TOPIC:

Hi fellas,

I'm hoping you can assist me with both the confirmation of a blown head gasket and whether there is likely anything going on that may have led up to the blowing of my head gasket, if it is the issue. I've read that the Kawasaki GPz's are known for head gasket issues. Unfortunately I was out on my maiden voyage on my GPz yesterday after repairing the tank and doing some other neglected items and about 10 miles in the head gasket blew out the left side (#1?) cylinder. While I've got the head off, are there other o-rings or other such items I should replace on this model? Anyone know where i can source a stock airbox? Someone put pod filters on this one and the airbox is long gone.





I'd also greatly appreciate if someone can point me towards a good source of a new, quality head gasket and/or top end gasket kit for my 1983 GPz550 - I've already sent a note over to Z1 Enterprises.

I've downloaded the Factory Shop Manual and have the Clymer (ergh) Manual. I'm not new to wrenching at all, so I'm not worried about the job, but I'm more of a Honda guy and just more familiar with them. I've always loved the look of the GPz and had to jump when this one came up - man I LOVE IT That said, I don't really yet know intricacies of the models, sub-terminology, etc. as I would between the Honda models. For instance, I know that the GPz is a sub-model of the KZ550 series, but I haven't yet really gotten the H1, etc. sub divisions.

Thanks so much fellas,, I truly appreciate your expertise on the Kawasakis!

S/F,

-Matt

Yep, Thats is where there is a oval rubber O-ring that seals the oil feed channel between the head and cylinder block is. It is common for the rubber to get dry and cracked with age, leading to oil pressure blowing out the ring and then you get what you see there.

The only worry, is that there is a another set of oil channel o-ring's between the engine case and and the cylinder block. If the top ones have gotten bad enough to blow, then the bottom ones probably need to be replaced while you have it apart. (I have a zr550 motor with only 4 thousand miles on it but sat for 24 years and the bottom o-rings leak like sieve's) Replacing the bottom o-rings leads to a lot of work.

You should refresh the head while you have it off. Assess the condition of the valves and seats, and at the very minimum, replace the valve guide seals with the OEM Kawasaki ones or the Viton rubber ones. Don't use the ones that come in the "All in one kits".

Definitely find a stock airbox, as running pods on CV carbs can be pure insanity. Usually leading to a very unpleasant riding experience and/or accidentally running so lean you destroy the motor.

Your bike is rare and in such great condition, it deserves the very best of repairs and care.

Good luck!

OEM Kawasaki gaskets are best. Kawasaki doesn't sell "gasket kits" so you gotta piece together what you need separate. Avoid Athena like the plague, especially the kits with green gaskets.

Daftrusty wrote: Yep, Thats is where there is a oval rubber O-ring that seals the oil feed channel between the head and cylinder block is. It is common for the rubber to get dry and cracked with age, leading to oil pressure blowing out the ring and then you get what you see there.

The only worry, is that there is a another set of oil channel o-ring's between the engine case and and the cylinder block. If the top ones have gotten bad enough to blow, then the bottom ones probably need to be replaced while you have it apart. (I have a zr550 motor with only 4 thousand miles on it but sat for 24 years and the bottom o-rings leak like sieve's) Replacing the bottom o-rings leads to a lot of work.

You should refresh the head while you have it off. Assess the condition of the valves and seats, and at the very minimum, replace the valve guide seals with the OEM Kawasaki ones or the Viton rubber ones. Don't use the ones that come in the "All in one kits".

Definitely find a stock airbox, as running pods on CV carbs can be pure insanity. Usually leading to a very unpleasant riding experience and/or accidentally running so lean you destroy the motor.

Your bike is rare and in such great condition, it deserves the very best of repairs and care.

Good luck!

Thanks very much for the assistance. I think you're right, if I'm in there I may as well replace the ones where the cases match the cylinders as well. Though you mention that makes it much more of a job. Is there a reason why? I'm assuming the head can come off without removing from the frame on this model, but I'm not certain (don't have the manuals here at work). Are the cylinders not able to pop off while in the frame? Also, I'm assuming the cam chain will need to be broken as well?

Yes I definitely want the stock airbox, but I'll be damned if it's not a bugger to find one. And since there are so many variations on the model years I struggle to know which one is correct since I've not personally seen one before - again, not a problem I face with my Hondas.

Thanks a bunch for the compliment btw, I really like the ole gal.

Nessism wrote: OEM Kawasaki gaskets are best. Kawasaki doesn't sell "gasket kits" so you gotta piece together what you need separate. Avoid Athena like the plague, especially the kits with green gaskets.

