1981 Kz650 head questions

The pistons from the cylinder you bought are designed to work with the later style head. I'm not an expert on part interchangeability but I think you may need the earlier pistons which match to your head. Hopefully I'm wrong about this and hopefully someone more knowledgeable will chime in.

As for porting, I did some port clean up work on my 750 head by smoothing out some sharp edges. I'm not sure how much good it will do in the real world though but you can easily do the same.

Not sure about the carbs but the stainless exhaust Z1 sells is getting good reviews.

Good luck

Well, I knew it would work with my bottom end but did not know for the top end. I thought that was a pretty good deal so I went for it. I guess I can check it out next week and get a 750 head if needed....

Jeff- for the exhaust, the 4 into 1 off the 2001 zephyr 750 slaps right in. It has the cross flow tubes and you can put any performance can on it you want. I'm running this on my 78 650, and I absolutely love it. It's got a good strong tune to it, and gives really good high end power. I'm running a stubby Yoshimura can on mine, bored to the 720 wiseco kit, stage 3 dynajet, and pods. Here's what it looks like mounted up. Clears the frame in every way, and just needs a support bracket for the tail (can mount to your passenger pegs if you're keeping them). Hope this helps.

Devin

Hey best of luck on the build and way way kewl!

I noticed no one touched on the pods topic, from what I have read from lots of other extremely sharp members here they can add a slim amount on the top end of the rpm range but often times sacrifice the low and mid range, plus if they get wet the bike will run like scat for 30 or so min until they dry out. Just a few things to consider, I think the crucial question to ask yourself is what type of riding you will be doing most, if it is stoplight blasts and general cruising then the stock airbox is probably more along the lines of the right call, but if you are going for absolute power and top end speed then maybe the pods are right for you.

If anyone has something further to add to this or I misstated something please correct me and tell me to STFU

Hope that helps,
- Irish

Thanks!

I think I will probably stick with the stock airbox then. Just for the water issue. I plan on mostly using it around town.

Anyone know about the kz650 head. I thought witht he HyVo system in the 81 kz650 csr that the block would just bolt on so I figured the Head would as well but that may be assuming too much....

Carbs VM24SS w/stage 3 kit - stock airbox with 4 to 1 pipes? Will this work? Not enough power? Right now I have it set to stage 1 and it had the stock airbox and a k&n filter and by the looks of the engine there is a lot of carbon built up so It may have been too rich...

jeffo wrote: Thanks!

I think I will probably stick with the stock airbox then. Just for the water issue. I plan on mostly using it around town.

Anyone know about the kz650 head. I thought witht he HyVo system in the 81 kz650 csr that the block would just bolt on so I figured the Head would as well but that may be assuming too much....

Carbs VM24SS w/stage 3 kit - stock airbox with 4 to 1 pipes? Will this work? Not enough power? Right now I have it set to stage 1 and it had the stock airbox and a k&n filter and by the looks of the engine there is a lot of carbon built up so It may have been too rich...

No problem hope that helped some regarding the pods, like I said I am very new to bikes but not new to mechanics or engines. At the end of the day it is still an internal combustion engine so the same principles applied to a small block chevy 350 will be true in many cases here. If there is something that I missed or was misunderstanding hope someone jumps up and tells me to STFU

- Irish

What range does it run rich at? Idle, mid, high end?

Good question. It has been sitting in my garage for 7 years not running so I have no clue. I just think there is a lot of cabon build up on the head and exhaust ports. Maybe its normal but it seems like its excessive to me....

Here are some pictures. Don't mind the dust from the last 7 years.....

When I cracked my engine to rebuild it at 30,000 miles I had similar build up. The piston tops on mine were fairly coated. Can you scrape any carbon off?

Well I have not tried to clean anything yet. I want to verify the head will work on the 750 block first. I just bought the 750 block with pistons.

Here is what the top of the piston looks like. It does have just over 30k...

I'm keeping an eye here as well because I've wondered the same thing. I'll post a picture of my old pistons up when I get home tomorrow. These actually look cleaner (if i'm remembering right) than my stock pistons do