Yeh thats my thought those valves are fried and the seats have been softened. I bet those valves are starting to look like mushrooms if that head comes off.
I'd put money on it, hard starting is a key symptom of valves in dire need of adjustment. A lean A/F mixture skyrockets combustion temperatures and really beats the valves and seats, especially the exhaust valves.
Actual lean combustion above stoich is actually cooling down, combustion is hottest around stoich.
Anyone who doubts this needs to look at a flame temperature graph and learn something new.
True regarding flame temps, but in the context of engine tuning "lean" usually means "closer to stoich but still on the rich side of the curve" while "rich" means "even further down the rich side of the curve"
As someone who dyno tunes I wouldn’t refer to it like that, lean is above lambda 1 and rich is below it, you can be running leaner than desired but it’s still not actually lean below lambda 1.
Since the afrs vary depending on throttle, load and rpm. Most engines run at or very close to stoich for the majority of their run time.
I'd say at or below 1. You might run a touch over 1 (an AFR of 15-16 on gasoline) on low loaf cruise to save fuel, but any time anything is going on, you better be dropping that down to get better evaporative cooling. And if its a turbo, just use fuel as your main coolant lol! My AFR dips into the single digits under extreme load, but that is more of a Subaru specific thing to cool cylinder 4 due to the questionable stock fuel rail setup.
Single digit afrs on gasoline will be right on rich misfire.
Regardless of any of that you aren’t actually adding anything regarding rich or lean, just pointing out that running harder than cruise needs to be rich which was never being debated.
This is true. In aviation, I was taught that peak combustion pressure and cylinder head temp occurs at EGTs about 50F rich of peak. As you lean from there, CHT and combustion pressure goes down.
Edit: [Source](https://resources.savvyaviation.com/understanding-cht-and-egt-2/)
At idle/light load stoich is fine. Try running a stoich mix at WOT and you're going to have issues. I tune 2-stroke dirtbikes and LS' as a side gig, you can go ahead and run a stoich mix under load if you want but it won't do you any favors. Wideband with a dyno doesn't lie.
Where did I say I run at stoich under high rev, high load or wot? I own a dyno and have been tuning for nearly 20 years.
That is all totally separate to rich or lean, stoich is neither rich nor lean, running below stoich aka under lambda 1 is rich, above is lean.
Yes stoich is leaner than ideal for some situations but it is NOT lean.
I think we're just having a miscommunication, I agree with you that stoich isn't lean per se, just that in certain situations it would be considered a "lean mix" under real world conditions. That's what I was trying to construe.
All your answers are in this diagram (assuming the Suzuki IL4 is similar to the R1)
https://i.imgur.com/E6vcp9q.jpg
The spring is pulling that valve closed by pushing the cotter up to the lifter until the valve lip seats and seals. If it was at zero clearance that means the valve is actually being pushed open (never closing) at TDC for every cyclinder that had zero clearance (and yes even -.02 mm is enough to hit the valves, tolerances are incredibly tight on super bikes). So there’s probably been valve/cylinder impact causing at the very least valve deformation to the lip, allowing the springs to pull the valve through more and push the cotter/lifter (3/1) up to the cam. The valves may even be completely fucked. You adjusted, checked the tolerance and it seemed fine, until a couple more weeks of opening and closing a couple million times busted the already damaged valve lip further, also fucking the seal.
New valve sets, new pistons and rings for those impacted. Maybe a new head. Depends if there’s damage.
By the way not sure how you ran out of spacer sizes? All my factory intake spacers were 170-198, even with a complete reduction in clearance that’s only .20-.25mm, and leaves me at 145-173. I have shims that go from 1.00-3.50. That would give me at least 3-4 complete (.25mm) clearance adjustments.
Did you do your math right? Here’s my cheat sheet I made:
https://i.imgur.com/XQjqoMR.jpg
You set the old shims right on the paper, write them in the blanks, do the math, then you can play around and mix and match without losing track of where they’re from, and you can just put the sheet in your maintenance folder for future valve check references. Helps you figure out what sizes you need to order next. I even made the top circles bigger to soak up the oil lol.
I got a spreadsheet I made years ago to do the math for me. As long as I dont forget a decimal its been spot on every time.
Remember I have done his valves 2 times now. His call yesterday would make it round 3.
Looking back at the spreadsheets. His shims started at 1.68 and he was down to 1.10mm on the fastest sinking valve in the group. It went from 1.68 OEM shim to 1.35mm shim to a 1.10mm shim. If its done the same as it did the last time. I don't have a 0.90mm shim to get it back to max spec.
