TOPIC:

This is the situation...
Lots of vibration in footpegs (and other places...), and also a ticking from, I think, 2:nd cylinder's exhust valve. Problem is, I have recently re-shimmed and checked the cam torques, all ok. No oil leaks on the cylinder head, or around it

Today I was driving to work (no snow in Sweden yet!), and because vibrations and ticking exists, I never go over 5-6000 rpm. Then a traffic situation arises that "forces" me the apply a lot more throttle than usual - redline throttle. The result is - NO MORE VIBRATION and a much softer ticking.

Question: Could this be explained by low oil preassure or maybe something obstructing oil flow up to the valves? All theoris (or knowledge!) greatly appreciated - maybe I shouldn't ride the bike at all in this state???

No stabs at this one yet I see...

Well, let's see....82 GP11....vibration problem...ticking noises...

First think I think of with a J motor vibrating is the crank...even though Kaw tried to claim the 82's didn't twist, we sent enough of them to Falicon and hey all needed indexing....funny thing that..

Check torque on all the motor mounts, footpegs and swing arm pivot...hell..check every nut and bolt on the bike...can't hurt..

Check your carb snych.

Check your cam chain tensioner.. those side load tensioners were prone to backing off....I'd dump that and get a manual lock down tensioner from APE.

Check valve clearances as follows:

One valve at a time, point the lobe directly away from the bucket and check clearance right there on the bottom of the base circle...set the intakes to .004" and the exhausts to .006".

Recheck carb snych after valve adjustment.

Post edited by: larrycavan, at: 2006/12/22 19:12

Howdy Swede! I doubt you have an oiling problem. Oil is picked up from the sump by the oil pump and pushed through the four oil journals which as the passageways around the outside cylinder head studs. Anyway, oil drools into the area where the cams sit. There isn't much pressure involved... it is a low pressure system with oil pressure at the cams at about 3-5 PSI... not sure what that is in metric terms but you can spit harder than that. Anyway, when you removed the cam cover, was there oil sitting under the cam shafts?

The ticking is generally a valve clearance that is on the wide side. You might want to remeasure. I have a link on my web site for checking / adjusting valve clearances you might find helpful. Typically, the clicking is kind of normal on these engines.

The issue then is vibration. Most of the time, vibration is the result of poorly synchronized carburetors. When was the last time that was done? Get a manometer (mercury or vacuum gauges, etc) and this is the way you do the job on your bike:

1. warm bike so it idles easily
2. shut bike down and remove vacuum plugs over vacuum fittings located on the top/front of each carb. There may be hoses or plugs on each of the fittings. Put the hoses from your manometer on the fittings.
3. Loosen EACH of the three locknuts on the sync adjusters while holding the screws themselves with a screwdriver.
4. start the bike. The theory here is that you FIRST adjust a pair of carburetors; that would be either 1&2 or 3&4. Get the mercury or vacuum gauge level even. You should see about 20-25 on whatever scale is on your gauge. Then get the other set of two carbs... say you first got 1&2 even, now do 3&4... You will note that 1&2 are even but at one level and 3&4 are even and at another. Use the MIDDLE sync adjust screw to even up 1&2 with 3&4. Once you are done, blip the throttle and make sure to readjust as necessary. Once you are done, HOLD THE SCREWS WITH A SCREWDRIVER and turn the 8mm locknut tight on each of the adjusters and replace the vacuum caps or hoses.

There is a special tool which is a long flat blade screwdriver inside an 8mm socket that I use for this job as the middle adjuster is especially hard to get to without it. You can get these tools from www.z1enterprises.com if they aren't available locally.

OK guys, here we go..!

larrycaravan wrote:

First think I think of with a J motor vibrating is the crank...even though Kaw tried to claim the 82's didn't twist, we sent enough of them to Falicon and hey all needed indexing....funny thing that..

NONONONO... Please... There is no way that kind of time and money exist. My crank is most definately in mint condition and straight as an arrow!

larrycaravan wrote:

One valve at a time, point the lobe directly away from the bucket and check clearance right there on the bottom of the base circle...set the intakes to .004" and the exhausts to .006"

This brings up some questions... in the Clymer it states 0,05-0,15mm on all valves? How come the differences on intake and exhaust? All my valves are now between 0,10-0,15mm (or at least I hope so...)

wiredgeorge wrote:

...Anyway, when you removed the cam cover, was there oil sitting under the cam shafts?

Hmmm... Yep, I think there was oil to the left of exhaust valve no 1. Bad?

wiredgeorge wrote:

The ticking is generally a valve clearance that is on the wide side. You might want to remeasure.

Will do.

wiredgeorge wrote:

The issue then is vibration. Most of the time, vibration is the result of poorly synchronized carburetors.

Have NO idea when last sync was done, and I have never done one myself... Although I have all the manometers and hoses lying waiting in my garage... guess I will have to use them!

