I bought my Honda cbx550f about one year ago from a guy
who sells and fixes somewhat older motorbikes. The cbx
had done about 57.000 km until then. I bought it because I
needed some kind of transport for the road, and the offroad
motorbike I had then, my Honda XR250R, was not very
suitable for this (not fast enough, but still a great bike for
offroad never had big problems with it).
I bought the CBX because I liked the looks of it (I like the
naked ones, where you can see the engine), and it was not
too expensive for me (I'm a student so...). I also bought
another completely disassembled (almost complete)
CBX550f from the same guy after a while, because I
thought some spare parts would come in handy, and I also
got the Haynes workshop manual from him.
After some test rides I found that the bike was reasonably fast, sometimes a bit unstable in high speed curves (this gave me a scare once!). Also the exhaust pipe that was fitted wasn't the original 4in2, but a partly selfmade replacement which was a bit low to the ground. When riding over big bumbs it tends to hit the ground, but now I've got used to it and this doesn't happen too much anymore. I also have a original exhaust, but this is rusted. Maybe I'll fix this sometime.
So I've been riding happily with my cbx until june this year.
But then when I was riding on the freeway I started hearing
a strange sound coming from the engine, and in a couple of
kilometres the sound got louder and louder, I continued the
ride with about 80km/h and at a low rpm.
When I came home the sound was very loud (it was like a
knock) and it was obvious there was something wrong with
my bike. So when I had the time I dismantled the engine,
looking for the broken parts. After removing the cylinders I
found that the third piston was the problem. The bearing
shell of the connecting rod was broken, it was still in place
but after examining I found that it had scratched the
crankshaft surface. I don't know what caused this
malfunction but it was probably due to lack of lubrication I
think. (I think I should have replaced the engine oil a bit
earlier ).
Since I had a spare crankshaft I decided that I would replace
the damaged one. I replaced also the connecting rods, I
thought it was better to keep the same rods with the same
crankshaft.
When done this I could reassemble the engine again, I
bought some 'liquid' gasket in a tube for sealing the two
crankcase halves. And I made new gasket out of gasket
paper (for tractors) this was a lot of work but since a
complete new gasket-set was hard to get and also expensive.
I just made a print of the gasket by putting hobby-paint on
the part that needed the gasket, and then cut it out with a
sharp(!) Stanley-knive. When I was at it I already made
some spare gaskets. For the cylinder head gasket I used the
old one (made out of 3 layers), cleaned it before assembling.
So when I finished putting the crankcase together again with
the torque wrench, one bolt broke while assembling (even
when I used the torquewrench
),
I reassembled the
cylinders and everything else (after cleaning). I put a new
oil filter in and then mounted the engine back in the frame. I
found that the replacing of the airchanbers before the
carburettors was difficult to do, but it worked.
Then I
reconnected everything to the engine and the engine was
ready for it's first test. This was after some days of work
at 12 o' clock in the evening. The engine started with the
second attempt of starting it, producing a lot of smoke and
noise since the exhaust pipe was not yet fitted. But I was
happy, it worked!
In the end this repair had only cost me some oil, a new filter
and the liquid-gasket(what's the right word for this?), but a
lot of time since I didn't have much experience with engines
and stuff so I had to check everything twice in the
workshop manual and by the expertise of some family
(thanks). I know it would have been better that I would
have fitted a new cylinderhead gasket, but I didn't have a
lot of money at that time. And this solution worked out
fine since the engine isn't leaking oil. I was back on the road.
After the first kilometres on the road I noticed that the gear
changing was a bit difficult but it seems to get better now.
Also one of the sparkplug caps came loose after a while so I
had a significant loss of performance (maximum speed
110!!), so remember to tighten the caps well after work on
your bike
.
That's the story of my cbx until now, I hope the repair was okay and won't have to do that again for some time, because I like riding my bike more than fixing it.
Here's a picture of my CBX in front of my parents house
getting a tan ;) Ooh it looks good!
Ride safe and greetings, Michel Heusinkveld
Michel Heusinkveld (michel.heusinkveld@wanadoo.nl)