Saturday August 16th 2025
Saturday August 16th 2025…
Honda CBR1000FX…
Work began today on getting the recently donated Honda running and tidied up. With a little persuasion it started but was clearly not running on all four cylinders, so it was time to remove the carburettors and have a peek inside. Keiran, Pete, Allan Guy and their team set about removing the fuel tank and removing the carburettors. At first glance everything inside looked clean although one of the CV slides had to be freed off. However a stuck slide wouldn’t have prevented it from starting on 4 cylinders (As it only comes into play as the throttles are opened and the vacuum being created by the engine rises enough to draw the slides upwards). Something else had to be at fault. Graham suggested that despite how clean the inside of the carburettors looked, all the main jets, pilot jets and emulsion tubes (That's the tubes that the main jets screw into) should be removed and cleaned. It was then discovered that two of the pilot jets were blocked up. A block pilot jet means that no fuel can be drawn from the small drillings at the edge of the throttle when it was closed. In other words two cylinders would not have starve of fuel at tickover with only fuel from the choke jet if the chokes were open (In the case of this bike the name 'Choke' was a bit of a misnomer but would have to do as 'cold starting device' didn't have the same ring to it.' The fuel metering screws were left untouched and the float heights could not be altered due to their design. Once the carburettors were reassembled and reinstalled the bike started and ran smoothly at tick over and on small throttle openings. Next it would be time to see if it transitioned smoothly to larger throttle openings. The spark plugs were checked and all looked fairly new and had the correct 0.8-0.9mm spark plug gap. Whilst the plugs were out we took the opportunity of checking the cylinder compression pressures. From left to right they were 150psi 155psi 155psi 160psi which is very creditable. The workshop manual that Graham found online statemed that the cylinder compression should be between 149 and 205 lbs per square inch. So, bearing in mind that the tests were done with a cold engine they are within specification. The engine has screw and nut valve adjusters. Would the valve clearances get a check at the next session. What this space to find out.
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| CBR1000FX Carburettors closely tucked in behind the cylinder head. |
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| Lots of lbs per square inch. |
Suzuki GSF1200 Bandit…
Our spray painting expert wasn't on hand at this session to complete tidying up the frame’s paintwork but Heinz had managed to rework the threads on the new rocker bolts, turning them down so that a six millimetre thread could be cut on them. This allowed them to be used with the threads that had been helicoiled with 6mm helicoils at some prior point in the bike's life. Now we could use all of the lovely shiny rocker bolts that came with the bike to make the engine look even better.
Kawasaki KZ550 Limited…
Our friendly Kawasaki specialist overcame the recent starting/running by locating the vacuum takeoff for the fuel tap and connecting it to the fuel tap. As if to frustrate us just a little longer, the starter switch button decided to break and part of it fell onto the floor. A ring of wider plastic (Designed to stop the button from pulling through the switch and falling) had detached itself from the rest of the button. Could it be superglue back together effectively? Could we locate another button? Could we find another switch? Also during this meeting we began to investigate ways to replace or mimic the missing seat lock. Although made for a wide variety of models, the lock could no longer be purchased from Kawasaki. Ebay prices went as high at £174.00 plus post and packaging. Watch this space. Would we be able to secure an affordable replacement switch? Would the superglue hold and would Keiran have to use his engineering skills to make something to imitate the missing seat lock?
Mash 400 Dirtstar Scrambler…
Graham had almost given up his ‘It or me’ battle with this bike. His despair was caused by the non-availability of important parts such as valve rockers and steering head bearing which according to Chas Man motorcycles were not available from their suppliers. In one last ditch attempt to overcome the non-starting issue Graham set to work grinding the decompressor projections from the side of the exhaust valve rocker foot. Grinding it was a time consuming process done in short bursts so as not to overheat the foot of the rocker and affect its hardening.
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| The exhaust rocker with the decompressor pad almost ground off about an eigth of an inch to go. |
Ducati 250 racer…
Jon joined us and spent some time fetling the seat assembly. Whilst searching for videos on the the Ducati 250 I spotted this video on a 2025 Ducati retro tribute to their 1960s racers what do you think?
Workshop News.
A huge thank you to Gareth for donating us a machine to print stickers and decals from vinyl sheets along with a generous supply of different colour vinyl. So if we have got the logo we can turn it into a sticker or decal. I could see lots of fun being had with this machine.
