waited too long
01-01-2011, 08:22 AM
#61
Senior Member
MotoGP
Join Date: Jul 2010
Location: Phoenix, AZ
Posts: 3,869
01-01-2011, 08:30 AM
#62
Senior Member
SuperBike
Join Date: Dec 2005
Location: South Lake Tahoe, CA, USA
Posts: 1,689
Just to finish off my thoughts on this long discussion of a short subject...
I can see how you could ding the bearings if you try to pull the cam and sprocket out from under the chain. But if you just tip one of the cams slightly, after removing the tensioner, you can take the chain off the sprocket and move it to the side. Lay the cam back in the bearings and take the chain of the other cam sprocket.
When the chain is out of the way, you just lift the cams out. I had degreed my cams and loctited the sprocket bolts, so there was motivation for not removing the sprockets.
Happy New Year!
I can see how you could ding the bearings if you try to pull the cam and sprocket out from under the chain. But if you just tip one of the cams slightly, after removing the tensioner, you can take the chain off the sprocket and move it to the side. Lay the cam back in the bearings and take the chain of the other cam sprocket.
When the chain is out of the way, you just lift the cams out. I had degreed my cams and loctited the sprocket bolts, so there was motivation for not removing the sprockets.
Happy New Year!
01-01-2011, 09:21 AM
#63
Slacker
Superstock
Superstock
Join Date: Jun 2005
Location: San Antonio, TX
Posts: 489
Hey RCVTR, that is what I was intending to accomplish the first try, but I think that I was only attempting to remove one camshaft (Rear EX) while the intake was still bolted down. Do you suppose this could be why I had such a difficult time? Should all the bearing caps for both cams be removed before attempting to lift the chain off from the first one? I seem to recall having found insufficient clearance to pull the chain off from one sprocket no matter how I tilted it. Is it best to start with the intake cam first?
I ask because it is not always desired to remove both camshafts if you only need to adjust clearances on one valve.
I ask because it is not always desired to remove both camshafts if you only need to adjust clearances on one valve.
01-01-2011, 10:44 AM
#64
Banned
MotoGP
Join Date: Aug 2007
Location: Lake View Terrace, CA
Posts: 5,942
With this logic using shims in .002 increments if your gap is .011 you can shim it up to .013 an both will be within tolerance which is .012 +/- .001. If you have a valve which is out of tolerance at .010 then changing one size up will give you a gap of .012 which would be right at spec. For a racing engine it could be beneficial to hit it right on spec, but since you are not blueprinting your entire engine then landing within tolerance is more than adequate.
I thought the same way as you do up to the point where I actually tackled the problem hands on. Having the shim selection on-hand before starting the job will let you get it done quickly and get the bike back together, allowing more time for riding, beer drinking and other fun with the woman.
I thought the same way as you do up to the point where I actually tackled the problem hands on. Having the shim selection on-hand before starting the job will let you get it done quickly and get the bike back together, allowing more time for riding, beer drinking and other fun with the woman.
So what if the gap is not quite .011? You have the choice of just leaving it and then have to do the whole job over again when it does tighten up a bit more or setting it to large.
My opinion is that if you have done all the work to get to the valve shims, you might as well do the job right not just close enough.
It is kind of funny how you imply that I have never adjusted the valve before......lol
Then there is the cost. Granted I can just run down and swap shims at my local dealer but most folks don't have that option. So in the last 14 years and 2 adjustments I have changed 5 shims total. So if I was buying them I would have a whole $25 invested in shims instead of the $70 for the kit. So even though I don't drink guess who has more beer money left after the job is complete.
So do whatever you want, it's your bike but I'm one of those people that would rather do it right than save a buck and get it kind of close.
Tightening the valve lash will move the power band down in the RPM range and loosening the valve lash will raise the power band. So while we are only talking a small change, by using your method you can end up with different lash on each cylinder which will make the motor vibrate more than it already does. While the motor with the lash set to the same spec front & rear will be as smooth as possible.
Like I said you can do whatever you want but I'll keep setting the valves to spec. for no other reason than to get both cylinders to work together.
01-01-2011, 01:12 PM
#65
Senior Member
MotoGP
Thread Starter
Join Date: Aug 2006
Location: altoona, pa
Posts: 2,934
wow! lots of good advice BeerHunter. I'm glad you're not hungover or we probably wouldn't be having this conversation huh. Thanks a bunch, I really appreciate these little things that can make things go south in a heartbeat.
