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Discussion Starter · #1 ·
So, last weekend I bought a Beowulf can and de-cat pipe at the NEC show. Bargain at £245 all up, nicely finished and all fitted together well. I tested the bike with a quick start up and it sounded great and ran fine but I didn't have time to take it for a run.

Today I had an hour to take the bike out so got kitted up and tried to start it but the engine won't catch. The only thing I can think of is that I broke one of the cables to the lambda sensor when removing the cat. However, I thought that the bike was supposed to run with the sensor disconnected so I tried disconnecting it at the block and tried again but other than a loud backfire, nothing.

Anyone have any ideas? Should the bike run without the lambda sensor or do I need to fit a 330 ohm resistor across the bottom two terminals to get it to run? Can you think of anything else I may have buggered up when fitting the pipe?

Thanks in advance

Barry
 

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I don't know what's causing your problem but you can start the bike without the lambda sensor connected, you'll just get the FI warning light on the dash.
 

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+1 to Nats post.

I'd check your battery is topped up first.
The CB is a bit sensitive to a low battery especially as the weather is a bit nippy. It might help temporarily removing the main light fuse until the engine fires up.

In any case probably a good thing to disconnect the battery for a while to allow a ECU reset since you have changed your setup.
 

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Discussion Starter · #4 ·
Thanks

Thanks guys, good to know that it should start with the lambda sensor disconnected, that's one less variable to worry about. I've disconnected the battery and put it to charge overnight and will see what happens in the morning. If that doesn't work I think then I assume it's some kind of interlock issue between sensors. If I rev the bike and press the starter it barks into life but is cut off immediately. If I don't apply any throttle it just won't catch and seems to reset - there's a relay click. If I run out of ideas I'll call Honda Assistance.
 

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I had the same issue when I removed the stock silencer to change the rear tyre. Starter was turning but the engine wouldn't fire, not even close. Took battery off and put it on charge and when I reconnected it I removed the headlight fuse for first start up. Fired immediately!:)
 

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Discussion Starter · #6 ·
Thanks Sax, that sounds positive. Hopefully tomorrow will see success after an overnight charge disconnected from the bike. I'll disconnect the light fuse too.
 

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Why should you disconnect the headlight fuse.
 

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same thing happened to me after i fitted a new exhaust, you,ve coked plugs up starting it and turning it off a couple of times,and not letting it run long enough, you probably have run your battery down a bit, once you charged it up , it will eventually start, take it for a blast for 15 mins and it will be back to normal... mine was any way :thumbup
 

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Discussion Starter · #10 ·
Thanks!

Thanks for all the advice guys, once again the forum came to the rescue! Overnight charge, headlight fuse removed and it started second time with a bit of throttle. Am going out for a blast in a few minutes!
 

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Thanks for all the advice guys, once again the forum came to the rescue! Overnight charge, headlight fuse removed and it started second time with a bit of throttle. Am going out for a blast in a few minutes!
Where in hampshire are you from. :thumbup
 

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Discussion Starter · #13 ·
In case it's of any interest/use to anyone, here's the explanation for the problem from my mate who's a senior engine development chap at Jaguar Land Rover and knows a thing or two about modern fuel injection and ignition systems: 'just changing the exhaust shouldn't affect the starting at all as the Lambda sensor will not start controlling fuelling until there is no risk of dew in the exhaust (otherwise they break) therefore I can only assume that seeing how most bike batteries are only just big enough to start the bike in ~ normal temperatures that it is a combination of cold weather and battery charge. The problem with fuel injected engines is the ECU only works properly to ~9v and then not at all at 6v the clicking you could hear was most likely either the main relay or the starter relay due to the voltage dropping. If you haven't got one get an Optimate or similar charger that is the best solution I have found for looking after the battery when the bike isn't being used regularly.'
 

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Good to hear it's sorted:thumbup, had a similar problem when I fitted a new exhaust, PCV and Autotune. TBH panicked a little when it wouldn't start as there were so many variables, anyways after a good overnight charge all was good.

I normally run an optimate over most weekends as I have a tracker and use heated grips most of the time, just not worth the hassle of the bike not starting on a monday morning. Thinking of getting a Lithium Ion battery when the prices come down as they have the advantage of being smaller, lighter and most importantly do not discharge over time.
 

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These battery problems will only be solved when bike manufactures fit a battery that can do more than start the bike, and understand that some do more than use a bike for a summer blast, and therefore fit heated grips etc:confused:
 

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Be careful with lithium or ion poly batteries as fitted to race bikes as these are used so the alternator can be removed and hold enough charge and only charged off the bike with a special charger , I use one and it's a 22 amp hour but did cost £220 have a look on you tube too see what happens when you use a normal battery charger , lots of bang and fire
 

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Discussion Starter · #18 ·
Also, lithium ion batteries are badly affected by cold weather so they're probably not a lot of use for people like me who leave their bike in a cold shed all week and then try and start it at the weekend!
 
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