Camshaft Top End Rattle

[Suzuki_Don]

I have this problem on my 650 head and camshafts and have been doing some investigations into the remedy for the problem.

The article on Cliff's site by Ian Grant says the head needs to be removed so the end play can be measured with a feeler gauge. For those in the know, do you think the end play can be determined without removing the head.

The reason being I have just rebuilt my motor and do not want to remove the head just to do some measurements. If the head is removed then I need to remove the cylinders as well to replace the base gasket. And I don't want to go through the hell of fitting the pistons to the cylinders again.

Would it be possible to lever the camshaft from one end and then from the other end to measure the side play keeping in mind that the cams are under spring pressure from the valve springs.

If this could be done without removing the head then the cam caps concerned could be removed one by one, machined and replaced for a far simpler job.

 

[Steve]

Was all the machining done to the cams? :-k

I though some of it was done to the head, too, which would definitly require removal.

If it's just that occasional knocking that goes away above about 1500 rpm, don't worry about it too much.
Yeah, it makes a bit of noise, but it doesn't seem to hurt anything. :-\\\

.

 

[hampshirehog]

I've never tried it but couldn't you remove the half moons, one at a time, and push a pin (modified punch / screwdriver etc) through so that it ran in the depression on the end of the camshaft, with the motor running.

You could then test if it was cam walk, which cam and in which direction it was. Probably have to rig up a temporary rubber seal (old half moon with a hole in it?) to prevent the oil peeing out. This would then at least let you know where you had to measure.

I've no idea how much force you would have to put on the pin.

 

[north49]

Suzuki Don................I'm in exactly the same position as you. Just did a top end rebuild and don't want to tear it down again. However... if you remove the head you definately don't need to remove the cyclinder. Please read my reply to you on your other post and let me know what you find.
cheers

 

[ddaniels]

Was all the machining done to the cams? :-k

I though some of it was done to the head, too, which would definitly require removal.

If it's just that occasional knocking that goes away above about 1500 rpm, don't worry about it too much.
Yeah, it makes a bit of noise, but it doesn't seem to hurt anything. :-\\\

.

As I understand it, all the machining is done on the cam caps only...plus having to make some half moon spacers to fit into the grooves machined into the cam caps that take up the slack.

 

[Guest]

You really shouldn't have to replace the base gasket if it was only recently installed. Even if oil leaks out from the base when you pull the head it will seal up again fine.

This happened when I replaced my head gasket only and I'd put 10,000 kms on the bike since I bought it at that stage. Judging from what the PO told me (he was quite selective in hindsight), I figured it was a couple of years old.

I put another 5000 kms on with no leaks till I stripped it down last week to put new pistons rings and cylinders in. I obviously replaced it then...

 

[Suzuki_Don]

Here guys, have a listen to this

Here guys, have a listen to this

I know it's probably not easy to diagnose an engine noise by listening to a video, but here goes:

Any or all comments and thoughts greatfully appreciated. Can anyone verify if this is the camshaft end float rattle that everyone has been talking about lately.

http://s226.photobucket.com/albums/dd105/donclifton/GSR Pics/?action=view&current=P1000267.mp4

Thanks Guys & Gals

 

[hampshirehog]

Job to tell Don, as you thought, but that doesn't sound 'metallic' enough to me. When I've heard it, it's been more of a 'tink-tink-tink' and your bike is making a more 'tack-tack-tack' noise to me (yeah, I know, bad idea to try and spell a noise....).

Just a thought - could be loose cam sprocket bolts? You'll be able to tell better where the noise is coming from but could also be that blo*dy clutch.

 

[Suzuki_Don]

Job to tell Don, as you thought, but that doesn't sound 'metallic' enough to me. When I've heard it, it's been more of a 'tink-tink-tink' and your bike is making a more 'tack-tack-tack' noise to me (yeah, I know, bad idea to try and spell a noise....).

Just a thought - could be loose cam sprocket bolts? You'll be able to tell better where the noise is coming from but could also be that blo*dy clutch.

Yes Wally, but it's only at idle. Does that sound like the clutch. And are you saying clutch rivets, etc. If so I checked them when I put the motor back together, but the extra power of this motor may have tested the 550 clutch out. Also it does sound to be coming from the top end to me, specifically exhaust camshaft. I am going to take the valve cover off later this week and will check the cam sprockets then.

BTW I took it out this afternoon and took it up to 80mph at 5500rpm and it didn't take long to get there. So the performance is terrific and because of this I am thinking the cam sprockets and chain are all OK.

Thanks for your thoughts though, keep them coming.

The reason I thought it was the camshaft end float problem was that the symptoms were exactly the same as the one quoted by Ian in his article on the camshaft cap modification. Which states no noise at idle when cold and the noise develops when the motor is fully warmed up and at idle. These are my symptoms exactly.

When I start the motor on choke and after a few minutes turn the choke off and it settles down to a good idle, there is no noise coming from the motor at all apart from the whirring of the straight cut primary gears.

 

[Suzuki_Don]

Info from ian grant from nz

Info from ian grant from nz

I have been corresponding with Ian Grant on this issue of camshaft end float as he was the person who wrote the original tome on the symptoms and the solution to the problem.

Below are some of the tips and suggestions that he sent to me and I am sure he would not mind me passing them on to those interested. Remember these are suggestions, not tried and tested procedures.

When Ian did his conversion he had the cylinder head off the bike and my question was enquiring about a method to do this conversion with the head still in place on the motor. So these tips/suggestions are in reference to doing this job and taking the measurements with the head and camshafts in place.

Ian Grant's suggestions:

"There seems to be quite a bit of interest in doing this mod at present. I've answered a few other questions by PM lately.

