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

sham

New Member
Been sketching over these pics of the frame with and without the tank, just seeing how things might come together...might scan some of them when I get the chance - the frame kicks up quiet a bit at the rear, which doesn't really let me do flat seat seat...


 

sham

New Member
It Sparks!

Yep - finally have a (small) but consistent spark everytime I hit the starter =)
All thanks to a super kind German eBay seller...
Awesome.


However, one of the wires is missing a terminal, so I'll need to get another one. I'm not a fan of crimping.
And I did break another 6 pin connector in the process (I accidently locked the wires in the wrong way and again couldn't get it out without (less) excessive force)
And I split one the rubber protection on one of the wires while crimping, so will have to electric tape that...


But all in all - very excited.


Time to clean up the tank and see if will finally start. Slightly worried that the spark looks a bit weak - I remember being told that it would be a noticeable affair, while mine was a little blue thing fizzing at the end of the spark plug...I've been reading up how to de-rust the inside of tanks on DDT, but I think mine's more surface rust, so I don't really want to go into the whole hydrochloric acid process and then have to recoat the insides. Might give the vinegar a shot again.


Another thing - my air filter is rubbish - the "sponge element" as the manual calls it doesn't exist, so I am tempted to go straight for a pod filter. Found this online for what I think is a pretty reasonable price? 9 pounds, not sure how much for postage.





I'll have to rejet, from what I've been reading, but someone in the KZ forums had narrowed it down to 2 sizes and it seemed to work, though they seem to have disappeared...


Anyways, very excited. Now, can anyone tell me if its ok to use 35V 20A fuse? Or do I have to have 250V - I don't believe the manual specifies. I'm running a 12V battery.


=]
 

Erskine

New Member
Mate I can't believe you're going to pay so much for a cdi box, have a look at the chinese 250cc bike and quad spares and I'm sure you'll find something for a tenth of the price. So long as the pulser is sending the signal out, the cdi will take care of the rest, just need to be wired right.
 

sham

New Member
I ended up paying 180 Australian for mine. Thought it was already pretty cheap for an original part.

I saw those Chinese ones, but after what I went through trying to build my own only to have it pointed out to me that the bike doesn't use a CDI bit a TCI, it all got a bit too complicated for me.

Have you tried these Chinese ones?
 

Erskine

New Member
sham said:
I ended up paying 180 Australian for mine. Thought it was already pretty cheap for an original part.

I saw those Chinese ones, but after what I went through trying to build my own only to have it pointed out to me that the bike doesn't use a CDI bit a TCI, it all got a bit too complicated for me.

Have you tried these Chinese ones?
Yup I've used a stock one and a race one. No probs at all, the magic pixies do what they are meant to. Spark'n'bang.
I did not see any benifit from the race one until I fitted a k&n type filter and and faster action throttle, then the engine picked up very cleanly from slow throttle and stopped hesitating/bogging.
Btw I am still running completely standard jetting and getting very healthy plug chops.
 

sham

New Member
So to clarify, you have a z250 and the chinese "CDIs" worked fine? LOL...that would be fail on my part...and you didn't have to rejet your carbs to use the pod filter?

I do have a question but - I'm looking at the space between the carb/airbox boot and the frame/seat and I don't see how the air filter can fit? I'll have to get its dimensions and have a bit of a measure but it doesn't look quiet possible without some sort of a mod.


Oh and would anyone be able to describe how "big" a normal spark should be? Mine's seriously this tiny thing coming out from the centre of the spark plug - when I "hot wired" the bike earlier, the spark was huge...like came right out...I can't try starting this thing until I clean up the insides of the tank...
 

Erskine

New Member
sham said:
So to clarify, you have a z250 and the chinese "CDIs" worked fine? LOL...that would be fail on my part...and you didn't have to rejet your carbs to use the pod filter?
Nope, crossed wires here ........... I'm running a generic single cylinder Honda engine that has CDI.
The CDI units are just components rated to different cylinder capacity ranges. If your engine had used a true CDI system you'd have been able to have found a unit that suited for very little $. With small capacity 4 strokes quite a few people have found that they've ended up leaning the carbs after fitting pods, strange and counter intuitive, but true!
 

sham

New Member
Oh right yeh. I had a lot of issues with the ignition trying to get a kit CDI to work and it wasn't until PJ or Teazer pointed out that it wasn't a true CDI that that kinda all made sense. So yeh, supposedly the HEI module would have worked but I was satisfied with my foray into electronics to not feel the need to go there lol. And yeh from what I've heard the 250 will need to be rejetted. I'll need to measure the space too. I'm dubious that it will fit, thought that's from imagining how big the pod actually is lol.

Do you have a build thread? Be interested to see what you've had to deal with.
 

sham

New Member
I'm too pussy to pull out the loom yet...maybe another time - I liked your inspirational curves but lol and its looks like its coming along nicely.

Well just a small update - the tank was cleaned of rust just using white vinegar and allowing that to soak for the night - I probably should have put a couple bolts in there to help scrap off some of the rust along the bottom, but I used a high pressure hose and that seemed to get most of it off. Rinsed it with bicarb to neutralize, followed by meth and a 2 stroke and petrol mix before running petrol through it a couple times. I was really impatient to get it hooked up to the bike to see if it would start, so after a couple rinses I put it all together, but no start...instead I got a kind of gassy puff sound (in my mind similar to that of a plane going mach 3 or something, but obviously to a much lesser scale, just the picture of the puff I guess) coming out from the exhaust.

