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350TSS · 22-02-2021, 08:21 PM

A small problem encountered last week, the 25mm flatslides were seized in the carburetor bodies (Dellorto). I have to get the carbs off to get the engine out. The carbs are clamp mounted on little stubs held into the head with a triangular flat face, you cannot undo the 3 x 5mm bolts which hold the triangular plate without the carbs being off. The carbs themselves were corroded onto the stubs and I could not get the slides out of the carburetor bodies so I could try to wangle the engine out with the carbs still on.

Three days of dosing the slides with acetone/diesel eventually got the slides out and the carb bodies off the stubs.
I wish I had taken pictures of the inside of the carb float bowls, about half filled with a waxy/resinous goo with the consistency of bees wax.
After dosing with carb cleaner (do not get it into cuts on your hands) and scraping out with a screwdriver and about 10 x 20 minute cycles in the ultrasonic cleaner the carbs and the jets were all clean, all exdept the pilot jet on the RH carb which was missing altogether. That inlet tract was horribly black and sooty, not surprising as the pilot jet was effectively a 6mm threaded hole.

The Dellorto flatslide VHB25 is a very rare carburettor, probably only fitted to Morinis, new jets or needles do not seem to be available anywhere so I shall smooth out the ridges on the needles with 600 wet and dry and drop the needle a notch to compensate for the slightly slimmer profile and see if I can make a pilot jet from some 8mm hex brass and the right sized drill.

22-02-2021, 08:21 PM	#19
350TSS Too much time on my hands member Join Date: Jan 2013 Location: Shipbourne Bike: M900 Posts: 1,421	A small problem encountered last week, the 25mm flatslides were seized in the carburetor bodies (Dellorto). I have to get the carbs off to get the engine out. The carbs are clamp mounted on little stubs held into the head with a triangular flat face, you cannot undo the 3 x 5mm bolts which hold the triangular plate without the carbs being off. The carbs themselves were corroded onto the stubs and I could not get the slides out of the carburetor bodies so I could try to wangle the engine out with the carbs still on. Three days of dosing the slides with acetone/diesel eventually got the slides out and the carb bodies off the stubs. I wish I had taken pictures of the inside of the carb float bowls, about half filled with a waxy/resinous goo with the consistency of bees wax. After dosing with carb cleaner (do not get it into cuts on your hands) and scraping out with a screwdriver and about 10 x 20 minute cycles in the ultrasonic cleaner the carbs and the jets were all clean, all exdept the pilot jet on the RH carb which was missing altogether. That inlet tract was horribly black and sooty, not surprising as the pilot jet was effectively a 6mm threaded hole. The Dellorto flatslide VHB25 is a very rare carburettor, probably only fitted to Morinis, new jets or needles do not seem to be available anywhere so I shall smooth out the ridges on the needles with 600 wet and dry and drop the needle a notch to compensate for the slightly slimmer profile and see if I can make a pilot jet from some 8mm hex brass and the right sized drill. Last edited by 350TSS; 22-02-2021 at 08:24 PM..