Help CBR250RR MC22 No spark

capncookie · Dec 6, 2016

Hey Guys

I've got a CBR250RR with a no spark ( that we can see), atm in the process of replacing fuel so the tank's off and has been drained and wanted to ask for advice on checking coils, leads etc. As far as we know the bike was running before it was garaged 12 months ago after a carby service. He said at some point he tried to get it going again and it wouldnt start, I'am assuming Iam now back to square one. Also.....the wiring loom where the fuse box meets the rest of the loom was chewed by a dog. Ive managed to reconnect almost everything and with a jump pack the starter really goes for it. However there's 1 black cable that has its own slotting over the top of the radiator that I have no idea what it went to. Tomorrow I'll be getting the battery recharged and desulphated to see if it can be saved. I'll also be filling a jerry can with a litre of fresh fuel. My neighbor is gonna borrow a lead tester. Also Iam an idiot when I lifted the tank out I removed the petcock and forgot the orientation.

Tldr
Most likely point of ignition failure? ( plugs have been replaced to no difference)
The wire mounted to the top of the rad, where does it go?
Fuel valve....how does the handle orient on the valve? What setting is all the way left, vs right etc.
The old fuel....its 12 months old, would I be able to run it through my CBR500 bit by bit? Or my mums I30? Ive got about 5-6L of it :/ I'll filter it ofc.

I can upload pics of anything if you guys want. The wiring isnt pretty and I'll be replacing the loom but I wanted to try and get the bike going first before I spent $130 and several days fitting a 2nd hand loom to a bike that wont run.

GreyImport · Dec 6, 2016

Fresh fuel would be a good starting point .... but the carbys are probably going to need a clean out again after 12 months

Check this with the leads and caps .... u can test the resistance of the coils with a multimeter but simple things first

http://2fiftycc.com/index.php?threads/trim-your-spark-leads.8032/

http://2fiftycc.com/index.php?threa...eads-spark-plug-configuration-inline-4s.8176/

http://2fiftycc.com/index.php?threads/honda-cbr-250-mc22-coloured-wiring-diagram.8761/

capncookie · Dec 6, 2016

GreyImport said: ↑

Fresh fuel would be a good starting point .... but the carbys are probably going to need a clean out again after 12 months

Check this with the leads and caps .... u can test the resistance of the coils with a multimeter but simple things first

http://2fiftycc.com/index.php?threads/trim-your-spark-leads.8032/

http://2fiftycc.com/index.php?threa...eads-spark-plug-configuration-inline-4s.8176/

http://2fiftycc.com/index.php?threads/honda-cbr-250-mc22-coloured-wiring-diagram.8761/

View attachment 22182
Click to expand...

Thanks for the gems , already had the coloured wiring diagram ( its why I registered an account). Its what I used to guide me testing and reconnecting everything. Ive got all the tools and know how to service the carbs, wanted to avoid doing so until I know I can rule out spark. Also thank you for the service manual photo copy, that'll definitely come in handy when I go to test them. Thanks

Murdo · Dec 7, 2016

The loose black single lead will most probably go to the thermostat housing to earth.

Damus · Dec 7, 2016

Murdo is correct about the lone wire. If your facing the bike it attaches to the bottom right of the radiator.

How far are you willing to go with this? I can assure you get spark but it will require some bypasses in the loom.
Typically the CDI wont give spark due to the following safeties failing:
1. the killswitch circuit
2. the neutral circuit
3. the side stand & clutch circuit

The other requirements that need to be met are:
- The spark rotor must be attached and intact/not damage (under the LHS engine cover)
- The pickup sensor for the spark rotor needs to be working, the ohm's required to be in spec are within the service manual (this is measured with a multimeter at the pigtail) however I have found that most are slightly out of spec but still seem to work fine. There is a yellow wire & creamish wire that go from this sensor to a pigtail and then the pigtail goes to the TCI under the seat.
- A healthy good battery obviously, but we can ignore that because your starter motor is "really going for it!"
- There is a black/white wire that goes from the TCI to both ignition coils and then to power
- There is a blue/yellow wire and a yellow/blue wire that go from the TCI, yellow/blue goes to coil 1, coil 1's ignition leads go to cylinders 1 and 4, it should be noted that resistor caps with a 5k ohm resistance should be used just like the OEM caps have. The blue/yellow wire goes to coil 2, coil 2's ignition leads then go to cylinders 2 & 3.
- The lime green wire from the TCI needs to go to the lime green wire adapter just above the gear box.
- The dark green wire needs to connect to a ground point on the frame of the motorcycle.
- The tci black box cant be broken.

