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I FEEL THE NEED...FOR SPEED.
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Discussion Starter #1
Hi, recently I disassembly the bike for the starter motor inspection/clearance and I find the time to check the valves after the bike now has 60.500kil.
Bought the bike with 40.000kil and the previous owner told me that a valve Clearance was made at 35.000kil. Indeed after I remove the Engine Head Cover I notice the Crankshaft Caps were pointed with marker and the bolts had obvious wear from tool, so i guess a valve clearance was indeed took place at 35.000kil.
I was told that the Exhaust Valves tend to open the gap between the Valve Lifter and the Crankshaft and the Intake Valves tend to close the gap between the Valve Lifter and the Crankshaft. Is that correct?
Indeed after the measurements I did, the Intake Valves came closer to the lower Number Yamaha gives (0.11mm) witch means the gap was closing. Most of them are near 0.14mm.
Two of them at Cylinder 4 and Cylinder 2 are way out of specs, near 0.29mm when the upper limit is 0.20mm. Wtf? Why do you think this happened?
The Exhaust Valves on the other hand were closing the gap too, all of them are near 0.19mm and 0.18mm, all out of Yamaha specs 0.21mm to 0.25mm.

I did a research and they say, when you adjust the valves you must get closer to the upper number, eg 0.11mm to 0.20mm you should reach close to 0.20mm, same for the Exhaust Valves, 0.21mm to 0.25mm you should go near 0.25mm.
Is that correct? or I should adjust them somewhere between?
I wonder, if the Exhust Valves tend to open the gap shouldn't they be adjusted near the lower number 0.21mm?
I'm trying to figure out why in my case all valves seemed to get tighter and closing the gap between the Valve lifter and the Crankshaft. Is this Normal or I'm missing something and it must get a closer look to the Engine Head?
Is it possible at the first Valve Clearance the mechanic did a wrong job?
Any advice and correction to the diagramm I made will be appreciated.

1013489
 

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Valves tend to tighten (make the gap smaller) as they recede into the valve seats, both in and out. You tend to go to the upper limit of clearance as not only do they last longer between services, but tight valves are a way bigger problem than slightly noisier loose
 

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I FEEL THE NEED...FOR SPEED.
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Discussion Starter #3
Thnks for the tip @Hoonicorn , so both intake and exhaust Valves tend to tighten, So I'll go for the upper limit at both.
I was misinformed in another forum saying the Exhaust Valves tend to open the gap, that confused me.
Do you think the 2 Intake Valves at cylinder 4 and Cylinder 2 , that are way out of specs is something to worried about? With so much gap 0.29mm did those 2 Valves stayed opened for less time?
May this affects engine performance?
 

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Middle towards upper limit is what I usually aim for, I’d just set them all to spec. I would check the clearance again in around 2000km to make sure that those 2 intakes have stayed in spec, if they’ve moved it’s time to change them
 

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I FEEL THE NEED...FOR SPEED.
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226 Posts
Discussion Starter #5
Checking clearance again after 2000km would be a pain in the ass job to do, I don't know if I can pass thru this procedure again tearing apart the whole bike , probably I'll adjust them towards the upper limit and live with that for now. Thanks for the info man.
 

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I FEEL THE NEED...FOR SPEED.
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226 Posts
Discussion Starter #7 (Edited)
@DarkHorse believe it or not, when I finished with bike disassemble for valve clearance the first think that passed my mind was, "wtf? maybe I should have lower the engine after all." The torque tool gives you a hard time to fit with the engine on the frame, especially with the intake camshaft caps bolts.
Probably I'll finish the valve clearance and at winter I'll re inspect the valves or take the bike to Yamaha dealer.
1013566


Question No1, Yamaha's Valve shims goes by 0.05mm step, In one Exhaust Valve that I measured 0.19 and it has 1.82 shim if I'll put 1.80mm replacement shim the gap will go to 0.21mm, probably I need 1.78mm(0.23mm) shim but that's not possible, if I'll use a 1.75mm the gap will go to 0.26mm, this is out of Yamaha's specs(0.21-0.25mm).
What should I do? I'm thinking putting the 1.75mm shim(0.26mm) and with the time the gap will come to specs.:unsure:
Question No2, tight Valves can be blamed for bike's hard start?
 

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An R1 kinda day!
2015 Yamaha YZF R1 Raven Edition
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Q2: Tight should mean the valves are being held open and you lose the compression. So yes.
 

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An R1 kinda day!
2015 Yamaha YZF R1 Raven Edition
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Q1: The difference between .25mm and .26mm is only .0004" of an inch. I would not think you couldn't be ok using the higher number. 4 ten thousandths of an inch isn't much at all especially if they get tighter as you go.
 

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An R1 kinda day!
2015 Yamaha YZF R1 Raven Edition
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If you have access to a surface grinder, you can make to fit any size you feel you might need.
 

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I FEEL THE NEED...FOR SPEED.
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Discussion Starter #12
thnks for the tips, see it the other way, for a lot of kilometers the bike was running with all exhaust valves at 0.18-019mm, 0.03-0.02mm out of Yamahas specs, putting a valve at 0.26mm probably there will be no problem I guess.
My brother mentioned a surface grinder but didn't give to much attention, didn't think it will be possible to such a tiny object like valve shims, I'll check it out.
Thnks for the advises guys, much appreciated.
 

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I’ve hand sanded them down by putting a sheet of 800 grit wet paper on a small sheet of glass and using inox as the lubricant, using your pointer finger in figure 8 you can get them down flat, make sure you have a micrometer or very accurate verniers so you can check your progress and get it spot on
 

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I FEEL THE NEED...FOR SPEED.
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Discussion Starter #14
I have a micrometer, but sanded them by hand? I don't know, sounds too risky. :unsure:
Next step is to measure Camshaft lobe dimensions especially at cylinder 4&2 where the 2 valves where way out of specs to see if i have a wear.

1013570
 

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I FEEL THE NEED...FOR SPEED.
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Discussion Starter #16
Camshafts are ok and in specs. Had to go to Yamaha Dealership to buy 2 shims 180mm.
Talking to the engineer there and asked him about Valves Clearance, He mentioned that when he finds a Valve way out of specs 0.30mm and above, they have strict orders from Yamaha to replace this valve, and from his experience Intake Valves took the hit most, he never had to change an Exhaust Valve. The problem is usually with the valve wear itself and not with the headrest.
Well that made me think I should replace those 2 valves eventually after summer time.
Well to be honest Engine timing has given me a very hard time! Definitely a pain in the ass job to do, those 28 camshaft cap bolts still hunt me at nights! :p
Bike is ready to take low altitude flights, thnks for the tips everyone, much appreciated.

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Awesome that you got the job done, sounds like the Yamaha tech was on the same page as me with being suss on those 2 valves. Which is why I would check them again at a short interval, I personally wouldn’t be able to sleep unt I did
 

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I FEEL THE NEED...FOR SPEED.
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Discussion Starter #18
I use the bike every year for 2000-3000 miles and especially at summers, so yes, after summer those 2 Valves will be replaced.
 
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