New development. Massive backfires but no starting. - Update

[Visitor Q]

Further to this thread there are new symptoms.

Bike now refuses to start. If the starter is held down (clutch in, lights off and with choke on) the engine does not catch, then after about 40 seconds there is by far the loudest backfire I've ever subjected my ears to.

The fuel pump is making weird clicking/solenoid noises, and the generator/stator area is just making whirring noises.

This is following the bike only running on full choke the other day, then running rough.

This to me seems like a fueling problem, but I'm not certain how to go about with it. Also the sparkplugs are a bit ancient, reckon that could cause all of this?

By the way, I'm not really that lazy. I'd love to fit all kinds of new things, but the way lack of any access makes most jobs a complete ballache. I just don't fancy tearing off the airbox and carbs just to change throttle cable or sparkplugs etc, especially as the thing invariably doesn't work afterwards.
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[Barry_M2]

Sounds like you have no fuel getting to the carbs.

The fuel pump will get louder and make clicking noises when there is no fuel running through it.


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[Visitor Q]

Will have a look at pipes and such. Really hate diagnosis

As for sparkplugs, a full set for mine is like 25 quid. It seems like an utter ball ache but I'll give it a go to rule it out.
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China traffic/travel bike vid - When I make a sweeping statement, please add the word 'statistically' in to the sentence before you bitch...
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[Itchy]

£25 for spark plugs? , sparks for a CBR are NGK £2.20 each, the ball ache is getting them out, tank off airbox off, then you can get to them.


I wonder if the CBR will take the NTV fuel pump bodge , ie if the fuel pump on the NTV goes you can disconnect the pipe and lead it into the carb and it runs ok if a bit rich.
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[Visitor Q]

Haha, you're all going to call me sucker now, but I just bought 4 Iridium ones for £30 delivered.
Considering EVERY normal spark plug on fleabay was £5 plus, and the sets of 4 were £25 plus I figure for the extra fiver. Treat the bike (even if it is a placebo) since I've omitted even checking them for 3 years

Just checked haynes and its adamant its a 1 spanner retard job. I could never see how you'd get to them so assumed it was a sod.

Ah well, post is still working fine so will whack them in asap.

Also haynes mentions nothing about how to drain float bowls. They don't exist apparently. And to get the carbs off is an utter swine, I remember it vividly from de-restricting it.
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China traffic/travel bike vid - When I make a sweeping statement, please add the word 'statistically' in to the sentence before you bitch...
From September 2014 to January/February 2015 I will not be using any English, nor reading any. As such, I won't be on here. PM at will, but I won't be checking/posting unless in emergencies. Certainly not for the first couple of months. Please berate me savagely if I break that rule...

[metal ken]

If you find the pump is working i would check if the Spark plugs are wet once you crank the engine over a few times.

Then I would check the plugs are sparking properley, Take them out & put them against the engine with the ht lead attatched and they should spark when you crank the engine, this will test the coils and leads aswel.

Check the feul filter aswel, make sure it is not blocked.

Good Luck, Ken
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[Visitor Q]

[Visitor Q]

[sickpup]

Remember I asked if you'd ever changed the fuel filter, are you sure you have and if so how long ago?

Fuel tank>Fuel filter>fuel pump.

As your bike doesn't have a vacuum tap either the fuel filter is blocked (or you've gone on reserve) or the tank is as if fuel was getting to the pump you wouldn't be able to hear it.

Disconnect the line from the fuel filter to the pump and see if any fuel comes out.

[GSXR_Warrior]

My GSXR was doing exactly the same a couple of days ago. Sure enough a change of plugs sorted it out.
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[Visitor Q]

[Visitor Q]

Found one for £7

Will check tomoro to see if it flow alright or not, as thats my last £7 in the bank


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China traffic/travel bike vid - When I make a sweeping statement, please add the word 'statistically' in to the sentence before you bitch...
From September 2014 to January/February 2015 I will not be using any English, nor reading any. As such, I won't be on here. PM at will, but I won't be checking/posting unless in emergencies. Certainly not for the first couple of months. Please berate me savagely if I break that rule...

[hmmmnz]

im gunna say what i always do when shit like this happens,
check your valve clearances/.
every one ignores doing them, as they think its a hard job, or are too scared,
buy a 5 quid feeler guage, leave the bike over night, whip the tank ect, plugs out and remove rocker cover,
then its just 10 mins work to check,
(write down all your clearances) and if all is good and clearances are with in spec, then all good,
if not, then it'll be time to get new shims,
the number of times its the root of evil .....

although i think its just a fueling issue, but may be not
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[Visitor Q]

[D O G]

Hmmmz lives in NZ, so unlucky.

What we need is a stikied thread written by someone who knows what they're doing (preferably Sickpup) on trouble shooting poor running, and correct setup and maintenance of fuelling and ignition.

Since it seems to me (and I would have thought is fairly true), that these are two major aspects of poor running. Other bits like top and bottom ends make noises which you can hear, but fuelling and ignition affect the quality of the bike's running, including most starting problems.

