TOPIC:

OK so the valve cover has the 'chain pusher' fitted. Its this jump in the chain that must be causing the carb back fire. I know I set the chain link number correctly prior to replacing the valve cover. I guess the chain has a stiff link or something..... I hope not becuase crank-case separation is my least favourite job

If you are turning it by hand with the valve cover off, you will get a jump in to chain when as it goes over the lobe. This is caused by the slack in the chain not holding it tight.

ya know anyplace else,if you had strange and unnatural and milk man in the heading youd probably have people out front from a church group picketing!

What is this vacuum switch you mentioned with flames in the tubes? Are you talking about the emission system connected to the valve cover?

This will cause backfires through vacuum tubes if the diaphragm is punctured.

You can disconnect all that and just block off the ports.

See this link:
kzrider.com/component/option,com_joomlab...ew/id,27190/catid,2/

Also, as others have said, the chain tensioner should not be in-place until after the valve cover is put on. The timing of the exhaust cam can be checked while the cover is off, but the intake cam can only be timed by counting links because the valve cover will take up slack between the cams.

Post edited by: loudhvx, at: 2006/03/04 00:03

say stalag, you said your ATU was rusted; so is mine. Was your rusted so badly that you couldn't read the markings? how did you restore it?

Stalag... This is likely a thread that belongs in the engine forum. I will let this go today but if it continues to turn towards your cam shafts, cam chain and smog stuff, I think it would be better in the engine section... sometimes it is a hard call if the problem spans both engine and carbs.

As for an answer to your problem, the ATU is the cannister your vacuum hoses (from the carbs) connect to? This thing is used to open/shut your reed valves. The reed valves are tied directly to the combustion chambers. I hadn't really thought of it before but if the reed valves stuck open, you would get flash back visible through the tubes. Since the problem is either the ATU is junk (I suspect I have a good one if you need it) OR the reed valves are sticking open (I don't see how they could), you have a choice....


Either get a new ATU and see if that clears the problem OR block off the reed valve ports on your valve cover and cap the vacuum ports. Just make sure the reed valve covers seal good and that the reed valve are closed beneath.

As far as your cam chain... THIS IS AN ISSUE. If the chain seems to be buckling or bunching (however you describe it) when you turn the engine by hand there can only be TWO possible causes to my way of thinking...

1. You need to pull the cam chain tensioner and ensure the rod is popping out when it is released. I know you have done this but the inside of the tensioner body can sometimes get scored and the rod CAN hang. I have had this happen. You should FEEL the rod pop out when you release it. If you did this to your satisfaction and you are SURE the tensioner is OK... then...

2. REPLACE CAM CHAIN AS IT IS VERY VERY VERY STRETCHED. You risk significant engine damage when the thing jumps a sprocket tooth as the bike is running. If you have all the tensioner bits in place and it can bunch that far, the chain is SHOT. I know that SOME Hyvo chains have a master-link replacement so replacing the cam chain is a snap. The only issue will be the need to buy a tool to break the old chain and press/stake the pins on the new. These tools are kind of pricey. Contact www.z1enterprises.com for a new chain, master link and tool.

Hi Phish, sorry George
The ATU was rusted bad, I wire brushed it - the markings are imprinted so they wont disappear. I had to use a lever to get the central spindle off, then I filed out the spindle and regreased the internal cut out band. Pulled the springs and bob-weights off and sanded the axels. Threw it back together and checked to see if rotating the central spindle threw out the weights. Thazzit. Spindle can only go back two ways so, with the TEC mark there is easy. Good luck

George, I think the thing you are calling the automatic timing unit is the vacuum switch valve, part of the Kawasaki clean air system. I ripped it all off and piped the two reed valve covers together - its much better now.

Yep, you are right, i just dont want to face it. It is the cam chain, I know. Thanks for the breaker link

I had a similar problem with the camchain jumping. I discovered that the little rubber blocks that hold the tensioner wheel?! in place was squished up against the side of it and not allowing it free movement. I couldn't understand the problem at first because my automatic tensioner was working correctly so I pulled the head again and this is what I found. Ground a little of the side of the rubber blocks and presto everything worked fine.

There are rubber pads on the front and rear rollers as well as the large all-rubber center roller between the engine case and block. All have the rubber pads. The ones on the center roller are slightly larger. ALL SHOULD BE REMOVED AND SWAPPED FOR NEW ONES WHEN REBUILDING AN ENGINE. These pads are intended to cushion the cam chain roller parts and tend to harden with age. If you don't use new ones, the old ones can crumble and break and the rollers will move around. They should also be reglued. Most shop manuals recommend super glue.