Author Topic: The 'build thread' of a Kawasaki Z250 C, a total beginner's point of view...  (Read 57144 times)

Offline sham

  • Posts: 309

  • Intro:
    So, after having posted in various sections, inevitably asking for help of sorts, I thought I would start a build thread, seeing as this has been the first day I've attempted to see what's happening with this bike. I'm not sure where this will go, to be honest I have 0 experience in any of this and have 0 skills which could be of much use as of yet, but I'm hoping to at least get this bike running again and from there, I'd love to make it as cafe as possible.

    I'm hoping to use this as a log from a complete noob point of view, so that if there is anyone else out there who decides to buy a non running bike and then have no idea what to do with it, hopefully this can be a point of reference - for better or worse though I'm not sure.

    Bike background:
    Got this bike from Scott's Motorcycles in Sydney for $750. I sent them an email asking if they had any project bikes lying around and this one one of them. It had been sitting in the garage for 2 years, having run well before that before succumbing to a CDI issue. From my point of view, it looked like it was in a pretty good condition compared to the other bikes I was looking at in that price range, so I got it.

    Photo of the bike as taken by the shop. I did see it in person, but honestly, it made no difference.

    So once it was delivered, I had no idea where to start. The helpful people on the Australian DDT section definitely helped point me in the right direction. I was told to do the following:
    • Check if the motor turns - did this by seeing if I could roll the bike (slightly) while shifting through the gears. If the bike seized up, then the motor was no good.
      This was fine, but I had a slight complication with the bike not going into first, but that was fixed by rolling it around more.

    • See if I had a spark - take the spark plug out, put it back on the lead, ground it against the engine and hit the starter.
      No spark. I wasn't expecting this to work seeing as I'd been warned about the CDI, but I looked around anyways and found what I believe is the culprit...

      I had no idea what this was, so I DDT'd it. Hillsy came up with a great diagram which showed it was most probably the CDI. Great. I knew I had a CDI problem, didn't expect not to have one...

    • If all that went well, put some fresh petrol in it and start it up.
      Well, I haven't got up to this yet.

    Progress so far
    So as I was saying, today was the first day of the build. I had a friend over who helped me roll the bike into my house, which was super helpful. So first on the list - see if it was really the CDI, so I went and stripped the bike.

    How she now stands...

    So, turned out it was the CDI. After stripping off the seat and those side panel things (no idea what they're called), I found the regulator, which was what other people thought it might have been, so damn...I was going to pay the 456 euros for a new one, and seeing as there didn't seem to be any after market ones for my bike at a decent price, I thought I'd try Jaycar...they had a CDI kit online for 98 bucks, which I thought was a bargin if that's how much I was expected to pay for a second hand one which looked rather mangled. So off to the shops it was, for that and some brake cleaner. Again, this was from advice from the Australian DDT, and would be used to clean up carb.

    First up Jaycar. This is what a kit CDI looks like

    Looked simple enough if it had decent instructions (read lego instructions, or IKEA instructions, or anything which is step by step)...too bad the instructions came from some article on CDI's. It would be helpful to people who actually know anything about electronics - I believe someone did warn me last night. But here, I've put up the link for anyone interested, or is looking into making their own

    And seeing as it only turned out to be 20 bucks, I thought whatever, I'll give it a shot. Its a cheap stab in the dark. So I got that and a solder and I'm looking to try to put it together this weekend. I'm hoping my uncle can help me out, he's an engineer or sorts so I imagine he'd have more of a clue than me.

    Up next was SuperCheapAuto, where I got some WD40 and brake cleaner.

    So, at this point, I have to say it again - if anyone has a pdf copy or a print copy of the 1980 - 1983 Kawasaki Z250 Single Manual Service Manual, please let me know and, if its a printed copy, I will be more than happy to pay for it. I went about trying to dismantle the carb following the Z250 Twins manual (which I do have and if anyone needs I can send them the link) but realized pretty quickly that things were slightly different. So I improvised and here are the results.

    Now I was too scared to dismantle this bit - the manual said I needed to use special tools, but people on this site do talk about cleaning the jets and needles and all that, so if anyone could tell me how to dismantle it, if it needs to be dismantled and cleaned, that would be great.

    This seal thing caused me a lot of trouble - it attaches the 'butterfly valves' to the engine, but just wouldn't come off. You can also see the rubber has deteriorated pretty bad. Does anyone knows what this is called, and if I need to get a new one?

    This is what I got it down to. I sprayed the other bits and pieces that were attached to it with brake cleaner, but I was wondering if this piece still needs to be dismantled further to be properly cleaned? It already looks pretty clean to me, but I do want to do a good job while I'm here. Another thing is that I'm not getting a very polished look other people are getting, just all the gunk is falling off it - is this what I can expect from brake cleaner? I saw another build where someone just soaked it in coke - is this a decent option? They're turned out pretty well, though I don't remember who it was, sorry.

    So that's pretty much where I'm at right now. I'm planning to open up the engine just to make sure there's no surprises there, and hopefully if that's the case, clean it/soak it and work on the CDI while I'm waiting...

    Really excited about all this. I realize its a bit of a ramble and there's a lot of unnecessary photos, but yeh.

