TOPIC:

1983 KZ750 ltd four

So I've taken the cam and valve head off to check the valves. They seem ok, but wanted to ask if I'm wrong. I did a leak test, flipped valve head upside down, put fuel over the valves and nothing was wildly noticeable in terms of leakage from the top. I looked in the carb manifold opening and saw if anything a very very small amount of 'something' in there for maybe a couple intake openings but it was nothing major.

Would the possibility of a very very small amount getting through but nothing too noticeable mean I need to buy new valves or investigate their seating?
Also is the rusted/deteriorated look of the exhaust valves enough to warrant buying new ones or can I possibly get some mileage out of these still?

Last thing I noticed was spark plug 4 was slightly more backed out than the rest. Not sure if that matters.

Side question - it was suggested to get new carb manifold boots if i was running lean. I noticed though that the boots are still pretty pliable. Is this still a good standard just to go ahead and get them even though they're pliable? 

Thanks,
Jakob

Can't judge based on external photos.  The critical features are the valve sealing faces on the valves/seats, and the valve stem to guide clearances.  All is explained in the factory service manual (available for free download on this site.)  

If forced to judge based on the photos, there is not a lot of carbon.  Some new valve stem seals and lapping of the sealing surfaces may be all you need.

BTW, PLEASE click "insert all" when posting photos.  That way the photo show up instead of stupid small thrmbnails.    

Your head looks good. Gently clean the head gasket surface with a finger nail brush (no steel brush) and an 50/50 mix of ATF/Acetone.
The combustion chambers need some good clean with a brass brush and 50/50 mix of ATF/Acetone.
Some new intake boots is a must do task. Dont worry about your ex valves and spark plug backed out.
If you have the tools you can remove and lapping the valve seat surface and renew the valve oil seals but it´s not nessesary if the oil consumption is good.

 

Thank you all,

Will think about how far to go with the valves. Maybe oil seals, maybe do so some lapping. 

100% will be getting replacement shims to update clearances and intake boots and also had some gasket stick to the metal so will get a new one for between body and valve head. I am also going to probably add a little oil around the piston heads to see if it goes anywhere and clean the heads and carbon off valve area too.

Another step closer to hopefully improved compression once I get the shims replaced.

Oh yeah, will check the manual for some of the specifics here and make sure to insert all pics from here on  .

Thanks,
Jakob

 

When you have the same nice light brown color on all four of your exhaust valves. That is a sure sign the motor was in a good running condition and the jetting was pretty close!!!

Remove the carbon, lap the valves in, and new valve seals and you should be ready to go!!!!!!


 
 

Thanks might go ahead and get valve removal tool and lap then just for peace of mind and seal replacement because I'm already in it. Dang head gaskets are expensive apparently so if I do this now won't have to later. I'll get it nice and clean replace shims and put it back together. Looking forward to that moment.

You would do well to remove the cylinder and replace the base gasket now that the head is loose.  Common thought is that when the clamp load is released the base gasket will relax too so best to replace it.  

When it comes to gaskets I recommend OEM parts.  They are expensive but worth it.  Aftermarket gaskets range in quality from passable to pure junk.  It's not worth taking a chance.  Aftermarket viton valve stem seals on the other hand have a good reputation.  You can save some money that way.  There is a member here that sells them.  Can't remember his name but it should be possible to find the info by searching.

Here ya go Ed.

www.kzrider.com/forum/profile/18962-dfigpz

Thanks for that suggestion on the base gasket change. I was seeing things about viton valve seals so will follow that link. The PO said he replaced the gaskets on the engine so the base gasket might be newer. Knowing that do you still think it's best?

If you haven't disturbed the cylinders, the base gasket will be fine.