The 'build thread' of a Kawasaki Z250 C, a total beginner's point of view...

For some reason, still no luck. The fuel level doesn't seem to want to budge from the bottom of the bowl...any ideas? Is it possible this has something to do with something blocked or the removal of the air box? I'm at a loss. Apart from the tang, I haven't adjusted anything else on the carb.

Set dry float height to 23mm as recommended by some old post somewhere - will run fuel through on the weekend.
Found this useful thread on re jetting - thought this would be a good place to keep it: http://www.kzrider.com/forum/3-carburetor/156322-1980-kz250d-air-filter

Just posting another useful link for now. Decided to rejet for pods so didn't recheck the float height as I believe all this will change. But found this old post from kawasakimotorcycles.org which solves my air filter element issue, which means I don't have to run the pod if I don't want - however, seeing as I've done the research, chewed up the slow in the main jet, I feel like I should go ahead...any suggestions?

For other's reference:

The OEM air filter element has been superceded but kawasaki didn't update the code, the same part can now be found under this code 11013-1039, and fits the kz250 as well as the following models:

KZ250-D1 (KZ250) (1980)
KZ250-D2 (CSR) (1981)
KZ250-L1 (CSR Belt) (1982)
KZ305-A1 (CSR) (1981)
KZ305-A2 (CSR) (1982)
KZ305-B1 (CSR Belt) (1982)
KZ305-B2 (LTD) (1987)
KZ305-B3 (LTD) (1988)

Original post here - www.kawasakimotorcycle.org/forum/vintage...filter-81-kz250.html

I'll put up the rejetting as well:

Haven't actually tested this yet, but recommendations from previous people over on kzrider indicates that CV32 on my KZ50 should go with the following:

Jet Original Size New Size
Primary #68 #70
Secondary #98 #125-130

Will update with results once I rejet and get the bike started, which 1. will be a while, 2. depends on if I rejet or buy the air filter element...

Got the same bike, also doing a resto. Did you manage to get the man for it? I'm stuck with the z200&kl250 for reference.

Having a timing/carb problems with mine after fitting a new cam chain and having left a dirty carb for 7 years. Do you know which cylinder head marking and camshaft sprocket marking your bike uses? Would be a massive help if you could check.

Hey jrod,

The camshaft sprocket has the KZ200 mark on it. I'm not sure about the cylinder head as I haven't removed it and am trying to avoid having to do so for now. If you need, I can copy you some info from the manual. Let me know.

In other news, parts have been arriving, so hoping to finally find a carb dip (if anyone knows of one and where to get it in aus that would be great) and reassemble the carb. Big thanks to Mike from Z1 who was awesome to deal with.

Got a little bit done - rebuilt the carb and fitted the new filter - need to recheck the float levels now, so made temporary "gas tank", still a little bit of rust in the tank and don't want to send that through the system if it starts. Waiting for compression gauge - looks like this should have been the first thing I bought to see if this whole project was worth undertaking or not in the first place.




Hot glue gun'd a barbed off take from bunnings - total cost < $3. Bargin.

The KZ250 Kawasaki was based on the KZ200, and has a reputation of head problems, and my this case, the bike had only 8,000 km on it when I got it. The camshaft turns in two aluminum bushings, the larger one showed a lot of wear and scoring. The problem began in the factory when the oil feed to the camshaft was misaligned by about 1/8 of an inch, resulting in the starving of oil to the larger bushing and the cam lobes.

So, check your cam lobes and rocker arms for wear ( flat spots, grooves ). If they are nice and shiny, just keep the oil topped up and change often. If you see wear, remove the camshaft and check the alignment of the oil supply hole in the right side cam bushing. It supplies ALL the oil for the top end, and oil must pass into the camshaft via a small hole and groove to lubricate the rockers and the big cam bushing on the left side.

I drilled out mine to provide better flow, and installed a roller bearing on the left end of the camshaft.




- Dwarf

Thanks for the heads up Dwarf - looks like something else to add to the check list.
Right now, I'm keen on staying away from the engine block if possible and get the bike started first, so stupid question, is this head issue likely to be a reason for the bike not starting? Liked you're website btw - good info there.

Tried starting the bike today - couldn't check the float levels as I couldn't level the bike out (issues with wrists and what not), so looks like I'll have to get a rear stand after all. But went ahead anyways and tried to start it up, but to no avail - instead, sparks were coming out from the key as well and it got quiet hot...any suggestions on that one? In terms of the floats, looked like I was getting some fuel in there, but again, not a lot, but I think this might have more to do with the pressure/location of the temp fuel tank, as I didn't have a longer piece of fuel line and was using the normal one.

Signals also don't work anymore, which I guess seems to suggest I have some sort of electrical issue happening as well, the battery was reading 12.56 but, which seems ok to me?

So all in all, looks like I've gone backwards a bit. Not really sure if I should fork out more money on the stand and tank sealer to get the set up right. Compression gauge should be arriving soon and I'll probably make a decision after doing that test, though Easter is coming up and I should get a full day or two to work on it.

