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ChilledRider

Looking for advice on my poorly cylinder head

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Greetings folks.

A little backstory, last time it was running i was riding with a friend and whilst on a long straight and i heard something that I shouldn't have heard down below and started to lose power, i pulled over and my friend had told me the exhaust had been smoking for about 2 miles (yeah thanks for catching up and letting me know) Turns out that I had an oil leak and it was starved. Pulled the engine apart and the piston and barrel had started to grind together. So I purchased a replacement head and cylinder put it all together started her up but she only ticked over once then just cut out. Thankfully I never revved it or anything so I opened her up and one of the valves were out of place ( I think I made a fatal error and didn't check the valve clearances). Knocked it back in turned it a few times seemed to be smooth, then took it to a garage for them to check out. 

 

First thing he saw were that the intake valves were lower than they should be and that I would be better off  buying a new engine or cylinder head although he said he checked the valve clearances and they were bang on. Until he manually turned the engine then the intakes just wouldn't come back up.

 

Here are some images that I have just taken of what I have found.

 

There is about 2-3mm clearance on both intake valves, obviously something not quite right there.

2-3mm.thumb.jpg.c2d1a7dbf0ec0db03c1e92b52e600392.jpg

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Exhausts bang on, intake hmm

20181206_115319.thumb.jpg.05bfc7b3f677ca02d354a4f059864a2b.jpg

 

20181206_115411.thumb.jpg.40d03917f9d6eec2ae96e96933ff7d5c.jpg

 

20181206_115300.thumb.jpg.9880ab586b914808d5ffc1ed90d14aee.jpgimageproxy.php?img=&key=b3312acf975e3c5420181206_115247.thumb.jpg.dc4ddab0108dcb3bfa40a7b69caae79a.jpg

 

Intakes are very stiff so not sure if it's springs or possible bent valves? Piston head in perfect condition so it doesn't look like they have hit the piston but I'm not sure. I have done quite a lot of work on the bike and I totally love it, but I do feel I need some assistance with this and I know there's folks on here who have a wealth of information and experience.

 

I reckon there's a few options, get the cylinder head sorted out, buy another one, or another engine. Unfortunately being in the UK there's not as many parts around but there are a few here and there. So what are your thoughts on my little predicament?

 

I'm quite happy to take out the valves, just need to learn how as I don't have the correct tool for it even if to just learn something from it and to see if they are bent. I do have a caliper which I could check against the valves to see if that was the issue. I'm unsure so I am looking to you folks if you would be so kind. :)

 

Thank you for your time.

Edited by ChilledRider

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If the valves do not seat with the valve lash caps removed, the valves are bent.
An easy fix for a shop that repairs cylinder heads.

The bigger question is...... What damage happened originally?  Not common for a piston and cylinder to seize from lack of oil and not damage the cam bearing journals... Actually on this motor Ive never seen or heard of it happening. But anything is possible so....

Did you check the oil pump and oil pump drive gear? If not Id do so.
Did you check the crank / rod for serviceability?  Side clearance and deflection? If not Id do so.

If everything checks out, have the head repaired (new valves, seats cut)  or better refreshed completely with 4 new valves, new springs, seals and all seats cut to match new valves.  Double and triple check you cam timing before spinning the motor over BY HAND the first few times, then quadruple check the cam timing again before attempting a start

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Could just be the photo but they do look a little bent.

I have removed valves before just using a socket as I don't have the correct tool.

Put something under the valve to stop it moving downwards and place a socket (with small extension as a handle) over the retainer and press it downwards.

0900c15280251628.gif

Doing that will flex the spring inwards and release the pressure on the valve locks which holds the retainer in.

Now the tricky part, do the above whilst holding the head upside down. If you manage that you can usually shake the valve locks loose so they fall into the socket, at that point the spring might fly out if you release it suddenly so release the socket slowly.

You could also just buy a valve spring compressor tool but where's the fun in that. 

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yeah I have a feeling there may be more damage as I haven't stripped it down any further as of yet.

I was still 20 minutes out from home and at that point didn't have anyone who could have helped me move the bike, so I cautiously drove home. There was still oil in the engine just wasn't quite enough. it wouldn't surprise me that there's more damage. I may invest in a replacement engine for the time being but with that I know someone who has a pretty well kitted out garage who i'm sure would help me in servicing it before making use of it. Would rather know that it's in tip top form than just pop it in and hopefully ride.

 

Maybe use my engine as something to have fixed and maybe sold on, or for spares. Spares would be a better choice to be honest. 

 

Thank you for your response. I will be looking into these extra checks that you have mentioned.

