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Another newbie with questions

Posted: Wed May 16, 2018 2:30 pm
by BSir
Hello everyone

New owner, new biker really. Currently awaiting the opportunity to go and do my tests and get the full licence, so I can move on from my CBT/L-plates on my existing CBF125 :smt003

I picked up a my ZXR400, as project bike, in boxes, a few weeks ago, as I like the character of these classics. Yes, the bike was pretty much in boxes, the only thing not boxed was the frame and fork/wheels attached. So they were duly dismantled and loaded into a borrowed 4x4 shocking

Anyway, it is G reg, 1990, just under 21000 kms. It was advertised as a H1, but the VIN number site shows it up as a H2 ? confuddled

I decided to take the opportunity to do a massive restore/rebuild job, so I can learn about this bike, and bikes in general, with the help of my neighbour, who is pretty handy with bikes and mechanics as he's played with bikes for about 40 years. (Pics of the progress will be posted up soon :) )

The frame and a few bits have gone off to be cleaned up/aqua blasted, then powder coated to the factory looking silver/aluminium colour. The wheels have been stripped and resprayed Kawasaki green, all new bearings, tyres, valves, etc. The calipers have also been completely stripped and new pistons/seals, etc. installed with new SPS pads and branew new HEL braided hoses (2 hose set up on front instead of using the splitter) purchased.

Been working on the engine the last few days, sump off, completely cleaned and sprayed up, all the bearings, etc inside look clean. So will clean up the rest of the engine, spray it and then new gaskets all around.

While donig this, I checked the thermostat and sender unit housing, and it looks like the bike may have been run with just water in the past :smt018 , as there was dry white powdery bits at the point where the hoses were connecting to the housing. So the bits were removed, and I have cleaned that up, but I discovered the hose that goes from the water pump to the radiator is cracking, so I really want to get new hoses (which I was planning to get anyway).

But this is where I am stuck.

The radiator I have is the curved one - is that the correct one for my bike ? Some sites seem to say the flat one is the correct one ? Just need to be sure whether I need get the 3 hoses (1 small, almost 90 degree hose, then the one that's like a flat C shape, and finally the one from the water pump to the rad ?

Samco seem to do sets of hoses for ZXr400, but it says 'Not for H2 model' on their site, and no other option for H2 :smt017

Any H2 owners have pics of how the radiator is mounted and hoses (if possible) so I can compare please ?

Re: Another newbie with questions

Posted: Wed May 16, 2018 4:07 pm
by watsonm359
Hi and welcome,

Firstly, the curved rad is the correct one for an H2 model which is better as it has a larger surface area and is easier to both check and top up if required. The H1 has a rectangular shaped rad and is much smaller, however the pain with the H1 is that in order to check the coolant level you have to remove the tank and air box. The radiators are interchangeable between the two models, but the hoses are different and the H1 requires a number of addititional part for both the rad and the oil cooler to be fitted. The oil cooler on the H2 will only fit an H2 rad as it connects directly to it, whereas the H1 oil cooler requires brackets to be fitted to the upper engine mounts.

Basically, you are better off sticking with the rad you have.

You can still pick up a new hose that connects the water pump to the rad for the H2 and Samco do not manufacture a set for the H2. The hoses between the H1 and H2 are different, although I'm unable to confirm if the one you are after to replace the cracked hose is the same as a H1.

Hope this makes sense!

Good luck with the resto.

Re: Another newbie with questions

Posted: Wed May 16, 2018 4:57 pm
by BSir

Thank you for the reply and information. Good to know the H2 rad is the better choice to have, I just wasn't sure if I had the right bits.

Here is a pic I had taken of some of the items the day I picked up the bike...does the rad and the fairings look correct for the bike ?


So I fill up the rad on the top left corner where the cap fits (when looking the bike from the front) ? Do the fairings/tank not need to come off to be able to access that cap ?

Re: Another newbie with questions

Posted: Wed May 16, 2018 7:57 pm
by Ewetea
The radiator cap is accessible without removing anything. Does the bike have a speedo in KPH, and is there no side/headlight switch on the right hand clip on? If there is a "yes" to these, the bike is likely to be an import. That means the top speed is restricted. Check the speedo for a pink wire, which connects to the CDI. That will limit the bike to 100mph. There are several ways of sorting this: a small blue gearbox which is inserted between the speedo cable and the speedo. This gears down the turns of the inner cable so that the KPH speedo will actually read MPH, increasing the top speed. Another method is using a little electrical box of tricks to which the pink wire is connected and somehow it prevents/reduces the signal to the CDI. There is also a thread on this site which shows how to install a resistor in the loom to defeat the effect of the pink wire, and another showing how to open the speedo and remove the tab that activates the CDI. Or you could get a MPH speedo and an unrestricted CDI with a letter L or M which will allow full power. Since the bike is 30 years old it would be a very good idea to check the wiring loom as there could be some corrosion/degradation of the copper wire. There are a lot of threads in which members have experienced problems with the white wire, which supplies power, and the regulator/rectifier. But there is also a manual on the site which details methods of checking the various electrical components. It also has "small" wiring diagrams for specific items, like charging/ignition/lighting etc, which saves time trying to trace wires on the complete wiring diagram.
This is an excellent way of learning about the bike and I will be interested to see a few photos of the rebuild. For any more problems you may encounter, do use the search box at the top right first, before starting a thread. Others may have experienced the same problem as you and so the answer may already be there.

Re: Another newbie with questions

Posted: Fri May 18, 2018 7:06 am
by BSir
Thank you for the info Ewetea

The speedo is definitely in KMH, but I have bought a MPH one (from a L model, hope it will be a straight swap).

I took a look at the wiring loom and this is what I believe is the CDI ? If so, no markings apart from something along the lines of ZXR400 H written with marker pen, faintly visible.


Looking closely at the wiring loom, I did find this pink wire.


Is that the one you are referring to ?

And will this be a straight swap or do I need to do anything else anywhere ? Not looking to race/track bike, trying to restore as closely as possible to original, with a few subtle 'updates' :smt003

Re: Another newbie with questions

Posted: Fri May 18, 2018 9:25 am
by Ewetea
This should show the difference between the two types. As you can see you have an H cdi, with the pink wire. I'm not sure if the wires from the MPH speedo will trigger the cdi. Have a look at the H and L wiring diagrams to compare the destination of each wire.

Re: Another newbie with questions

Posted: Fri May 18, 2018 9:30 pm
by watsonm359
A minor point ref the radiator cap on a H2 is you will need to remove parts to get access. Nothing massive and will involve just one screw and disconnecting two electrical joints. On the right side of the frame sat just above the radiator cap is a bracket that is bolted to the frame spar. This bracket serves two purposes:
1. It holds the throttle cables in place where they pass under the frame.
2. It holds the wiring loom that comes from the R/H/S switch gear in place where it then connects to the main loom by means of two electrical connecting blocks.
Once these have been disconnected and removed you will then have access.

The main difference between the H and L model CDi's is with the left side connection which on the L has 6 male tabs, where as the H has only 4. This can be seen in the picture.