasket and/or contaminated it by some means. Usually touching it with 'dirty' hands which caused it to fail between the oil and water circuits. Those surfaces must be impeccably clean upon reassembly.

I'd recommend looking up the correct 'installed height' for the valves in order to verify you haven't sunk the valves into the head. If that's the case you'll need a machine shop to install new seats and perform a 'valve job'. If the valves have begun to 'tulip' then new valves would also be required.

A lot of times 'weakening' valve springs can cause the above mentioned conditions due to the weak springs not controlling the closing of the valve which causes it to 'slam' into the seat during closing instead of gently coming to rest as the camshaft rotates onto the 'base circle'.

Best wishes
 

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Discussion Starter · #10 ·
Yes all new valves and valves seals, piston and rings, along with a new gasket kit. I think the most likely culprit is a leaky head gasket. The head had to be removed after it was installed, as I had not put in the cam chain guide, and perhaps it was damaged during the removal/re-installation process. All seemed good but water sure has its ways. I will pull it back apart and put in another head gasket and report back.

thanks for the input
 

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Yes all new valves and valves seals, piston and rings, along with a new gasket kit. I think the most likely culprit is a leaky head gasket. The head had to be removed after it was installed, as I had not put in the cam chain guide, and perhaps it was damaged during the removal/re-installation process. All seemed good but water sure has its ways. I will pull it back apart and put in another head gasket and report back.

thanks for the input
You can't reuse head gaskets, even if they're still "almost new". The KLR uses a thin metal gasket that crushes slightly when torqued and does not spring back when torque is released. Almost certainly that is why coolant is leaking into the oil.
 

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You can't reuse head gaskets, even if they're still "almost new". The KLR uses a thin metal gasket that crushes slightly when torqued and does not spring back when torque is released. Almost certainly that is why coolant is leaking into the oil.
That's a fact 💯
 

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Everything went smoothly and Saturday afternoon she fired up third kick (significantly more compression, idled smoothly at atouch below 1000rpm, and sounded excellent I must say). I let it idle for 15 minutes a few times yesterday, and this morning did the same. However, it didn’t want to sit so comfortably at a low idle.
Sorry to read your current trouble. I use a sharp wood chisel to remove old gasket material, in a circular pattern around the cylinder & cylinder head combustion chamber. So any minor scratches don't lead into the combustion chamber or into the cam chain tunnel. Then wipe the surfaces with acetone or lacquer thinner to remove all residual gasket coating from the metal surfaces.
Then wipe them again just prior to assembly to ensure that no oily finger prints interfere with gasket adhesion.

You should set your idle speed UP to about 1300rpm. And you should actually ride it 'Briskly', shifting at about 4000-5000rpm, preferably uphill to load the piston, rings & cylinder to promote ring & cylinder break-in. Slow back down & repeat about 5 to10 times. Rather than simply allowing it to idle, til fully warm.

The higher idle speed will help oil flow to the camshaft bearings, cam lobes & rocker arms.
My oil flow modification #s 8, 9 & 10 from this thread would help even more.
 

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Discussion Starter · #14 ·
Does anyone know much about these head gaskets? I just received the new head gasket and it is significantly different than the one I have installed. The one currently installed is a metal type and quite thin and was part of a Namura gasket kit. The one i received as a replacement is a fiber gasket with a metal ring at the interior and is maybe 2 or 3x thicker. Anyone know which one of these is the right gasket? They were both advertised to fit the KLR250 and are identical shapes.

Thanks!
 

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Different manufacturers, I prefer the rubber coated 'metal' gaskets but so long as the 'coolant passages' are a match ect. You should be fine. The composite gasket is going to 'crush' down when torqued. Depending on thickness it's most likely going to lower the compression ratio a commensurate amount. Best wishes

In the future try and use 'factory' gaskets for less stress.

Around here we like to see pics.....
 
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Your current new, thicker gasket may have been used in 'other countries' KLR250's to de-tune the engine for low octane fuel usage and / or to lower power output for drivers license reasons.

I believe that you started working on this bike partly because of lowered compression creating starting difficulties?
I'll suggest that you should purchase an OEM head gasket from a local Kawasaki dealer or USA based OEM parts supplier. Part # 11004-1121.
Get all the engine compression & performance that it had when it was a new bike.
 
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Discussion Starter · #18 ·
Thanks for the advice on OEM. I am typically all about going that direction but I had trouble sourcing parts. One source would have one part, the next have another. And in the end bought most of the stuff off EBay to avoid having my pants torn off me (money is tight around here, I.e. fixing up a 33 y/o KLR250). Put it all back together today and all seemed good so took for a ride down the road. I now have a little coolant coming out of the weep hole beneath the water pump cover. Looks like it was the water pump seal after all…

Peter, you were right on the money. The thicker head gasket changed the whole nature of engine. I never rode it with the last metal gasket, but it kind of sounded like it would rip. She is back to the benign KLR250 now : [

Here is a photo of the Steed from todays test ride for ya boys (best color way KLR ever had, IMO):

Tire Wheel Vehicle Plant Automotive tire
 

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Discussion Starter · #19 ·
Edit: it was Briggs and PD who mentioned the gasket thickness and compression. It’s okay, I intend to get this thing cherried back up and pass it off. I’d like to get something with a bit more displacement for when I do ride on-road.
 
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