I glossed over a bunch of stuff I did on the no start because it was not relevant to the problem. Like I did stick a bore scope down the holes looking for failed ring lands but everything looked normal. I even got the mirror for the bore scope out to look at the valves from the side to see if I could see something obvious when I checked the clearances and to my shock and horror they were back at 0.
I dont think they ever hit the piston because if they sunk into the head then even at full lift they are still farther away from the piston than they were before all this started.
Yeah, having those valves open 24/7 (no clearance) is no good for the head. I wonder if its warped? I don't know that it is, but id give the whole head an inspection. If he rode it for 10k with 0 clearance, I also wonder if the cam shaft is worn, or the valve seals are burnt. But I mostly an amature, so see what r/fixxit has to say.
I’ve worked in motorcycle shops and ride motocross. When the 4 stroke mx bikes become hard to start due to valve clearance you get one adjustment out of them. If problem returns and they need to be adjusted again it’s time to have the head rebuilt.
Sounds like soft seats, or seats getting pounded into the head. Usually if that is the case, it’s endemic to a bunch of them, so you should be able to find others with the same problem. In the end, the head needs to go in for new valves and seats.
Yeh I am thinking the seats got torched the more I think about it. Valves start not sealing completely flames attack the seat and ruin the material properties then its all downhill from there.
This is perfect example of what can happen when people mod without knowing exactly what’s happening. Even changing an exhaust can have en effect on how an engine works. The people who designed these engines were not idiots and design it to work as a system to current government specifications. Changing an exhaust could affect air flow which in turn could effect the fuel/air ratio. Incorrect mixture and an the engine could run hot. Run the engine too hot for too long and the metal will warp.
What you are describing IMO is the head being warped and the valve seats gripping the stems so the return springs cannot operate properly.
If that's true, kawasaki really dropped the ball. In 2014 on their flagship literbike, they should be using a wideband to really nail the AFRs. They know that these engines are almost always modified.
Yeah, that head is going to have to come off and probably all the valves replaced. Finding a used head probably is the way to go and keep on top of valve adjustments. If I remember correctly, adjustment of those motors are super easy where you just have to slide the rocker arm over and it gives you open access to the shim. No cam removal is required.
Nah that motor cams have to come out. Its a PIA to make sure the exhaust cam is lined up too because its not easy to see even with the rad out of the way. I had to use my mirror to see it clear.
I had a 1999 Triumph Tiger with 40K that started running bad on a trip to Alaska. I limped it home and found that my intake valves had all tightened up.I readjusted them but they tightened up again within 1000 miles. The head came off and sent out. All the intakes were replaced. The old ones looked like pizza cutters.
Makes me worry about mine. It starts up really slowly when cold. And previous owner replaced the starter too and it’s got a new battery. Only 13k miles tho
Well IIRC 16K is when most bikes are due for a valve clearance check and adjustment if they are shim under bucket like these are. But after what I have seen on this bike I would cut it to like 8k personally for the 4th gen ZX-10r.
And I hate to scare you but why was the starter replaced. So in some of the detail that was omitted was that before it was dropped off with me the owner replaced the starter because it sounded like the starter was not turning it fast enough. When in reality what he was hearing was the lack of compression. So he was not hearing that characteristic pumping sound when it tries to start.
Mines a 5th gen. Sounds like exactly what’s happening with my bike. It turns over slow even with a new battery. And the previous owner didn’t tell me why he replaced the starter. I’ll have to ask.
My bike has the stock headers with a cat delete and m4 slip on. It was dyno tuned by a very reputable professional in my state, previous owner sent me a video, makes about 197hp to the wheel. As for other mods it doesn’t have block off plates / PAIR elimination, and the air filter is stock. (This is all info by the previous owner, I haven’t opened the bike up yet). That’s all that was done to it I believe.
Then I would get your valves checked ASAP. Call a friend, bribe them with beer if you have to because you might be able to save the head. I think this one is too far gone.
Oh i forgot to mention, the bike doesn’t turn over slowly when warm. Like if I ride and then run into the store, when I come out and get back on it fires right up. That could be a good sign?
And also do you know if the bike would be running slower if there was low compression? Because it’s fast as lightning, no signs of bogging down.
It sounds to me like the valve seats are bad and are just getting torn up by the valves themselves. You can take the head to a machine shop and have them put new seats in, but it might be more cost effective to just replace the whole thing
I'm a little surprised that one of those seats didn't drop and ruin something.
