Backfire - EGR

Hello,

I'm sure someone can help with this enquiry. I have a 1999 Kawasaki KZ1000 Police which has been restored. I purchased it about 5 years ago from the USA and imported it to the UK where it lay in storage for 12 months before I restored it. I took it for its MOT a few weeks ago, this is the first time its been on the road since I purchased it; it passed the MOT but I had some backfire issues on the run to and from the MOT station.

I have been informed of the most likely causes and have narrowed it down to the EGR system. It has been suggested I block this off which is easy to do. My question is: Will this have any adverse effects on the running of the motor? How easy would it be to remove, change or clean the valves?

Any assistance would be very much appreciated.





Thank you.

It's not really an egr system that you want to block off. You never want to block off any crankace vents either.

What you want to block off is the air injection system. This is clean air from the airbox being routed to the exhaust in order to allow for more buring in the headers to clean up unburnt fuel.

The problem is, you don't want the clean air at high vacuum, low throttle positions, so they put in a control valve. When that valve goes bad, it causes backfires when you close down the throttle.

You can remove the whole control valve and block of the two big ports on the head. Also, there should be a big hose connection to the airbox. That needs to be blocked. There should also be at least two small hoses going to the intake manifolds to register vacuum. Those ports should be capped.

This should not affect the carburetion at all, unless it was leaking and a previous owner took efforts to correct the lean condition caused by that. Then removing the clean air system will cause a problem, likely being too rich. If no one messed with it, then there should be no need to make corrections after removing the clean air system.

Thank you for your help and guidance. I have identified the areas requiring attention from your post and have taken the action suggested.

Your description of the problem is very accurate and indeed is what was happening with the bike. After making the alterations the bike runs smoothly with no indication of a missfire or backfire.

Can the control valves you mentioned be easily replaced?

I would very much like all aspects of the motor to run and work correctly.

They can be easily replaced if you take the tank off. I'm not familiar with the KZP, but if you can get to it, the valve/diaphragm assembly is easy to replace.

Finding a good one may be tough. Many people have taken them off and stored them, but I think the rubber diaphragm gets old and cracked which is why they fail. You'd really want a new one if you can find one.

The only down side to having it disabled is you will have more hydrocarbons in your emissions.

If the purpose is to retain a totally-original stock appearance, it should be easy to fake it. Just put some objects in the hoses and tubing which will seal off the hoses internally. To prevent the backfires, you really just want to prevent the movement of air in any of the contraption's tubing and hoses.

Thank you for your help, it's very much appreciated. I'm not very good when it comes to mechanics, I tend to fumble through and I'm new to motorcycles!

I have sourced new parts from Palmetto Kawasaki in Florida, I've used them many times before for parts during the restoration. The cost was not too bad. I first log on to www.buykawasaki.com and enter my VIN. It brings up the bike history and all the parts diagrams with manufacturer part numbers. I then email Bill at Palmetto with the shopping list.

12021-1008 Valve Assy Reed x 2 $ 41.01 each-avail
14075-5018 Cap Assy Reed Valve LH Silver x 1 $ 41.01 backordered
14075-5019 Cap Assy Reed Valve RH Silver x 1 $ 41.01 avail 11060-1066 Gasket Reed Valve x 2 $ 4.05 each avail

As I would rather the bike was original I will order the parts and change them. I've also had a look at where they are, you're correct, with the tank removed they are quite accessable.

Thanks again for you guidance.

Very best regards,

Allan

The most likely part that failed is 16126-1014. It is the "valve, air switch".

Hello,

Thanks.

Might as well order this part too.

Very best regards,

Allan