You know, like a checklist as to what they would do if someone brought the bike to them with a starting/poor running issue. I think it would be so helpful, and stop the wasting of shitloads of time and money (like I did) of the people like me who have a poor knowledge of how to diagnose and isolate a running problem.

Oh, and posting in the thread should be restricted to a select group of people (maybe 5 on here) to preserve its quality.

Unlikley to happen, but it would be marvellous.

[sickpup]

[Barry_M2]

[Visitor Q]

Right. Quite pleased with my diagnostic foray earlier;

- We have a good spark.
- Took out all plugs, will be replacing them but asides from looking old and a /bit/ oily. Look exactly like the 'normal' plugs from Haynes.
- Fuses are fine, no (visible) breaks
- Fuel is getting through the tap
- Fuel is getting through the filter at full speed
- Breather pipes etc are not blocked, cracked etc

- Pump didn't pump (into a jerry can) when still hooked up and the starter was pressed, yet pumped fine (quite impressively even) when hooked up to the battery...

So either that (^^^^) is normal, or it's something to do with the wiring to the fuel pump?
In which case why is the generator making mental noises too?

Oh and with the full tank and the on main full the bike did originally try to catch, could hear it doing the normal cold start chugging. Then big backfire and nothing but electrical clicks/whirs.


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China traffic/travel bike vid - When I make a sweeping statement, please add the word 'statistically' in to the sentence before you bitch...
From September 2014 to January/February 2015 I will not be using any English, nor reading any. As such, I won't be on here. PM at will, but I won't be checking/posting unless in emergencies. Certainly not for the first couple of months. Please berate me savagely if I break that rule...

[m0l0t0v]

Checked for fuel in the carbs yet?
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[sickpup]

Bypass the fuel pump relay.

The relay is a switched supply which closes on a signal from the CDI when it is producing a spark.

So take off the relay and check the plug with a multimeter. There should be 3 wires. one wire should have continuity to the fuel pump, one is a switched live that only works when the engine is turning over and one is a neutral. Any other result and you have a wiring problem. If it all checks out its the relay.

[Visitor Q]

[Timmeh]

When I first bought my CBR it was doing exactly this.

Turns out it was a blocked fuel filter and also an air leak past one of the carbs.

HTH
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[Visitor Q]

Righto.

Replaced the fuel pump cut-off relay.

No joy. Still does the same thing. Would even try to catch this time and the alternator/generator is making a lot of noise. I don't know if it's normal (and the engine noise would block it out) or a symptom.

Either way, can someone please give me a clue as to how to use the CDI to check;

The wiring from fuel pump to relay
The relay
The CDI/Wiring

I'll love you forwever. G'wan, it's Christmas.
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China traffic/travel bike vid - When I make a sweeping statement, please add the word 'statistically' in to the sentence before you bitch...
From September 2014 to January/February 2015 I will not be using any English, nor reading any. As such, I won't be on here. PM at will, but I won't be checking/posting unless in emergencies. Certainly not for the first couple of months. Please berate me savagely if I break that rule...

[Robby]

Remember that around 90% of fuelling problems turn out to be electrical.

So, quick check for fuel getting to the carbs - open up a carb float bowl drain screw, and see if some fuel comes out. Should be about an eggcup full in each carb, and most bikes I've had will run for about 200-400 yards with what's in the float bowls. So it will start and run for a short while.

No fuel there? Carry on with diagnosing the fuel system upstream of the carbs.

Another branch is the electrical system. If you're getting a flat blue spark on all four plugs, you can expect that this is working well.

Still no life? I'd be looking at valve clearances. Depending on which way they tend to wander on your bike, they will either make the valves open less, meaning less air and fuel getting into the combustion chamber, or they will make them open more, resulting in low compression.
I think on your bike they will tighten up - meaning the open less. Combine this with a closed throttle and you don't have a lot filling your cylinders when you try to start it.
A compression test never hurts as well, if you have a tester.

Gypsy option, just for you. Hook up a car battery and crank it for ages. See if it catches.

I've had a couple of hondas that showed similar symptoms. One was my old NC24, it was just a dog. The other was my CB250RSA, which I also never fixed. Looking back I think it was the valve clearances, and the knackered battery didn't help.

Final thought - stop putting the airbox back on, you'll just be taking it off again. Faults like this always take ages to sort. In the end you'll have knocked the killswitch.

[Kickstart]

Hi

Not sure on the exact layout of your bike, but as a quick try take off the fuel tank, and the fuel pump. Connect some fuel pipe to the carbs fuel intake (or just use the pipe from the pump to the carbs), put a small funnel in the end of it and put petrol into the funnel. Then try starting the engine. If it fires up then you know the problem is the feed for the fuel from the tank (ie, pump or its circuits).

The pump is there as the carbs are higher than most of the fuel tank. If the pumps is dead then as a very short term bodge you could probably remove the pump from the feed, run fuel pipe directly from the tank to the carbs and run the bike with the tank brimmed (just be aware it will probably stop running when there is still 2/3~3/4 of a tank of fuel left).

To check the cdi, best thing to do is probably to just crank it over and use a strobe light to check the timing.

All the best

Keith
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