IMHO, any crack is not good (or too bad), and will grow over time. How much time? Depends on how much you are willing to gamble. I personally would not use any head that has visible crack(s). Just my opinion...
That was my opinion too, but it seems that there aren't many 900/1000 heads left that don't have cracks. Will check out the other one tomorrow and see how it looks.
You have any info on crankcase interchangeability? Couldn't find anything on the site which I thought was a bit strange.
All the kickstart Z1 (903cc) - Z1000 (1015cc) kickstart engines ( not including the 1015cc MK2/ST) share the same basic cases mechanically speaking with subtle visual differences (MK2/ST has a different bolt pattern for the trans cover as you have already discovered ).
Some early 900 cases need the crankcase mouths opening slightly to accept the 1000 liner spigots. ( not a big job ).
You should use cases as a matched pair.
So, I found a cheap ST crankcase, just need an A4 or J transmission cover and I'll be good to go. Still well under what I expected to pay for a motor so I'll chalk that up as a win
Had another win today - got a set of RS34 carbs (including intake boots and oval K & N pod filters) and also a stainless exhaust system - a good quality copy of the Schüle system: www.schuele-maschinenbau.de/produkte-artikel/z-1000.
It was all new and unused, but had been sitting in a climate-controlled garage for the last 10-15 years. Carbs have never seen any petrol and the exhaust was just mounted up to see how it fits but has never been on a running engine. Paid about half of what it would have cost new.
All the rubber on the filters, boots, vacuum plugs etc. ist nice and pliable. The only thing I'm not sure about is the choke. I have no idea about these carbs but the choke plungers seemed to have been greased and the grease is pretty old - not completely hardened but getting there (you can just see it around the end of the shaft in the picture below). Should I pull out the choke and clean up and regrease the shafts? Also, is the choke supposed to spring back unless it's fully open?
Guess I need to learn about these flat slide things now.
I don't want to start an argument with others that clearly have more knowledge than I do of Kawasaki engines, but my limited knowledge of any engine tells me cracks are not the thing you want in a cylinder head or block for that matter. I have a crack on the head of my KZ-1000 that extends to an exhaust stud and I had two very reliable places tell me it's nothing to worry about "just be careful when you tighten the exhaust nut". Well what the he** does that mean?? How much torque is "careful"? I did as I was told and left it alone and 2,000 some miles later I think it's okay, but I don't really know what the crack is doing cuz I can't see it. I should have just spent the money and had it fixed for nothing more than my piece of mind. If it develops an exhaust leak at that stud and I can't re-tighten the nut safely that means tear the thing apart AGAIN and fix it. Had I fixed it when I found it this wouldn't be an issue now and I wouldn't have to worry about it. Just my two pennies worth.....
I hear you Rick. I'm thinking the same but everyone I have asked that has a lot of experience has told me it'll be fine. I will ask the guy doing the work on the engine and see what he says.
I figure these cracks won't be that bad though. They'll progress up the head through th spark plug threads before anything happens to the valve seat - I figure I'll hear some popping or spitting if it ever gets that far
The other head has the same cracks and I have yet to see one for sale over here without them. Fixing them is apparently expensive and not that reliable - probably why the consesus is to just leave them as is.
I'll post back when I've heard from the engine guy.
Been working away on the Zephyr and getting some pieces together so I can get the KZ1000 head repaired and the valve seats cut. Found a guy just down the road that laser welds up those cracks between the plugs and the seats. He looked at the head and said I only really need to sort out two of them.
Now I need some advice again
The guy I've been planning the motor work with did a 180 on me . Up until now he'd said that 38mm intakes and stage 2 Web cams (110) was the way to go (not just that it was OK, but that it was the way to go). I checked back with him yesterday before getting the valves as I went with the Yosh stage 1 cams and wanted to make sure the increase in valve size would still work (I wanted to leave my options open and maybe drop in the stage 2 web's without needing to get the head done again). He got back to me and said that he'd only go with 38mm intakes if I was putting stage 3 cams in (109's). Basically, he just completely contradicted what he said before and told me to just stick with stock valve sizes and open up the inside of the seats by 1mm.
This has basically put me off doing any more work with this guy. It's not so much that I don't think he knows what he's doing, it's more that I feel like he's not taking me seriously - complete turnaround on his recommendation without any sort of explanation as to why he's changed his mind. I can get most of the work done by the local guy who is doing the head. That leaves me looking for someone to do the MOT and someone to weld and balance the crank.
So, after that wee rant, here's my questions:
- What would you guys recommend for the valve sizes? I know Zed said 37 IN & 33 EX, but that was for 410 lift - a full mm more than my cams (.374/.354). I'd still like to be able to just drop in some .395 cams (web 110's) - assuming there's enough clearance between the 1075 Wiseco pistons and valves for the extra 0.5mm lift.
- Do I need to get the crank welded or is that just over the top for this setup?
The biggest inlet you can fit is a 38mm , This would be a GPZ type with 1mm shorter stem.
Ideally you want an inlet that is at least 51% of the cylinder bore but i have a couple of 1075 motors on stock size valves and they still fly.
A 37mm inlet however though is 51.3 % of the 72mm bore diameter and large enough for 1075cc and is what i would stick with and open the throats to suit.
A 38mm will flow sufficient to feed a 76mm bore 1200cc but you likely won't notice any difference to a 37mm in a 1075.
Providing you have the correct valve to valve / valve to piston clearance you can use any cam you like
I would also get the crank welded to at least provide some insurance against the top end work.