Hi everyone, I just picked up a 1988 FZR250, a 3HX1 model according the frame number. It has the 2kr carbs, but exup and a different CDI, which seems like it's the worst of both worlds for part availability. I've been trying to get it to the point where it can run before ordering carb rebuild kits and other things it needs. However, it has no spark. I have used other threads and tried to test most of the recommendations. Here's what I've done using a 12v car battery for now. Cleaned up the the kill switch and starter switch to get the starter to work. After that, the fuel pump and the exup valve both came on with the key. Coils test good (~3 ohms on primary, 14k secondaries), two plug caps were bad, but fixed now (reading ~10k ohms). I got new spark plugs too, no change. I tested the reg/rec, it seems to do what it should, also cleaned up the grounding point there. The three white wires that go to the reg/rec all measure 0.6 ohm between one another The battery to the engine ground is good, I can't remember if I checked any others. There's 12V reaching one post of each the coil primaries, which seems to be correct, but no hint of a spark on either of them. The only other modification is that someone has made their own switch for the thermostat, which is currently disconnected. Is there anything else I'm missing before I cut the CDI open and look for failed components? I'm not sure how great my test of the pickup was, is there a way to tell that it is passing a signal to the CDI? If that is unsuccessful, what do I do for a CDI? This is the 3hx-82305-00 model, which has most of the wires of the 3ln cdi, but no bullet connectors. Could I somehow use one of the aliexpress 2kr cdis as the one that runs the bike, but plug in this CDI for exup? Or ignitech at this point.
Did u check the plug leads ? .... the wires can become corroded where the caps screw into the lead Pinned - Trim your Spark Leads | 2FIFTYCC.COM - Home of the Quarter Litre Pinned - FZR250 2KR TCI Testing | 2FIFTYCC.COM - Home of the Quarter Litre
Yes I had to take the two bad caps apart and clear the corrosion, one from the spark plug end, one from the wire end. I trimmed the wires when putting them back together and tested that I could read the 10+10+14k ohms from one plug cap through the coil to the other. My CDI has 5 pins instead of 6, and I don't know what v.b, f.p, and s.s mean to match them to mine. For the things like coils/ground that are in the same place the readings are similar. Edit, actually they aren't similar, I get an unstable reading from coils 2/3 to ground, ~5 M ohms from 2/3 to 1/4
3LN ( EXUP ) CDIs have a different pinout to th 2KR ones, but they share the same plug. This I'm 95% sure on as I tried/ am trying to swap exup into my 2kr. Although some 2krs had it from factory? Not certain about that, mine didn't so i never looked into it super hard. If you can get some clear photos or make a diagram of the current CDI part number and what colour wires go to what pins on the connector and maybe even the same for the wiring harness side, I can compare it to my notes. If someone has just plugged a 3LN cdi in it probably won't work. Another thing, can you hear the EXUP servo priming and spinning open then closed when you power the bike? Sent from my SM-G991B using Tapatalk
Yes exup consistently primes with key on. This seems to have been a factory install, there's another thread with someone with the same thing of a later 2kr with exup, and it's on the FZR info site too I think. The CDI seems to be factory, it matches the part number for this year and model, and is a weird hybrid of the 2kr and 3LN. Here's the wiring, I'll see if I can figure out what the two unknowns are based on the wiring diagrams.
And just to add, I realized the white red / white green are the pickup, and it measures 230 ohms coming from the stator, which seems normal
I was going to suggest checking the pickup coil. Failing that, check the safety circuits - clutch and side stand. Some models will still crank the engine but provide no spark when the safety cutouts are active.
Ah well there goes my main idea. Maybe worth double checking the CDI wire colours don't have any mismatches with the harness? Although it sounds like it's okay. New spark plugs might be an idea too especially if it's got some ks on it, never hurts. Sent from my SM-G991B using Tapatalk
It looks like there's no sidestand switch until it gets to the 3LN1 model, and the clutch switch works, I need to find where those wires end up and check they connect, but so far nothing concerning.
You've covered all of the other bases, good troubleshooting methodology. Check and double check the pickup connections - we had @gregt recently dealing with a no spark condition on several TCI boxes and it turned out to be the plug connections into the TCI box.
ive heard rumours of an extra cutout in the back of the speedo? a speed limiter or something? not sure which model has, or doesnt have though. hey, its the oddball variant, the in-betweener... probably has everything! ive always trended towards depopulating plugs, and giving all the terminals a bit of a squeeze with pliers, make sure theyre all tight and biting into the pins when re-assembled.