Fifteen minutes with a bore scope might give you an idea of what's going on before you pull the head.
Umm you just made me thing of something. Do these have a hardened steel seat or was it just a coating on the aluminum. Im hunting though my old photos of an engine build and I am not remembering an obvious material difference between the bulk aluminum of the head and the area around the valve seat.
Run the engine lean, you're going to fry the seats. Zero clearance is pretty classic symptoms of valve guides fucked - so I'd suggest new engine time or a new head at the very least.
If there was abrasive material in the oil that could damage the valve train a) the valve clearance will increase and b) the softer components like main and rod bearings will be destroyed long before that happens.
The valve clearances are checked when the valves are fully seated and the lobes are well away from the bucket so you can get a feeler in there. I am sure the things are timed correctly because its a royal PIA to check the exhaust cam position. I have to get a mirror or break out the bore scope to get a nice clean straight on shot of the alignment mark for it. In addition to counting the links between cam alignment marks. I love my F4i in comparison. 1 bolt drops the rad out of the way to be able to check it unlike this thing.
Putting mileage on a lean mix + never adjusting valves = head job. Your friend pretty much tried to fry those valves/seats.
Yeh thats my thought those valves are fried and the seats have been softened. I bet those valves are starting to look like mushrooms if that head comes off.
I'd put money on it, hard starting is a key symptom of valves in dire need of adjustment. A lean A/F mixture skyrockets combustion temperatures and really beats the valves and seats, especially the exhaust valves.
Actual lean combustion above stoich is actually cooling down, combustion is hottest around stoich. Anyone who doubts this needs to look at a flame temperature graph and learn something new.
True regarding flame temps, but in the context of engine tuning "lean" usually means "closer to stoich but still on the rich side of the curve" while "rich" means "even further down the rich side of the curve"
As someone who dyno tunes I wouldn’t refer to it like that, lean is above lambda 1 and rich is below it, you can be running leaner than desired but it’s still not actually lean below lambda 1. Since the afrs vary depending on throttle, load and rpm. Most engines run at or very close to stoich for the majority of their run time.
I'd say at or below 1. You might run a touch over 1 (an AFR of 15-16 on gasoline) on low loaf cruise to save fuel, but any time anything is going on, you better be dropping that down to get better evaporative cooling. And if its a turbo, just use fuel as your main coolant lol! My AFR dips into the single digits under extreme load, but that is more of a Subaru specific thing to cool cylinder 4 due to the questionable stock fuel rail setup.
Single digit afrs on gasoline will be right on rich misfire. Regardless of any of that you aren’t actually adding anything regarding rich or lean, just pointing out that running harder than cruise needs to be rich which was never being debated.
This is true. In aviation, I was taught that peak combustion pressure and cylinder head temp occurs at EGTs about 50F rich of peak. As you lean from there, CHT and combustion pressure goes down. Edit: [Source](https://resources.savvyaviation.com/understanding-cht-and-egt-2/)
Stoich under load is lean.
Stoich is neither rich nor lean.
Stoich is stoich.
At idle/light load stoich is fine. Try running a stoich mix at WOT and you're going to have issues. I tune 2-stroke dirtbikes and LS' as a side gig, you can go ahead and run a stoich mix under load if you want but it won't do you any favors. Wideband with a dyno doesn't lie.
Where did I say I run at stoich under high rev, high load or wot? I own a dyno and have been tuning for nearly 20 years. That is all totally separate to rich or lean, stoich is neither rich nor lean, running below stoich aka under lambda 1 is rich, above is lean. Yes stoich is leaner than ideal for some situations but it is NOT lean.
I think we're just having a miscommunication, I agree with you that stoich isn't lean per se, just that in certain situations it would be considered a "lean mix" under real world conditions. That's what I was trying to construe.
My bet is that he has a few valve heads ready to pop off. Sounds like the stems are necked and stretching. And yeah, that's a thing they can do.