And i'm glad I'm not hungover either cause I just got back from a New Years Day 100 mile ride. Yee Haw! 40 degrees, 70% chance of rain, and no traffic on my favorite local version of Deals Gap. I'm lucky to have an XR with Hot Grips and an anti-fog shield to be able to enjoy gravel strewn roads in colder temps.
definitely gonna take you words of wisdom seriously and stuff some rags down the buckets. I am very good at dropping **** down holes. haha
I measured the gaps at TDC and they are .005 Intakes and .010 Exhausts with the shims in. I removed the rear CCT to do the bolt mod noted earlier. thanks again Beer Hunter.
And i'm glad I'm not hungover either cause I just got back from a New Years Day 100 mile ride. Yee Haw! 40 degrees, 70% chance of rain, and no traffic on my favorite local version of Deals Gap. I'm lucky to have an XR with Hot Grips and an anti-fog shield to be able to enjoy gravel strewn roads in colder temps.
definitely gonna take you words of wisdom seriously and stuff some rags down the buckets. I am very good at dropping **** down holes. haha
I measured the gaps at TDC and they are .005 Intakes and .010 Exhausts with the shims in. I removed the rear CCT to do the bolt mod noted earlier. thanks again Beer Hunter.
01-01-2011, 01:55 PM
#66
Slacker
Superstock
Superstock
Join Date: Jun 2005
Location: San Antonio, TX
Posts: 489
Anywhere between .011 and .013 IS setting the valves to spec. If the gap is 'almost .011' but tighter, then I would call that a .010 and shim it down a size which would yield about .013 on the tight side...which would really be very close to .012. If it is 'almost .011' on the loose side then button it up and go get some pizza, because you are already very close to .012
So long as the valves are within range then you can do a proper vacuum idle synchronization of the carbs. It is interesting now that I think of it... I have pulled the carbs 12+ times for various jetting changes to try different configurations and have yet to twist on that synchronization bolt. The vacuum is always balanced.
01-01-2011, 03:07 PM
#67
Slacker
Superstock
Superstock
Join Date: Jun 2005
Location: San Antonio, TX
Posts: 489
+1 to that!
I tried removing the cams on the rear cylinder of my spare parts engine first, just for practice before digging into the good engine. While attempting to maneuver the cam/sprocket assembly out from under the chain I accidentally scored one of the cam bearing surfaces,on the cylinder head, with a nice thick and noticeably deep groove. I did not even realize what had happened right away since the edges of the cam lobes are quite sharp and apparently very little effort is needed to cause damage. Steel beats aluminum in any fight.
Removing the sprockets is easy and adds a few extra minutes to the job, while making other things easier and SAFER.
I tried removing the cams on the rear cylinder of my spare parts engine first, just for practice before digging into the good engine. While attempting to maneuver the cam/sprocket assembly out from under the chain I accidentally scored one of the cam bearing surfaces,on the cylinder head, with a nice thick and noticeably deep groove. I did not even realize what had happened right away since the edges of the cam lobes are quite sharp and apparently very little effort is needed to cause damage. Steel beats aluminum in any fight.
Removing the sprockets is easy and adds a few extra minutes to the job, while making other things easier and SAFER.
After review of this thread I see that I misunderstood your sentence, RCVTR. I took it to mean 'You can remove the cams without taking the sprockets off FROM THE CHAIN.' I suppose I was imagining having the sprockets zip-tied to the chain.
Obviously I was sober and not thinking clearly....have mercy on me!!
01-01-2011, 03:23 PM
#68
Slacker
Superstock
Superstock
Join Date: Jun 2005
Location: San Antonio, TX
Posts: 489
wow! lots of good advice BeerHunter. I'm glad you're not hungover or we probably wouldn't be having this conversation huh. Thanks a bunch, I really appreciate these little things that can make things go south in a heartbeat.
And i'm glad I'm not hungover either cause I just got back from a New Years Day 100 mile ride. Yee Haw! 40 degrees, 70% chance of rain, and no traffic on my favorite local version of Deals Gap. I'm lucky to have an XR with Hot Grips and an anti-fog shield to be able to enjoy gravel strewn roads in colder temps.
definitely gonna take you words of wisdom seriously and stuff some rags down the buckets. I am very good at dropping **** down holes. haha
I measured the gaps at TDC and they are .005 Intakes and .010 Exhausts with the shims in. I removed the rear CCT to do the bolt mod noted earlier. thanks again Beer Hunter.
