accelerator pump question

[Guest]

i have a 1978 s550 which has been seriously modified,engine is the only original part on it,has ellmouths on the carbs,has been stood a while,having trouble starting,i,m thinking it is fuel starvation,would this year carbs have an accelerator pump on?a mine does not,also how would i find which model carbs are on it,serial numbers etc,in case not original carbs,appreciate any help as i,m running out of my limited knowledge-cheers john

[Nessism]

You can look up the parts info here...http://www.alpha-sports.com/suzuki_parts.htm

and get the factory service manual for your bike here...http://members.dslextreme.com/users/bikecliff/

BTW, do those pipes have baffles inside? Hope so anyway.

[tom203]

No accelerator pump. If bike has been sitting a while, carb internals for low speed and enrichment (for cold start) are likely gummed up. Can you spot the "choke" lever ?

[hoppy57]

slightly baffled,thanks for info

[hoppy57]

did have carbs off and were surprisingly clean,choke lever seems to operate normally,if it does fire,which is rare,dies as soon as key is released

[geol]

You have Mikuni VM series carb assy based on the pic you posted. Suzuki models didn't have an accelerator pump but Kaw models starting in about 1979 did. The bowl on the #2 carb is longer/bigger than the others and there are small fuel lines between the carbs. Most of them don't work due to being clogged. The pilot circuit on you carbs is like gummed up as is the enrichener circuits. There is no "choke" although the arm that lifts the enricheners is stamped choke to confuse people. A bona fide choke has a butterfly that closes over the carb venturi to limit air; thus making the starting mixture richer. The enrichener circuit adds extra fuel and makes the starting mixture richer. The arm marked choke lifts the four enrichener plungers and fuel is pulled from the bowl and up into the venturi. You should NOT open the throttle while on enrichener circuit as this negates the effect with the slides opened farther.

Suggest you rebuild the carbs, change the pilot jets and ensure all internal passageways are clear as well as the check valves for the enrichers which are in the bottom of the well on the bowl edge where the brass tube fits into. Also make sure the small nozzle hole on the brass tubes are clear.

Starting issues may not be carb related; check voltage at coils and compression. If coil voltages are down (under 11.5 VDC with bike not running), use a relay to power the coils. If compression is down, check valve clearances. If you have points/condensor, check points gap or use a dwell meter and check the timing of the bike and see if the mechanical advance is working as it should using a strobe timing light. Last, inspect the carb holders to ensure they are still supple and not hard/cracked and even if they are just hard, replace them.

[hoppy57]

very informative,much obliged,no points has electronic ignition,might change carb holders,they do feel a bit solid-cheers john