Shortly after that, I hit the starter again and it literally sounded like something inside the engine broke, or a loose bolt fell and hit the frame, but it was a loud clatter, so I stopped. Haven't opened up the engine to see what it was, but it didn't seem like a bolt or anything to me...

Here is the video - I've also posted it up on 1800 cafe, but if anyone would have any pointers as to where to look I would really appreciate it.

http://s1139.photobucket.com/albums/n560/shamjay/?action=view¤t=4616e55e.mp4
http://s1139.photobucket.com/albums/n560/shamjay/?action=view¤t=3703fb78.mp4
 

sham

New Member
Ok so after some suggestions from kz forum, I've found one reason which may contribute to the fail starting. The fuel level in the float is too low - the recommended levels from the manual are 2.5mm ± 1mm below the bowl. Mine started off at 5mm. To fix this I was suppose to adjust the tang, the issue is I seem to have the wrong tools and have been making it worse...

I adjusted the tang twice, moving it towards the valve (wrong) and then away from the valve (right), however, the fuel level was getting lower and lower each time. I have a feeling this is because of pliers, that I must be inadvertently pushing the point of connection between the tang and needle towards the valve as I've been adjusting.

Can anyone suggest how they've been doing this?

 

4eyes

Active Member
DTT BOTM WINNER
Kudos on having the courage to learn by trial and error!
On the plus side, your spark looks good. On the minus, I wish I were there to help with the carbs. ;) Do you have a fuel filter between the tank and carbs? Schmutz will keep working its way out of your tank, and muck-up your nice clean carbs. Thus making your efforts to set float levels......difficult.
Have you pulled the valve cover to see of the valves are opening properly? That may account for the "rattling". A loose timing chain, or a dropped valve.
 

sham

New Member
Thanks 4eyes,

Think the others were right when they said the noise was from the starter motor - has happened again once or twice but it doesn't seem to be an issue. The real issue now is getting this fuel level right, and whether I adjust the tang up or down, the distance just seems to be getting bigger and bigger. Its been suggested that I reset them but I'm not sure what the dry float height is meant to be - the only thing in the manual which might be it is the "design fuel level" (?) which is 33mm.

Rather frustrated, though I did find out how to adjust the tang - there is a good diagram here : http://www.salocal.com/sohc/tech/carb/asmpg_mgs/adjsttang.htm

I was worried I would ruin the tang by using it as a lever but that gave me some confidence.

Anyways, just trying to figure this out now. My fuel level, according to the clear tubing test is 25mm beneath the bowl at the moment...

I'm not sure what a fuel filter is to be honest, but there doesn't seem to be anything between the tank and carbs - only the petcock? The valve I'm assuming you mean relief valve, which seem ok, though tell me if there's another kind lol.
 

Erskine

New Member
If you fit an in-line fuel filter, make sure fuel can actually get through it, and it is not one designed for pressurized/ pumped fuel flow rather than gravity feed. Or one that creates it's own air lock.
I spent a few annoying hours twice trying to remedy a problem that turned out to be fuel starvation caused by a selection of in-line filters I'd fitted. :(
 

4eyes

Active Member
DTT BOTM WINNER
What Erskine said. ; )

And don't worry about getting WD-40 on electrical stuff. That was part of what it was designed for Water Displacing-40. It works better at that, than as a penetrating oil. (I prefer "Liquid Wrench" or "PB Blaster" for that role).

The valves I was refering to were the intake and exhaust valves in the head. But if the starter is where the noise was coming from, don't bother with them now.
 

sham

New Member
Don't think I have any filters in that case - just a petcock I think. The flow out of the tank is fine, its just that the fuel isn't drawn through the carbs, so once I fix the tang/float levels I'll probably have to look into the jets and stuff again. Mightn't have done it right the first time.

I know they sell PB Blaster down here, but the distributer doesn't open on the weekends which is a bit of a bitch. Don't really get that much time to work on the bike, or go down to the shops apart from then. Hopefully get more done this weekend.

It was suggested that I could start using water instead of fuel, which would definitely save on time and my health in general. Thinking of just funneling some water into the carb from the fuel line and adjusting the tang that way. Should I be worried about rust or anything like that?
 

Maritime

Well-Known Member
use a piece of plastic card and cut it out to the height your float needs to sit, remove the float bowl and adjust without using any fuel at all. Saves a bunch of headaches. There is a "how to" on the site somewhere but basically you take a pisce of card, like an old credit card, wide enough to go across the carb bottom, then cut a float sized rectangle into it at the desired height. then adjust the tang until the card will pass under the float without hitting it and with little or no space.

Pic
 

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Erskine

New Member
sham said:
It was suggested that I could start using water instead of fuel, which would definitely save on time and my health in general. Thinking of just funneling some water into the carb from the fuel line and adjusting the tang that way. Should I be worried about rust or anything like that?
Are you sure they are not taking the piss?

Top tip there from Maritime, I shall remember that one.
 

teazer

Well-Known Member
DTT BOTM WINNER
S T O P

Use the clear plastic tube method. It is really the best way. Forget everything else you have read about float levels which are not the same as FUEL levels. They are related but they are not the same. Focus on one method - fuel in the tube, aka "wet".

In your case, you want top raise the fuel level and that means raising the floats and to do that the tang has to be bent down towards the floats to allow the float assembly to rise more. You don't care what distance the floats are from the gasket surface, but to riase fuel level, the floats will be closer to the gasket flange.

Do not use water. Use petrol and do it in a well ventilated space and wear nitrile gloves to stop your hands from smelling forever of stale gas.

You do want both floats to be at more or less the same level when you eyeball them.
 
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