And i'm glad I'm not hungover either cause I just got back from a New Years Day 100 mile ride. Yee Haw! 40 degrees, 70% chance of rain, and no traffic on my favorite local version of Deals Gap. I'm lucky to have an XR with Hot Grips and an anti-fog shield to be able to enjoy gravel strewn roads in colder temps.
definitely gonna take you words of wisdom seriously and stuff some rags down the buckets. I am very good at dropping **** down holes. haha
I measured the gaps at TDC and they are .005 Intakes and .010 Exhausts with the shims in. I removed the rear CCT to do the bolt mod noted earlier. thanks again Beer Hunter.
Ohh, the hole that needs to be covered is the valley where the chain connects to the crank, just to be clear.
01-01-2011, 04:33 PM
#69
Senior Member
MotoGP
Thread Starter
Join Date: Aug 2006
Location: altoona, pa
Posts: 2,934
I saw an opportunity to shed light on your problem and hope that I have not misguided you in any way. I just get tired of reading posts that always suggest you ' do a search ' and felt like lending a hand. Good luck with the procedure! It is not so difficult once you really comprehend what needs to be done.
Ohh, the hole that needs to be covered is the valley where the chain connects to the crank, just to be clear.
Ohh, the hole that needs to be covered is the valley where the chain connects to the crank, just to be clear.
I notice that sometimes, but not always, when the mechanically skilled offer advice, they respond like they're talking to mechanics, and most of us are really not mechanics. I've rebuilt a couple motors, dismantled and rebuilt a house, and a whole bunch of other ****, but when I get into something new, it takes practice for me to start understanding how things come apart and go back together. It took me a bunch of times, for example, with the carbs and the only reason I got to repeat this many time in close proximity was in the process of helping another member with his Hawk.
So what i am trying to say is that i appreciate your helping me and know others in similar circumstances do also.
01-01-2011, 04:49 PM
#71
Senior Member
MotoGP
Thread Starter
Join Date: Aug 2006
Location: altoona, pa
Posts: 2,934
01-01-2011, 08:08 PM
#72
Banned
MotoGP
Join Date: Aug 2007
Location: Lake View Terrace, CA
Posts: 5,942
Anywhere between .011 and .013 IS setting the valves to spec. If the gap is 'almost .011' but tighter, then I would call that a .010 and shim it down a size which would yield about .013 on the tight side...which would really be very close to .012. If it is 'almost .011' on the loose side then button it up and go get some pizza, because you are already very close to .012
So long as the valves are within range then you can do a proper vacuum idle synchronization of the carbs. It is interesting now that I think of it... I have pulled the carbs 12+ times for various jetting changes to try different configurations and have yet to twist on that synchronization bolt. The vacuum is always balanced.
So long as the valves are within range then you can do a proper vacuum idle synchronization of the carbs. It is interesting now that I think of it... I have pulled the carbs 12+ times for various jetting changes to try different configurations and have yet to twist on that synchronization bolt. The vacuum is always balanced.
If one valve is at .011 and the other is at .013 (using the exhaust as an example) it will not run as well or make the same power as a engine with both set at .012 even though they are all technically in spec.
Also if one cylinder has both valves set at .011 and the other cylinder is at .013 on both valves, it will run rougher with more vibration and less power than a engine with all the valves set to the same value.
So like I've been saying, sure you can just get things "in spec" and it will run fine or you can take a little time and get it to run a well as it possible can with just a minor amount of extra effort, the choice is yours.
As for your carb sync example, I don't get that one at all. The valves can be way out and you can still sync the carbs.
Personally I'm going to take a few extra minutes and get all the valves to the same value instead of doing all the work to get to the cams and then only getting it "good enough" but if it works for you, no worries. Then again that is why I want access to all the shims instead of a kit the skips every other one.
01-01-2011, 08:10 PM
#73
Banned
MotoGP
Join Date: Aug 2007
Location: Lake View Terrace, CA
Posts: 5,942
01-01-2011, 09:48 PM
#74
Banned
MotoGP
Join Date: Aug 2007
Location: Lake View Terrace, CA
Posts: 5,942
I will say the carb example is pretty good. Spec for the carbs is +\- .5" Hg if you set the carbs to this the bike will run ok and technically be in spec but if you take the time to get them as close as you can you end up with a much smoother running engine. I know I can feel the difference between the 2 settings.
