Hi all, i will give a little history of my bike to start with, knackered old 94 GS, over 80k on the clock, i believe the piston rings are slightly worn and the carbs do need doing. Right a couple of weeks ago my GS started bogging down at high speed or when i opened the throttle all the way, i was adviced to change the air filter and spark plugs, which i did and it went back to normal. Same thing has happened again, its ok through 1st and 2nd, then if you try to open the throttle all the way it just makes alot of noise and doesent want to increase the revs, but when you roll back off the throttle slightly you get a jerk of power. So i changed the air filter to a pattern one (i am poor) and new spark plugs, it improved from what it was but still when i open the throttle all the way... nothing really.
Now as i say it has a new air filter (of which is only held in my 2 of the 4 screws that were originally there), i say that because in my haynes manual it says a possible cause could be an improper seal between the air filter. I have a screw in the top left and bottom right of the air filter and its held in tight, you cant wiggle it by hand. I understand that if my piston rings are worn it could be a lack of compression? im hoping it will just chug away with worn pistons, it does go through oil but i can live with that... considering i paid only $500 dollars for it (£250). I also am aware my carbs need doing. Could mucked up carbs be causing this?, i have been using the petrol attidive Redex for a while now to try and get rid of excess carbon... Basically looking for advice, i am quite poor atm and would like a good idea of what could be causing it before i take it to my mechanic, as i can only afford a couple hours labour ie to do the carbs or the pistons... not both :(... Thanks in advance.
first thing i would do is run it on prime, that will tell you if your filter in the tank is gunked up.
if its still bogging, i would lift off the tank, remove all the gas ect, you nay as well clean the filter while your there, then i would rip off the carbs, turn them upside down rip off the float bowls, clean them, they will be full of crap at that mileage, take out the floats and have a look at the float pin thing to see if its ok.
screw in the pilot jets talking note of how many turns in they are then pull them out and have a look and see if they are blocked. screw them back in
but the float ect back on the clean bowl, the clean tank and lines, and try again.
also when you pulled your plugs what colour were they?? you can tell alot from the plugs
I always run it on prime to get around that starvation issue, i know for a fact my fuel lines are clear, If you mean clean the air filter, its a new one...
Is your train of thought leaning to a carb problem, because i am just tempted to take it in to my guy and tell him the do what needs to be done to the carbs... btw i dont have the knowledge to do that myself, i can do basic things like chain lube, fluids etc...
I am having the exact same problem along with a non-idle issue that I just cannot figure out. :dunno_white: Do you have any issues with idling??
I would be more than inclined to say it was the carbs, take them off, pull them apart and clean them up, they aren't hard to do at all honestly. :thumb: A mechanic is likely to cost more than the job is worth. IMHO
Post any progress you make, and I'll do the same.
Cheers :cheers:
No problem with idle richmore as long as its warmed up, when its cold i cant take my hand off the throttle for more than 5 seconds... but its and old bike and its always been like then, once up to temperature its good.
The most worrying thing is since i posted that on my way back here now, i started the bike up, and some smoke came from the engine area, and now there is a slight rattle/knocking i can just hear at idle and a different sound on the move, it is not a nice sound and im taking the bike to my mechanic because i cant have it going BANG... will update wiith any news.