imdying
5th December 2007, 09:27
A friend roped me into making a new throttle cable for a bandit 250 for a friend of his. No worries there, works good. So I went along with him for something to do, as he had to go visit this guy because the bandit still has some troubles. Big mistake... never show an interest :lol:
I get there and they're convinced the fuel system is dirty, so they take the tank off, empty the fuel out, and proceed to remove the ball bearings that are for some reason rattling around inside it.
Tank strainer looks fine, fuel filter has a small amount of little black gunk bits in it... looks like a fuel line breaking down to me. So I take a float bowl off, to see if any crap has made it further down the line. Doesn't appear so, but cleaned the bowls and checked the pilot and main jets for cleanliness... all good so far.
So finally they get it back together, and I get to hear it run, which is good cause by this stage I've yet to be able to get a straight answer as to why it had to be taken to bits in the first place (I'm lazy, would rather leave things be if I can avoid it).
Won't start on the starter, battery is healthy enough at 13.1v and winds over good, but doesn't make an effort... so they push start it. That doesn't help. Eventually gets back in the garage, I give it full choke, thumb the starter for a little, and eventually it chugs into life.
I get the distinct feeling that it's running on three.
Any touch on the throttle makes it stall, so I let it warm up.
Eventually I figure out I can get the revs up if I open the throttle incredibly slowly, still doesn't rev above 8000 though, definitely sounding on three.
Now that it has warmed up a little, it lets me use a little throttle, and I can get it to idle (a little roughly) without the choke.
So I start giving it some grief, and it starts to rev albeit slowly. A few backfires and a pretty flame out the exhaust and it appears to clear whatever cylinder is giving it grief, and it starts to respond well, reving cleanly and quickly. But pretty much straight away it starts to bog down (presumably a cylinder is dropping off) and becoming hard to rev again. Continued abuse on the throttle sees it repeat that cycle, cleans out, runs on four, then drops back to three.
I haven't had the plugs out, it was late and I wanted to go to bed and also have an opportunity to consult other KBers. I'm thinking that they're probably as neglected as the rest of the bike, and worth a look. I think pointing a infrared heat reading gun at the headers might help figure out which is the crook one.
Normally I'm a grumpy shite and whilst generally happy to help with the things I specialise in (brakes, cables, drinking), I've only got so much time to give away. However, this fella is young (I'd pick about 17), at Polytech, so therefore not really flush enough to take it to a professional.
So I'd like to have another crack at this bike... can't be much wrong, has spark, fuel and presumably compression. What should I check next? Cleanliness of the plugs? I've not got a compression tester, but it seems to healthy to be that... although such a tiny wee 16v motor at such high revs, perhaps it has bashed an inlet valve?
Or is their an obvious solution that someone experienced can point out?
I get there and they're convinced the fuel system is dirty, so they take the tank off, empty the fuel out, and proceed to remove the ball bearings that are for some reason rattling around inside it.
Tank strainer looks fine, fuel filter has a small amount of little black gunk bits in it... looks like a fuel line breaking down to me. So I take a float bowl off, to see if any crap has made it further down the line. Doesn't appear so, but cleaned the bowls and checked the pilot and main jets for cleanliness... all good so far.
So finally they get it back together, and I get to hear it run, which is good cause by this stage I've yet to be able to get a straight answer as to why it had to be taken to bits in the first place (I'm lazy, would rather leave things be if I can avoid it).
Won't start on the starter, battery is healthy enough at 13.1v and winds over good, but doesn't make an effort... so they push start it. That doesn't help. Eventually gets back in the garage, I give it full choke, thumb the starter for a little, and eventually it chugs into life.
I get the distinct feeling that it's running on three.
Any touch on the throttle makes it stall, so I let it warm up.
Eventually I figure out I can get the revs up if I open the throttle incredibly slowly, still doesn't rev above 8000 though, definitely sounding on three.
Now that it has warmed up a little, it lets me use a little throttle, and I can get it to idle (a little roughly) without the choke.
So I start giving it some grief, and it starts to rev albeit slowly. A few backfires and a pretty flame out the exhaust and it appears to clear whatever cylinder is giving it grief, and it starts to respond well, reving cleanly and quickly. But pretty much straight away it starts to bog down (presumably a cylinder is dropping off) and becoming hard to rev again. Continued abuse on the throttle sees it repeat that cycle, cleans out, runs on four, then drops back to three.
I haven't had the plugs out, it was late and I wanted to go to bed and also have an opportunity to consult other KBers. I'm thinking that they're probably as neglected as the rest of the bike, and worth a look. I think pointing a infrared heat reading gun at the headers might help figure out which is the crook one.
Normally I'm a grumpy shite and whilst generally happy to help with the things I specialise in (brakes, cables, drinking), I've only got so much time to give away. However, this fella is young (I'd pick about 17), at Polytech, so therefore not really flush enough to take it to a professional.
So I'd like to have another crack at this bike... can't be much wrong, has spark, fuel and presumably compression. What should I check next? Cleanliness of the plugs? I've not got a compression tester, but it seems to healthy to be that... although such a tiny wee 16v motor at such high revs, perhaps it has bashed an inlet valve?
Or is their an obvious solution that someone experienced can point out?