The same thing goes for the valves. Getting them close will make it run ok, getting them dead on will make it run the best that it can. Though I do feel like I'm beating a dead horse so this will be my last post in this thread.
The same thing goes for the valves. Getting them close will make it run ok, getting them dead on will make it run the best that it can. Though I do feel like I'm beating a dead horse so this will be my last post in this thread.
01-02-2011, 07:07 AM
#75
Slacker
Superstock
Superstock
Join Date: Jun 2005
Location: San Antonio, TX
Posts: 489
01-02-2011, 07:19 AM
#76
Senior Member
MotoGP
Thread Starter
Join Date: Aug 2006
Location: altoona, pa
Posts: 2,934
that sounds too simple according to what others have described relative to all the switching around and experimenting with +- tolerances.
Continuing on this line of thinking, is there a standard size shim, that is OEM shim size for all new SH engines or are there variations even within new motors?
Because if there were same size OEM shims, it would be just a matter of calculation to determine the exact shim needed to get into spec before removing the cams. But that probably can't be true.
Continuing on this line of thinking, is there a standard size shim, that is OEM shim size for all new SH engines or are there variations even within new motors?
Because if there were same size OEM shims, it would be just a matter of calculation to determine the exact shim needed to get into spec before removing the cams. But that probably can't be true.
01-02-2011, 08:58 AM
#77
Senior Member
MotoGP
Thread Starter
Join Date: Aug 2006
Location: altoona, pa
Posts: 2,934
As far as "beating a dead horse", let's not throw the baby out with the bathwater here. Opinions are like ********, everybody has one. We need all the ******** we can get because, basically, we're all ******** with something the say, some of it may even be illuminating. It's just that some of us haven't learned this fact yet. So fight nice, we can all get along, and maybe even help each other to learn something in the process.
We learn through adversity, so we need diverse points of view to bring us to real understanding of reality. In terms of myself learning things, I can hear, see, feel, etc., trying to understand and in many instances, one specific way of explaining, or doing, or other will spark an awakening of understanding which carries me out of the abyss. It's happened to all of us if you think about it.
I'm convinced that there is a definitive right and wrong in most cases, but most don't have the staying power to see it through to the point of resolution.
Now there's my sunday sermon for those who haven't yet been to church this morning. So put some money in the collection box so I can order some shims.haha
Happy happy 2011!
01-02-2011, 09:42 AM
#78
Senior Member
MotoGP
Join Date: May 2008
Location: San Clemente, CA
Posts: 3,451
As far as getting the valves right on, I've always been **** about that (since you're speaking about ******** nath). It's way easier with set screw adjusters though. With shims you don't know "exactly" what you've got until it's back together.
Most important is measuring the lash accurately before pulling the cams. There should be a slight "drag" on the feeler gauge. From my experience, many people expect the feeler gauge to slide through with no resistance.
Most important is measuring the lash accurately before pulling the cams. There should be a slight "drag" on the feeler gauge. From my experience, many people expect the feeler gauge to slide through with no resistance.
01-02-2011, 10:34 AM
#79
Senior Member
MotoGP
Thread Starter
Join Date: Aug 2006
Location: altoona, pa
Posts: 2,934
As far as getting the valves right on, I've always been **** about that (since you're speaking about ******** nath). It's way easier with set screw adjusters though. With shims you don't know "exactly" what you've got until it's back together.
Most important is measuring the lash accurately before pulling the cams. There should be a slight "drag" on the feeler gauge. From my experience, many people expect the feeler gauge to slide through with no resistance.
Most important is measuring the lash accurately before pulling the cams. There should be a slight "drag" on the feeler gauge. From my experience, many people expect the feeler gauge to slide through with no resistance.
If i knew what size shim was in there OEM, I could do the calculations before, but I'm gonna have to wait till i get them out for the rear, do that, button that up and then do the front. Right now, I got the R cct out and am going to mod that first.
Looking at the OEM CCT, it's hard to think that the whimpy-assed spring in there could affect anything, but i guess it's just enough slack to allow the chain to dislodge itself.
01-02-2011, 11:26 AM
#80
Banned
MotoGP
Join Date: Aug 2007
Location: Lake View Terrace, CA
Posts: 5,942
Well as you guys asked......lol but really I'm not trying to sound like an *** or know it all..... just I can't agree with somethings that have been said, with that here goes.
