Owners bike: Patrick Mees, red MBX80

This owners bike comes from Patrick Mees, whom like myself owned a MBX80 35 years ago so jumped at the chance to own another. The new bike has just had a full engine re-build and is ready to enjoy!

original bike

new bike

Did you own a MBX in the 80's and have you got one now, please get in touch and share your story!

MBX50, the creature from the black lagoon!

So... I seem to have acquired a MBX50, she is not pretty and she has missing wheels, but she was very cheap. In fact I have seen this bike before as a friend showed me it for sale on facebook and I remember commenting that I think its been stored at the bottom of the sea...

What we have here is a bike with a V5, some brand new gaskets and piston and a complete spare frame. To be honest my plan was just to sell the usable parts, maybe keep the engine to make a cross section for future shows and bin the rest, certinally the second frame is so rusted it is fit for the skip. But there is also part of me that thinks because of the V5 is it possible to save? Sure it will take a bit of cash to resurrect, but that depends on the final finish you want to achieve and of course finding a set of wheels.

So the question is, do I break it or save it?

rusty spare frame, this won't polish out!

My bike restoration update, almost there....

Some new detailed pics of my MBX80, I have a couple of things I want to change but these are mainly the colour/ finish of specific bolts.

My bike, restoration updated, handlebar fairing

With the new faring mount fitted the nose fairing went on. The fairing is NOS and has turned a little yellow over the years, so I will t-cut it to try and bring it back, if I can't bring the colour back it might have to come off for painting.
This is another landmark moment as for the first time in this whole process the bike is 100% complete and working! There are several niggles to resolve like correct bolts and warning labels, but here it is.

My bike; restoration update, starting her up

Saturday 9th March,

Firstly I fitted the fuel hose and then I bought some unleaded petrol. I did a pre-mix of 15ml 2-stroke to 500ml fuel and added to the fuel to the tank.

I kicked the engine over a few times then turned the ignition on and a few kicks later the bike fired up!

Next I set the air-screw and the tick over and then turned the bike off, removed the fuel tank and topped the radiator coolant up up. Next I fitted the rear foot pegs, rear rack and mirrors.

The next job was to fit the handlebar fairing bracket and fairing, unfortunately for some reason the lower mount did not line up with the fairing so would not fit. A search on ebay found a NOS bracket with the correct lower mount so that was ordered as a replacement. 

My bike, oil pump bleed

this is a retrospective post as I did this job a couple off weeks back and forgot to post!

One of the most important jobs is bleed the oil pump and set the correct cable movement to that the throttle delivers the correct amount of oil with the fuel.

To set the cable you need to make sure the marks line up when the throttle is fully open, Honda say + or - 1mm on the tolerance of this, but its quite simple to get this spot on.

Next was to get some two stroke oil in the reservoir and bleed the pump. There is a 7mm nut on the top of the oil pump (the middle one) which needs loosening to expel any air. Access is very tight here and it helps to remove the airbox. I found gravity was not enough to get oil though the system so I actually pressurised the oil reservoir to force oil down the lines, through the pump and out the bleed screw. This sounds highly technical, but I just stuck my mouth on the filling neck of the res and blew hard! 

Next there is a second oil line which runs from the pump called the bypass line, this one I just bleed with a syringe.

**** Even after bleeding both parts the Honda manual recommends you add oil to the fuel (25-50 parts fuel to 1 oil) when you first run with the pump fully open.

""Made sure that there is fuel in the fuel tank (25-50 parts fuel to 1 part lubricant). Start the engine and run it for about 10 minutes with the oil pump control lever in the fully open position so as to force air out of the oil pass tube with the oil."" Page 2-7

Update - just on the above point, that would be 10-20ml of oil per 500ml petrol (1/2L)

My bike, restoration update, fluids

This week I started by bleeding the front brake system with DOT 4, filled the cooling system and filled the gearbox with oil (0.9l).

With the brakes, to save mess (DOT 4 is highly corrosive) I used a hose and a syringe on the caliper bleeding nipple, when the syringe fills you can just re-cycle the fluid back in to its container. You also need a clear hose so you can see any air bubbles that come out. For those who have never bleed a brake before its quite simple.

1/ fill reservoir and pump lever.

