New here - Z650B1 - Looks like it'll be a long project !

Hi everyone, and thank you Bill for the fast approval !

It's finally time to get the old beast back on the road. I've had the Z650B1 (UK spec) for well over 30 years, but it's spent the last few languishing and dead. Too much real life getting in the way.

've decided it's time to bring her out of retirement, so I charged the battery and gave her a kick to make sure there was enough life to make it a viable project. Amazingly, it fired up after just two "dry" kicks and four with the ignition & fuel on ! Then I looked down, saw the last tax disk and realised that "a couple of years" off the road had actually somehow turned into nine years.  Ben Inamura makes good engines !

But this is one of those projects where a huge amount will need doing. I'm not looking to make a pretty restoration at this stage, just get to a point of being safely and reliably rideable. The reason she went away in the first place was carb problems, so that's where I'll be starting, and I've already got a couple of questions I'm hoping the experts here can help me out with.....

 

There are some pretty good carb guys here so fire away.  I'm currently doing a 650 myself.

Show us a couple of photos.

Welcome fellow UK resident.
The first 650 model, have you done the double disc mod?
There are a few different carbs through the range, are yours the original as the B2 had a mod on the slow running?
lets have some pics. Green one?????

Regards
Rob B

If you've never done carburetor work before, it's not that hard.  I had removed the bowls a few times & maybe the floats, then decided to do the complete disassembly & cleaning >> it seemed easy to me & I do mean easy. The same thing is done 4 times on most stuff & everything goes back together pretty much only one way, so it's hard to mess up. Use good fitting tools. Expect to replace the gaskets & rubber bits.  Don't order any parts until you know exactly what you need. There are 2 or 3 different VM bowl gaskets, so verify before buying.  I soaked the carb bodies & brass bits in a good professional carb cleaner (Berryman's original formula. it's kinda toxic).

Carburetor note. since yours is a B1, it may have VM22 carburetors. most 650s have VM24s. the 650 carburetor internals can vary from year to year & sometimes within a model year, especially 1977, so your stuff may not be exactly the same as somebody else's. in case you find something weird or unusual.

Just thought i would share my carb cleaning method. I do have a compressor but wanted to flush the internals with a IPA.
After removing the jets etc (placed in an egg box labelled 1-4) I got out my large syringe from the brake bleeding box and rigged up a high pressure jet wash with the aid of tubing and suitable plugs. 

I blanked the inlet blasted it, then blocked the outlets and blow out again with IPA in the syringe. then as many of the internal bit i could before a blow out with the air line. I try to avoyd carb cleaner cans as they can affect the rubber seals.

the pics are from my Bandit cleanup but same works on the Z500

Thanks for the warm welcome !

I've popped in a couple of photos, although they make the bike look far prettier than she currently is - it doesn't show the true awfulness of the chrome and paintwork. I've also added one "just because" from a few years ago starring Sooty the Cat when he was still a stray before we adopted him (sadly he's no longer with us.... he was FIV+ with all kinds of other health issues, but we gave him the best life he could possibly have).

So far on the carbs, I've picked the best of the three sets I've got, VM24SS type with the air screw at the back rather than the pilot screw hidden under the float bowl. I've stripped them down and given them a good ultrasonic cleaning to get rid of the varnish and accumulated spider webs. The main issue is the choke, which doesn't feel right (spongy and resistant, as if it's got some kind of vacuum lock going on), so I'll strip that back over the weekend and post begging for help if I can't figure it out
 

Hi Sean! Hello from Virginia in the states...I too have a '78 KZ650B and love it! But I had to comment when I saw your method of cleaning the internals of the carbs with IPA...at first I thought you meant 'India Pale Ale' (!) but then of course I saw the can of alcohol...

But your method is Brilliant! And the carbs look Great! I too have a lot of IPA laying around, I use it to balance the carbs - much safer than gasoline; but I never thought of using a syringe to 'blast' the internals...good job!

Welcome Sean.

 

Spongy choke lever is normally caused by the tiny hole in the bottom of the brass choke pickup tube being blocked which causes a vacuum under the choke plunger when you try to lift it with the lever. 
The choke pick up tube is the brass tube at the back edge of the body pointing down into the bowl. 

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Your carbs look pretty good! I also have a z650b1, cleaning takes patients and time but its worth it especially if you look after them in my opinion.
Such as: fit an inline fuel filter, not a screen but a proper filter, cheap as chips, throw away yearly. Drain carbs if laying up for more than a week (applies to uk crappy fuel), use low ethanol fuel as much as possible, keep air cleaner clean and when removing it vacuum out air box before refitting, avoid oiled type if possible, paper superior, use oem or best quality parts where possible, especially fuel inlet needle float valves. Check fuel cock bowl for water from time to time, water is the enemy in carb bowls and promotes galvanic corrosion. Doing this has meant my carbs are still squeaky clean after 10 years! Don't be tempted to junk your existing original brass jets and needles unless they are really badly damaged, these mikuni parts wear very little and are way better than any after market replacements.
When doing fuel levels on bench I use Aspen fuel which I keep in a can for such purposes, and just keep reusing, its very safe, almost drinkable! No nasty additives, solvents, not as flammable and long lasting in storage. Do not be tempted to use methylated spirits or such like it can foul up the internals and dull the brass instantly, in addition its density is too far different from gasoline and it will affect the float level you set by up to 25%! Paraffin (kerosene) may be another option but haven't used that before or of course just plain old petrol.
All my opinion of course and I am not telling you what to do, just my views and hopefully a tip or two that may be of use?  

Oh its defo worth getting the rubber ends on the choke plungers replaced, they will be hard and won't seal well, not a disaster but can cause anoying fuelling issues.

Dave, I was always taught to set the float highs with the exact fuel i would use in the bike as the surface tension etc can affect the reading if you do the method in the Kawasaki manual. As fuel level is critical to correct running. I use E5 as it is the only stuff the bikes get.