Saturday, May 23, 2015

CR250M-Many Problems Solved

Over the past couple of weeks all of the issues with the CR have been sorted. First of all, the rear tire was finally mounted about two weeks ago. All tolled, I mounted the tire six times before I finally got it done. The forth time that I mounted it the tire did hold air, but when I went for a ride the tube blew out. I had repaired it...obviously not well enough. The last time I mounted the tire I used an extra heavy duty tube...which was even harder to mount, but I suspect that it will be with the bike until I die or sell it to someone else.

The next issue to present itself for solution was the right side cover...see above. After removing the cover to take a look at the clutch, I remounted the cover only to discover that the kick-start shaft was binding in the side case cover. I tried numerous strategies to solve the gasket...old gasket...nothing really worked. So I proceeded to very slightly enlarge the opening for the kick-start shaft in the side case with my Dremel tool. I had no worries about creating an oil leak because the opening the the side case has an oil seal, and the oil level in the side case is well below the opening. Right now...everything is cool.

The next issue was the rear suspension. When I finally received the bike, it was clear that the right rear shock absorber had received a mighty blow. It was bent inward at least 2.00cm...a little less than an inch. I was going to replace the shocks so this discovery was not a heart breaking event. I ordered some Betor shocks from Spain. Delivery was promised in mid-March. By early May nothing had arrived so I had to look at my options. My first thought was Falcon Shock Absorbers. The guy there is Robin Packham. I have used Falcon shock absorbers on my TLR for many years and I am very happy with them.

You get very personalized service with Robin. We ended-up talking on the phone for a long time finalizing all of the specifications. Every shock is custom made at Falcon . My shocks turned up on my door step about two weeks after we completed the order. They are beautifully made.

Unfortunately my Betor shocks showed up shortly after I placed my order with Robin. One of the nice things about the Betors is the fact that the body of the shock is the same color as the bike. Take a look at the picture below. Leaning against the rear sprocket are the Falcon units.

Less fortunately, the Betors needed a lot of work to mount. Grinding was necessary and some hacksaw work was required. On the other hand, the shocks seem to hold up the swing arm just fine. I am looking forward to trying the Falcon shock absorbers. I ordered the Falcon shock absorbers with 70 lb. springs, and I am sure that the Betors came with 100 lb. springs. I expect to prefer the lighter springs.

After all of these successes with the CR I had to go for a ride. Things did not turn out perfectly. I rode out about ten miles from my house along some dirt roads and the beach. At my turn-around spot the CR did not seem particularly interested in idling. I pressed on keeping the revs up. About three miles from home, I was left with nothing about a very rough idle. I made it home and the next day I took the carburretor apart expecting to find a thoroughly blocked main jet...that was not the case. I did a ultrasonic clean and put everything back together.

On the trail the day before,  I had discovered that the plug cap was very loosely attached to the spark plug. Back home I replaced the original cap with one of my NGK units which I much prefer. It appears that the plug cap was the problem. I had discovered that there was nothing wrong with the carburretor, and when I started the bike after going through the carburretor and replacing the plug cap...all was well. One more long ride will give me an answer. What I really do not want to do is start chasing some heat related ignition problem. We will see.

Monday, May 18, 2015

The Art of the Bultaco-Restored

To those of us of a certain age there is an expectation of what a Bultaco is supposed to look like. And, I think a lot of us, are of the belief that is is the prettiest motorcycle engine ever. There is the clean egg shaped cases...the upswept exhaust with the rich chrome finish... the relatively crude expansion box...and finally the very clean inlet tract with the screw-on air filter. You can easily picture the mixture entering the engine...combusting...and exiting the high mounted exhaust.

I was forced to toss the original Monobloc Amal Carburettor which came with the bike. And, by the way, that carburettor was not original to the Campera. It was originally equipped with a Zenith which was not only ugly but also prone to wear. The Monobloc and the intake manifold which came with this bike when I bought it was from a Mercurio. It was over jetted and worn out. My solution was to install a Chinese copy of a Mikuni which was originally intended for a wide range of Japanese 175 cc trail bikes and MX machines. This installation involved two different adapters bolted on to the intake manifold. An air cleaner was eventually discovered which would fit between the carburettor and the frame. It was not a pretty picture. You can see the installation on one of my earlier posts.

The Chinese Mikuni worked well but I could not bear to look at all of those mismatched pieces. It was absolutely disrupting the graceful lines of the Bultaco engine. The solution was provided by .British Bike Bits. I was able to source a Amal (Wassell) carburettor which is intended for a 175cc BSA Bantam. It is a Concentric and its concentricness means that it is somewhat longer from top to bottom than the Monobloc which it replaced which in turn means that I had to find a spacer to move it out just a bit from the mounting studs to create some clearance. If you check the picture above you will see that there is on a tiny clearance between the bottom of the carburettor and the case. The spacer, between the carburettor and the intake manifold is also clearly visible. That little spacer raised the carburettor up just enough so as to clear the cases.

I have gone out on two test rides and it works perfectly. For me if a motorcycle starts easily and idles I am about 80% perfectly happy with it. The Wassell/Amal carburettor makes the Bultaco even easier to start than the Chinese Mikuni. Just use the tickler to run some gas down the intake manifold and off you go. Never more than two kicks.