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1975 CB400F "un-cafe"
kartin:
Back from UK trip with a suitcase full of goodies! The above mentioned exhaust looks pretty good so I might re-visit whether to paint black or not. I think I now have most of the clips/brackets/grommets that were missing. Also got some correct handlebar switches as well as an ignition switch. The handlebar switches check out fine on the meter but the ignition switch didn't show any continuity and wouldn't even turn to the park position. It has clearly been opened before but not cured. I found two issues inside:
- one of the springs that press the little "bridging" pieces onto the contacts was not in place. Maybe this was meaning it didn't sit properly and was preventing the switch from turning properly? Just a guess...
- the strips that form the connector spades are attached to the actual switch contacts by a sort of rivet affair. I found continuity to the rivet head but not on into the strip. I cleaned the rim of the rivet and adjacent strip with a dremel wire brush and bridged the two with solder (being quick so as not to melt the plastic holder). I only did the 3 that are easily accessible - the other 2 seem fine.
The combination of those 2 things resulted in correct operation and continuity in both key positions. In my haste to try it I forgot to take pictures of the solder fix but they are on the back side of the piece in the top-right of the picture with the fabric background (not my picture - just one I found). The other switch picture shows what I believe is the correct orientation of that piece into the housing to get the correct connections for each switch position (TBV when finally fitted to the bike). Continuity testing is made a bit confusing by the fact that there are 2 brown wire locations which are not connected when the switch is stand-alone but are connected in the loom, so you need to try both.
A huge "thank you" to people who have posted colour-coded wiring diagrams, including what wires should be connected in each switch position - they are invaluable for this sort of testing.
kartin:
Continuing to clean up the various bits. The hardest work so far has been the front brake components. I thought I would give the OEM originals I picked up a try before resorting to reproduction items but they have put up a good fight! Even the pads were well seized into the caliper halves, never mind the piston itself... So, freeze, heat, penetrating fluid, tap-tap-tap with a hammer and keep repeating the cycle, trying to break the corroded joints... Eventually the master cylinder piston yielded with some heavy blows via a drift in the banjo end. The bore looks surprisingly good so we'll see what happens there. On the caliper end of things I had to get really brutal to get the old pads out, basically drilling and chiseling until they came free. As for the piston, I thought I was being clever by drilling and tapping a hole in the face then using a bolt + washers to pull it out but all that did was pull the face out of the piston! I tried hammering the sides of the piston in to try and collapse it, to no avail. Eventually I did the drill+tap thing again, this time with the bolt bearing on the inside face of the caliper and out it came! You can see the big pile of grease on it from the attempted grease gun method (which failed). The sealing face is on the piston (which will be new, obviously) and the groove in the caliper (which looks good) so again, worth a try. I'm lucky in that I live in a neighbourhood with 25mph limit and only one entrance/exit to "regular" streets so I can test extensively in a benign environment. If the brake doesn't behave flawlessly, I will ditch it in favour of new parts before I venture out onto "real" roads.
McCabe-Thiele (Ted):
Yikes that caliper piston removal sure was a swine -10/10 for persistence.👍👍👍
Johnny4428:
Good work there. That brake hasn’t functioned for a considerable time.
Matt_Harrington:
Good job it wasn't a twin post caliper. I'm not sure you would have succeeded! Good effort...
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