Wednesday, February 6, 2013

CB250N Cafe Racer The Hornet and the 5K wall


Here is a photo taken by the seller of me riding away from his house..



So now the saga..

Well I have spent the last few days rebuilding the carbs on the bike, had them off about 15 times, checking and rechecking cleaning and checking again.

A photo of my work area, I am in a small unit with no space..


I spent a lot of time reading blogs, forums and tuning guides and kept coming to the 5K wall that honda twins of this vintage had. This was the problem I was having with the CB250N it would not rev past 5k  and I now was pretty sure it was not the carbs.

Okay this led me to electrics, COOL.... I know but in a past life I did this as a job and my hobby is Ham radio and electronics so now I went from an area i was okay in (Mechanics) to an area I actually loved electrics.

I was able to get the bike running so the first thing i did was put a timing light on it to see if the high RPM pulser was triggering the advance, it was advancing but I noticed that as the bike surged and lost power it lost spark, okay so it really is looking like an electronics problem.

Okay next I pulled the wiring to the CDI on the left hand of the air box... WTF I just noticed that the frame has been resprayed with the bloody wiring loom on the bike, there is paint in the connectors, there is paint on the earth points and paint everywhere it should not be....

So out came the dremel (mini grinder) and I started to sand all the paint of the earth points for the coils and CDI. I removed some extra wire that had been spliced between the CDI and the stator and reran the loom to get an extra two inches to rejoin the loom.

A photo of the "new" rewired loom you cant see much but I replaced connectors in the harness and removed a 6 inch splice someone had added to the stator wiring (blue white CDI voltage wires) and reran the loom to allow for the shorter length



Gapped the plugs and cranked it,.... Its alive its alive it is revving to red line and just sounds heaps better.

I hosed the stator with with a dry silicon lube I use that repels water and doesnt harm wiring to protect it and stop corrosion.

So I have been over the bike and so far have a small list of things for RWC (MOT) they are as follows...

Replace Brake Lever (I broke it putting the bike in the car)
Re wire front brake switch
Plastic weld LH side cover crack
Lube Clutch and Throttle cables
Pull apart RH switch block and clean Hi/Lo switch
Replace Fuel line and add inline filter
Sync Carbs
Reweld header it has a small crack near the muffler

On the plus side the previous owner who could not get it to run well had done the following already...

New chain and sprockets
New Rear Indicators
New Brake pads and bleed brakes
Replacement seat from wrecker
New brake light

Anyway that will do for this post... but for those that didnt see the last post in the welcome section here is a rendering of what I want the bike to look like when done


Friday, February 1, 2013

My New Project CB250N Superdream


I decided I needed a project bike as the XJ is getting tired and I didnt want to do it up as it is a bit heavy for me as I have a back injury (From a stack at 18 years old on a CX500 shaftie at 186 KPH or about 115 in the old currency) and I wanted a lighter bike.


Today I sealed the deal on a 1980 CB250N for AU $800 and went to pick it up. I got an unregistered vehicle permit to allow me to ride it home, this is a temp permit for moving a vehicle to a new home or to a mechanic etc for repair.

I got 1.5km or about a mile from the sellers house and that was it the needles in the carbies got shit in them and it started flooding, what to do, what to do.... I had my wife following me in the car a Ford Falcon station wagon as she had driven me down to pick it up. I was about an hours ride from home and not going anywhere fast, top speed I could get was about 20kph.

Okay pull the bike on to the verge on the side of the road and drop the few litres of fuel I had put in to ride it home it will evaporate off the road and I didn't do it on a drain or anything like that, I didn't want to but had no jerry can to collect it.

Next I had to lift the rear wheel in to the back of the wagon with a snatch strap attached to the rear wheel, the strap was so my wife could pull it from the front while I lifted the bike, with my back I could not lift the dead weight and push it in to the car at the same time. Between dropping the fuel and wrestling the bike we blew an hour on the side of the road.

The tailgate would not quite close so I strapped it closed and set off home but hey I got the bike up to 100kph. better then the 20kph it was doing earlier even if it was in the back of the car.

Well now it is home and out of the car, I forgot to take a photo of it in the car, oh well you can all imagine that. So now it all begins. The bike is not in to bad condition it has an oil weep from the rocker cover, the carbs need work and the muffler weld is cracked at the headers, oh and as I found out it starts in gear so will have to sort that out.

The course of action is to repair the small things I need for a road worthy and get it registered. Then I am going to attack it and I really do mean that.... This is my mock up of what I want to do with the bike.



It may not be exactly the same when finished but I mocked this up as a guide of what I would like it to look like when finished, I am going to do what I call a rolling resto in that I will be riding it and taking it off the road for a week here and there to do it in stages

The first photo is how it was when I picked it up, and the second is the mockup i did

Looking forward to your ideas and input on the project as it moves along