Coils?

[wsn03]

Bandit 1200 mk1, parked up for 4 months in Jun after months with normal unleaded after a rebuild, however I think some of that unleaded was already almost a year old - didn't mean to lay it up in June but another job took over my life.

Come to start it in Oct, can't get it to fire. Assuming blocked pilots (so tiny) from petrol turned to shite, overhauled carbs - all good. Balanced carbs. Changed plugs. Put in fuel stabiliser - cack fuel plus some superunleaded. Bike runs ok, but I notice cold starting is a bit of an issue (though its not cold in the garage yet)

Bike has 12000 miles.

6 months later - bit of a pig to fire up, stuttering and spluttering. Can't rev it for what seems like an age, definitely missfiring like crazy. Cylinders 2 and 3 exhausts colder than others. Get on the dual carriageway for 10 mins and running well. Ever so slight lumpiness - however, most of the fuel is old. I manage to squeeze in £8 of super unleaded for the journey home, opened her up, running well, not 100% but pretty close.

I'm thinking either - this will fix as I get decent fuel through, perhaps I'll do another balance of carbs after next fill up.

OR

Coils? Plug leads?

My GSXR F is famous for having crap coils, and life changed when I fitted Dyna coils back in the day before they started making them in China (still going strong). This bike is low miles but could the coils corrode / breakdown - you can see she doesn't get a lot of use. Same question for plug leads and caps?  If the problem doesnt go away with a refill of good new fuel I'm going to have to look at leads and coils - what type to get, oem? Are Dyna still unreliable since being made in China?

 

Thanks

 

Edited April 4, 2021 by wsn03

[TonyGee]

should of completely drained the tank and got all the old fuel out,  the bandit coils are pretty reliable. my guess its a fuel problem. the bandit carbs are getting on in life now and ive seen countless problems with the float valves,  the rubber tip wears and fuel can leak in causing a rich mixture and lumpiness but runs good at speed as the extra fuel is being used. check the colour of the plugs.  

[no class]

....also check your needles for wear.... they rub on the emulsion tubes .... this will also cause cruising issues .

[wsn03]

Thanks chaps.

I'm ok with the carbs, needed to check on the electrics - the GSXR coils were known for failing even at low miles. Thanks for confirming Bandit coils have a better reputation - I wasn't sure if they were crap as well.

I overhauled leaking fuel valves at only 9000 miles (unbelievable!!) - the miles are real, I've had the bike from new. Diaphrams also full of holes around the same time! Carbs are bang on, and I flood tested them too just to be properly sure (I hook up a remote tank and leave it for 24 hours - if no fuel level dropped the valves are good).

Didn't think about needle wear - one to remember to check for next time. I'm guessing at only 12k though this shouldn't be an issue yet.

 

I'll run through the fuel, as I think about it some of it is 2 years old I think.

If the problem persists I'll take the carbs out again. However it ran really crisp on the way home like normal with more new fuel in it. So I'll see what happens.

 

Edited April 3, 2021 by wsn03

[colinworth79]

I would also have check of the  connectors in the loom  and the main ground connection on the engine just to rule out  . From what you describe I would say its carb problems tho. 

[wsn03]

3 hours ago, colinworth79 said:

I would also have check of the  connectors in the loom  and the main ground connection on the engine just to rule out  . From what you describe I would say its carb problems tho. 

Thank you, that's a good call. We had to do some frame work, so the loom was all apart, connectors cleaned and a blob of vaseline smeared in each, so as far as I recall all good.

That's 3 people theorising carb - so we'll see what happens when she's on good fuel only