Well, in my experience, the most I've ever had to turn the sync adjustment screw is right around 1\4 turn. That is with a little more than 1\2" Hg difference.
So to extrapolate that out, you have 4 turns either way on the adjuster. With each complete turn equaling 2" Hg that is 8" Hg each way or 16" Hg total. So if you can start the engine, you should have enough range on the adjuster to get them to sync up. At least that is how it has worked for me.
That would be nice but no it doesn't work that way. There is no set shim size to start with. They are all close to the same size (I.E. all the exhaust valves will use close to the same size shim and the same goes for the intakes) but they do vary due to manufacturing tolerances.
Also, even though the shims are etched with the size ( which should always face down so you don't wear the number off while you are running the engine) it is also good practice to measure the shim when you remove it, not just trust the etched number, in case the shim has worn (not common but can happen)
It is one of those projects that look intimidating before you start, it is pretty straight forward once you start doing it. Just take your time and get your measurement as accurate as possible.
Then take your measured clearance and subtract the specified clearance (if you end up with a positive number you need a thicker shim, a negative number means a thinner shim) Then add that number to the shims size that is already installed and that will give you the size of the shim that needs to be installed.
Sounds kind of complicated but is pretty straight forward once you get in there. Just measure everything twice and take your time. Also always measure the shims, never just trust the number etched in them.
When you get done and have everything back together, remeasure the clearance to make sure you got it right and then button it all up.
So to extrapolate that out, you have 4 turns either way on the adjuster. With each complete turn equaling 2" Hg that is 8" Hg each way or 16" Hg total. So if you can start the engine, you should have enough range on the adjuster to get them to sync up. At least that is how it has worked for me.
Continuing on this line of thinking, is there a standard size shim, that is OEM shim size for all new SH engines or are there variations even within new motors?
Because if there were same size OEM shims, it would be just a matter of calculation to determine the exact shim needed to get into spec before removing the cams. But that probably can't be true.
Because if there were same size OEM shims, it would be just a matter of calculation to determine the exact shim needed to get into spec before removing the cams. But that probably can't be true.
Also, even though the shims are etched with the size ( which should always face down so you don't wear the number off while you are running the engine) it is also good practice to measure the shim when you remove it, not just trust the etched number, in case the shim has worn (not common but can happen)
It is one of those projects that look intimidating before you start, it is pretty straight forward once you start doing it. Just take your time and get your measurement as accurate as possible.
Then take your measured clearance and subtract the specified clearance (if you end up with a positive number you need a thicker shim, a negative number means a thinner shim) Then add that number to the shims size that is already installed and that will give you the size of the shim that needs to be installed.
Sounds kind of complicated but is pretty straight forward once you get in there. Just measure everything twice and take your time. Also always measure the shims, never just trust the number etched in them.
When you get done and have everything back together, remeasure the clearance to make sure you got it right and then button it all up.
01-02-2011, 02:09 PM
#81
Senior Member
MotoGP
Thread Starter
Join Date: Aug 2006
Location: altoona, pa
Posts: 2,934
yeah, and that's a good thing. We're big boys and don't need agreement. We need the facts, the truth, the right info, and that's usually what it takes to sift through the horseshit so we can find out what everyone has to say, and then what everyone has to say about that, and eventually arrive at the best solution.
I think what were doing in terms of communication, helping others on this forum, is nothing short of amazing. It's easy to take for granted, but contributors like yourself have taken our knowledge, skills and abilities to a level difficult or even impossible to achieve on one's own. For example, I only know of two SH owners locally and both are recent acquaintances and know relatively nothing. I bought my Hawk in 2000, so previous to this forum, it was basically me and the Manual.
Anyway, tomorrow I'm going to pick up a thread tap and some bolts for the CCT fix, and then try to pick up some shims locally. And then fun begins. thanks.
I think what were doing in terms of communication, helping others on this forum, is nothing short of amazing. It's easy to take for granted, but contributors like yourself have taken our knowledge, skills and abilities to a level difficult or even impossible to achieve on one's own. For example, I only know of two SH owners locally and both are recent acquaintances and know relatively nothing. I bought my Hawk in 2000, so previous to this forum, it was basically me and the Manual.
Anyway, tomorrow I'm going to pick up a thread tap and some bolts for the CCT fix, and then try to pick up some shims locally. And then fun begins. thanks.
