Kz650 b3 no compression on 2 and 3

I wouldn't assume the guides are bad.  Remove the valves and inspect everything, then an informed decision can be made.

I'd remove the cylinder too and check the bores/pistons, and replace the base gasket.  

By the nice dings on the exhaust valve reliefs on the pistons on #1and #4 I would say you need to order at least 2 new exhaust valves. If you have those same dings on the other two pistons, just order four new exhaust valves!!!

 

Ok so then that brings up this question. Where is the best place to get new valves? Whats the best valve brand?

Kawasaki brand from eBay.  

You should be able to get Kawasaki valves through Partzilla.  Z1E may also sell them.  A lot of their stuff is OEM.  Just check the P/N on their site and compare with the KHI number.

VALVE,EXHAUST12005-008
VALVE,INTAKE12004-1011

Kawasaki discontinued them, however there are lots of NOS parts on eBay for fair prices.

 

Thanks i have ordered 4 nos exhaust valves from ebay. 54 bucks. I also took all the valves out and found that all the exhaust valves are bent. The intake valves look good though. Good even wear all around the face and the seat. Im gonna lap all the valves though before i reassemble 

When you reassemble double check your cam timing and turn it over by hand several times before trying to start (any resistance with the plugs out, stop and check again)

So i got the valves lapped and the head installed and i did the timing and checked it 4 times and this time i am confident that i did it right. There is very little resistance with the plugs out and when rotated 2 rotations from 1-4 tdc all the marks still line up. Then i redid the valve clearances. I had to change a couple shims and now all clearances are in spec. Then i did a compression check. This was done with the carbs and exhaust off the bike. All 4 cylinders are at 120psi cold without the carbs and exhaust installed. Everything is looking up for my precious kz650.

before i put the carbs back on however i need to find out what the stock main jet size is. I dont want to have to take them off again. Everything on my bike is stock so i wanna make sure i have the stock jets in the carbs. I looked in the service manual and it doesnt specify any stock jet size. Does anyone know what the stock main jet size is for a 1979 kz650b3?

Thank you guys for all your help and advise. It sure made this whole process a little easier. 

I think that is dependent upon where the bike was intended to be sold new.  They were jetted leaner with fewer adjustments in the US than elsewhere. I have added a list of some of the (K)Z650s carb tables from factory service manuals.

Ok so it looks like i do have the correct main jet installed. Thank you for the info.