Description
My Honda CB650F has had an annoying cold-start problem since I bought it. From cold, the engine hunts, runs roughly and will eventually stall — but once warmed up, it behaves normally.
In this video I start working through the problem properly.
First I remove the air filter and discover something I wasn't expecting: broken/missing plastic pieces from the airbox sitting inside the filter. I replace the filter with a genuine Honda item, but unfortunately that makes no difference.
While everything is apart I also give the faded plastics a bit of attention with a hot-air gun, which brings them back remarkably well.
Then I find something much more interesting...
With the MAP sensor connected, the engine hunts and struggles to idle. Unplug the MAP sensor connector and suddenly the engine settles down and idles almost perfectly.
That puts the MAP sensor — or something associated with its signal — right at the top of the suspect list.
A replacement sensor has now been ordered, so this video ends with a diagnosis rather than a cure. Part 2 will pick up from here and we'll find out whether the MAP sensor really is responsible.
I also give a brief look at the CPMC Android Auto / Apple CarPlay screen that I later fitted to the bike.
The CB650F rabbit hole continues...
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