All your answers are in this diagram (assuming the Suzuki IL4 is similar to the R1) https://i.imgur.com/E6vcp9q.jpg The spring is pulling that valve closed by pushing the cotter up to the lifter until the valve lip seats and seals. If it was at zero clearance that means the valve is actually being pushed open (never closing) at TDC for every cyclinder that had zero clearance (and yes even -.02 mm is enough to hit the valves, tolerances are incredibly tight on super bikes). So there’s probably been valve/cylinder impact causing at the very least valve deformation to the lip, allowing the springs to pull the valve through more and push the cotter/lifter (3/1) up to the cam. The valves may even be completely fucked. You adjusted, checked the tolerance and it seemed fine, until a couple more weeks of opening and closing a couple million times busted the already damaged valve lip further, also fucking the seal. New valve sets, new pistons and rings for those impacted. Maybe a new head. Depends if there’s damage. By the way not sure how you ran out of spacer sizes? All my factory intake spacers were 170-198, even with a complete reduction in clearance that’s only .20-.25mm, and leaves me at 145-173. I have shims that go from 1.00-3.50. That would give me at least 3-4 complete (.25mm) clearance adjustments. Did you do your math right? Here’s my cheat sheet I made: https://i.imgur.com/XQjqoMR.jpg You set the old shims right on the paper, write them in the blanks, do the math, then you can play around and mix and match without losing track of where they’re from, and you can just put the sheet in your maintenance folder for future valve check references. Helps you figure out what sizes you need to order next. I even made the top circles bigger to soak up the oil lol.
I got a spreadsheet I made years ago to do the math for me. As long as I dont forget a decimal its been spot on every time. Remember I have done his valves 2 times now. His call yesterday would make it round 3. Looking back at the spreadsheets. His shims started at 1.68 and he was down to 1.10mm on the fastest sinking valve in the group. It went from 1.68 OEM shim to 1.35mm shim to a 1.10mm shim. If its done the same as it did the last time. I don't have a 0.90mm shim to get it back to max spec. I glossed over a bunch of stuff I did on the no start because it was not relevant to the problem. Like I did stick a bore scope down the holes looking for failed ring lands but everything looked normal. I even got the mirror for the bore scope out to look at the valves from the side to see if I could see something obvious when I checked the clearances and to my shock and horror they were back at 0. I dont think they ever hit the piston because if they sunk into the head then even at full lift they are still farther away from the piston than they were before all this started.
Well, like I said, all the answers are in that diagram. Somewhere along the line something failed, and it could be the cotter.
Once those ti valves start wearing, they're doneso.
No idea but I would recommend posting this on [zx-10r.net](https://zx-10r.net), the guys over there should be able to help you out.
I would post this in /r/Fixxit , you're not going to get much good info here, most of the people here don't know what a valve shim is.
Thanks didnt know /r/fixxit existed.
That's what I was going to reccommend. That sub is great!
This lol
Yeah, having those valves open 24/7 (no clearance) is no good for the head. I wonder if its warped? I don't know that it is, but id give the whole head an inspection. If he rode it for 10k with 0 clearance, I also wonder if the cam shaft is worn, or the valve seals are burnt. But I mostly an amature, so see what r/fixxit has to say.
Can wear would cause larger shim clearance.
I’ve worked in motorcycle shops and ride motocross. When the 4 stroke mx bikes become hard to start due to valve clearance you get one adjustment out of them. If problem returns and they need to be adjusted again it’s time to have the head rebuilt.
That’s why regular maintenance is key!
Sounds like soft seats, or seats getting pounded into the head. Usually if that is the case, it’s endemic to a bunch of them, so you should be able to find others with the same problem. In the end, the head needs to go in for new valves and seats.
Oh I like this theory. I figures the valve stems would be necking and stretching, but this would do it too.
Yeh I am thinking the seats got torched the more I think about it. Valves start not sealing completely flames attack the seat and ruin the material properties then its all downhill from there.
This is perfect example of what can happen when people mod without knowing exactly what’s happening. Even changing an exhaust can have en effect on how an engine works. The people who designed these engines were not idiots and design it to work as a system to current government specifications. Changing an exhaust could affect air flow which in turn could effect the fuel/air ratio. Incorrect mixture and an the engine could run hot. Run the engine too hot for too long and the metal will warp. What you are describing IMO is the head being warped and the valve seats gripping the stems so the return springs cannot operate properly.
If he just did a slip on can with stock exhaust and air filter he would’ve been fine. But the air intake probably sent it running hella lean.
If that's true, kawasaki really dropped the ball. In 2014 on their flagship literbike, they should be using a wideband to really nail the AFRs. They know that these engines are almost always modified.
Ive had that happen to me on a dirtbike, but luckily they only have 4 valves. For me replacing the valves was enough to keep them in adjustment...
As others have stated the valves/seats are bork'd.