Trace your wires and ensure there are no breaks or high resistance connections. Pickup coil to TCI unit, TCI unit to coils, TCI unit to tacho, etc. Ohm out the wires one at a time to make sure they are good (with components disconnected, testing only the wires themselves). If suspect, run a temporary bodge wire. Repeat until you find the problem.
Thanks everyone, I was testing the pickup by checking ohms between the two connector pins (both wires and whatever they're connected to in the pickup itself), is that enough to rule out the pickup as an issue? I think I was getting 200ohms I tried the TCI to coil connections, all seem to be okay, no more than an ohm or two. The one thing I haven't tried is the tach. Which wire goes from the tach to the TCI? I have brown, grey, black, green w red and blue coming from the tach wiring harness, the only one I can find that traces back to the TCI is the black ground, and it was fine, around 2 ohm I think. I think generally I don't have a perfect understanding of the TCI inputs/outputs and where they're coming from. I understand the pickup signal is coming in on the white/green & white/red wires, but in the in the 5 pin harness, my current understand is: orange wire for 1 coil (output, both has 12v at the coils), grey for coil 2 (same as orange) - are these what the TCI cuts power to for spark to occur? red/white - not sure what this does, maybe gets signal from the kill switch (is this actually an earth connection when the kill switch is on?) black - ground, works blue/white - not sure - in the wiring diagram seems to go through a circle that might be the water pump fan motor? I think I've now thoroughly confused myself looking at the wiring diagram, In summary, how do I test the tach? Then where are the blue/white and red/white going? Is it through a relay I need to test?
The TCI unit gives the coils 12v for a brief moment each cycle to charge them (dwell time) then abruptly cuts that voltage to generate the spark - you have 12 volts at the coils, therefore consider that part satisfied. You've got continuity through the stator pickup - it's the connection from it's plug at the TCI - the smallest amount of verdigris at the plug could be an issue. The suggestion of @gyro gearloose to give those connectors at the plug end a slight squeeze/tweak is a good one. TCI units are generally very reliable - if anything fails it's usually the driver transistors which are responsible for the coil/spark generation. We've got a thread on here about them. The driver transistors are fairly well easily accessible and available to replace, but don't go there right now. The TCI unit as a whole doesn't contain a lot of components, I have actually been through mine and replaced all of the electrolytic capacitors. What sort of condition was/is the plug from the rectifier/regulator like? Are all of the bulbs in the dash working? Earth connection(s) clean and tidy at the frame from battery. Did the previous owner/seller give you any hints about what happened when it stopped running, or was it just left for an extended period of time then unable to get back to running? There may be a clue there. I don't know the colour coding of the rest of the wires as I've never needed to delve into tracing the wire(s) and their colours. I am thinking safety interlocks, clutch switch, side stand switch and neutral switch?
Spark is present! I'm worried the only reason was that I wasn't cranking it hard enough (I was just giving it little bumps of the starter) which is a possibly embarrassing reason for no spark (maybe also there's a minimum crank speed detected by the TCI?), but maybe also going through all this fixed something? One can hope. I did however make a couple other changes at the same time, like connecting the fuel pump, plus the water pump connector that had been disconnected. I will now pull the valve timing cover off to verify the timing is actually okay and that I don't need to do a valve job or distrust the rest of the engine.
Regardless of if there was a problem, it's always a win to get more familiar with your machine... Sent from my SM-G991B using Tapatalk
Valve/cam timing is a visual check at the LHS end of the cam - I have a feeling (not an actual verified fact) that if a cam were one tooth out, depending on direction that the motor would not turn over due to valve to piston contact. Yours turns over, consider that check to be a peace of mind confirmation. I wrote a howto on valve clearances ages ago, I prattle on a bit and would probably re-write it a little differently now, but it's methodical and accurate. https://www.2fiftycc.com/index.php?threads/fzr250-zeal-fzx250-valve-clearances-howto.1697/
Definitely good to know how it all works, now if it stops sparking again I'll know all the places to check, and someone in the future reading this should too. I'm guessing I'll have to figure out a bit more for the turn signals, but we'll see, the signals on my old Honda only worked properly when the engine was running. Thanks ruckus, I followed your guide just to be sure, the timing was good and valves were within spec, maybe a couple getting close to tight, but I think I'll try getting the carbs rebuilt first.
