(http://img703.imageshack.us/img703/2735/voztuvutarpai.png)
Exhaust gaps way to big and intake to small. What the hell? :dunno_black:
Now questions. How to remove the shims without a special tool. And what size of shims do i need?
Quote from: KlaXon on September 29, 2011, 10:55:48 AM
(http://img703.imageshack.us/img703/2735/voztuvutarpai.png)
Exhaust gaps way to big and intake to small. What the hell? :dunno_black:
Now questions. How to remove the shims without a special tool. And what size of shims do i need?
Factory spec is .03mm ~ .08mm
So your intakes are in spec and shouldn't need changing........
You exhaust are just a little too big gaps....but many would purposely adjust them that big.....
Many also say the the gaps only get smaller over time due to wear....another reason not to adjust anything right now....
Is bike running good?? Do you hear too much valve noise?
Bigger exhaust gaps mean exhaust valves stay closed and stay cool....
There was recent thead on using various tools, or modifying stuff from your tool box to hold down the valve (bucket) while removing shims.......even taking the cam loose or off...Hey..the principal is the same..whatever you use....the tool is nice in my opinion because it stays in there by itself and leaves two hands free to get the shim out...getting the shim out can be a bit "fussy". And don't drop into the engine....cover up big hole around valve chain...
The shims are 29.5mm Available lots of online places...usually dealer/shop will have to sell new or sellused or possible trade used....
Link to chart which will easily find the shim you need:
http://www.bbburma.net/Documents/ValveAdjustmentVideo/GS500_Valve_Shim_Selection_Chart.pdf
Frankly, I prefer buying the tool for $15...it works great for me...........others have trouble with the tool and prefer screwdriver or whatever......If I were you I would do nothing at this point , not buy tool...and not change shims.......or buy tool now for use later...
In theory shims come in every .05mm.........
So you could reduce the .13 exhaust to .08 which would put in spec. but be still to the large side of the spec.
The .11 exhaust would reduce to .06 which is in the middle of the spec.
Changing the intakes would put both over spec...don't do that...extra wide clearance on intake is not important or helpful, like some do on exhaust.
But factory OEM shims are sometimes "in between sizes"...and they don't always measure what they are marked...so what you realy have to do is get a dial or digital caliper, and measure what you really got...and then measure what you need (to be sure it is correct...install..then measure the gaps again!! Phew!!!
Again...I would just leave 'em at this point!!
Cookie
Your intakes are OK - factory specs are 0,03 to 0,08 mm.
The exhaust valves are loose, I'd just change the right-side exhaust, if you don't usually rev it too hard don't bother messing with the left exhaust. 0,11 mm is still OK IMHO.
Shims come in 0,05 mm stepped sizes (2,70 - 2,75 - 2,80 etc.); factory-fitted shims might be any thickness though (like 2,63).
Pull it out, see the number on the bottom face - better yet measure it with a micrometer - and get a 0,05 mm-thicker shim.
Shim removal - many swear after pulling the camshafts. Personally I don't like it, or frankly speaking, I don't feel too confident about doing it myself, chances are you could mess timing up doing that. Your choice.
Others use a flat screwdriver inserted vertically between camshaft and shim bucket.
You have to depress the bucket first, there are basically two ways for this:
-rotate the engine till the cam pushes the bucket, insert screwdriver then rotate the engine again till the cam goes up and away
-push it down with another screwdriver (what I did before buying the tool).
Hope it helps.
Anyone feel free to comment if I'm wrong.
EDIT --- Whoops - Cookie beat me to that.
I agree, you might just want to adjust the R-EX, or leave them all as they are.
Especially when it comes to exhaust valves - which run hotter and wear faster - loose is definitely better than tight.
Thanks for replay.
Bike not running really well.. When i done the compression test right cylinder had 6 bar (87psi), left 6.5 bar (94psi) I think its little bit to low?. 5k miles ago it had 11.5 bar (166psi) so i decided that so huge psi drop caused bad valve clearances.
If you saying that my valves are good, that means my rings is done..
Quote from: KlaXon on September 29, 2011, 12:06:20 PM
Thanks for replay.
Bike not running really well.. When i done the compression test right cylinder had 6 bar (87psi), left 6.5 bar (94psi) I think its little bit to low?. 5k miles ago it had 11.5 bar (166psi) so i decided that so huge psi drop caused bad valve clearances.
If you saying that my valves are good, that means my rings is done..
I don't see how too big valve CLEARANCES would give low compression reading...I mean the valves are closed during the reading for compression......TOO small, (actually no clearance) might give a bad (low) compression reading, IF the valve is staying open.......
