I rode into the City on Friday with the intention of buying myself a Christmas present - a 400 Monster Ray Quincey Motorcycles had advertised on bikepoint with an "immobilisor issue". I figured that theoretically my software would allow me to just disable the immobilisor section of the ecu and it'd be fixed and ready for me to onsell, making a few bucks along the way. But, as it turned out, the rest of the bike was a bit too rough for me to buy with the intention to fix and resell as I just can't help myself and want to fix everything and profit goes out the window.
I did go for a short ride once we got it going (it was a lottery as to whether or not it would be immobilised every time we turned the key on, probably more so than not overall) and it was just such a sweet thing to ride. The injected M400 have the APTC clutch and 6 speed gearbox like a 2006 620 or S2R800, along with the 2 piston front brake calipers. The light clutch and injection make them so much easier to get off the mark and ride at low speed in general compared to the carby models. It was a real pity it was so nice to ride, I'd have had no trouble walking away from it (as I did in the end) if it wasn't.
One thing I did notice about M400 ads is that everyone seems to list them as M400 S ie regardless of whether they're carbed or injected. Injected ones are from 2006 onwards and have dual front discs. The earlier carbed models have a single front disc and little plastic pods sitting inbetween the frame rails above the horizontal cylinder. More importantly for riding, they have a heavier clutch lever effort (typical non APTC wet) and flat spot from a closed throttle that can be more disconcerting than an actual issue when riding.
I did check and reset the cam timing on one carbed model - advancing the cams from 119 and 113 to 107 degree inlet centrelines which really made a difference. The carbed 400 have the old 750 cams, which were run at 110 degree inlet centreline in the F1, not the 119 they spec in the post '86 motors (the injected M400 have the 800 cams). We also raised the gearing at the same time from 14/46 to 15/46 and the bike still went better than before. But as most M400 are bought by L platers who generally have no interest in spending money other than what they absolutely have to and certainly not anything that (I say) might make it better to ride, I doubt I'll do many others. Pity.
This bike also got the Exactfit ignition coils, so it's a well set up M400 compared to how some of them (barely) run as they've come into the workshop.
I did get one in that was an early 95 model (94 to 97 have silver engine covers with the clutch slave cylinder in the clutch cover on the RH side of the motor) and i suspect it had the very early 600 primary drive ratio. I replaced chain and sprockets as part of a service with 15/46 from the previous 14/46 and even then it was near 8,000 rpm at 100km/h. No wonder the owner had found it breathless above 110 before - it would have been well over 9,000 rpm. I figured 15/41 would be what it needed, but didn't have the time and the owner seemed quite reluctant anyway. The varying spec can make it hard to set them up as they need to be, it seems the importers just put the same thing on all of them regardless.