2/ pull and hold brake lever

3/ open bleed nipple (8mm spanner)

4/ close bleed nipple

5/ pump lever as this re-fills the lever piston.

6/ repeat until no bubbles come out of the bleed hose and the lever firms up.

*** you can reverse step 2 and 3 (it doesn't matter) but you have to close the bleed nipple before releasing the lever or it will suck the expelled air back in.

Next I fitted the fuel tap and filler cap to the fuel tank, fitted the tank mounting rubbers and re-fitted the fuel tank, side panels and seat. Unfortunately I don't have a fuel hose otherwise I would of ran the bike, so this will have to wait another week. Running the bike is also important to properly circulate the coolant, which needs to be re-checked after.

its me! 

My bike, restoration update, wiring loom, brakes and the MB8

This week’s updated started with installing the battery and adding power to the bike for the first time in about 4 years, after doing this I turned the ignition on and some weird stuff happened! Firstly the oil and neutral lights were around the wrong way, easily fixed, then when I indicated right the tail light came on. Next came a lot of studying the wiring diagram and head scratching, Japanese bikes tend to be really easy to follow, for example a black and white wire will always connect to a black and white wire, in the end it came down to the two six pin plugs reversed, even these are colour coded so it was my stupid mistake. Now we have power and working electrics. 

I also fitted the rear brake light switch and spring, front brake lever and front brake light switch, clutch cover hood and finished the brake calipers with the small sliding pin boot. The brake calipers were then fitted to the forks and the brake lines installed.

Lastly I re-fitted the headlight to make the front look tidy.

MB8 – update, one thing that bothered me with the MB was the tear in the seat cover. The replacement cover came from the M Shop along with some MBX spares and using a heavy duty staple gun I re-fitted the cover. Its by no means perfect, but 100% better to what was there before.

my bike, restoration update, more brakes, indicators and stuff!

A solid weekend in the garage this weekend saw the bike take another big step forward.

Firstly I had the indicators turn up from www.cmnsl.com which I assembled mid-week.

Next some more parts from the M Shop  which meant I could crack on with the brakes, however It soon became apparent that one of the boots for the sliding pin part of the caliper was wrong so these were ordered from ebay for speed. I also put the lever together but I am waiting on the inspection window.

Next the speedo cable went on and the cable guide plus the clutch cable. I also took a little time over cable routing and getting the loom tidy at the front of the bike. Front and rear indicators were fitted and wired in, as was a new horn.

Next I was planning on fitting the NOS headlight but soon realised it was wrong. Size wise it is perfect but had no provision for a side light, so I need another. Fortunately fellow M Club member on facebook Skungheeney Harrison offered me a genuine Honda part he had as a spare which I swiftly took him up on.

Lastly I fitted the NOS belly pan, fitting kit and radiator cover and its really starting to look good!

Update, I now have all the missing brake parts and a battery, next job is get the front brake on and bleed and get the battery on to check if I have it wired up correctly!

my bike, restoration update, front brake part 2

The front brake has proved to be quite time consuming and I would categorise the refurb of it as one of the more major jobs on the bike.

Strip down; most jobs are relatively simple nuts and bolt removal with the exception of the caliper pistons. The manual tells you to drain all fluids and pop the pistons out with air, my home made solution was using a bicycle pump (track pump), a home made adaptor to fit in to the banjo hole and a bicycle puncture patch as a gasket so I could get as much air in to the brake as possible. Not shown in the picture but you need to leave the bleed nipple in the caliper or air will escape.

note: leave the bleed nipple in to plug that hole!

Once all the parts, bolts and seals were removed all parts were scrubbed in a parts washer to de-grease and the surfaces scrubbed ready for paint.

Using VHT caliper paint I then gave everything 3 coats and left to dry for a good 6hrs. Following the instructions I then oven backed at 200 degrees for 1 hour to properly cure and this final process makes the paint chemical resistant.

This presented another problem, it completely ruined the sight glass window in the reservoir. fortunately replacements are available on ebay so a new one was promptly ordered. The replacement is a press fit which isn't as alarming as it sounds. The reservoir only has to deal with fluid expansion and is under no real pressure as brake systems only have pressure between the lever piston and the caliper piston.