The last serious work I had done on my 99' r6 was 2.5 years ago. The valve clearances were checked, some shims replaced and valves adjusted. Carbs rebalanced. Plugs changed.Since then I have kept the basics maintained. Regular oil and oil filter changes. Also replaced the air filter recently. Chain cleaned and lubed.
Since it has been a while since anything major was carried out, I decided to speak to the mechanics and gain advice on what could be done to renovate. I already had a new set of 4 pronged spark plugs. They suggested rebalancing the carbs and that the valves would surely not need any attention after less than 20000km since the last adjustment.
They fitted my new petrol filter, changed plugs, adjusted steering dampeners, fitted a new front tyre and balanced the carbs (which they told me were well out of sync). Upon collecting the beast, it sounded very different, far chirpier. However, the clutch had been adjusted horridly leaving virtually no play and once the bike was warmed up on the journey home I noticed the revs were hanging on their way down. At around 2-2500 rpm. I hoped it would go away, but it didnt. For the next week or two whenever the engine was warmed up, the revs would hang at 2-2500rpm. Blipping the throttle seemed to raise the revs and then it would fall to the 1500 rpm idle. However, almost every time the throttle was closed the hanging occurred.
I took the bike back and explained the problem. I was told that it was running lean, and it was probably due to misadjustment of the carbs. So I went back again the next week. Left the bike there for 4 hours returned to find it exactly where I had left it. Didnt seem to have been moved. The mechanic told me that the balancing was fine and 'shit happens'. I explained I had never experienced this hanging revs routine before and it was surely due to the adjustment of the carbs. They told me to come back yet again the next week.
Again I left the bike there at lunchtime today. Returned after work, eager and hopeful. I was speaking with the owner when the mechanic turned up on my bike, cut out the engine as he tried to ride it into the workshop, then wheeled it out in front of me, by its mirrors, which were turned fully inwards leaving them useless, kicked the stand down as it was still moving, letting the stand scrape on the concrete as it came to a stop, then walked off, leaving the engine running.
My look of disgust was seen by the owner who called the mechanic back and told him to turn off the engine. Then asked him to explain to me how carb balancing was not carb tuning...
So this chap, the same mechanic who worked on my bike 2.5 years ago, adjusting the valves and balancing the carbs began to explain to me what he thought was the problem.
He told me he had balanced the carbs again, and they were fine, perfectly in line. How he did this without taking the seat and tank and airbox off as well as dropping the radiator, I do not know...is that possible???
he said it was probably the valves, since the 'running lean' problem happened only when the engine was warmed up. Asked me when the last time I had the valves done was, I explained 2.5 years ago, by HIM. Ok, so likely not the valves then. So then he kept saying that he could tell the carbs were taking in too much air by spraying something over them and the carbs had a fit. Again, how he did this without dismantling the fairing and removing the seat and airbox, I do not understand. Is this possible???
he told me that the air screws were misadjusted, and whoever adjusted them last left one at 2 turns and another at 4 turns, which he has now righted. The last person to adjust them was HIM, 2 weeks ago, then before 2,5 years ago.
We moved on from that and he suggested it could be the manifold. And to check it would need the radiator dropping, fairing removed, seat, tank airbox removed. At least 2-3 hours work he told me.
I asked why I had never had the problem before and his explanation was...
Your carbs were so out of sync, that the problem wouldnt be seen until the carbs were balanced properly. As they are now balanced the problem can be seen. The balancing of the carbs did not cause the problem, it merely revealed it. You know, with old bikes, these things can happen at any time.
He told me had made a few adjustments and to see how it goes...
As soon as I rode off the hanging issue was worse than ever before. It seemed more constant, and at higher revs. Much closer to 2500rpm. The revs also seemed to be lurching.
Now...I am not technically capable of making sense of all of the above. I do not trust these goons. I think they are lying to me. Before I take the bike elsewhere, I would very much appreciate some advice from you smart folks!
Does their story make sense???
Can they have checked the balancing without taking the seat, tank, airbox off???
Would the problem have been revealed, not caused by their attempts to rebalance the carbs??