Terrible motor swap idea kz440

A friend of mine races with a 615cc setup and ZX camshafts. He revs to 12,000 rpm without any problem, with the intake lobes centered at 94°. You still need to do some checks, though. Check the piston-valve clearance. Check the compression ratio. The difference between KZ and ZX cylinder heads, if there is one, isn't that significant. I'm going to do this modification. I have Cruzinimage pistons, ZX and KZ550H cylinder heads, and 280° and 270° camshafts.

Thanks for that info! My main concern was the PTV clearance but from the sounds of it, there still is a little clearance. The final killer for me was the lower compression ratio since the cruzin image pistons are replicas of the kz550 C model, A model, and zr550 pistons which sit at 9.5:1 compression vs my 10:1 compression. With all of the expenses added up, it would just be easier and cheaper to find a running motor. In my case I found a running motor and a rolling frame with title for $200. Does your friend use cruzin image pistons or wiseco? That wasnt clear to me 

Without measuring the compression ratio, we can't be sure of anything. The ZR550 pistons and camshafts are identical to the KZ550H. The cylinder heads, however, are different, that's for sure, which explains the 9.5:1 compression ratio. In my opinion, you have to assemble it in different configurations and measure it; otherwise, you think it's like this, but it's actually like that.

My friend used pistons other than Wiseco or Cruzy. I don't remember which manufacturer.

 

  

Bloobaba wrote:

Without measuring the compression ratio, we can't be sure of anything. The ZR550 pistons and camshafts are identical to the KZ550H. The cylinder heads, however, are different, that's for sure, which explains the 9.5:1 compression ratio. In my opinion, you have to assemble it in different configurations and measure it; otherwise, you think it's like this, but it's actually like that.

Only my opinion but I think getting into "custom" motor builds requires significant knowledge and access to machining facilities or "plenty" of money. A working motor makes more sense if you are lacking in the previously mentioned requirements

Wookie58 wrote:

Only my opinion but I think getting into "custom" motor builds requires significant knowledge and access to machining facilities or "plenty" of money. A working motor makes more sense if you are lacking in the previously mentioned requirements
 

Yup.

Also your next post will be number 6000  

Yes, I agree with you, you shouldn't assemble engines without rigorously checking the metrology, otherwise they break or age poorly.

Yep wookies right. I dont really want to deal with the engine i currently have due to financial reasons. It was a good motor to learn on but now I want something that works. My biggest issue with getting that other bike is its 1000 miles away. Maybe I could go check out niagra falls 

Without measuring the compression ratio, we can't be sure of anything. The ZR550 pistons and camshafts are identical to the KZ550H. The cylinder heads, however, are different, that's for sure, which explains the 9.5:1 compression ratio. In my opinion, you have to assemble it in different configurations and measure it; otherwise, you think it's like this, but it's actually like that.

I was under the impression that the difference in cylinder head was for the porting, not the combustion chamber since they used bigger carbs but i am not an expert as you know. If or when you install those piston could you pretty please post the compression ratios if you choose to check? I think it would be good information for anyone interested, such as me since I now have a set of pistons laying around here somewhere... 

Bloobaba wrote:

Without measuring the compression ratio, we can't be sure of anything. The ZR550 pistons and camshafts are identical to the KZ550H. 

Im pretty sure that the gpz are different high compression pistons with a bigger dome. On page 5 you can find comparisons of the gpz550 pistons to each other and they have a visibly larger dome shape. You are right about the camshafts though, they are the same. Im pretty sure the zr550 was 9.5:1 CR like all of the other kz550s.

Yes, you're right and I'm wrong about the pistons. All 550s have the same pistons except for the GPZ. The GPZ550D1, H1, and H2 have identical pistons, with a more domed crown that increases the compression ratio. The ZX has rather flat pistons, but they have the same compression ratio as the GPZ. I'll do a short report, but not right away; I still have a lot of prep work to do before assembling this engine. Basically, it will be a 615cc displacement, a ZX 280° camshaft, and a CVK30 or 32 carburetor (I'll take whichever works best). For now, everything is in boxes.