I think the plot is beginning to thicken here now....Poor running...low compression....Hmmm..
You've got some diagnostics to do now.....valve guides, bent or burnt valve...rings...etc?? Is it burning oil?? What do the plugs look like??
Cookie
Its burning some oil. Not very much, but i think a little more than normal gs needs to burn. But there no white smokes from exhaust. And then the oil rings is done the compression always mostly go bigger?
About the spark plugs.. Before my exhaust change its been lean. After exhaust change i adjusted and synched my carbs so now spark plugs looks normal. I will upload photo tomorrow
How to know that my valves arent burnt or bent?
And i think i need to do another compression test with some oil..
Quote from: KlaXon on September 29, 2011, 12:27:20 PM
Its burning some oil. Not very much, but i think a little more than normal gs needs to burn. But there no white smokes from exhaust. And then the oil rings is done the compression always mostly go bigger?
About the spark plugs.. Before my exhaust change its been lean. After exhaust change i adjusted and synched my carbs so now spark plugs looks normal. I will upload photo tomorrow
How to know that my valves arent burnt or bent?
And i think i need to do another compression test with some oil..
I'm not sure on motorcycles...but in our airplane shop we always do a "leak down test"..(differential pressure test)
We put a know amount of pressure into the cylinder and measure how much pressure it can "hold"...typically 80 PSI in and it will read (hold) in the 70's.
If there is a bad leak...you can hear where it is coming from...leaky valves..you hear air pssssss at the carburator.......leaky rings you hear at the oil filler(crankcase)......
Bad valve guides will sometimes only leak (and burn ) oil when cold or run rough at idle but runn better at speed...Will smoke at start up then smoke goes away as it warms up...
I'm sure sombody will know better diagnostics for motorcycle
Cookie
Valve clearance is spot on. Factory exhaust clearance spec is overly tight IMO. Opening the clearance up to .08-.12 helps keep the valves in spec. I did this on my race bike with no issue.
Here's a couple of hints:
1. Do both a cold and hot compression check. Too tight valves will cause the hot compression check to fall, since the valves won't quite close, lowering compression numbers.
2. After doing your hot compression check, pour a little oil into the cylinders. The oil will help seal the rings. If the numbers jump significantly after adding some oil, it confirms bad rings as the cause of your compression problems.
If that fails, do a leakdown test.
Subscribed for future reference. Great info.
Beat me to it. Put oil in the cylinders and see if that improves.
I can add this though, take out both spark plugs when doing the testing. That way you don't have to fight the compression of the other cylinder. (If you leave the other plug in, at least unplug the spark wire... :icon_eek: that was exciting...)
Quote from: burning1 on September 29, 2011, 05:38:29 PM
Valve clearance is spot on. Factory exhaust clearance spec is overly tight IMO. Opening the clearance up to .08-.12 helps keep the valves in spec. I did this on my race bike with no issue.
Here's a couple of hints:
1. Do both a cold and hot compression check. Too tight valves will cause the hot compression check to fall, since the valves won't quite close, lowering compression numbers.
2. After doing your hot compression check, pour a little oil into the cylinders. The oil will help seal the rings. If the numbers jump significantly after adding some oil, it confirms bad rings as the cause of your compression problems.
If that fails, do a leakdown test.
I thought the valve clearances got bigger as the engine gets hotter.........so I have that wrong??
(I remember reading somewhere, I can't remember where, that some bike used exactly zero clearance when cold, betting on the fact that the clearances went correct (bigger) when hot..
Maybe I have that completely backwards too??
Cookie
I was always under the impression it was the other way around, but it's possible I'm mistaken... The aluminum head would tend to expand more than the steel valve when heated, but OTOH, the exhaust valves get very very hot.
Huh... Exhaust valves run much hotter than intake, and usually spec 25% more valve clearance. Also, IIRC, extremely tight valves can cause hot starting problems (low compression?) so... Yeah, I'm pretty sure the clearances close when the engine heats up.
When doing compression test throttle need to be wide open right? If yes then shame on me :icon_lol:
Exhaust going loose is not quite a problem. In fact anything going loose is fine cos that means the wear is not on the valve and seat. Its on the cam and in fact shim believe it or not.
Intake going tight = shitty material in the intakes, kawi's specalise in that. You're valves are good. I'd set the exhaust back to spec and ride ...
Cool.
Buddha.
