Hi guys, hopefully you can help, I've had my j1 now for nearly 12 months and still can't sort out it stutter/misfire when on part throttle ie just creeping in traffic but also when exiting corners, I've balanced the carbs to no avail but something tells me it's fuel related still, is there anywhere I could find out what the standard jetting should be so I can strip mine and see if they have been altered, but any other advise would be greatly appreciated, thanks robin
Is it the same hot or cold ? And does the bike ride normally above 3000rpm ?
Has the bike been stood at any time? I would be tempted to dropt the float bowls off, give them a good clean and dose all the bits of he carbs you can get to with carb cleaner. If it's been stood it could the idle/slow speed jets gummed up and as they are really really small are a bugger to clean.
it is the same hot or cold and seams to smooth off above 3000rpm and ride ok, until you roll off then back on exiting corners, ive had the carbs off, stripped and cleaned the jets and float bowls but no change really
Cdi?
Have you lubed/adjusted the throttle cables ?
ive got no other issues with the bikes with regards to battery going flat or cutting out, occasionally when started from cold though I have had a loud bang from the exhaust
the throttle cables are well lubed and free moving
Pilot screws dirty or wrongly set.
Apologies if I'm being stupid but which are the pilot screws?
Where the float bowls are on your carbs there will be a visible gold coloured plain slotted screw in each carb.
These are the pilot screws.they control 99% of the fuelling up to around 2500/3000rpm.
there is a screw then a spring then a washer then an o-ring. Before you remove any ,screw them in completely
just until you feel light resistance and record on a piece of paper how many turns each is at. You can use these amounts to set back to. I'd recommend 2 turns out. If you have an after market exhaust i'd go to 2 1/8 to 2 1/4 turns out. You may need to tweak them slightly to get the best results.
make sure you use a rubber safe carb cleaner when spraying the pilot screw passageway and screw.
I had a feeling it was those, I've tweeked them but never removed them, I'll have a check of them thanks
does any body know what the standard jet sizes should be? im going to strip the carbs again as im not sure the pilot jet holes are clear as it still runs crap at low revs, thanks
I had this exact same problem with a G2 I had many years ago. It was like riding with a power switch that flicked itself over at about 3 1/2 4,000 revs and took off like a scolded cat.
It was cured by replacing a stick coil that was shorting out. If this is causing it you'll be able to hear the cracking noise at low revs. Get the tank and airbox off and check them out.
I'll have a look at that ta, I've got the tank off already and I've had it running with a remote tank, do the coils just pull out ?
me again, just spent some more time on the bike, ive found the coils to have a little dry rusty dust on them but no real signs of them arcing, the plugs look ok apart from a little blow by on the porcelain section at the bolt head, and on number 4 cylinder plug bolt there is sign of rust which could cause an arc, so gonna get some plugs and try again, but in the mean time im going to strip the carbs again completely clean them.
i have the same problem with my r6 runs fine upto 3000rpm then splutters like hell between 3-4000 rpm then takes off like a scolded cat had the carb cleaned rejetted and balanced also changed the plugs but it's still the same only way i have found around it is to wind it on a little more, going to change the airfilter to a k&n as it only has the standard one in to see if that makes any diffrence :undecided:
Good luck with it, mines peeing me off now but I'm determined to sort it
Quote from: robin46 on November 05, 2013, 05:51:25 PM
Good luck with it, mines peeing me off now but I'm determined to sort it
same here just ticking things off the list as i go along i am determined to get to the bottom of it :undecided:
Have you guys elimanted 'carb icing' from the list?
Quote from: Jonesy on November 06, 2013, 05:27:44 PM
Have you guys elimanted 'carb icing' from the list?
i have as i had the carbs rejetted and cleaned and balanced about 2 months ago the guy who did it said it just needed cleaning this is not something that has just started it has been doing it for a while.
I'm not really ruling anything out to be honest, I've got the bike in several bits right now and checking everything over, I did find a slightly corroded connection in the white multi plug to the ignition switch, I've sorted that out and Ive got the carbs in bits and part way through the thorough clean, I'm confident the coils are ok, gonna get some new plugs and start the rebuild then hopefully will have some good news
my money is still on a coil breaking down...
Quote from: m6rk on November 28, 2013, 04:12:44 PM
my money is still on a coil breaking down...
Mine too Mark, I've had other people ask me about this type of fault on G J and A models over the years and it's always been a coil. They just seem prone to it for some reason. I'd have a look on ebay for a spare and just swap them 'til you find that it's fixed.
Just had quick look and there's loads on there.
ive done a simple multi meter check of the coils and all seam fine but obviously that's not with the bike running, the fault occurs either hot or cold at idle or very low revs, high revs its fine
Quote from: m6rk on November 28, 2013, 04:12:44 PM
my money is still on a coil breaking down...
bought some coils today off ebay hopefully that will do the trick :grin:
I had similar with my E9f changed the coils and it was like a different bike!
Quote from: ben68 on January 10, 2014, 05:36:30 PM
Quote from: m6rk on November 28, 2013, 04:12:44 PM
my money is still on a coil breaking down...
bought some coils today off ebay hopefully that will do the trick :grin:
How much did you pay for them ?
[/quote]
How much did you pay for them ?
[/quote] there were no bids on them so i got the set for a bargain £15 :cool:
well back to the drawing board put coils on put everything back together put some fresh fuel in and took it out to test it and still got the problem :(
I've got the carbs back on the bike after stripping and cleaning them, I changed the seals on the pilot jets while I was there as they looked a little flat, so now I know the carbs are dirt free and the float heights are all identical, just got to get some spark plugs now the run and balance them to see how it runs, I'm pretty confident it's not the coils as you would get running problems when loading the bike up in higher gears, the only fault I have is a stutter/hunting at idle and small throttle openings.
took my bike down to a local bike shop spoke to the guy that owns it explained to him as best i could as to what it was doing told me to take the carbs off and drop them back in at the shop which i did turns out it had the wrong jets in bike running sweet as a nut now :laugh: :cool:
Could it be the float bowl height? I had this on my bike engine kit car......sluggish/misfiring/struggling below 3000rpm and also at WOT. We (well..Dave Wood) changed the float height and sorted it