Rough Idle and Aftermarket Tach - Motorcycle-Journal Forums

Breeze · 06-20-2008, 01:49 PM

I had my M in the shop recently because for the last few months, it would develop a rough idle after it was warmed up (about 10 min). I would have to blip the throttle evey few seconds or the bike would almost die, and it did die a few times on me in just about a weeks time. I also noticed that the fan had not been coming on at all and the weather had been real hot lately. I figured that a temp sensor might be the culprit. I have close to 31,000 miles on it now and had the valves adjusted and spark plugs changed too - a little early but it was close to being due. The tech had recently went to a Suzuki seminar and said that one of the items covered was The M and C50 having idle and running problems when aftermarket tachs were installed. Somehow it confuses the ECU. I did not beleive him at first, but all he did to cure the problem was un hook the tach. The bike runs great now - much better throttle response - smooth idle. The fan also came on a few times when idling in traffic and waiting at the drive thru. I really don't need the tach, but I liked having it. He said that part of the problem could have been the taps I used to connect it (he found some corosion in them) and that soldering it in may work better but no guarantees. I may try that later, but for now I'm just glad to have the M back and running good.