Testing for continuity on all of the above is essential to isolating the problem.
Assuming your diagnosis is correct and all 4 spark plugs are not shooting spark I would do the following:

- Get multi-meter and set it to beep when it achieves continuity.
- Turn on the key at the ignition, if all the lights come on that means power from the battery is making it at least to the fuse box.
- From here I would test the pickup sensors ohms are correct, followed by testing continuity from the pigtail to the yellow wire and cream wire at the TCI connector
- If that is okay the next step is to turn the kill switch ON and remove the "ignition" blade fuse from the fuse box 10a and check for continuity between the fuse box and the black/white wire at the TCI connector. If you do not achieve continuity at this point you will know that the killswitch circuit has failed.
- Following this check the lime green wire from the TCI to the connector at the top of the gear box has continuity.
- Confirm dark green is making it to ground
- Confirm continuity from the dark green/grey wire from the TCI is AT LEAST making it to the wires at the top right of the clutch as this wire requires to be grounded or obtaining power to the TCI for it to allow spark when the bike is in neutral.
- Confirm black/wire from TCI is making it to both ignition coils, whilst doing this confirm yellow/blue and blue/yellow wires are also making it to the correct ignition coil.
- Being that neutral bypasses the need for the side stand to be up or for the clutch to be in you can now try and start it now.
- If you still don't get spark confirm both ignition coils are within spec, again ohms and testing is covered in service manual.
- If both coils haven't blown (likely) you will have but no choice to remove the left hand side engine cover to confirm the spark rotor is intact and okay/correct.
- IF it is, then your TCI is broken and will need to be replaced.

I have left nothing out and have been as specific as I can, I have created a coloured wiring diagram you can follow within this forum, go find it as it will help you to achieve the above allot easier.

capncookie · Dec 7, 2016

Ok so I tested the primary side of the ignition coils and they were high. Doesnt matter now, turns out previous owner had botched some of his wiring and I managed to trace and fix the fault. The bike actually fired today, unfortunately we've now gone from a 'no spark', to a 'No fuel'. Carb jets look to be blocked so I'll now be tackling that on the weekend. Will have to clear my workbench and remember screw settings as I dont have a carb balancer. Is it possible to unblock the jets without removing the mixture screws?

Note, this'll be my first ever carb service, am I better off just cleaning it then sourcing a 4 cylinder carb balancer? Or hiring a mobile mechanic to just do the balancing?

my67xr · Dec 7, 2016

The Pilot's can be cleaned without removing the mixture screw's
But if it's just the pilot jet's that are blocked, then you'll most likely need to remove the mixture screw's to clear the port's at the bottom of each hole that lead's into the carbys' main bore as well
Take note of how many turn's out each one is set to before you remove it, eg turn the mixture screw's in till they just touch the bottom while counting each full turn and write it down (2 turn's out carb 1, 2.5 turn's out carb 2 etc) so when you reassemble it you can set them to what the were at.
Make sure each mixture screw has the spring, the washer and rubber seal on each one

See how it goes after cleaning them, it might be ok to ride without tuning it after

Damus · Dec 7, 2016

I want my time back!!!

With the carbs, what do you mean no fuel? More info on the behavior is needed.
If the carbs actually need to be cleaned most people will tell you to do it once properly, it's worth the time and effort if you can succeed without botching something.
One thing Kiffsta pointed out to me and a common amateur mistake is accidentally turning the idle speed mixture screw too high, it won't start/hold idle if you do that.
Also keep in mind the pilot mixture screws are not the same as the synchronizing screws, the sync screws control the butterfly's in the carbs and have nothing to do with the fuel/air.

GreyImport · Dec 7, 2016

Balancing a set of carbs is the last job on the list and if the balance screws are untouched then they wont need to be reset .... sure they may be out to start with but unless u seperate multiple carbs they arnt touched.

Jets can be cleaned using threebond and compressed air .... jets dont wear out and dont go madly sticking wire or wateva in them .... u can hold a jet up to the light and see if its blocked

http://2fiftycc.com/index.php?threads/cleaning-carburettors-using-threebond.3800/

http://litetek.co/Carb_Kit_Honda_CBR250RR_MC22.html

http://www.litetek.co/Guide_FuelScrews.html

Pilot screw will look something like this .... and this is the order everything should be in ...

capncookie · Dec 7, 2016

Damus said: ↑

I want my time back!!!

