Friday, May 5, 2017

Bringing them back alive…

It was another week of bike wrangling at Casa de Honda as the month of April winds down. Recent sales included a 2015 Sym 150 Wolf (after the BAT sale of the CR93 tribute bike, a Suzuki GN400 and the 2400 mile Yamaha XS650). Most recently, I swapped out a mint condition 2013 PCX150 scooter for a non-running 299 original mile 2008 Honda 250 Rebel.

If that wasn’t enough, I spotted a survivor 1968 CL125A Scrambler in the local Craigslist postings, which had been on and off their site for a week or so. When I contacted the seller to find out about the basics like: Does it run? Is it registered currently? Are there any big problems with it? Etc..
The initial response was “I don’t know much about motorcycles.” Digging deeper in the communications, it appears that the bike was bought because it “looked cool” and it was a first motorcycle purchase for him. As I expected, it was a good 10-footer, but when you got close-up it became obvious that the bike was basically all original: cables, tires and body paint. The tank had been re-sprayed with some kind of close to Honda Silver color, but the rest of the Candy Blue paint was untouched, apart from the scratches, dings and general wear and tear that you would find on a 49 year old baby Scrambler.

Both bikes needed new batteries and fuel system maintenance. Despite the stinky green fuel that exited the petcocks, the carburetors were relatively easy to clean after wrestling them out of their respective chassis. These two bikes must be somewhere in the TOP 10 of “hard to remove” carburetors category. The CL125A carb is sandwiched in between the cylinder head intake port and the rigid air cleaner tube that flairs out over the opening in the frame. The only way that I could see to remove the carburetor was to take off the two 6mm nuts, then, using Vise-Grips, work the two intake studs out of the head, so the carburetor could slide sideways out of the frame.

The idle jet was plugged up and all the rest of the jets and emulsion tubes were cleaned and checked for open passages. This was Honda’s first attempt, that I know of, to create a CV (constant velocity) carburetor. The slide has a delicate rubber diaphragm secured to the top by way of a plastic plate with 3 tiny screws attached. In the middle of the plastic plate is a spring-loaded plunger which is pressed down by the carburetor arm which resides inside the top cover. While CV carbs on 350 twins from 1968-73 used a light spring to press the slides down in the carburetor body, the tiny slide on a 125 (remember this is a 360 degree firing engine with a single carburetor) is too small to control in the same manner, so Honda put a big heavily weighted spring in the top cover to push the slide down firmly whenever you let off the throttle.

While the diaphragm was probably original and felt/sounded very brittle, there were no holes or tears in the rubber, so it was gently reassembled and seemed to hold vacuum properly. The carburetor flange is sealed with a 32mm o-ring, which has been discontinued from Honda. I had been buying some various sized o-rings from eBay sellers in China for use on Honda Dream carb flanges, so one of those was popped into the groove when the carburetor was installed.

The fuel tank was purged of the old gas and refreshed with some of 7-11’s finest 91 octane brew. With a new piece of OEM Honda fuel line, the carb was again reconnected to the fuel supply. The original battery was a small electronics store item, which was marked “Removed in 2003.” The battery wire ends were changed to the small push-on connectors, but I had ordered an old-school lead-acid battery which is big enough to support an electric starter, but these bikes never had that option. I snipped off the wire ends and found some ring terminals that would fit the 6mm battery bolts normally used with these batteries. With the fully-charged 6v battery installed, the switch was turned to ON and the bike lit up with all functions working as designed. Yeah!

With fresh gas on the tank, A few good kicks and the bike started up, sounding sweet and healthy with no smoke out the muffler (thankfully no muffler rot for some reason). The original tires were rock-hard, so a brief and gentle spin around the block was enough to confirm that the transmission and clutch seemed to be working properly.

2 weeks later…
The little CL125A was treated to a new set of tires and tubes, plus fresh carburetor parts that amounted to $60 worth of purchases. I re-learned a valuable lesson about setting up the carburetor diaphragm system when I installed the central plunger in upside down. There is a long and short end to the spring-loaded plunger and when it is installed with the long end up, the throttle goes to wide open revs as soon as the engine lights off. This is VERY disconcerting, to say the least. After a few rechecks, I finally looked at the illustrations of the carburetor and saw that the long end of the plunger goes DOWN. Properly installed, the carburetor assumes normal function once again.

The exhaust system is all stock and the drain hole at the back was still open and there seemed to be plenty of material underneath the muffler, instead of finding the usual rot that happens with time and operation. When the muffler was removed, a surprising hole was discovered on the back side of the muffler relief where it curls around the rear shock. Apparently the rear mounts were bent or not installed correctly and the shock wore a whole in the muffler body. A trip to my friend Rob North’s shop resulted in a mended muffler which then needed a hard-to-find muffler packing for the slip-in left exhaust header pipe. After tracking down a small batch of them, the muffler was finally installed and should function as designed.

NOS old school cables were ordered and installed. The clutch cable installation requires removal of the rear sprocket cover which revealed that the front sprocket was a 16t instead of the stock 15t size. Test rides showed that the bike was unable to sustain a good speed up the long hill to the house from the local PO. It would rev high in 2nd to about 40 mph, then just bog down in 3rd gear under full power. A 15t sprocket was ordered and installed when the cable was changed. The clutch adjuster was found to be extremely tight in the side cover, requiring cover removal and a good bit of time to extract the adjuster and then refit it in the hole so it turned more easily. All these little tasks wind up taking up quite a bit of time to correct during a revival process…

Next improvements are a new right side fork ear, fork seals and a new headlight rim.

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