VE258
New Member
that's the reason! tight them by hand,not some powerful heavy duty impact wrench. screw that..
Valve Adjustment Step-By-Step
- Thread starter Antarius
- Start date
mtiberio
Member
Didn't read all the posts on this thread. I realize some folks are just learning their way around motors. I want to repeat what someone said a few pages back...
There is no need to remove the cam inspection plug. The best way to make sure you are on TDC compression is to rotate the motor until you see the intake valves open and close. Continue rotating the motor (should be between 90 and 180 degrees more), until you see the TDC mark for that same cylinder. If you do this, rest assured, you are at TDC compression. This is because an internal combustion motor sucks in air and gas while the intake valve is open, and then compresses it on its way up to TDC compression. Most intake valves close shortly after BDC (bottom dead center) 1) so they can take advantage of most of the up stroke to generate compression (closing at BDC would generate the max theoretically), and 2) they stay open a bit after BDC so the "inertia" of the intake charge will continue to stuff mixture into the cylinder even though technically the piston has begun to come up.
Just my $0.02, from an old fart, who raced bikes for 18 years, and has been rebuilding motors for 44 years...
there are other ways to tell when you are at TDC compression. As mentioned, Making sure the rockers have some play is good, but not as definitive as the method I describe above. On some motors, you can pull the spark plugs, and hold your finger over the hole, rotate the motor and wait to feel the "push" of air meaning you are on the up stroke just before TDC compression. This of course requires pulling the plugs, which by the way, does make turning the motor over much easier, should that matter to you.
There is no need to remove the cam inspection plug. The best way to make sure you are on TDC compression is to rotate the motor until you see the intake valves open and close. Continue rotating the motor (should be between 90 and 180 degrees more), until you see the TDC mark for that same cylinder. If you do this, rest assured, you are at TDC compression. This is because an internal combustion motor sucks in air and gas while the intake valve is open, and then compresses it on its way up to TDC compression. Most intake valves close shortly after BDC (bottom dead center) 1) so they can take advantage of most of the up stroke to generate compression (closing at BDC would generate the max theoretically), and 2) they stay open a bit after BDC so the "inertia" of the intake charge will continue to stuff mixture into the cylinder even though technically the piston has begun to come up.
Just my $0.02, from an old fart, who raced bikes for 18 years, and has been rebuilding motors for 44 years...
there are other ways to tell when you are at TDC compression. As mentioned, Making sure the rockers have some play is good, but not as definitive as the method I describe above. On some motors, you can pull the spark plugs, and hold your finger over the hole, rotate the motor and wait to feel the "push" of air meaning you are on the up stroke just before TDC compression. This of course requires pulling the plugs, which by the way, does make turning the motor over much easier, should that matter to you.
Bines
New Member
Hi.
Can someone explain the T1, T2 and F marks?
I wound up checking with my feeler gauges at all marks, several times, and didn't get the results consistently. Finally, I used the 'little bit of play in the rocker' technique. I was able to slide the feelers in with no adjustments.
Just an observation, and not advice on this being a valid means of valve checking, I noticed the paint marks on the screws and nuts were perfectly aligned.
Can someone explain the T1, T2 and F marks?
I wound up checking with my feeler gauges at all marks, several times, and didn't get the results consistently. Finally, I used the 'little bit of play in the rocker' technique. I was able to slide the feelers in with no adjustments.
Just an observation, and not advice on this being a valid means of valve checking, I noticed the paint marks on the screws and nuts were perfectly aligned.
D
Deleted member 1183
I have to disagree to a point. I totally agree with your assessment of how to achieve TDC on compression. However the purpose of the marks as designated by Honda is to ensure that you check the clearances in the exact position where they want you to check them. An old hand might be ok with doing things his way but a total novice should follow exact instructions to avoid confusion.
Maybe I'm just an experienced mechanic, but I'll never remove that cam inspection plug again. It is a waste of (my) time. It is quite clear from inspection of the rocker arm play which part of the cycle the cam is on. The only purpose removing the plug might serve is to verify the cam chain didn't jump a tooth, should I ever have any reason to suspect that it did.