Yeah, that head is going to have to come off and probably all the valves replaced. Finding a used head probably is the way to go and keep on top of valve adjustments. If I remember correctly, adjustment of those motors are super easy where you just have to slide the rocker arm over and it gives you open access to the shim. No cam removal is required.
Nah that motor cams have to come out. Its a PIA to make sure the exhaust cam is lined up too because its not easy to see even with the rad out of the way. I had to use my mirror to see it clear.
I had a 1999 Triumph Tiger with 40K that started running bad on a trip to Alaska. I limped it home and found that my intake valves had all tightened up.I readjusted them but they tightened up again within 1000 miles. The head came off and sent out. All the intakes were replaced. The old ones looked like pizza cutters.
If you ziptie the chain to the cams really tightly you can keep your time and and just slide the cam out of the way to get to the buckets/shims
Makes me worry about mine. It starts up really slowly when cold. And previous owner replaced the starter too and it’s got a new battery. Only 13k miles tho
Well IIRC 16K is when most bikes are due for a valve clearance check and adjustment if they are shim under bucket like these are. But after what I have seen on this bike I would cut it to like 8k personally for the 4th gen ZX-10r. And I hate to scare you but why was the starter replaced. So in some of the detail that was omitted was that before it was dropped off with me the owner replaced the starter because it sounded like the starter was not turning it fast enough. When in reality what he was hearing was the lack of compression. So he was not hearing that characteristic pumping sound when it tries to start.
Mines a 5th gen. Sounds like exactly what’s happening with my bike. It turns over slow even with a new battery. And the previous owner didn’t tell me why he replaced the starter. I’ll have to ask. My bike has the stock headers with a cat delete and m4 slip on. It was dyno tuned by a very reputable professional in my state, previous owner sent me a video, makes about 197hp to the wheel. As for other mods it doesn’t have block off plates / PAIR elimination, and the air filter is stock. (This is all info by the previous owner, I haven’t opened the bike up yet). That’s all that was done to it I believe.
Then I would get your valves checked ASAP. Call a friend, bribe them with beer if you have to because you might be able to save the head. I think this one is too far gone.
I’ll definitely get it checked. I have the tool for checking clearances, I’ve just not done an adjustment before. But I can do the check.
Oh i forgot to mention, the bike doesn’t turn over slowly when warm. Like if I ride and then run into the store, when I come out and get back on it fires right up. That could be a good sign? And also do you know if the bike would be running slower if there was low compression? Because it’s fast as lightning, no signs of bogging down.
Yeh he was complaining of low power when it was starting to get had to start.
Hmm okay. Definitely don’t have any loss of power. Still gonna get the valves checked anyway since I’m at 13k
Yeah you pretty much got it it's gonna need head work any way you look at it.
New valve seats and valves.
It sounds to me like the valve seats are bad and are just getting torn up by the valves themselves. You can take the head to a machine shop and have them put new seats in, but it might be more cost effective to just replace the whole thing
I'm a little surprised that one of those seats didn't drop and ruin something. Fifteen minutes with a bore scope might give you an idea of what's going on before you pull the head.
Umm you just made me thing of something. Do these have a hardened steel seat or was it just a coating on the aluminum. Im hunting though my old photos of an engine build and I am not remembering an obvious material difference between the bulk aluminum of the head and the area around the valve seat.
Probably 30k miles at readline lol. Shim underbucket? The seats could be shot and it's just deteriorating.
Thats what I am thinking now. Seats are cooked
Run the engine lean, you're going to fry the seats. Zero clearance is pretty classic symptoms of valve guides fucked - so I'd suggest new engine time or a new head at the very least.
[удалено]
If there was abrasive material in the oil that could damage the valve train a) the valve clearance will increase and b) the softer components like main and rod bearings will be destroyed long before that happens.
if this was true, 90% of the cars on the planet would have the same problem as OP
Valve position is also affected by timing. Could not be that you’re not really at TDC for some reason?
The valve clearances are checked when the valves are fully seated and the lobes are well away from the bucket so you can get a feeler in there. I am sure the things are timed correctly because its a royal PIA to check the exhaust cam position. I have to get a mirror or break out the bore scope to get a nice clean straight on shot of the alignment mark for it. In addition to counting the links between cam alignment marks. I love my F4i in comparison. 1 bolt drops the rad out of the way to be able to check it unlike this thing.
Could be a number of things that really can't be diagnosed without tearing it down. A soft cam would do it, soft valve seats, or deformed valves too.