To summarize, re-check valves and sync carbs. This is all doable. But what puzzles me is why the vibration disappeared after pulling up to 9-10 000 rpm??? I mean, this change can't have anything to do with valves och sync, can it?

/Cheers

Carb synch can make the bike idle rough and tick as well.

Carb synch becomes less of an issue as throttle openings increase.

Exhaust valves need more clearance for cooling the valve.

I would not use the OEM manual method to check valve clearances...haven't used that method since 1984..... Pointing the lobe away from the bucket is IMO the best way to go...you do what you feel is best...

OEM cams are less of a problem. Aftermarket cams can sometimes have base circles that are not concentric to the quality of OEM cams.

IF you get a particular cylinder that ticks in the valve train, even after meticulously adjusting carb / TB synch and clearances are within spec....try another shim in that bucket.

Don't over look that shitty OEM cam chain tensioner setup as the root of valve train noises....

Example of poorly ground cam:

You check clearance between the base circle of the cam and the shim or bucket surface if UB setup.

The base circle runs from the end of the closing ramp to the beginning of the opening ramp. Some manufacturers label a portion of the lobe as the silencing ramp...either way the same concept is there.

Theoretically, you should be able to measure the same clearance anywhere on the base circle. It doesn't always work that way in real life.

I've seen cams where if they are positioned using the 2 valve at a time checking method, yield different readings than if checked using the lobe away method. I've measured .002" difference in clearance on the same lobe in different sections of the base circle.

It's possible to have .004" clearance at one point and have .006" at another point...

The OEM method does NOT use the same position of the base circle on every lobe. The one position you are guaranteed the most seat time for the valve is when the lobe is pointed directly awyay from the bucket. That position would position the cam in the middle of the base circle for checking clearance.

Post edited by: larrycavan, at: 2006/12/23 08:04

larrycavan wrote:

Exhaust valves need more clearance for cooling the valve.

First time I have ever read anything from Larry the I disagree with

I think exhaust valves need more clearance simply because they run hotter, the hotter metal gets the more it expands, so you have to allow extra room for valve stem expansion on the exhaust valve versus the intake valve.

On the subject of vibration, have you checked all the engine mounting bolts to ensure they are tight?

This situation sounds familiar to the days when "blowing soot" seemed to cure an odd running motor.
Perhaps one cylinder was loading up for one reason or the other. Running to redline would usually make an improvement, and if it didn't you knew some more maintenance was in order.
Are you running the Exhaust Emission Control System, that came standard on the US models?

Kawaduce, there are lots of folks on this board smarter than I am but I feel that Kawasaki probably knew what they were talking about when they recommended .5 - .15mm clearances on the valves. I set valves to that clearance because it is what Kaw recommends PLUS I have no desire to listen to valves clatter... they tend to get fairly noisy with some of the clearances suggested. I have set valves to the wider clearances and it seems to do no harm... its one potential value would be to extend the duration between adjustments of clearance since the clearance tends to decrease with wear. I prefer to check and adjust rather than little to clatter. In any case, I suspect valve clearance isn't the reason for the vibration... I suspect carb sync is the issue. I also suspect that you wouldn't be able to run to redline if the crank was bent. I have some experience with bent cranks and the bike will typically not start or want to run much at all but perhaps I bent cranks more than what Larry exerienced. My crank bending expertise was on big GS engines which I used to race a bit. The Falicon folks sent their kids to college using my racing as their funding source hehe

lmullisZ1 wrote:

This situation sounds familiar to the days when "blowing soot" seemed to cure an odd running motor.

Yes, maybe? Because as you say, the vibrations disapeared on the whole rpm range after redlining. We'll see if they really stay away (or normal, rather).

And yes, I have been over the mountigbolts some months ago, should probably do it once again to be on the safe side.

larrycavan wrote:

...many wise things

Thanks for sharing, Larry! Actually, I did it your way, because when I tried the OEM-way it didn't feel precise enough. And, on the exhaustvalve issue, Stell's thoughts seem rather straightforward...or
??

The exhaust valves need to cool....they cool by getting seat time...it's the only time during the cycle when they can shed heat...

Yes the heat, [depending on the material the exhaust valve is made from] could affect the running clearance and further the need for extra lash....I won't totally disagree with that statement...more heat is concentrated in the exhaust port area of the head so expansion of parts can definitely come into play...but the bottom line is they MUST GET TIME TO COOL OFF...more time than the Intake valves require....simple method = more lash...

No matter which way you want to view it, the end result is the same....give 'em the extra couple of thou clearance..

Don't forget...more lash = more compression as well. Set yours to the tight side and check compression...then set them max loose and repeat the check..

Max Loose settings with the lobe pointing directly away from the bucket are what the Kawasaki Hot Line recommended way, way, way back in the 80's....I used to speak with those guys on a daily basis....they knew what was best for their bikes...they lived with the problems on a daily basis...


WG...how many clutch baskets did your Suz eat on ya?
What a mess they make when they decide it's quitting time...