With the carbs, what do you mean no fuel? More info on the behavior is needed.
If the carbs actually need to be cleaned most people will tell you to do it once properly, it's worth the time and effort if you can succeed without botching something.
One thing Kiffsta pointed out to me and a common amateur mistake is accidentally turning the idle speed mixture screw too high, it won't start/hold idle if you do that.
Also keep in mind the pilot mixture screws are not the same as the synchronizing screws, the sync screws control the butterfly's in the carbs and have nothing to do with the fuel/air.
Click to expand...

dw man, chances are good I'll be saving that for when the ignition does die. When we cranked the engine we watched the jets and they weren't jetting fuel. The fuel hose isnt blocked so there's something going on inside the carb. Should've pointed out when we actually got the bike started, it was with deodorant ( not my idea) but propane is propane. So yeah will be buying carb cleaner and rewatching vids of people dismantling carbs on honda 4 cylinders. So whats the differential for no jetting, blocked jets? float stuck? The list goes on, it'll hopefully be sorted by a good clean. And yeah wasnt about to go sticking wire into brass fittings for no reason Will definitely be taking my time to make sure the mixture screws have their turns counted etc. Will be replacing the fuel and vaccum hoses for good measure since its all going to be out on my work bench.

Damus · Dec 7, 2016

I have to admit i find it odd that ALL 4 carbs where not providing any petrol. Regardless of if the fuel hose is clogged or not the secondary vacuum hose is required to be attached under the carb at cylinder 1 to feed the petrol through to all 4 carbs.
The floats are non adjustable and honestly the mc22 carbs are quite well built and reliable in my opinion.
If to bowls are getting fuel it literally will be as simple as cleaning them, but again the symptoms don't seem to match up with the diagnosis, for all 4 not to be working someone either seriously tampered with the carbs or they are stupidly dirty or you have missed something trivial like the vacuum hose.

capncookie · Dec 8, 2016

Damus said: ↑

I have to admit i find it odd that ALL 4 carbs where not providing any petrol. Regardless of if the fuel hose is clogged or not the secondary vacuum hose is required to be attached under the carb at cylinder 1 to feed the petrol through to all 4 carbs.
The floats are non adjustable and honestly the mc22 carbs are quite well built and reliable in my opinion.
If to bowls are getting fuel it literally will be as simple as cleaning them, but again the symptoms don't seem to match up with the diagnosis, for all 4 not to be working someone either seriously tampered with the carbs or they are stupidly dirty or you have missed something trivial like the vacuum hose.
Click to expand...

ok

Anything to make my job easier would be swell to try. The fuel was pretty nasty and was 12 months old. So best way to test the vacuum hose connections? They were connected, but if there is a blockage would it be in the connection points or in the hose itself? Will be getting new hose as the rubber is a little meh. Yeah it certainly felt like the bike wasn't getting any fuel, when we sprayed the start ya bastard substitute it fired but only appropriate to the volume of gas we sprayed. Since the bike has been barely run in that time and the carbs cleaned hopefully, I'd like to believe the bike would've at least run if not very well but at least self sustained.

capncookie · Dec 8, 2016

Also just to clarify, so Iam looking for a vaccum line from the carb at cylinder 1. How long is the line? what would be the dead giveaway for its identity? Also the vacuum line to the fuel valve, null void at this point since when we disconnected the lines it was obvious the diaphragm in the fuel pet cock is knackered by the fire hose of petrol that came out when the tank was full of old fuel. Dont suppose its possible to access the line without removing the carb from the inlets?

capncookie · Dec 8, 2016

Ok so please ignore the text before hand as Iam now far more enlightened of what is actually going on. Today I tested to make sure the jets definitely weren't jetting at any throttle. I then tried to blow down the new fuel hose into the carb. Nothing, totally sealed, and sucking produced a vacuum. Tried blowing on the fuel bowl overfill relief/return and old fuel still inside the carb squirted out at me from one of the nozzles facing up. Its now clear fuel isnt actually entering the carb due to some problem inside the carb. Iv'e now got the carb off the bike and benched. Before it goes back on will likely buy a carb refurb kit to replace washers/o rings etc and give it a good clean. Hopefully I'll be able to figure out the valve thats stuck.