01-02-2011, 03:22 PM
#82
Senior Member
MotoGP
Join Date: May 2008
Location: San Clemente, CA
Posts: 3,451
Also, even though the shims are etched with the size ( which should always face down so you don't wear the number off while you are running the engine) it is also good practice to measure the shim when you remove it, not just trust the etched number, in case the shim has worn (not common but can happen)
I used to send my students to the dealer with a micrometer when they went to buy shims. I wouldn't even attempt to do a shim adjust without an accurate micrometer.
01-02-2011, 04:41 PM
#83
Slacker
Superstock
Superstock
Join Date: Jun 2005
Location: San Antonio, TX
Posts: 489
Well, in my experience, the most I've ever had to turn the sync adjustment screw is right around 1\4 turn. That is with a little more than 1\2" Hg difference.
So to extrapolate that out, you have 4 turns either way on the adjuster. With each complete turn equaling 2" Hg that is 8" Hg each way or 16" Hg total. So if you can start the engine, you should have enough range on the adjuster to get them to sync up. At least that is how it has worked for me.
Of course you could hook up a vacuum indicator of some sort and turn the screw to make both sides the same. I know that is possible. The problem is that carburetor synchronization is the process of making all throttle butterflys open at the exact same time. Using vacuum gauges is an indirect way of measuring the throttle opening on each cylinder.
But, when the valve lash is beyond the specified range there will be a noticeable change in engine vacuum. Trying to get both carbs to open at the same rate using vacuum as an indirect means of measure on a cylinder with out of spec valve clearance will only allow you to de-synchronize the throttles.
This is very important in tuning a multi-carb engine. That was what I was getting at.
01-02-2011, 06:54 PM
#84
Banned
MotoGP
Join Date: Aug 2007
Location: Lake View Terrace, CA
Posts: 5,942
Of course you could hook up a vacuum indicator of some sort and turn the screw to make both sides the same. I know that is possible. The problem is that carburetor synchronization is the process of making all throttle butterflys open at the exact same time. Using vacuum gauges is an indirect way of measuring the throttle opening on each cylinder.
But, when the valve lash is beyond the specified range there will be a noticeable change in engine vacuum. Trying to get both carbs to open at the same rate using vacuum as an indirect means of measure on a cylinder with out of spec valve clearance will only allow you to de-synchronize the throttles.
This is very important in tuning a multi-carb engine. That was what I was getting at.
But, when the valve lash is beyond the specified range there will be a noticeable change in engine vacuum. Trying to get both carbs to open at the same rate using vacuum as an indirect means of measure on a cylinder with out of spec valve clearance will only allow you to de-synchronize the throttles.
This is very important in tuning a multi-carb engine. That was what I was getting at.
The error in your reasoning is that these bikes use CV carbs. That and what you want to sync is the slide opening, not butterfly position.
On non-CV carbs, yes you measure the slide opening to get things sync'ed up. On CV's it is totally controlled by vacuum. So butterfly position really has nothing to do with it, that is why there is no mention of checking the butterfly position on an engine with CV carbs.
If you want to try it out, pull the carbs and get the butterfly openings matched exactly. Now go ride the bike. After that hook up a vacuum gauge and set the vacuum to the same value on both carbs and try it again. Which one do you think will give you the best results??
Last edited by 8541Hawk; 01-02-2011 at 08:14 PM.
01-02-2011, 06:58 PM
#85
Banned
MotoGP
Join Date: Aug 2007
Location: Lake View Terrace, CA
Posts: 5,942
yeah, and that's a good thing. We're big boys and don't need agreement. We need the facts, the truth, the right info, and that's usually what it takes to sift through the horseshit so we can find out what everyone has to say, and then what everyone has to say about that, and eventually arrive at the best solution.
Well I guess getting bitched out about being a know it all has kind of made me back off a bit from these discussions.
Anyways back to the thread......
01-02-2011, 08:33 PM
#86
Senior Member
MotoGP
Thread Starter
Join Date: Aug 2006
Location: altoona, pa
Posts: 2,934
you could be right. you could be wrong, but someone else will have to be the judge of that. Ya hear that wise ***?haha
01-02-2011, 09:47 PM
#87
Senior Member
MotoGP
Join Date: Jul 2010
Location: Phoenix, AZ
Posts: 3,869
that sounds too simple according to what others have described relative to all the switching around and experimenting with +- tolerances.
Continuing on this line of thinking, is there a standard size shim, that is OEM shim size for all new SH engines or are there variations even within new motors?
