Fuel coming out of exhaust Z1

bluej58 wrote: So you can remove the spark plug and see a spark when running?
Be very careful, if you are getting gas in the exhaust system.
I am not familiar with a Z1 exhaust but on my bike a working cylinder can touch off the raw gas in the pipe and cause a explosion and possibly damage to the system

Thanks for the heads up, I'm being very careful, it's taken me 6 years to get this far, would hate to spoil it now.

In my opinion the float needle valve on carb #1 is not seating right or float level is set to high.

Did you set the floats using the clear tube / wet method. If not they are not set right.

slmjim+Z1BEBE wrote: Assuming stock VM28's here.

If the enrichener (choke) plunger is not seating and sealing when the choke lever is fully down, an extremely rich mixture will be introduced into that cylinder. Check that the plunger on the problem cylinder is seating completely when the choke lever is down.

Good Ridin'
slmjim & Z1BEBE

That's a good point. I haven't messed with the choke at all, but will look into this when I get some time tonight. However, I would have thought that if the choke for that carb was still on, it would still fire wouldn't it, although very rich. After all, the other 3 cylinders all work when the engine is cold and the choke is on. I'll take a look and let you know.

Zedsded wrote:

slmjim+Z1BEBE wrote: Assuming stock VM28's here.

If the enrichener (choke) plunger is not seating and sealing when the choke lever is fully down, an extremely rich mixture will be introduced into that cylinder. Check that the plunger on the problem cylinder is seating completely when the choke lever is down.

Good Ridin'
slmjim & Z1BEBE

That's a good point. I haven't messed with the choke at all, but will look into this when I get some time tonight. However, I would have thought that if the choke for that carb was still on, it would still fire wouldn't it, although very rich. After all, the other 3 cylinders all work when the engine is cold and the choke is on. I'll take a look and let you know.

And yes, stock VM28's with standard jets.

baldy110 wrote: Did you set the floats using the clear tube / wet method. If not they are not set right.

When I had the carbs on the bench, I manually set them to 24mm, but I didn't clear tube them on the bench, should have done that! I did clear tube #1 when it was back on the bike, and found it to be out, and adjusted it again, but that didn't fix the problem. I'm going to take the carbs off tonight, and I'll adjust the floats again, and post some pictures. Appreciate all the comments.

All pointing towards a blockage for my way of thinking. Whilst off dont forget to clean al the air passages.
Just occured to me, are they fuel and air screw or just air screw? I've seen carbs where the fuel screw tip has snapped off due to being done up to tight. Then to extract the broken tip they have been drilled. A new fuel screw fitted. They never worked correctly again due to the taper in the carb body being out compared to the fuel screw and its always letting in far too much fuel. Either that or the tip is still blocking the hole and it lets no fuel through without adjusting the air screw. Hence my comment earlier about leaning the airscrew way out.
The only way to get them back to half decent is to block the fuel screw hole in the carb throat and use that carb as just airscrew type. Either that or try to find a replacement body.
Another thing to check if they are fuel screw. Check the tapers one all 4 against each other. After market kits, if they've been replaced, are not always the greatest quality compared to oem mikuni parts.

How do I put this...? I screwed up. I took the carbs off, and the pilot jet was hanging in by one thread! Somehow, I missed tightening up the jet, and now I've wasted everyone's time, very embarrassing. Put the carbs back on, hit the starter and it fired right up. Oops.

If anyone comes over to Sydney the beers are on me. Thanks again for all your help, great community.

Warren3200gt wrote: ... Just occured to me, are they fuel and air screw or just air screw?...

VM28's are airscrew only.


Check that the brass overflow pipe(s) in the float bowls aren't plugged. That could allow excessively high fuel level without obvious fuel drainage.

And, this is a long shot: check that the enrichener plunger lifter claws are correctly positioned between the upper & lower lips of the nylon barrels at the top of the plungers' shafts.

Good Ridin'
slmjim & Z1BEBE

Zedsded wrote: How do I put this...? I screwed up. I took the carbs off, and the pilot jet was hanging in by one thread! Somehow, I missed tightening up the jet, and now I've wasted everyone's time, very embarrassing. Put the carbs back on, hit the starter and it fired right up. Oops.

If anyone comes over to Sydney the beers are on me. Thanks again for all your help, great community.

Hehe, we all do it sometimes. Last one for me was refilling with oil having foggoten to refit the sump plug.:blush:

We've all been there. Glad you found it.
Steve

That's funny, glad it was an easy fix. In my youth I've forgotten to install the piston on my Yamaha DT250 after a rebuild. All I heard as I cranked was a loud clanking sound. My father watched me as I put the engine together and offered me advice but I didn't liten to him. He laughed and walked away.