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18 minutes ago, Erik Marquez said:

The bigger question is...... What damage happened originally?  Not common for a piston and cylinder to seize from lack of oil and not damage the cam bearing journals... Actually on this motor Ive never seen or heard of it happening. But anything is possible so....

I think the engine (head & cylinder) in the picture is a different one to the one which died of oil starvation.

Edited by DrzDick

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1 minute ago, ChilledRider said:

yeah I have a feeling there may be more damage as I haven't stripped it down any further as of yet.

I was still 20 minutes out from home and at that point didn't have anyone who could have helped me move the bike, so I cautiously drove home. There was still oil in the engine just wasn't quite enough. it wouldn't surprise me that there's more damage. I may invest in a replacement engine for the time being but with that I know someone who has a pretty well kitted out garage who i'm sure would help me in servicing it before making use of it. Would rather know that it's in tip top form than just pop it in and hopefully ride.

 

Maybe use my engine as something to have fixed and maybe sold on, or for spares. Spares would be a better choice to be honest. 

 

Thank you for your response. I will be looking into these extra checks that you have mentioned.

If the cam bearing journals are not damaged, its unlikely the crank was damaged.. If the cam bearing journals are not damaged, its unlikely the oil pump or drive gear is damaged... They are just smart checks to do.

If the crank, rod and head (other then bent valves) are serviceable, no need to get a replacement motor whose true condition you will not know without complete disassembly and inspection...Something it sounds like your not going to be doing. 

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no it's the same engine. I'm quite baffled to be honest. I thought there would have been  more damage but there wasn't it's strange.

 

I'll pop those valves out and see what's what

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6 minutes ago, DrzDick said:

I think the engine in the picture is a different one to the one which died of oil starvation.

Perhaps but 
 

Quote

Turns out that I had an oil leak and it was starved. Pulled the engine apart and the piston and barrel had started to grind together. So I purchased a replacement head and cylinder put it all together

 

4 minutes ago, ChilledRider said:

no it's the same engine. I'm quite baffled to be honest. I thought there would have been  more damage but there wasn't it's strange.

 

I'll pop those valves out and see what's what

Have any pics of the damaged cylinder and piston? 
Did you check the oil restricter that is the cases under the cylinder for blockage when the motor came apart the first time?

 

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So is it the same head & cylinder or not. I'm totally confused now.

The first posts suggests replacements were bought after the oil starvation, and that is what were are looking at???

Edited by DrzDick

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6 minutes ago, DrzDick said:

So is it the same head & cylinder or not. I'm totally confused now.

The first posts suggests replacements were bought after the oil starvation, and that is what were are looking at???

@ChilledRider please confirm.
The ENGINE is the same
But you installed some replacement parts.
What specifically were the replacement parts or assemblies? Head? Cylinder? Piston? 

If the Head was replaced, what was the condition of the cam bearing Journals in the old head ?
Pics of that and the piston and cylinder if yo have them as well please.  

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Sorry I'll try clear this up with you guys.

 

So I damaged the original piston and barrel which I replaced. Here is a photo of the barrel, I can't quite find the piston at the minute but there was only some slight scoring on the side of the piston.

 

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Had I continued it would have for sure seized but it got me home. then when I pulled it apart I had noticed this damage. I mentioned oil starvation as I believe that was the cause. I checked the bolt underneath the engine which allows oil out to drain and it was loose. No doubt an error on my part at some point during my previous oil change.

 

The new issue is this cylinder head with it's valves. Of which I am trying to currently take apart as suggested by drzdick :)

 

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 " bought a replacement head and cylinder" , obviously the head that was bought to replace the original has bent valves so what's needed it to find out for sure why the loss of oil , and have the head rebuilt with new valves, springs and such along with seats cut .

The cylinder looks a bit like it's been cooked , doesn't run long with no lubrication .  Nice buddy for not saying something as soon as he noticed smoke , I'd not ride with him much .

.

Edited by jjktmrider

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Ok they were pretty easy to pop out, well not so much the valves. They are looking a bit wonky :p

 

20181206_151531.thumb.jpg.1fb34f2ab625ac20c8cbefbb16a0dc08.jpg20181206_151444.thumb.jpg.18fe9387358cfd301e8b2c8509dbfd6a.jpg20181206_151509.jpg.bb51daa824d47136d673eb12c3ae6a77.jpg

 

Springs don't seem damaged but how could I know. At least I know now why the intake valves didn't want to spring back up into their proper position

And sorry I must be getting confused with the names of certain things. erm it's the barrel and piston that I purchased not the cylinder head. that's still original.