    A quick  thanks to everyone who has already given me pointers and told me what to do, as by now you've probably realized I really don't know what I'm doing. My friend tried talking me out of it when he was over today, but just taking that carb apart got me excited. Ha.

    Anyways, I'll try to keep this up and I suppose my future posts will be more to the point and less long. Every moment I'm here, I'm not working on the bike!



Offline sham

  • Posts: 309
Would anyone know how to disconnect the tacho cable from the cylinder head cover? According to the z250/305 manual there should be a bolt and tacho pinion holder stop? I can't find it, but the cable definitely doesn't want to come out. Should I just yank it or will that damage it?

On another note, the $20 dollar socket set I got today already broke. Lesson learned, don't buy cheap tools...

Offline teazer

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  • Posts: 9152
Don't try to pull the diaphragm off the slide.  That doesn't need anything other than a clean and to be handled carefully.

The carbs needs a few more parts removed.  Remove the jets and clean them and blow through all the small holes and drillings.  Don't be tempted to take out the shafts and butterfly valves. They are not supposed to be removed and there's no point.

Then carefully reassemble it and order a new intake manifold gasket if the bike came with one.  There appears to be the remains of a gasket stuck to the face of that rubber intake manifold but many bikes don't use a gasket there.  There's a  raised ring around it that acts to seal it, but if your bike is designed to have a gasket there, make or get one.
« Last Edit: Jul 30, 2011, 17:47:51 by teazer »

Offline cyclone

  • Posts: 111
 yep, you have a good platform to start with there....
is that a drum brake on the front or a disc under cover?
maybe worth converting to twin disc if the cost isnt too prohibitive?
we had the gpz305 over here after the z250..maybe worth looking to see if the engine top end fits and if the front end is twin disc see if that fits also for any future plans as you improve it..just food for thought.. ;)
as for stylin..i will just leave these three here.........

Offline cyclone

  • Posts: 111

Offline cyclone

  • Posts: 111
cut down mudguard, fit a small light, take some packing out of seat and mx type bars..not too many bucks and stylish...have a kwak

Offline sham

  • Posts: 309
Teazer - thanks, I was a bit unsure if I should take out the butterfly valves. Yeh there was a gasket on it, I had to rip most of it off cos it was badly deteriorated, but there doesn't seem to be one in this carb diagram I found last night:

The raised ring that you mention is also slightly cracked on the outside, though not inside, so I'm not sure if I need a new one yet.

Cyclone - that white and black CB is exactly the paint scheme I'm thinking, though in terms of mudguards and seats, I saw this on JobCrane92's build which looks to me like a z250 - I was originally thinking of cutting the subframe and not having a mud guard but supposedly its hard to get it registered in Australia if we do that, so I think that's definitely the way to go. I might try to get as close as that as possible - I'd be happy to get the bike running and looking nice for now - creativity can strike next time :)

Both my brakes are drum breaks btw, so yeh, the plan is to get some disc brakes on her, but probably not at this stage. Priority is to get her running first, then probably getting more familiar with riding,  then cosmetics, then upgrading hardware if required.
« Last Edit: Jul 31, 2011, 02:53:52 by sham »

Offline sham

  • Posts: 309
So, the whole don't run before you learn to walk thing, and the 'remove all rubber before you soak your carbs in brake cleaner' thing...

Missed this obvious one.

Do I need to throw it out and order a new 'o' ring? I've been using spray on brake cleaner if that makes a difference - I realize you guys must all be using something else if you're posting photos up of it actually soaking in tubs...

Feeling pretty stupid about this one lol.

Offline sham

  • Posts: 309
Just another question to add to my every increasing list. I've been reading about how people are using 'simple green' to clean their parts of rust and gunk in general, and some people have been soaking engine bits in it...

Just to clarify, seeing as I've been using this spray on brake cleaner stuff for the carbs, can I get some of that and just throw my carbs and other nuts and bolts in for a good clean? muffler too? I've read that it doesn't harm rubber, so I assume that's what people have meant when they said to just clean things like the diaphragm.

I'm looking at using Koala Kare, which I read on some bike (like cycle bikes) sites as being pretty decent. And its only $7 for 2.5L at supercheapauto. Has anyone used this before?

Anyways, I might give the CDI a go tomorrow night when I'm less tired and less bummed about this O ring business.

Offline sham

  • Posts: 309
So just a quick update, begun work on the CDI. Had to get on youtube to see learn how to solder, and after the first two or so it got alright...I think. I hope I didn't do any damage on the first couple ones, I kept that soldering iron on the lead for quiet a while. Got some advice after posting up on 1800-cafe in regards to the connectors, so I'll ask around the mechanics to see if they have a plug I could buy. Otherwise I guess I'll have to order (and wait) online.

Hoping this CDI will work. It doesn't seem too hard to put together - I was wrong about the lack of instructions, its just that its not clearly written. The only thing you need to read is the last paragraph - and the outline of the parts are all drawn onto the electronic board or whatever its called. Will try to finish it tomorrow. Anyways, pictures below.

Wasn't very good at cutting these leads off...I'm just using the cutty bit on the pliers - hopefully having them jut out so much doesn't affect its functionality?