Valve clearances increase as the engine heats on a engine with overhead cams and an aluminum head. Aluminum expands more than steel as they heat lifting the cams away from the valve ends/tappets and increasing both intake and exhaust valve clearances. Years ago I quickly pulled the tank and valve cover on my hot CB750K to check the hot clearances and found valves that were set .002-.005" cold were around .015" hot. When I had an exhaust valve that was actually tight enough to not have cold compression on one cylinder of my 97 GS lt started on the other cylinder and idled roughly and then smoothed out quickly as the valve clearances increased as the head heated, generally took less than a minute to do so.
My 97 GS had an exhaust valve that ran for tens of thousands of miles on the tight side of the Suzuki specs and constantly required a smaller shim at valve adjustment time. It was down to a minimum 215 shim before it hit 80k miles. When a similar min clearance exhaust valve began requiring similar shim changes around 30-40k miles on my 02 GS I started setting the exhaust valves at the .003-.005" clearance leaving the intakes at .001-.003" Suzuki spec and didn't change another shim for another 40k miles.
I've never experienced any cam wear on my GSs and never had to put in a larger shim at valve check time. My 97 went 80k miles and my 02 just turned 90k miles all on the original intake valve shims. I did change one marginal intake shim once and then changed it back next valve check. The increased exhaust valve clearance gives more cooling seat time to the very hot exhaust valves stopping the valve erosion into the seats on the GSs and stabalizing valve clearances over the long run. If you plan on keeping your GS for many years and tens of thousands of miles you might want to consider running my increased exhaust valve clearances, if your gonna "move up" in a year or two it won't matter.
http://img.photobucket.com/albums/v443/jcp8832/GSvalvelogs.jpg
Quote from: burning1 on September 30, 2011, 12:14:22 AM
I was always under the impression it was the other way around, but it's possible I'm mistaken... The aluminum head would tend to expand more than the steel valve when heated, but OTOH, the exhaust valves get very very hot.
Huh... Exhaust valves run much hotter than intake, and usually spec 25% more valve clearance. Also, IIRC, extremely tight valves can cause hot starting problems (low compression?) so... Yeah, I'm pretty sure the clearances close when the engine heats up.
OK...then really important to check...and make sure not too tight when cold..esecially exhaust...because you don't really know how much tighter they are going to get....like exhaust at .03 might not cloas at all if the tighten up my .03..
Cookie
Quote from: burning1 on September 30, 2011, 12:14:22 AM
............................Yeah, I'm pretty sure the clearances close when the engine heats up.
No, clearances increase as the engine heats up!Increased exhaust valve clearances are to allow more cooling seat time for the hot running exhaust valves.
Quote from: gsJack on October 01, 2011, 08:55:13 AM
Quote from: burning1 on September 30, 2011, 12:14:22 AM
............................Yeah, I'm pretty sure the clearances close when the engine heats up.
No, clearances increase as the engine heats up!
Increased exhaust valve clearances are to allow more cooling seat time for the hot running exhaust valves.
Ok...this is what I originally thought...This is a good thing....because if you at least have "some" clearance (even to the low end of the spec)...you know the valves aren't going to stay open when the engine heats up.........The clearance is only going to bet bigger...
Yes, exhaust.. gapped larger gives more cooling...less chance to burn exhaust valve...
Cookie
I did some reading on this and realized something... Checking the clearances hot is different than checking the clearances running. In the time it takes to get under the valve cover, the exhaust valves are going to cool down, and the temperature of the engine is going to normalize. If the valves are resting on their seats, they are resting on their seats. Moving the cams further from the valves shouldn't do anything more than reduce lift.
Quote from: burning1 on October 03, 2011, 04:40:40 PM
I did some reading on this and realized something... Checking the clearances hot is different than checking the clearances running. In the time it takes to get under the valve cover, the exhaust valves are going to cool down, and the temperature of the engine is going to normalize. If the valves are resting on their seats, they are resting on their seats. Moving the cams further from the valves shouldn't do anything more than reduce lift.
That's why I say, "Always check them COLD"
Michael
Valve clearances increase as the engine heats up. When I had an exhaust valve that was actually tight enough to not have cold compression on one cylinder of my 97 GS lt started on the other cylinder and idled roughly and then smoothed out quickly as the valve clearances increased as the head heated and the compression was restored to the dead cylinder, generally took less than a minute to do so. It remained smooth running until it was shut down and cooled to ambient again, would run smooth all day while hot. If you don't believe it set one of your exhaust valves a little tight and try it. If moving the cams further from the valves doesn't do anything more than reduce lift why do you set your exhaust valve clearances wider than the Suzuki spec? I set mine wider because it increases cooling seat time of the exhaust valves increasing valve life and reducing required shim changes over the long run.
Actually... Now that I think about it, it reduces duration as well as lift...