Hello, all I think this is my first post on here so here it goes......
Ok... when I'm riding along in any gear past 4krpm and hold the throttle gently the bike sounds like it's starved of fuel. It splutters, coughs and poofs (scientific term) back through the carbs. Letting go of the throttle it barks and cackles more than usual. It has literally happened overnight. Nothing has been done to the bike.
Spark plugs are ok and leads are ok. It doesn't do it under accleration nor letting go of the throttle completely. My theory is that under very light throttle one carb isn't getting enough fuel?
So is it a simple case of balancing the carbs and doing the mixture? All help appreciated
I would next go on to check that there are no intake or exhaust leaks. If you are sure that everything is good there then you can start looking at maybe making any carb adjustments/tweaks if the problem persists.
What air filter and exhaust system are you running? Have the carbs had anything done to them previously jetting wise. Any idea what your current set up is?
Yeah saw it was my 9th after posting
There are no leaks from what I can see and pipe up to the valve is all good.
I have Danmoto GP pipes, k+n filter and I have different jets from standard but I don't know what.
It did literally happen overnight.
Under acceleration it pulls like a train, let go completely it's fine. It's just holding it gently above 4k.
Took the airbox apart today. Removed the base after taking off the air funnels etc and the crank breather hoses. Connected to the box are 2 2" vertical pipes from the carbs.What do they do and what would happen if one were to be restricted?
dudehog wrote:Took the airbox apart today. Removed the base after taking off the air funnels etc and the crank breather hoses. Connected to the box are 2 2" vertical pipes from the carbs.What do they do and what would happen if one were to be restricted?
Carb vents. Should not be restricted. They allow air in under the diaphragm.
As NZ said these feed atmospheric air to the carb diaphragms. Depending on how squashed/restricted it is would determine the amount air pressure speed or even block it totally and effect the lift speed on the slide. Refit the airbox with these connected properly and see how things run. I'm guessing it's the front one. If so you should be able to get a hand around the frame crossbar in front of the airbox and get your hand under the box and fit both pipes. Or at least feel around to confirm you have them connected correctly.
Well I sorted that. No better. Changes the petcock rubbers, front coil and spark plugs. No better. checked for vac leaks and tightened everything up and went for a ride and the further I rode it got better.
Now when I put the filter back on I used the K+n oil spray. My theory: is it possible I used to much oil in effect clogging up the air filter causing it to run rich at higher speeds when it tries to draw more air but couldn't. So the fuel is being supplied but not the air turning the mixture rich. Sound plausible?
The K&N airfilter takes some setting up (dynojet kit/dyno time) - so it''s not a plug&play mod like on most fours. If it hasn't been fettled to run with a K&N you could try reverting to a standard air filter.
With the K&N did you wash it clean with the 'special' solvent cleaner before reoilling?
It may be that your whole purpose in life is simply to serve as a warning to others.
I think this is my first post on here so here it goes......