jazzhunt · Dec 9, 2016

I'll be the first to recommend Litetek

http://www.litetek.co/Carb_Kit_Honda_CBR250RR_MC22.html

capncookie · Dec 10, 2016

Hey guys thought I'd give you an update. Jets were slightly clogged with gelled fuel but here's the real culprit...... the float needle valves, not only are they all sticking, but they're totally the wrong type ( they dont have the metal recess to cling to the float bowl). Rubbers are all new, but it looks like who ever did the service cheaped out and used some generic valves that would end up sticking more easily. It would totally explain why the carbs worked at first but after a while stopped working. Damus you were totally right, it was odd, and hopefully Ive found the culprit. New valves of the right type ordered for express post. Thanks guys, you can I can hopefully let this thread finally die.

Damus · Dec 11, 2016

You've done well I reckon!!! That would be the problem and you have a keen eye to spot that the float needles where incorrect, it would be easy to overlook. If you have gone this far you should do as @GreyImport said and use threebond to clean the carbs out completely, I also second @jazzhunt 's advice about getting a litetek seal kit from @maelstrom to reseal all the carb components.
I have done both of these tasks along with using components of a keyster repair kit to rebuild my carbs along with a good sync with a morgan carb tuner and new OEM rubber boot insulators. Comparing that to a bike that hasn't had this work done the difference is worth every bit of blood and sweat.

If you really want to go the extra mile I also personally like replacing the middle 2 long velocity stacks with 2 short velocity stacks the same as the outside 2 carbs and replacing the inner 2 #102 main jets with 105's. (not proven to be better)

Let us know how you get on.

capncookie · Dec 11, 2016

Thanks mate. I think what with most of the rubber being in good nick ( the exception is the carb boots, they were replaced but look and feel a bit dry, will probably leave them in a jar of boiling water to soften them up, assuming I can even remove them from the carb) I will save the rubber replacement kit for when I next service the carb. Yeah a guy Iam talking to locally said if you're gonna keep the bike it'll be worth getting a carb tuner. Also gave the carbs a clean with threebond engine conditioner, holy cow that stuff works.

So yeah replacing jets would be an interesting one. The different length tunnels weird-ed out a few people who saw them. What would be a good place to source replacement boots and the jets? Also a good price source for a morgan carb tuner if you know one

Murdo · Dec 11, 2016

For $16 why would you NOT replace them?
http://www.ebay.com/itm/331505477773?_trksid=p2060353.m2749.l2649&ssPageName=STRK:MEBIDX:IT

capncookie · Dec 25, 2016

Ok so since there's few other threads active and I cant close/delete this one thought I might as well use it. GOOD NEWS EVERYONE bike runs, runs very well actually, 2 idle jets *were* blocked, boots were replaced and everything rubber was resealed using silicone grease.

All the electrics work but before I take the bike out I have a slight issue. During run up I noticed the temp gauge needle did not move at all. I'd like to be able to know how hot the bike is in the event I have to replace the thermostat. Also note the thermo switch ( the switch that controls the radiator fan) the terminal was corroded and broken off at some point ( hence I found the wire loose when I went about fixing the wiring the first time round.) So I grounded the cable to keep the fan on 24/7 ( 35'c days atm not too worried about bike being too cold). A temporary solution. My plan is to;

go looking for stats for the sensor

test wiring to and from gauge and sensor to make sure there are no breaks.

Check terminal connections for corrosion ( already diagnosed and replaced a bad indicator crimp)

Failing to find it a fault I'll drain the coolant, get new fluid, thermo stat ( replacements that work are dead cheap http://www.supercheapauto.co.nz/Product/Tridon-Thermostat-TT239-180/7838

if sensor checksout and thermostat is replaced I'll refill and dismantle/replace temp gauge

But I'd just like to establish how the temp gauge actually works. Ok so thermo sensor is a variable resistor that changes based of temp. The hotter is gets the less resistance it has, so higher current powers an electromagnet and moves needle. So its getting its current based on the sensor and how much current it lets through to ground. Is it possible sensor isn't being grounded? Does the thermostat housing have its own path to ground? Is it a wire or a bare metal mount to chassis?

Am I talking out my arse...again or am i on the right track?
Iam assuming i can test the gauge by shorting the wire to the sensor to the chassis to cause 0 resistance.

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