Matjaz's CBX 550F story

My name is Matjaz and I'm from Slovenia.
I bought my motorcycle Honda CBX 550 F on July 1999. The engine was already then in bad conditions so I payed around 2000 DEM for it. In 1999 it runned for a about 1500 km and then the engine stopped running. It was completley blocked because the cam chain fell off. The cam shaft slide bearings, which are assembled from two half bearings, were looseneed so the camshafts were floating in the air. At that time it consumed around 10 liters per 100 km (way too much!).

I opened the engine for the first time in the winter that year. The cause for the enormous fuel consumption were two bended exhaust valves which didn't seal the combustion chamber. At that time I saw that the engine was a 400 and not 550. I've decided to make a complete renewal of the upper part of the engine. In Italy I've found an CBX 400 on the junk yard only 30 km from me for 400 DEM.

The found motorcycle was complete but it had one cylinder and a piston dammaged (they were ribbed). So today I have still a lot of spare parts from this motorcycle and some parts I bought with my motorcycle. If anybody arond me needs anything, contact me.

I honed the cylinders slightly so that they had the net for friction reduction ( the surface shudn't be polished ). The cylinder diameter didn't change so I used the same diameter pistons. I've also changed the two dammaged valves and brushed the seats at all the valves. Unfortunatley I didn't open the lower part of the engine to check in what conditions were the other parts. At the same time I've sold the main shaft (what a mistake!!!). At the begining the engine was running smoothly but after 300 km I've noticed a strange sound comming out of the bottom part of the engine. It was like someone would hit metal with hammer ( TIN TIN TIN ...) with frequency about 3 times per second. This rummor was heard only on idling revolutions.

From there I've made 2500 km from stoping the second time. And here I am today. Recently I have tracked out an used motorcycle in Italy but I have to get some more info about it before I go to get it because I have to travel 400 km in one way. I will let you know about it.

Now about te look of my motorcycle. It's a standard metallic red-white with black stripe. I have two exaust silencers. The first is four in one MICRON perfect for racing; it starts pulling from 9000 rpm up. The other is a classic four in two-cromed.


Hello Yasu!

I've sent a letter about my Honda about 14 days ago. Thank you for uploading the info about my problems on your web. I already had an contact from a CBX owner from Slovenia, who saw my adress on your web page. Now I'm sending some photos of assembled motorcycle and internal look of engine.
The photos were taken during repairing works in winter 1999.

mot1.jpg Totaly striped motorcycle

mot2.jpg Assembled motorcycle with four in two chromed conical exhaust tubes

mot3.jpg assembled motorcycle with four in one with a Micron exhaust tube mounted

mot4.jpg picture of honed bores where we can see the "net" inside

mot5.jpg my workbench where I striped the engine

I'll write you again when I'll get that engine from Italy.

Thanks again
Here is the next story from Matjaz in July, 2001.

Matjaz Kariz (