I can only surmise that Honda wrote the procedure that way to remove any chance of error in the valve adjustment process, and thus any responsibility for any procedures done improperly.
I can only surmise that Honda wrote the procedure that way to remove any chance of error in the valve adjustment process, and thus any responsibility for any procedures done improperly.
Well, I have to disagree with your disagreement. While exact positioning is important for some procedures (like installing the cam chain) it is less important for valve clearance checks because there is a significant dwell at the base circle of the cam. Close enough here really is close enough.
D
Deleted member 1183
Point taken. However the dwell at the base of the cam is not always uniform and accordingly I revert to my point that the clearance be checked where Honda want it checked rather than another position on the dwell.
1T = top dead center for cylinder #1
2T = top dead center for cylinder #2
F = ignition timing mark (at idle, light connected to cylinder #1, no advance)
There is an observation I have made, that I find interesting. It simply came to mind. It's not directed at or based on any specific person, place, or thing. But, in general, motorcycle owners have opinions about the way things should be in/on their motorcycles, even going against the manufacturer's recommendations. Owners sometimes decide the stock air filter is too restrictive and needs to be changed immediately, or that the oil change intervals should never go as long as 8000 miles, or that the brake fluid doesn't need to be changed until it's black, or the stock fuel mix is always too lean so you need a module of some sort, or that the spark plugs are really good for 80,000 miles, but by golly, no one has ever questioned the Honda valve clearance specification. For that, we need to do exactly as Honda says.
Now, I'm not saying the specs are not right. I'm certainly not one to second guess Honda engineers, nor do I have any incentive to. My point is, I'm surprised no one has ever said they know better than Honda and came up with their own valve clearance specs for some reason or another, as is the case with other maintenance items.
Now, I'm not saying the specs are not right. I'm certainly not one to second guess Honda engineers, nor do I have any incentive to. My point is, I'm surprised no one has ever said they know better than Honda and came up with their own valve clearance specs for some reason or another, as is the case with other maintenance items.
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lootzyan
Well-Known Member
D
Deleted member 1183
Certainly it is perfectly round in the drawing and that is the theory. However as I have found over the years, a small movement of the cam off the designated point, can sometimes result in a tightness or looseness on the feeler guage that is not always evident in another position on the base circle. Perhaps it will only be a tiny amount such as a thousandth of an inch but nonetheless the irregularity was evident on occasion.
happy
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For what it's worth, keep sharing and discussing your own experiences and knowledge but keep it civil and friendly.
I have been mobbed before in several forums by "experts" just because my views did not agree with theirs and they make it personal. One forum even banned me because i questioned the admin.
We all have different views and we need to allow others to say their opinion without any hard whiplash.
Sent from my LG-D955 using Tapatalk
I have been mobbed before in several forums by "experts" just because my views did not agree with theirs and they make it personal. One forum even banned me because i questioned the admin.
We all have different views and we need to allow others to say their opinion without any hard whiplash.
Sent from my LG-D955 using Tapatalk
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lootzyan
Well-Known Member
I hope we are discussing here our experience with Honda NC (CTX) engines.
Difference of 0.02mm of clearance on feeler gauge can be easy felt. But I don't think it is because of deviation from roundness of cam base. Most likely it is a sum of clearances of rocker arm-to-shaft and cylinder head-to-camshaft. When valve clearance is checked on e.g. 1st cylinder, depends from camshaft position, tension from valves springs of 2nd cylinder is also changing - hence different tightness on feeler gauge.
When analyzing Honda's specifications for cylinder head/valves assembly, surprisingly, Honda allows pretty big clearances of rocker arm-to-shaft (0.058mm) and cylinder head-to-camshaft (0.084mm).
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D
Deleted member 1183
Be assured, nobody is either being uncivil or unfriendly. We are merely exchanging views so if You want to contribute with regard to the subject to hand, lets have your views. Otherwise........
