KZ650 Sleeper Build (KZ1000 engine transplant)

I got some work done on this later in the day today.

I was able to coil up the extra cable length in behind the headlamp bucket.

 

It turned out I only had a short length of the heat shrink required to cover the RFI shielding, it was short by about 2". I cut some short sections to capture the cut ends of the covering so it would not "walk". I tucked it up and fastener it to the frame to clear the gas tank, hopefully it won't need adjusting.

 

I bent the mount bracket and tucked the O2 sensor wiring up under the tail piece without issue.

 

I put some 93 octane gas into my auxiliary tank and filled the float bowls. I will install the battery and start it tomorrow morning. I am hoping my new stator is going to take care of the charging issue and I will see if the jetting will be good enough to leave the garage and do some on road testing.
 

Got it started today with no issues, first start was without the AFR gauge hooked up because the cylinders had lube in them from Winterizing so there was a bit of oil to burn off and did not want that to mess with the O2 sensor.

I checked the voltage to the battery at 4000 RPM and only got a 13.6 Volt reading. Will need to double check FSM and maybe check it again tomorrow to make double sure. Not what I expected but I will take it out like this and get some miles on it with some short rides.

After the engine was warm I plugged in the AFR and restarted it. AFR was working but it seems I am too lean at idle with 14.8 to 15.0 running a #17.5 pilot. When I revved the engine to 4K the AFR did not swing richer. Plugs are still black after being burned clean before startup, even with new choke seals installed. I trust the AFR over my gut instinct.

The Mikuni manual suggests jetting a KZ1100 with those carbs to a #17.5 and #127.5 main, and jet needle at clip #4. Air jet #1.2 which I have installed.

Currently I have main at #127.5 and switched the pilot to a #20. I am raising the jet needle from clip #3 to #4. 

I think I overestimated the idle circuit on the lean side because of the air box and dual exhaust. I went from a #22.5 pilot to a #17.5 only because of the black plugs. 

Still working on re-clipping the jet needles. Will get back on it tomorrow.

 

You will probably need to ride it to get meaningful AFR readings with the sensor mounted where it is I would expect it to be a little slow to respond (also don’t forget the sensor needs to be around 300 degrees plus to read correctly)

Yes the positioning of the sensor is not ideal. I believe a sleeve between the head pipe and muffler may be a better way to go. 

Right now I don't have time on my side to address it so I am thinking just get it out on the road and get it good n hot then see what the numbers are. 

I richened it up and that won't hurt, will see tomorrow if its a step in the right direction.

I ended up taking the AFR gauge off for now, much easier to take off than put on. I will get it working with some changes when I have more time, right now is a distraction I don't need.

I did get the needles shimmed richer back to the Mikuni stock setting. My first time doing the needles on the bike with these carbs. I had to run out and buy a 3/16" x 8" long screwdriver for the #2 slide because my 6" screwdriver would not reach the cover plate.

Having to leave in the middle of the day kind of blew my time as people arrived for a visit when I got back. A test ride did not happen.

Tomorrow I will have more time to clean out and mount the gas tank in preparation for a ride.
 

I remembered I had a second set of these mufflers in a 17" version which could be fitted with a sleeve pipe to attach the threaded bung for the sensor.

 

I should be able to make a mount bracket to extend the length further to match the 26" muffler better. The closest I can get the bung to the end of the head pipe is about 32" which is still not ideal but better than what it was.

I will look into this further towards the end of the month.

I took a look at the FSM for the engine (1979 KZ1000) and the spec for battery voltage @ 4000 RPM is 13.5 to 14.8 Volts. 

I am on the lower end of the spec so I am going invest in a new rotor. I will order a new one from the same local dealer that sold me the stator. I am looking to have that charge voltage above 14 volts like I have it on my 750.  

Well I had a weird couple of hours. Went to start the bike to check Color Tune and ignition timing but I found a fuel leak on #1 float bowl.

Thought I had a float valve issue, but it ended up being a fuel pipe leak between #1 and #2 carb bodies. Performed the smack it with a screwdriver handle trick to no avail.

 

Sort of surprising since last year there were no gas leaks, and when I put gas to the carbs just the other day I let them sit overnight with fuel in them before starting it for the first time this year with no leaks. Now all of a sudden it leaks? Did not expect that at all, that is why it took me a while to come this conclusion.

The center pipe and the pipe between #3 and #4 are OK.
It took me a while to figure out what was happening because there are no overflow tubes so right away I thought float valves, so I had to drain and remove both floats on the left side. I then cleaned the seats with a Q tip and confirmed they held gas back one at a time. When I put it back together I saw it was leaking around the front of the bowls and between the bowls then I clued in!

I just thought I was going to restart it and go for a ride, I was so sure it was OK I even put the side covers on and put the tool bag in place

 

I drained all the bowls and came in for dinner. Tomorrow there is one last trick to try before throwing in the towel, fill the bowls with 100% Nitro for 5 minutes and see if it stops the leak. Nitro swells non Viton O rings really quick, no need to wait overnight like gasoline, plus it does not smell

 

Taking off the carbs now would entail a lot of work, possibly two days. If the Nitro does not work then there is a split in one O ring. I looked hard at those O rings and thought they were good. Will assess after tomorrows test which I have done successfully more than a couple of times.

The whole aim in getting this one running was to ride it to the bike swap Fathers day weekend. I have been in this same spot a few times, two weeks out is too soon to be messing around with a bike you have to ride to a event. 

This was the same with my 831cc Hot Rod build, seemingly on thing after another!

 
 

I got that leak stopped today, Nitro sealed it up in 7 minutes but I left it in there for another 8 minutes then drained it. Flushed the carbs with alcohol to remove any traces. Filled the bowls back up with gas to make sure the leak was fixed.

Now I want to check the idle with a ColorTune plug and recheck the timing, I believe it is slightly retarded but not sure. After that I will install tank and seat then take her out for a spin.

Went to start the engine and carb #1 was leaking again at the bowl gasket. A slight leak but persistent, not pouring out like before.

Drained gas and took the float needle seat out, forgot these have a mesh dome that sits on top of the seat so trash does not get to the float needle. Tried cleaning up the seat with grinding paste and Qtip, really shined it up then rinsed. Verified that the float "floats", no holes/bubbles. Put it all back together and it still leaks!

I think some parts need to be ordered. There are not too many of those original 2.8 seats out there, I see more of the 2.5's for sale. I have a call into a local guy who might have one, he told me to call back tomorrow once he looks thru his spares.

Glad I did not put the seat and tank on, but all my riding gear was dragged out in anticipation.

If I find out I can get a replacement seat right away I will need to park this bike for a bit. If that's the case the 750 is going to get woken up.