Thanks very much - I know all about those crappy Athena gaskets. They should really call them Achilles gaskets...

So I've put together a list on one of the online sites; do I appear to be missing anything?


I think the most glaring thing I noticed so far is a cam chain master link - which I assume is required if it's like my CB450 DOHC engine. Anything else though?

Are you in the UK? I have an airbox for the 750, might fit?

There is absolutely no need to break the cam chain. Once the cams are removed, you can simply work around it.
When removing the cylinder head, you may find that the base gasket has turned to stone and can be very difficult to scrape off as the head studs get in the way.
It is tempting to replace piston rings while you are in there, but take a compression test first before tearing it down. That will tell you if you need to bother. If it has good compression, then I would leave them alone unless you have an unlimited budget.
Putting the cylinder block back over the pistons is the only difficult part of the whole deal. I have had a track record of damaging oil rings for some reason using hose clamps and soft plumbers strapping as ring compressors. So research different methods of DIY ring compressors if you haven't already.

Don't make that parts order until you have the top end all apart and cleaned up. You may find you need to replace the guide pins in the head and block, exhaust crush gaskets or maybe wrist pin clips. If you drop a clip or get gasket scrapings in the engine case by accident, you will have to take the oil sump off to clean it out and then you will need a new gasket. It's a bummer to repay for shipping on a .75 part after you just received your order of new parts.

Partzilla shows that the air box is specific to the 82-83 GPz550. The 81 and 84-86 gpz550's are totally different bikes, so I don't believe that they will work on yours.

JoHNY wrote: Are you in the UK? I have an airbox for the 750, might fit?

Hey Johny. No sir, I'm not in the UK, I'm in the good ole state of Texas. I appreciate the offer though!

Daftrusty wrote: There is absolutely no need to break the cam chain. Once the cams are removed, you can simply work around it.
When removing the cylinder head, you may find that the base gasket has turned to stone and can be very difficult to scrape off as the head studs get in the way.
It is tempting to replace piston rings while you are in there, but take a compression test first before tearing it down. That will tell you if you need to bother. If it has good compression, then I would leave them alone unless you have an unlimited budget.
Putting the cylinder block back over the pistons is the only difficult part of the whole deal. I have had a track record of damaging oil rings for some reason using hose clamps and soft plumbers strapping as ring compressors. So research different methods of DIY ring compressors if you haven't already.

Don't make that parts order until you have the top end all apart and cleaned up. You may find you need to replace the guide pins in the head and block, exhaust crush gaskets or maybe wrist pin clips. If you drop a clip or get gasket scrapings in the engine case by accident, you will have to take the oil sump off to clean it out and then you will need a new gasket. It's a bummer to repay for shipping on a .75 part after you just received your order of new parts.

Partzilla shows that the air box is specific to the 82-83 GPz550. The 81 and 84-86 gpz550's are totally different bikes, so I don't believe that they will work on yours.

whew, that's good to hear. I hate break the cam chain. I also doubt myself on my master-linking abilities.

Good advice on waiting to order until I see what I mess/or is in need of replacement. I'm not big on changing parts that don't need changed - I know how expensive that can get. I'll definitely check the compression before the tear down. I know what you mean about the rings - I just put the barrels on a CB450 yesterday w/o the compressor - such a pain in the arse. I can't imagine doing it with two more of the little buggers fighting me. It'll be my first four cylinder.

Thank you!

The 550 barrels have a bevel at the bottom. You can fit rings carefully and slowly by hand.
I use a decent amount of assembly lube and take my time.

R

rrsmsw9999 wrote: The 550 barrels have a bevel at the bottom. You can fit rings carefully and slowly by hand.
I use a decent amount of assembly lube and take my time.

R

Fantastic, that'll make it moderately easier.

Z1 Enterprises got back to me regarding the top end gasket kit; they actually do have them. Does anyone know whether their gasket sets are pretty quality? Tempting price there, not going to lie - half the cost of my list and it includes some o-rings and the exhaust gaskets that I neglected in my previous list. I know ya get what you pay for, but not all aftermarket gasket sets I've used a bad!

www.z1enterprises.com/product/SU609-0855

Here is some video of the top end. I have several 550 vids out there. Not an expert but the vids are informative IMHO. R

There is also an oil-feed restrictor. Make sure to note which way they go in, and make sure to put them in the correct way.

You may want to read the valve train warning page in my signature. It also has details about cam timing when you get to that point.

rrsmsw9999 wrote: Here is some video of the top end. I have several 550 vids out there. Not an expert but the vids are informative IMHO. R

www.kzrider.com/forum/8-about-the-site/6...ink-to-youtube-video

Good Fortune!