Edited by ChilledRider

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33 minutes ago, ChilledRider said:

Ok they were pretty easy to pop out, well not so much the valves. They are looking a bit wonky :p

 

20181206_151531.thumb.jpg.1fb34f2ab625ac20c8cbefbb16a0dc08.jpg20181206_151444.thumb.jpg.18fe9387358cfd301e8b2c8509dbfd6a.jpg20181206_151509.jpg.bb51daa824d47136d673eb12c3ae6a77.jpg

 

Springs don't seem damaged but how could I know. At least I know now why the intake valves didn't want to spring back up into their proper position

 

Looks like the valve guides are cracked as well.  common when bent valves are cranked though the guides image.png.0604fc97c7819dfe102f52a8fc2a19c2.png

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13 minutes ago, ChilledRider said:

Sorry I'll try clear this up with you guys.

 

So I damaged the original piston and barrel which I replaced. Here is a photo of the barrel, I can't quite find the piston at the minute but there was only some slight scoring on the side of the piston.

 

20181206_150357.thumb.jpg.87b09ad83f36388f14a7f32e1ac27096.jpg

 

Had I continued it would have for sure seized but it got me home. then when I pulled it apart I had noticed this damage. I mentioned oil starvation as I believe that was the cause. I checked the bolt underneath the engine which allows oil out to drain and it was loose. No doubt an error on my part at some point during my previous oil change.

 

The new issue is this cylinder head with it's valves. Of which I am trying to currently take apart as suggested by drzdick :)

 

That is not what I would expect to see on a a DRZ motor that had no oil. Piston is mostly cooled by heat transfer to the cylinder and that is coolant cooled. There is a small squirt of oil to the underside of the piston... if that oil passage is blocked, it MIGHT allow for enough heat expansion to cause the piston to seize.. But a lack of oil resulting in the piston not getting its squirt of oil, would see the cam bearing journals damaged excessively as well..
In one post you said you replaced the cylinder head, in follow on posts you did not.
 Did you install a replacement cylinder head? And that replacement with bent valves is what we are looking at now. 
 

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Sorry, I replaced the damaged piston and it's chamber (Cylinder barrel - not cylinder head). I imagine that was the damage being caused whilst my friend said I was smoking for a few miles before the engine started losing power and playing up.

 

The cylinder head I have taken pictures of is the original. I have not replaced anything except the piston and barrel at this point. I hope that clears it up. Sorry for the confusion

Edited by ChilledRider
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4 minutes ago, ChilledRider said:

Sorry, I replaced the damaged piston and it's chamber (Cylinder barrel - not cylinder head). I imagine that was the damage being caused whilst my friend said I was smoking for a few miles before the engine started losing power and playing up.

 

The cylinder head I have taken pictures of is the original. I have not replaced anything except the piston and barrel at this point. I hope that clears it up. Sorry for the confusion

It does, and  it firms up my position, the failure was not lack of oil related. No oil being pumped though the system results in cam bearing journals being damaged.. and that damage is the first to happen in oil loss.

In any case, you replaced the piston, rings and cylinder so its a moot point. Confirm the oiling system is working (I would pressurize with some air and make sure you have flow where appropriate. Confirm the rod and crank are serviceable in side clearance and deflection. Take a look at the oil pump and idler gear just because, have the head repaired and put it back together...paying close attention to cam timing and clearances.  

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4 minutes ago, Erik Marquez said:

Confirm the oiling system is working (I would pressurize with some air and make sure you have flow where appropriate.

How do you do that, rig up a compressor to the frame oil tank lid maybe?

So what do you think happened Erik?

Piston/cylinder death unrelated to the valves getting bent... I can't help but think those were two separate things. Sounds like the timing wasn't set up correctly when the cylinder was replaced.

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5 minutes ago, DrzDick said:

How do you do that, rig up a compressor to the frame oil tank lid maybe?

So what do you think happened Erik?

Piston/cylinder death unrelated to the valves getting bent... I can't help but think those were two separate things. Sounds like the timing wasn't set up correctly when the cylinder was replaced.

Pressurize at the oil pump cavity in the case... I use a rubber tipped air nozzle.

Had to say based on what is available... if the cylinder in the pic is oriented Exhaust side to the front as in riding...it looks to have overheated the piston / cylinder and then seized on the exhaust side of the piston which is a common way .. Why did it overheat??? Yes good question.....
Was it stock components or after market? What are the signs and indications on the piston? Was there damage to the rings? Had the bike been significantly overheated previously? Been run out of coolant or boiled over? 
 

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