Strip, mod­ify and re­build R1 car­bu­ret­tors

Classic Ford - - CFTECH -

Check the body of the carbs for cracks and re­pairs around the float bowls and fuel in­let. Op­er­ate the but­ter­flies. If they’re seized, spray pen­e­trat­ing fluid around the spin­dles to free them off.

Use a pair of long-nosed pli­ers to ex­tract each float. Store in or­der of fit­ting. Check the nee­dle valve is still at­tached to the float when ex­tract­ing it.

Us­ing a flat-bladed screw­driver, slacken each main jet. They are usu­ally very tight, so be care­ful not to slip and dam­age the head.

Use an 8 mm span­ner to undo each main jet holder.

Re­move the float cham­ber cov­ers. Each one is fit­ted with three crosshead screws. Store the cov­ers in or­der of fit­ting be­cause they are man­u­fac­tured to fit ac­cord­ingly.

Each carb has a small fil­ter that’s se­cured with a re­tain­ing screw. Undo each screw…

Care­fully re­move each main jet with your fin­gers and store in or­der of fit­ting.

Re­move the hinge pin for each float. Use a sewing nee­dle with a bent end to push the hinge pin through, then pull it out with a pair of long-nosed pli­ers.

…Then ex­tract the fil­ter and store in or­der. Clean these fil­ters with carb cleaner.

Once each one has been fully un­done, ex­tract them with your fin­gers and store ac­cord­ing to the or­der of fit­ting.

Ex­tract each di­aphragm cover and spring. Store them in the or­der of fit­ting.

Use a flat blade screw­driver to re­move the pi­lot/ idler jets. Check they’re not blocked by hold­ing them up to the light. Blow through them if they are blocked.

Care­fully ex­tract each di­aphragm. Don’t dam­age the di­aphragm. In­spect them for split­ting and re­new any that are.

We’re ready to re­build the carbs. Start with the fil­ters from Step 5, the main jet hold­ers from Step 7 and the pi­lot jets from Step 8. Avoid over­tight­en­ing any of these parts.

Turn the carbs over. Undo and re­move two crosshead screws for each of the four di­aphragm cov­ers. Each di­aphragm cover is spring loaded, so hold it down when un­do­ing the sec­ond crosshead screw.

Wash the car­bu­ret­tors in a de­greaser and lightly scrub them with a soft brush to re­move any var­nish and dirt. Wash with water to re­move the de­greaser and dry with a heater or hair dryer.

Check the pointed end of each nee­dle valve isn’t blunt. Lower each float and nee­dle valve into po­si­tion and re­fit the hinge pins that were re­moved in Step 3.

Turn the carbs up­side down to make sure the floats move freely.

The main jets will need to be en­larged with a drill. Con­tact Bogg Broth­ers to find out the rec­om­mended di­am­e­ter of the main jet ac­cord­ing to your en­gine. If you don’t fancy drilling, the same sized main jets from the We­ber DGAV can usu­ally be fit­ted in­stead.

Check the seal on each float cham­ber cover is not dam­aged. Clean it with carb cleaner. Re­fit them, then turn the carbs over and re­fit the di­aphragms, springs and cov­ers. Avoid over-tight­en­ing the re­tain­ing screws.

Most bike carbs are se­cured to the in­let man­i­fold with flu­oro-lined sil­i­cone hoses (the lin­ing is suit­able for petrol). These can be fit­ted onto the car­bu­ret­tors first and re­tained with nar­row band hose clips.

The carbs and hoses from the last step can now be ma­noeu­vred into po­si­tion and fit­ted onto the in­let man­i­fold. Se­cure them with more nar­row band clips. Ju­bilee clips are not suit­able as they will foul the throt­tle link­age.

Us­ing a flat blade screw­driver, wind in the idle mix­ture screws, then turn them out three-and-ahalf turns. These may need to be fine tuned when set­ting up on a rolling road.

Con­nect the choke and throt­tle ca­bles, the throt­tle po­si­tion sen­sor (if fit­ted) and fit an air fil­ter.

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