1978 KZ750 Twin B3 that used to be a off road bike

Got the starter clutch parts in the mail today. The size of the box that the pins and strings came in was the size of a shoe box. The starter clutch rebuild will have to be a different day.

The JB weld and new HF motorcycle lift worked out well. I thought you guys would get a good laugh at my custom sprocket spacer while the shop is working on the OEM one.

Making a little head way. Got her all buttoned up and filled her back up with oil. Hot wired the ignition and hit the starter and it fired. So with a little bit of tinkering and over choking (hand over air inlet of carb) she fired right up. I had too many gas leaks from the carbs and or hose connections to the carbs, so I had to stop there and take a step back.

pulled the carbs back off and removed the bowls. Nice and clean but a few of the screws were not as tight as I thought I had them. Well one was stripped so that was a fun fix.

A run to town for some new fuel hoses and thin clamps and then I staged it on a mount for leak testing. I have it setting over night to see if it leaks or not. If not, back on the bike and get her running and carbs synked .

Other good news got all the blinkers working and what seems to be all the electrical issues. Lots of cracked wires and connectors that were in need of replacing. I was shocked that the horn worked with the push of the button. I think that has to be a first for one of my older bike overhauls.

The hub that had broken off sprocket bots is back on the bike. For now this back wheel will have to do as I want to take it out for a shake down ride to see how it feels before I get too carried away.

Took the brake system off and cleaned it up, the master was in really bad shape. At least the fluid was still more or less pliable and not hardened. The holes were all plugged and or gummed up. Cleaned it up and hit it with high pressure air. Put is all back on and then started to bleed the system.

I have a vacuum bleed system and that didn't even work. So after "priming" the top bleed nipple that did it. Brakes are good now.

I also put the carbs back in and tried to start her, well it flooded right away. Took the pugs out and sure enough they were wet. Took care of that and tried again, fired right up and ran until it was out of "test gas".

Once I hung my test tank up and got pressure to the carbs I cold see a little gas coming out of the right carb over flow. This was strange as over night I had pressure tested it on the bench with my test tank and paper under the carbs. Gas was in the tank this morning and the paper was dry, so why is my carb now leaking from the overflow. I know, hit the side of the carb could be a stuck float.

If that fails the float height might be next. I can't seem to find it in the manual it is just says test with specialty tool. I would hope there would be a height like most other carbs have. If not, I will have to improvise the test tool and see what I can do.

Another note, my new repaired starter seems to not be working as well as I would like, any news if this is a common problem with this model and if I should keep burning through $40 a hit on the rebuild kit?
Thanks in advance.

Tim

The clear tube method is the only reliable way to check fuel height. It ain't complicated. Do a search on this site, it has been described and discussed a lot.

You talking starter clutch or actual starter motor?

Starter clutch if newly serviced just make sure it is put together properly and that the flywheel/rotor bolt is tight with medium strength loctite.

Electric starter? Never used a kit on any bike, just a good dissasemble thorough clean and lube

Its the starter clutch. I put new pins and springs in as the old ones were either broken or rusted away. It started off working great and then started to free spin a bit. I will let it be until it starts to totally free spin.

Clear tube method for the carbs then, need to find an adaptor for the bottom of the bowl.

Thanks for the info, always glad to get any advice.

Tim

After getting the brakes taken care of and some other things on the bike so that oil and gas would not leak out of all the places it should not be. I really wanted to see if I could get her running. Took off the timing plate, points and cleaned the timing advancer. Not too sure if the advancer was frozen up with rust or not but it was very dirty.

I noticed after setting the point gap and then trying to set the timing using my analog volt meter that it would not set correctly. I still need to move the plate counter clockwise another 1/4" or so. That plate adjustment holes are not long enough to allow for propter timing. I did a quick search and fond that I was not the only one having problems with this. I will take the plate back off again and elongate the slots to allow for correct timing.

Another search for electronic timing will be needed but I don't want to fork over the $150 or more for an aftermarket unit either. I think I saw that some are using the components from a 1982 KZ twin, now just need to find them.

The starter clutch is working okay, still misses now and then but I would guess that is a normal thing. Maybe with a little more running time and a oil change it will start to function as designed. LOL

We;; the old girl is running and has been test drove. Not too bad for a little twin. I still have to finish off the exhaust somehow. I will run it down under the bike again, keeping the slip on that came with it. Right now it sounds good, just need to get the seat finished or make a new one. For now it will only be used to drive around my property and maybe later on I will use it on the ATV trails in my area.

It has been a while, the bike that started this post had no title. I found three more KZ750's, two B's and a CSR for a price I could not pass up. The two B's are both 77's and the CSR is a 81. The two B's have titles but the CSR does not.

I swapped out everything from the 78 that stated this post to one of the 77 frames. Yep, motor, wiring forks, tire ect. Cleaning up the frame and streamlining the wiring loom soon. The other 77 I was able to clean up and get running as original.

One of the Bs had a frozen engine (the frame swapped one) and I will see what the deal is with that. So the scrambler project is back on!

Thanks to all the videos out that on how to clean and electric anode a tank! I was able to save all three of the KZ tanks!

Got one of the bikes running (77 KZ750 B ), took it out for the test drive loop about 8 miles. At the end of the run it started to stall, it was a hard stall felt like it lost spark. Good thing it was the down hill leg as I was able to coast it into the driveway.

Let is sit for a day and then put it on the center stand and started it up. Put a fan in front and let her run, played around with the throttle to see if I could recreate the trouble, could not.

Once the rain stops will take it back out and see if I can find the issue. I would guess it is the heat causing a electrical issue in the coil or causing a partial short to open in a wire. Just having it run in the garage is really not the same test as the engine was not under load moving the bike.

Tank is clean with new gas, new fuel lines, filters and carbs have been cleaned. I do need to sync them but that will not cause the stall. I am guessing electrical issues with heat, any other ideas what it could be?

It's possible that the coil fails when it gets hot. You can try using a hair dryer to heat up the coil with the engine running and the fan on to see if that recreates the problem. Ed

Ed, thanks that is what I am hoping it is, I know the coils on these bikes went out a lot. Well I will have to see about a paint stripper gun set on low, as I do not have a hair dryer