Because if there were same size OEM shims, it would be just a matter of calculation to determine the exact shim needed to get into spec before removing the cams. But that probably can't be true.
Continuing on this line of thinking, is there a standard size shim, that is OEM shim size for all new SH engines or are there variations even within new motors?
Because if there were same size OEM shims, it would be just a matter of calculation to determine the exact shim needed to get into spec before removing the cams. But that probably can't be true.
In the end, what you need are all the valves in spec and equal to each other.
Where the simplicity gets a bit more complicated are all of the little steps we're taklking about:
"in spec" seems to be under discussion that is better articulated that I could... but my understanding of it was to get in the middle of the range, but error on the positive side of things. As in, if two shims are equally distant from the middle of spec, go with the one that gives you more clearance.
And it sounds like just as importantly, try to get all of the valves equal to each other so that they run smoothly (don't set one valve to the bottom range of spec and the other to the top of the range)...
NOW, where it got a little complicated (I'm still saying it's simple haha!) is that the valves may not wear evenly. So even if the shims started the same from factory (8541Hawk says they don't anyway) you won't be thinning the shims evenly. So you have to measure all of them, remember where they went (I drew a picture and marked what the tolerances were and how much more thickness I needed), and may replace all of them. Hawk has replaced only 5. At 26K miles I needed to replace 8, although only one of those was out of spec. I had to measure mine with a micrometer as well b/c the numbers had worn out. Pretty sure I didn't put the numbers up either, so if I have to do this again, I'll have worn out numbers again, heh
What you can do to make it simple, is just make a list of all the shims that you need and go and swap them out. If you have a shop that will do this, hey, free adjustment!
The coolest part of the job is after assembling it all, sliding that feeler gauge in there and having the tolerances all work. It's so weird that those little shims make a difference, and that you can measure it.
Kind of redundant what I'm saying, but part of this is just organizing it in my head as well as I am pretty new still and need the practice
01-02-2011, 10:15 PM
#88
Banned
MotoGP
Join Date: Aug 2007
Location: Lake View Terrace, CA
Posts: 5,942
That is why it is common & normal for the clearances to tighten up. As the valve seat wears the valve moves up into the head, thereby tightening the clearance.
This is also why if you have too large of a clearance when you do the check you need to inspect the buckets and the cams as loosing material off of these surfaces is the normal cause of it and neither one is a good thing, though it is also possible to have a bad shim that is wearing which is another reason why you measure them when you take them out.
01-03-2011, 06:14 AM
#90
Slacker
Superstock
Superstock
Join Date: Jun 2005
Location: San Antonio, TX
Posts: 489
The error in your reasoning is that these bikes use CV carbs. That and what you want to sync is the slide opening, not butterfly position.
On non-CV carbs, yes you measure the slide opening to get things sync'ed up. On CV's it is totally controlled by vacuum. So butterfly position really has nothing to do with it, that is why there is no mention of checking the butterfly position on an engine with CV carbs.
On non-CV carbs, yes you measure the slide opening to get things sync'ed up. On CV's it is totally controlled by vacuum. So butterfly position really has nothing to do with it, that is why there is no mention of checking the butterfly position on an engine with CV carbs.
With CV carbs, which are frequently referred to as 'constant velocity' or as stated in the Honda Common Service Manual 'constant venturi', the throttle cable directly controls the movement of the butterfly valves. When unitizing a bank of CV carbs after having been separated from one another the butterfly valves MUST be bench-synched before being reinstalled back on the engine. With CV carbs there is normally no need to visually check the throttle openings on the bench since separation of the unit is rarely required. This is one of the several benefits of CV vs slide. Routine maintenance is simplified.
It matters not which type of carburetor system is dealt with since BOTH require an eyeball adjustment prior to fine tuning with a vacuum adjustment.
Your logic appears as follows:
A. exact valve lash adjustment is best (true)
B. the valves can be way out and you can still synch the carbs (false)
C. what you want to sync is the slide opening, not butterfly position (false)
D. On CV's it is totally controlled by vacuum (true in relation to throttle opening, or butterfly position)
E. butterfly position really has nothing to do with it (false)
If these were all in fact true, then one could possibly surmise that: regardless of valve lash and differential in throttle opening the carburetors will synchronize themselves, and therefore exact valve lash adjustment is not necessary.
Am I reading this correctly? My head hurts...
