1975 Z1B - back on the road... hopefully!

glad that you finally got some seat time :evil: .

leon

Apparently, the bike won't let me win that easily!

Rode to work Friday, excited to be on the bike and enjoying the cruise. Not far, about 8 miles through the county roads to town.

Everything seemed fine. Bike fired right up at home, ran well 90% of the way. Just before I got to work, seemed like I had a cylinder dropping out at idle occasionally. Didn't think too much about it.

After work, the bike fired up, but not easily and it was only running on 3 cylinders. Couldn't get the 4th (cylinder 4) to kick in. I may have over-choked it, but only cylinder 4 was dead. I'm kick-start only at the moment. Decided to call for a ride rather than limping home on 3 cylinders.

Came back Sat. morning with some tools hoping to pull the plug, swap it with one of the other cylinders, and ride it home. No dice. Pulled all the plugs. 1 & 3 are lightly black on the ceramic near the center, I would guess about right. 2 was almost white, too lean. 4 was black. After I swapped plugs with cylinder 2 and it still wouldn't go, I pulled cylinder 4 again to find it wet with fuel. There was fuel in 3 of 4 vacuum port caps on the intake boots but I'd been using the choke.

I have some ideas about what might be wrong, but not sure. Would a choke plunger failure cause this? Seems like cylinder 4 must be getting too much fuel all the time. I have the opposite problem with 2, but it is firing. Probably just an adjustment to be made there. My other thought is that the float level is too high in the bowl on 4 and maybe too low on 2.

Does that sound reasonable? If I pull the carbs back off, how do I tell if the choke plunger is bad? Plan to do a good synchronization this time. First go around, I didn't move them hoping the PO had it in good shape. I'm not sure that's the case.

I love sites like this. I've had several older bikes over the years. Somewhat due to price, but I really dig bikes with character. I've been fortunate to find forums similar to this one for each of the rides I've owned. From my '79 Bonnie Special, to my '86 GS1150E, to my current '75 Z1-B. You guys that know all about these bikes that hang out and post information for us relative noobs are a great resource.


I thought I was road-worthy, a couple weeks ago only to have my bike leave me stranded at the office. Picked it up with the truck and brought it home. Got lots of tips/pointers from folks on this forum. Ended up being primarily a problem with float adjustment. I had one cylinder (4 that was fouling plugs) that was way off from the others. Checked the level and it was at least 1/4" high. Actually above the top of the bowl. I adjusted that, and mechanically synched the carbs while I had thing apart.

I've got about 60 miles on it so far. Numerous starts and a decent amount of low RPM travel in town. So far, so good. No problems at start-up and it seems to be running well. I'm still adjusting to the huge leap in power from my XT225 to this 903cc screamer. Pulled the plugs and found none are terribly rich or lean.

Now that I've put a few miles on it... appears I need fork seals, a footrest stud, and a new right-hand switch cluster. I had the right switches apart to install the new throttle cables. My front master cylinder leaked in storage all into the switches. Corroded like mad in there. I'm hoping I may actually have electric start after installing the new parts. No way it could work now.

I got the bike up and running just in time. The Mrs. crashed our Suburban into a tree on our 1/2 mile driveway. To be fair she is constantly managing our menagerie of children. Turns out she was trying to get them some gummy worms... s#%t happens.

Thanks again, hopefully I'm good to go for a bit. Planning a 2 hour test ride later this week assuming commuting goes well.

Sounds like everything is going right for you. The forks are not too bad. Very nasty at first until you dispose of the old oil. Taking out the allen bolt at the bottom of the forks is the tricky part. I ended up buying a gator grip socket from Walmart and it made it a breeze to take the bolt off and on. But you may not even need it. Good luck.

KZJOE900 wrote: Sounds like everything is going right for you. The forks are not too bad. Very nasty at first until you dispose of the old oil. Taking out the allen bolt at the bottom of the forks is the tricky part. I ended up buying a gator grip socket from Walmart and it made it a breeze to take the bolt off and on. But you may not even need it. Good luck.

First effort to remove the Allen bolt should be attempted before the fork cap is removed, because the spring pressure might afford enough resistance to hold the internal parts in position until the bolt breaks loose.

Also best that the first effort be with an impact wrench.

Good Fortune!

Parts arrived yesterday. Got the new RH switches installed and the electric start is now fully functional!

Removed the carbs, fixed plugged pilot for cylinder 1, and readjusted idle. Better, but still not smooth. May vacuum synch next.

Fork seals are here, but haven't tackled yet.

Another flurry of parts replacement/repair last night.

Installed new progressive fork springs, replaced fork seals, replaced rear shocks, installed new exhaust gaskets, installed new clutch cable, and added the chrome grab rail that was missing.

I also got the opportunity to throw some vacuum gauges on the carbs. They were actually pretty well balanced. Not enough difference that I could improve upon it. The bike still won't idle super smooth. Does fine just over 1000 rpms, doesn't like it below that. My oil pressure light comes on then too.

Overall, the improvement was very noticeable. My old clutch cable had developed a snag as you released it. This made it very difficult to take off smoothly. New cable solved it. The suspension was in sad shape up front. Fork seals were shot and there wasn't much oil left in them. Springs were a good 1"-1-1/2" shorter than the new ones. Much less sag now, and the new forks didn't bottom out on my way down the driveway.

I'll post up some photos when I get a chance to capture my progress. Paint may be the only major hurdle left, but I'm saving that for winter.