How was the Z250 to ride etc?

Nice mod on the cam. Did the same with my GF's cb200 due to the same problem with oil. Great minds think alike

Sham, the cam/oil problem would not cause a starting issue. Do check that there is SOME play in the tappets when they aren't opening the valves. Sounds like your electrics need the most attention. The carb problem may be some small dirt in the fuel line or float valve seat.

The 250 was a blast to ride! Light weight and low seat height. It was at it's best around town, but my son would commute an hour to work on the highway at 120km ( 70mph). The left crank bearing went after a couple of years, and I haven't fixed it yet ( 4 years! replaced the bike quickly with a 1983 KZ305 twin).

Bert Jan, the first bike I replaced the cam bushings with roller bearings was a Honda CL175 (1967?) in 1973 ( Honda didn't learn, did they?). I modified my daughter's 1982 Honda CM250 the same. Those two were much easier. On the KZ250 the left bearing has to be big enough for the CAM LOBES to fit through!
- Dwarf

Dwarf - that's a good point, its the one thing (I think) I didn't remove when I disassembled and reassembled my carb, as I wasn't sure how to get it out. The exploded diagram in the manual doesn't show it, but the microfiche does. Anyways, any ideas on how to get this out?

I'm going to brain dump here for a sec as I try to formulate some other questions to put onto 1800 cafe...

The compression tester arrived today and I tried to do the compression test. According to what I could find, this is just removing the spark plug, inserting the gauge and turn over the engine (in my case, this meant hitting the starter button a lot of times). However, nothing happened, no compression reading at all.

Instead, I had orange sparks coming out of the key hole again, which in turn heated up my keys and produced a burning smell.

I'm not sure why I got a 0 reading, and I'm not sure that my engine has absolutely no compression. Is it possible that there are other components failing, causing the engine not to turn over? I checked starter relay and that was good, and in my mind, there really shouldn't be a problem with my starter if I'm getting a spark anyways...is this correct?

So, not sure where to go from here. I'm borrowing a bike stand over the weekend to do the float level, but this compression thing is slightly ominous...I was reminded of that the ignition switch has several switch positions, but my handle bar controls are totally worn out for me to see what's what. Is it possible that all of this is because its in the wrong position? But my understanding is that I shouldn't be able to hit the starter button and get a spark if this is so...

Compression test Steps:

Remove spark plug, screw in tester tightly (not too tight to bugger threads). If carb is on, make sure you have throttle wide open to let air in. Fuel off, you hit the starter and you should get puff puff sounds until the needle stops climbing. Cold compression will be lower than when engine is at full operating temp. If you get nothing, you likely have a valve timing or adjustment issue. If a valve is not closing on the compression stroke all your air goes out and your tester needle does nothing. Check timing and valve adjustment if these check out, pull head and check valve seats to make sure they are correctly seated. The sparks from your ignition switch likely means a short or a wire not run right, I would check that out. Maybe do a the compression check by using the battery with neg to ground and touching pos to the starter terminal to bypass the ignition.

Hey Maritime,

Thanks - I did forget to have the throttle open the first time around. But I did try it again with throttle open (carb on) and still 0 compression.

I will try again with carb off tomorrow.

your loosing air somewhere, you may need to do a leak down test. Check your valves and valve timing also put a little liquid around the sparkplug hole and see if you get bubbles or even spray, that would mean the tester isn't sealed enough to keep the compression in. Make sure also the little pressure relief valve on the dial is not stuck in the open position letting your air out.

Hey maritime,

Thanks for the tip - I'll go get some oil and do that over the weekend. Hoping I won't have to do a tear down - my learners expire in 3 months and I want to get my P's!

NP but taking the head off a small single like that would only be a few hours work with a manual in hand. Just need a torque wrench to put it back on. I am not sure what brand of compression tester you have but the one I just bought has an adpater the right thread size for the sparkplug hole, then a hose with o ring that screws into the adapter and then a quick release air fitting at the dial. It is easy to not get the hose tight enough and loose air past the o-ring.

Haha a torque wrench is something I don't have yet, so I wouldn't be able to put it back on with the correct amount of torque for now. I'm finding it difficult to keep things budget when I lack so many of these basic tools.

The compression tester sounds very similar to yours. Its the equivalent of a no brand I think, bought from some cheap online store. I might try to test my car with it to verify if it works or not.

Fail!

Feeling pretty stupid. Wasn't getting a compression reading cos of two reasons I think:

1. I didn't have the bike in neutral (duh)
2. Relates more to the sparking at the key - I hadn't grounded the spark plug wires correctly, actually what I did meant I hadn't grounded them at all...

Meaning CDI is potentially damaged?

Fail.

Compression of 30 PSI.

Fail.

Just saw this... You can pick up an inexpensive deflection torque wrench for next to nothing. I just snagged one for like 8 bucks, rated to within 4%. Good enough for me and the girls I go with, and I don't have to borrow my dad's any more. You just have to be smooth and learn the feel with the torque wrench.