D
Deleted member 1183
Well actually my experiences with variations in the roundness of the cam base were on the GL1800 and several other OHC motors of varying makes where the cam acts directly on the bucket atop the valve stem. On those it was most obvious and more or less indisputable. Obviously there are indirect aspects to the NC valve gear but the point is basically that cam bases are not always perfect.
robskinn
New Member
Thanks for this post Antarius. Excellent work!
Wish I'd have found it sooner as I suffered from having one of the Service Manuals that said to align the camshaft marks to the top index point. I started her up and it was clicking quite badly. Tomorrow I'm going to repeat the process using the left mark. Do you know if I have damaged the bike in any way by starting it up with the incorrect clearances?
Wish I'd have found it sooner as I suffered from having one of the Service Manuals that said to align the camshaft marks to the top index point. I started her up and it was clicking quite badly. Tomorrow I'm going to repeat the process using the left mark. Do you know if I have damaged the bike in any way by starting it up with the incorrect clearances?
Antarius
Site Supporter
I'm sure it's fine. You noticed it and shut it off and will correct it. No worries.
Prolonged out of spec valves can cause problems (either running poorly, or damage to the valve if too tight), but in your case I'm sure it's fine.
If you read back you'll see a good way to ensure you're correct is the rocker arm you are checking, should have play. As in, you should be able to wiggle it up and down a little bit - in any stroke, let alone the compression stroke. That play is, afterall, what you're measuring. If you don't have any play on the rocker arm, odds are you are mis-aligned and the cam is applying pressure to the valve (either opening or closing) and thus, no play.
So line it up as you now know how, and verify that you're correct by wiggling the rocker arm. It will move, and you'll go "ah ha! heck yes!" and adjust away.
Therapy
Member
Excellent writeup.
We should have found it before we did the service.
So. Another data point on the 8000 mile valve adjustments.
The younger son and I did the 8000 mi. service on his 2012 NC. The valves were all just a little tight. Only on a couple intake could we not get the feeler gauge in though.
I also adjust valves to err on the loose side.
We took off the radiator like the book says.
We could not find a mark or a place in the manual that said which cylinder was which. We both looked. We both failed. I just used the old Set it to TDC an wiggle the rocker arms. Plus google. Whew!!
Not bad really and the boy learned how to do valves, a bit about coolant, bleeding brakes and maybe a little more.
I used to get a lot of personal satisfaction out of doing my own wrenching but not any more. Now it is a chore.
I did get some today though seeing my son learn and get satisfaction. Plus he now knows what it takes to come up with $350.00. So coming up with only $20.00 or so helped him smile.
We should have found it before we did the service.
So. Another data point on the 8000 mile valve adjustments.
The younger son and I did the 8000 mi. service on his 2012 NC. The valves were all just a little tight. Only on a couple intake could we not get the feeler gauge in though.
I also adjust valves to err on the loose side.
We took off the radiator like the book says.
We could not find a mark or a place in the manual that said which cylinder was which. We both looked. We both failed. I just used the old Set it to TDC an wiggle the rocker arms. Plus google. Whew!!
Not bad really and the boy learned how to do valves, a bit about coolant, bleeding brakes and maybe a little more.
I used to get a lot of personal satisfaction out of doing my own wrenching but not any more. Now it is a chore.
I did get some today though seeing my son learn and get satisfaction. Plus he now knows what it takes to come up with $350.00. So coming up with only $20.00 or so helped him smile.
rmezei
Member
Hello everyone,
curious if anyone has experienced any issues because of lack of valve adjustment, i.e. just ignore an don't do valve adjustment... assuming 60000 miles gone by, could something actually happen with the valves burning? Has this actually ever happened.
Thank you.
curious if anyone has experienced any issues because of lack of valve adjustment, i.e. just ignore an don't do valve adjustment... assuming 60000 miles gone by, could something actually happen with the valves burning? Has this actually ever happened.
Thank you.
sumo
Site Supporter
I've got 34000 km and should have checked the valves at 24000. I'm going to get to it. I think I'm due for a radiator flush too so will do both at the same time. My bike seems to be running fine.
