Dear Andy,
A big thank you again for your sound advice.
Am 95% certain the rotovator was a good machine before it was put away 25+ years ago. The only nagging doubt I have is over the clutch, why is there some ‘feel’ on the handlebar lever only when both adjuster are tightened to their full extent. Do not want to spent time and money on it, only to find there is something broken that cannot be fixed with the clutch. If it is just worn friction plates, or the bearing knackered on the engine adaptor plate, then obviously can do those. But as you say, can only assess this once I have split the machine. Was really after advice from someone who had a lot of knowledge of Howard Gem clutches and what to look out for before I undo the bellhousing. Decided the re-commissioning process was to get the engine running first and if that was good, move onto the clutch. Like to do some research before I tackle a job I am unsure of. Find that the experience of others is invaluable in that respect. It can save time and possible damage if you try to disassemble a part that has a retainer you are not aware of.
Have always used petrol and an airline for small parts cleaning. Found Gunk and a pressure washer great for removing thick oily sludge on engines. Mostly petrol and a good brushing has removed gum on carburettor’s, except the really hard to shift historic coatings. Have googled ultrasonic cleaners for carbs and some say they are brilliant, others say so-so because the small passages are not fully cleaned. But am going to take your advice and see if I can find someone with one and chuck the carb in.
Have got a Zenith 24T2 carb with an adjustable jet on the Jap 5 on my Trusty. Replaced the original Jap carb with the Zenith and it was that that I made up the new linkage for. The Zenith was removed from a Trusty that was left outside for decades. Put a service kit on it from Villiersparts, that included a new throttle spindle. The old one had a big flat on the linkage side, so air could be sucked into the carb. The new spindle then made a huge difference at tickover and throttle pickup, which is so important on a Trusty. But sometimes it will start by the third swing of the starting handle, others not even after twenty on full choke. It appears it is not getting enough fuel to start it from the main jet to the orifice in the ventri, with the chamber not being clean and smooth, preventing the petrol from being sucked through it with a single swing of the handle. Luckily a Trusty can be started with a strap, so I can get it to go. But re-built it last year, so it has full compression, getting a bit long in the tooth to keep having to turn in over with the strap. When I find someone with an ultrasonic cleaner, will take both the Walbro and Zenith carbs for a clean.
Have attached the pictures. One way or another I know I can get the fuel system sorted out quite easily. Have a feeling it may be the petrol tap only delivering a fast drip, in turn making the original diaphragm on the fuel pump let air bypass it, delivering frothy petrol to the carb. That could be the real cause of the problem. But having the carb ultrasonicaly cleaned will not hurt either. Will be very interested to see the results to both carbs. Have you ever taken a clutch apart and if so, what did you find.
Grahame
