rug_burn
Member
Recently my bike has started to miss on 2 cylinders (it seems, but not sure) when I'm starting from a stop, at real low RPM. It kind of stutters, emits dark gray smoke, and then quickly catches itself, and runs strong on all four. Never seen the smoke myself.
I been doing a lot of real short run local riding at very low rpm, so at first I tried some Lucas injector cleaner, thinking it was maybe missing from clogged injectors. It helped the power all through the engine's range, so it seemed, but the miss came back once I was not being careful to keep it at a higher rpm. I used to dismiss kind of this stuff out of hand, but recently, after dealing with vehicles that have sat a long time with questionably old gas, I'm convinced it can be a big help, and a helluva lot easier than actually working on the car or bike... It has saved the day more than once for me now.
Next I figured maybe that since I have 72,000 miles on the bike, and have never adjusted the valves (yes, true, no kidding. I am that lazy) that maybe the valves were not closing entirely, and the burning gases from the powerstrokes were blowing back into the intake, or something like that. So I bit the bullet, disassembled the bike by the service manual method, and found that the valves were not that far worn down. For those who don't know: overhead cam valves like these don't get looser when they get worn, and start clicking like pushrod driven valves, they get tighter because nothing wears out on them but the valve seats, believe it or not. A service manager told me that if you never adjust your valves, they will eventually stay open because the clearance to the cam follower cap gets to zero, and then even less as the seats supposedly continue to wear. But I digress...
Anyway, I checked the valve clearances, and all had clearance. the worst was the number 1 cyl with 4.5 thou clearance on one intake valve, 4.8 on one exhaust. Not really too bad. All the intakes were actually within book tolerance, exhausts were all worn a little, but most were not that bad, 6 and 7 thousandths clearance where 9.8 to 11.4 thousandths is the desired range. The valves do not seem to have been the problem...
So now I'm wondering what it is causing that stutter.
Maybe ignition coils? It's a real quick miss that either misses or not- it doesn't slowly starve out like it's losing fuel.
Anybody have this problem?
An what's the most miles anybody has on their FZ8?
I been doing a lot of real short run local riding at very low rpm, so at first I tried some Lucas injector cleaner, thinking it was maybe missing from clogged injectors. It helped the power all through the engine's range, so it seemed, but the miss came back once I was not being careful to keep it at a higher rpm. I used to dismiss kind of this stuff out of hand, but recently, after dealing with vehicles that have sat a long time with questionably old gas, I'm convinced it can be a big help, and a helluva lot easier than actually working on the car or bike... It has saved the day more than once for me now.
Next I figured maybe that since I have 72,000 miles on the bike, and have never adjusted the valves (yes, true, no kidding. I am that lazy) that maybe the valves were not closing entirely, and the burning gases from the powerstrokes were blowing back into the intake, or something like that. So I bit the bullet, disassembled the bike by the service manual method, and found that the valves were not that far worn down. For those who don't know: overhead cam valves like these don't get looser when they get worn, and start clicking like pushrod driven valves, they get tighter because nothing wears out on them but the valve seats, believe it or not. A service manager told me that if you never adjust your valves, they will eventually stay open because the clearance to the cam follower cap gets to zero, and then even less as the seats supposedly continue to wear. But I digress...
Anyway, I checked the valve clearances, and all had clearance. the worst was the number 1 cyl with 4.5 thou clearance on one intake valve, 4.8 on one exhaust. Not really too bad. All the intakes were actually within book tolerance, exhausts were all worn a little, but most were not that bad, 6 and 7 thousandths clearance where 9.8 to 11.4 thousandths is the desired range. The valves do not seem to have been the problem...
So now I'm wondering what it is causing that stutter.
Maybe ignition coils? It's a real quick miss that either misses or not- it doesn't slowly starve out like it's losing fuel.
Anybody have this problem?
An what's the most miles anybody has on their FZ8?