CT70 Idle issue question

85CTrider

85CTrider

Member
i have a nice 1985 ct70 that i have had for many years... i know how to clean a carburetor.. i recently cleaned it and cleaned the main jet and cleaned all the holes and the tiny cross holes on the idle jet. after the bike sat for a few years - the bike starts fine and idles fine when first started.. after running for a bit when i stop at a stop sign or whatever - it likes to die on me... feels like the idle is to low or something... gas air vent is open,,, gas flows good...choke off - what else should i check? spark plug? what causes it to die when warm?? do i need to clean the jets again?? any other ideas?
 
Adam-NLV

Adam-NLV

Well-Known Member
Maybe its running lean? Take out the spark pug and check how it looks. You can tell how well an engine is running by the condition and look of the spark plug. Dry and clean is preferred:).
 
L

lukelaw1

Active Member
Does turning the air fuel screw have any effect on idle? If you can't dial in the air fuel mix id be looking into a vacuum leak
 
85CTrider

85CTrider

Member
All good ideas.... I saw the spark plug was black and dry.. the bike was sitting for 7 years.. i have not tried the air/fuel screw.. every time i mess with that it takes for ever to dial it in again.. when i took the carb off to clean it there were a few crusty gaskets.. namely the O ring between manifold and carb / where the carb bolts on with the two bolts.. that O ring was like half of an O.. would that make the engine die on idle???? points and condensor have never been changed either.... what would be best to start with???
 
6

69ST

Well-Known Member
dirtbkr188 said:
yes, that would create an air leak, try replacing that o-ring first and see how the bike rides.
Click to expand...

Absolutely!!

That will probably cure it. However, if the idle is still weak try turning the pilot air bleed (a.k.a. idle) screw 1/2 turn clockwise. That should richen the idle...too much. If it does, back it out (readjust) to get the best idle. If it makes no difference, the pilot/idle fuel circuit is restricted...not flowing fuel normally...and you'll have to figure out where the blockage is.
 
85CTrider

85CTrider

Member
think i would find an o ring that would fit in that at home depot in the small parts bins? or do i need to order from honda?
 
85CTrider

85CTrider

Member
Oh.. alos - that little o ring makes that big of a difference when the carb is connected to the manifold pipe with that black plastic triangle piece? air will still leak causing engine to sputter out?
 
85CTrider

85CTrider

Member
Does anyone know the size of that O ring.. ???? Honda wants 59.00 for a carb gasket set... not doing that - i will try to match it somewhere... or has anyone found an after market ring i can use???
 
saskct70s

saskct70s

Member
sounds similiar to my problem...does it run good for a bit before idle problems? my oring is new so im wondering if this is condenser
 
L

lukelaw1

Active Member
What is your compression? You stated the bike sat for some time possible a ring is partially stuck? Low compression can cause some weird things.
 
85CTrider

85CTrider

Member
OK im no compression expert - but would there be a problem with compression if when i kick start it, there are like 3 or 4 dead empty kick before one catches and causes it to start>>>>/?? or is that normal?>?? or is that a ring issue?? bike sat for 7 years...
 
85CTrider

85CTrider

Member
Ohhh... if it does not sound like the piston rings will a bad points gap make it stall on idle but run a bit better at high revs??
when running it does sound a bit funny and sputtery...
should i set the points again?
 
Top