I'm modifying an 850 head at present, so I've just looked into the practicalities of attempting to get accurate endfloat readings with the head still on the engine. If you rotate the engine until 2 lobes are just clearing of the shims, the other 2 lobes aren't in contact. That position will give the least resistance/drag when you lever the end of the cam against the end housing. You will need to be gentle with the lever or you risk breaking the housing part of the head. The only draw back to this method is you cant fit a feeler down the side of the thrust ring, as the bearing cap gets in the way.

Two suggestions:

1. Set up a dial gauge against any cam lobe and zero it. Now lever the cam away from that pointer to get a reading. Take your reading , then pry the cam back the other direction. It should return to zero again if you had it set right in the first place.

2. Use a feeler gauge to record the gap between the cam cap and the thrust ring of the cam. Lever the cam in the opposite direction and measure the same point to record the difference. This is the least accurate method, as the cam cap surfaces are cast, not machined.

Hope this helps Don. Let me know how you get on."

 

[almarconi]

I don't hear anything that alarming from the engine. Sounds like a bit of valve noise. You don't won't a completely silent valve train. Are there any other symptoms beside the noise you are hearing?

 

[hampshirehog]

I reckon the clutch can be ruled out - normally the rattle is worse cold when the carbs are 'out of balance' due to the choke being on.

Another thought. I can't remember which model provided your head / bearing caps and which one provided the cams. You could have an excessive clearance on the bearings and the cam is 'bouncing' up and down on tickover and the cam chain pulls it down when it's given a bit of throttle. Plastigauge check?

 

[Suzuki_Don]

I reckon the clutch can be ruled out - normally the rattle is worse cold when the carbs are 'out of balance' due to the choke being on.

Another thought. I can't remember which model provided your head / bearing caps and which one provided the cams. You could have an excessive clearance on the bearings and the cam is 'bouncing' up and down on tickover and the cam chain pulls it down when it's given a bit of throttle. Plastigauge check?

Good thought Wally on the cam bearing clearance. The head is from an Australian GS650 Katana and the cams are GS650G from the States so there could be a clearance issue. How would this senario relate to the fact the noise is not evident when the motor has not warmed up and is there when the motor is up to normal working temperature.

 

[Suzuki_Don]

I don't hear anything that alarming from the engine. Sounds like a bit of valve noise. You don't won't a completely silent valve train. Are there any other symptoms beside the noise you are hearing?

The only symptoms are no noise at idle when cold and plenty of noise at idle when fully warmed up. No syptoms that affect performance or evident when riding the bike. The clutch, and gears are very smooth. No problems there.

 

[Nessism]

Sounds nasty Don. My guess is it's something other than cam float, but its hard to say. I'd try to take some measurements on cam float and cam saddle journal clearance and then you can go from there. Also, double check your valve shim clearances since they often change after a few heat cycles on a rebuild.

 

[TheCafeKid]

Def NOT cam walk... I hate to say it, and I know you just rebuilt that motor, but that sounds like a shelled conrod bearing to me... I have heard that jack-hammer sound out of more than a couple plain bearing GS motors now..

 

[tkent02]

This is not a plain bearing GS motor...
The noise goes away as RPM comes up?
Bad rods I have had got louder at higher RPM, although they were on car engines.
Did the cam caps stay bolted down correctly?
Someone had a similar noise on a 450 or something and it was one of the cam caps that had come loose.

 

[TheCafeKid]

This is not a plain bearing GS motor...
The noise goes away as RPM comes up?
Bad rods I have had got louder at higher RPM, although they were on car engines.
Did the cam caps stay bolted down correctly?
Someone had a similar noise on a 450 or something and it was one of the cam caps that had come loose.

It's a 650G or no?? Certainly sounds like slap. What in the hell could make sounds like that in the top end and not result in destruction? Sticking valve (s)? Broken springs? That sounds nasty. And like i said the only thing I've ever heard come out of a GS motor that sounds like that is a blown conrod bearing. But if it's not a plain bearing crank... Then I'm at a loss as much as anyone. Is it possible that the cam sprockets are taller and the chain is slapping the valve cover?

 

[Suzuki_Don]

Thanks guys for all the suggestions.

JOSH it is a roller crank, no shell bearings in this motor and all radial clearances were checked when the crank was out of the motor by a velocette specialist who regularly replaces roller bearings on cranks for customers.

From the suggestions made I now plan to check the following after removing the valve cover:

1. If any of the cam caps are loose. (Done & OK)
2. If there is any play in the cam bearings. (Can anyone give me instructions on which plastigage to buy and how to use it on the cam bearings). (OK I
think)
3. Check cam end float. (Done & OK)
4. Check valve shim clearances. (Done & OK)
5. Check if cam chain is slapping against valve cover. (Done & OK)
6. Check the number of links between arrows 2 and 3 on the cam sprockets (make sure cam timing is correct). (Done & OK)
7. Check if cam sprocket bolts are loose. (Done & OK)

Is there anything that I have forgotten? Is there anything else that I should check?

Thanks again fellas.

 

[BadBillyB]

Before taking parts off the motor, see if you can at least pinpoint the general area of the noise. I am a professional car mechanic and I use a very simple device to pinpoint noises. A 36" piece of steel brake line with a length of vacuum hose attached to one end. Stick the vacuum hose in your ear and bend the brake line into any shape needed to get to the source of the noise. The better you can narrow down where the noise is coming from, the better chances of finding it during disassembly....I listened to the video numerous times and cant quite put a finger on it. An old shop towel put in the exhaust pipe would have made it easier for me to focus on the noise.....Billy