GUIDE: Fitting new seals to your GK76a Carbs!

[stripes1976]

brass nut in the centre of the picture. undo this. remove the jet block (must replace this gasket on overhaul).
strip the top of the carb and withdraw all from the top.
When refitting main jets do not overtighten or you will distort tubes.
Do not tighten idle mixture screws tight just until they touch.
Always wind out to base setting and adjust until idle returns without hanging.
There are 3 jets in the jet block. Make sure all 3 are cleaned. Do not use spray carb cleaner on the brass, plastic or rubber as it rots rubber and furs up the brass.
Do not use gasket sealer in the carbs as it will go like jelly and block jets.
I had started a carb rebuild guide. I spent best part of 20 emails or so helping tony sleep with his carbs and gave up a few years ago before the server changed and i lost thousands of posts with alot of technical info in.

If anyone is unsure ask. Some parts are impossible to get now and easily damaged if you don't know what your doing.

[templin]

hi ben if the bike is using to cold a plug or if mix/pilot screw to far turned out the bike will faul the plugs as for synchronizing the carbs an easy way to get you on the road quick (it ant the best way but works well enough for most folks)

step1.
with carbs in hand locate adjusters between the carb bodies (three in total) on the throttle shaft loosen all lock nuts starting at the end carbs first then to the center one turn them so the throttle plates open (2 turns will do)

step2.
turn the idle screw out till the the butterfly closes to a SOFT LIGHT stop (open close throttle valves repeated untill you when it closes and does not stick when opening) normally the number 2 carb is the control cylinder (cotrol cylinder is found by seeing which carb is direcly affected by the idle screw and not held open by the adjusters connected to the throttle shaft)

step3.
starting at the center adjuster turn the adjuster so that no3 carb butterfly closes to match no2 again open close throttle lever (cable end) to make shur you dont turn to far if you do number 2 butter fly opens and no3 gets jamed into the bore once happy holding the screw lock the lock nut

step4.
as with step 3 repeat action on the outer adjusters completing one at a time once done refit and start bike then adjust idle and warm motor up final set idle with a warm motor

note:-
if you did this correctly and carbs nice and clean bike will idle smooth and respond niecly to throttle if the bike running poorly or wont idle or just idles high or runs on three cylinders at idle but runes on four off idle you did not do the balancing correctly start again when you refitted the carbs the second time recheck that spark plugs are ok cause a fauled plug will miss up your day and have ripping the carbs on and off repeatedly

as for the o-rings i find the oil option better each to their own

[stripes1976]

no lock nuts on the balance screw. its retained by springs.
The 76a doesn't balance nice with visual balancing on the carbs.
balance the carbs on the bike with the engine running with gauges.
balance the carbs in pairs. 1 to 2 then 3 to 4. then balance centre screw to do the pairs.

[ben2306]

hi ben if the bike is using to cold a plug or if mix/pilot screw to far turned out the bike will faul the plugs as for synchronizing the carbs an easy way to get you on the road quick (it ant the best way but works well enough for most folks)

step1.
with carbs in hand locate adjusters between the carb bodies (three in total) on the throttle shaft loosen all lock nuts starting at the end carbs first then to the center one turn them so the throttle plates open (2 turns will do)

step2.
turn the idle screw out till the the butterfly closes to a SOFT LIGHT stop (open close throttle valves repeated untill you when it closes and does not stick when opening) normally the number 2 carb is the control cylinder (cotrol cylinder is found by seeing which carb is direcly affected by the idle screw and not held open by the adjusters connected to the throttle shaft)

step3.
starting at the center adjuster turn the adjuster so that no3 carb butterfly closes to match no2 again open close throttle lever (cable end) to make shur you dont turn to far if you do number 2 butter fly opens and no3 gets jamed into the bore once happy holding the screw lock the lock nut

step4.
as with step 3 repeat action on the outer adjusters completing one at a time once done refit and start bike then adjust idle and warm motor up final set idle with a warm motor

note:-
if you did this correctly and carbs nice and clean bike will idle smooth and respond niecly to throttle if the bike running poorly or wont idle or just idles high or runs on three cylinders at idle but runes on four off idle you did not do the balancing correctly start again when you refitted the carbs the second time recheck that spark plugs are ok cause a fauled plug will miss up your day and have ripping the carbs on and off repeatedly

as for the o-rings i find the oil option better each to their own

thank you so much for the reply. previously, i was using denso U27. after 2 times of all plugs became sooty black, i changed to iridium power denso IU24. it was a hotter plug. some told me g4 is rather an old bike, not suitable. some told me iridium good. as mechs in singapore , i chose to use iridium, retune & now just got to wait for my next oil change & see how's the plugs. hope everything is good. only issue now is when moving off @ around 2k rpm, it sounds abit funny, after that range, its alive!

[ben2306]

no lock nuts on the balance screw. its retained by springs.
The 76a doesn't balance nice with visual balancing on the carbs.
balance the carbs on the bike with the engine running with gauges.
balance the carbs in pairs. 1 to 2 then 3 to 4. then balance centre screw to do the pairs.

thanks. right now i'm trying my luck to see whether i can find any 2nd hand carb tune gauges in singapore. without that, its too risky for me to d.i.y. in singapore, i pay S$80 for a carb service. told him to set my mixture screw @ 1.5 turns, he insisted on setting it @ 3 turns which he was following the old setting when he opened up! it was running rich thats why i'm letting them do service but they are ! g4 is an old bike in singapore, where ever i go, that shop will tell me its time to scrap, dont waste $$. so i've decide to make it all good, to prove them its old but still alive.