My Cannondale MX400: Flawless performance status achieved!

Life with a Cannondale moto is a journey. Ask anyone who owns one, and they’ll confirm the roller-coaster-emotions of ownership. But hey! if it was easy and there were millions of these bikes made, everybody would be doing it, right? Anyway, here is the story of this year, AND it is a very happy ending (so far….). When we did the YouTube video last year at Greenfield Dirt Track with Max and the team from 999Lazer & Too Fast Media, I wanted to get back there to ride the bike as it’s a great location and track.

As I write this, it is 24 hours after an epic day’s riding there. However, this was my fourth attempt to actually ride there. My first three entries went like this; Cancelled due to me getting COVID. Cancelled due to the crap and very wet weather. Cancelled due to the bike not working. It’s this last cancellation that, whilst frustrating and disappointing, got me to achieve flawless performance of the bike. Here’s what happened………

Since I put the new Black Widow engine in the bike and all of the other parts I got from Dave Muller back in early 2022, the bike has been super-reliable, although it did cut out sometimes, annoyingly. The day before I was due to ride at Greenfield Dirt track, I pulled the bike out for a start up and run down the lane to check it over. The bike started easily as usual, but didn’t sound its usual self. Then it stopped. I started it again and the same thing. It stopped. Then it wouldn’t start. To check basics like fuel is getting past the injectors and that there is a good spark, some dis-assembly of the bike is required. Firstly, I have to remove all of the bodywork, fuel tank, frame brace, and other bits just to get to the spark plug. It’s a hassle I’m well aware of. Anyway, enough fuel was getting through to satisfy its insatiable thirst and the spark plug would light up the village at night, such was its brightness. Hmmmm, now what?

International rescue comes from experts in the global Cannondale community. The advice was, as a next step, to double check that both injectors are firing. This means removing the air filter that sits under the fuel tank, and then shining a torch down the inlet whilst pressing the starter button to see if the injectors are working. Before I got to the injector firing stage, I noticed that the rubber boot and bellmouth which seals the throttle housing into the airbox had deteriorated and I could see daylight out of it. I’m not sure how long it’s been sucking air and everything else through the hole in the side of it, but it certainly bypassed the two air filters. A quick message to Black Widow ATV gets me a new rubber bellmouth shipped over and with the friendly observation and advice “you’ll need to drop the engine out to fit it”. Doh!

After hearing this ‘advice’, I get through the emotional change curve (shock/denial, anger/fear, acceptance, and finally commitment to fix it!) quite quickly. The airbox that holds the rubber bell mouth sits just behind the headstock and really can only be fitted or removed with the engine out or dropped. The process starts with emptying the coolant, which I spilt on my nice clean workshop floor (Doh!), removing the bash guard, exhaust and after some studying of the easiest way to get to the airbox with the least amount of parts removal, the bottom frame rails came off and I lowered the motor, which was still attached to the bike via the swinging arm spindle. At this point, there are wires and tubes sticking out everywhere, and I managed to chock the bike up with the engine dropped down enough to get the airbox out. Success! 

The rubber bellmouth is riveted in so I had to drill out the old rivets and then put new ones in, which didn’t take long. What took longer was that one of the fixing eyes of the airbox snapped due to its age and 20+ years of slow cooking just above the engine. I fixed it and asked around the community to see if anyone had a spare that they could send me just in case this one doesn’t last forever, which it definitely won’t. Dave Muller has one for me. Phew! Whilst I’m waiting for the airbox repair to cure, I check the exhaust packing, which seems ok-ish, but is likely to be the original packing, so I put that on the to-do list. 

I’ll save you from the boredom of explaining how the bike went back together. The biggest stress is that a lot of work has to be done just to see if I had fixed the problem, which I hadn’t apparently, because it wouldn’t start. More checking, swapping of the main relay, checking all terminals, pipes, and anything else I could think of, and then I changed the already-newish spark plug for a new one and guess what? The bike fired up, and crucially, with a bit of raised tick-over adjustment, sounded better than ever. It’s at this point that I am both elated and suspicious! On the one hand I’ve fixed it, but on the other hand, I’m not sure what it was that I had fixed, apart from the obvious rubber bellmouth. Over the next week, the bike was wheeled out of its shed and started up and run just to make sure. It started every time, didn’t need any jumper box to help it on the cooler mornings and it ran superbly. This was the first time that it also wouldn’t (very annoyingly) conk out when it appeared to hit a flat spot in the throttle.

My confidence was starting to reach the next level, so when I saw another open practice day at Greenfield Dirt Track, I put it in my diary. Whilst still feeling a bit suspicious about the sudden change in performance, I thought that I would enter the event at the last minute, and every day of the four days leading up to entering, I would pull the bike out and ride it. The first three days of ‘pre-entering-testing’ went so well, I felt confident enough to miss/risk the fourth day of testing and just enter. The bike went in the van on the day of the event running perfectly as it’s three previous test days proved, and it emerged from the van at the track exactly the same, and started/ran perfectly. Phew! This was fortunate, because the bike always seems to attract some of ‘the curious’ when it is wheeled out for the first time, so not starting would have been embarrassing, and people would say something like ‘no wonder it’s called the worst MX bike of all time etc etc’ blah blah!

The weather forecast proved right on the day of the event, so a hot sunny day hosted our MX riding. The track had been well watered before riding as it would dry out to being hard and dusty 4 hours later. I went out as soon as the green flag was waived and plugged my way through the mud. I did about 15 minutes and came in for a drink and to peel off all of the mud from the bike, particularly the radiator guard which will happily invite all of the mud from the front tyre to ‘move in and get comfortable’. The second run saw some big ruts appear, which is fine for the Cannondale as its weight and power allow it to hit a rut and get through it. The third run was even drier and by the fourth run it was perfect. I did 2 hours total duration riding over the 4 hours I was at Greenfield, and then called it a day as I was just starting to make some mistakes due to tiredness. 

The bike had been super smooth to ride in the mud, dust and everything else, and started and ran perfectly “all f@@@ing day!”. Flawless performance status has finally been achieved! Ha!

Massive thanks to everyone that has continued to help me when I’ve needed it.

Link to Black Widow ATV in the sidebar

Link to Greenfield Dirt Track: https://greenfielddirttrack.bigcartel.com

Link to 999Lazer YouTube: https://www.youtube.com/@999lazer/videos