First of all, Hi

I've got a bit of a problem here! I tried to start my bike the other day and it wouldn't start, it was turning over but just wouldn't fire up, then after a while it would do a huge backfire! Battery got drained so I just fully charged it and same is happening again and again - turning over but not firing up! I thought maybe I had flooded it with petrol, so left it overnight to try and dry it out but it made no difference. Also tried to bump start the bike and still nothing.

Today I set about removing the plugs to inspect them. After struggling with the fuel tank and air box, I gained access (with difficulty) to the spark plugs, removed them and they looked like this:



As you can see they are wet probably due to too much fuel in the cylinders? Hopefully getting new plugs tomorrow and fitting them Wednesday/Thursday to see if that makes any difference.

Most of the info I got off other threads which has lead me to where I am now. But all I want to know is: What's causing this and how can I fix it?

Thanks a lot,
Steven

 

Can you give us some historical information on the bike. Such as, when was the last time it ran? Have you cleaned the carbs recently? Were you using the choke to try to start the bike? If you spray a little carb cleaner or flammable spray in the air box, will it try to start?

My guess would be you need to clean the carbs or use the choke when you try to start the bike...

 

Do you have a f2 petcock on your bike or is it an f3?

 

Of course - The bike ran two days before problems started happening. Started it up to let it warm up and it ran as sweet as a nut. I haven't cleaned the carbs, no, but thinking about doing that. Do you think it's worth doing anyway? I already have the fuel tank and airbox off, so I'm half way there already. Haven't tried to tackle anything like this before though.

I'm not sure, how can I tell?

Hopefully new spark plugs will arrive today and if I've got time I'll fit them tonight after work.

Edit: How important is it to clean the carbs? The bike has done 26k miles and although it has all previous MOT's it doesn't have much service history, so I don't know when they were last done.

 

When was the last time you fueled the bike? You might have run into some bad petrol. Since you have the fuel tank and airbox off the bike, get some carb cleaner or brake parts cleaner and squirt a little into the carbs and see if you can get the bike to fire.

Also, have you installed a fuel filter? This would help you see if you're having rust problems or junk in the fuel tank.

If you've already taken off the airbox and fuel tank, I'd recommend pulling the carbs and giving them a good clean.

Does your petcock have 1 or 2 lines running to it? If it has 2 lines, it is an F2 petcock. If it has 1 line, it's an F3 petcock.

Once you get the new plugs, test them and ensure you're getting a good spark from each one.

 

I put £5 worth of fuel in it the day after it stopped working, so there's plenty of that in there. You want me to keep the airbox and tank off and squirt carb cleaner directly into the carbs then turn it over?

I haven't installed a fuel filter, no.

I'm thinking of cleaning the carbs tonight, it looks like a lot of work though!

It had one fuel line and another little thin tube that went into it if that helps? The spark plugs didn't come today so that's tomorrows job!

 

As you can see from the picture, the air filter is virtually brand new, so that's not the problem.

I also quickly started to strip down to the carbs and took a quick picture (probably can't tell much from that), do you think it worth removing them and stripping them now?









To be honest I don't really want to tackle them unless it's a last resort. I'm thinking I should wait until my new plugs arrive tomorrow and try them first?

This might sound stupid but I couldn't clean them by squirting carb cleaner directly into the parts pictured, could I? :|

 

IT'S FIXED!!! So happy lol, took it a couple of runs up and down the estate and it felt great! Changed the plugs today and topped up the battery last night and probably a mixture of both seem to have sorted it! If the battery starts showing any signs of failure I will replace it.

Thank you to everyone who helped - great advice from you all. Appreciated, thanks!

 

i know you got your bike running but im gonna tell you this anyway. dont EVER spray carb cleaner or anything that your not sure wont mess rubber up brake cleaner and carb cleaner will ruin rubber gaskets like your diaphrams and you float bowl gaskets. just so you dont mess anything up in the future. glad to hear you got your bike running man have fun with it and be safe