Hi,

I've got the other thread going re: stage 1 kit and fuel overflowing the carb, etc. But now I've got the bike running great with issues....

Even when warmed up - at operating temp (I was able to take it for a real spin... OMG - I love this ride.... ) the issue is that if I put the choke all the way in --> IMMEDIATELY i get spitting out the carb, gaps, loss of power, etc I pull it out the SMALLEST amount - maybe 1/4" (hard to tell while i'm riding) and it runs real nice. No loss of power, or backfiring or anything.

I've had the carb off -hmmm - 8 times - could I have messed up the choke? I always keep it on the carb.

What is this symptomatic of? Could the float in the bowl be too high and causing the wrong mixture and needing the choke on to fix?

Anyways - I'm enthused because it's SO close and I think I can do the rest of the adjustments with the carb on if I have to.

TIA [sm=confused06.gif]

 

Dang, frustrating some times. Hang in.

Sounds like you're too lean. Pulling the choke closes off air and richens the mixture. You should wonder about jet size (maybe need larger) of course. Maybe a dirty jet. Maybe the float is too LOW. Maybe a fuel restriction. Do you have a big engine needing a bigger petcock?

What is the throat size on your carb? For that matter what carb do you have?

Too big of a carb can do this. Too big of an air passage (venturi) slows down the velocity of the incoming air and you lose vaccum which is the signal that pulls fuel into the air stream. That lets in lots of air, not enough fuel, and you are lean. Of course, pulling the choke, which is partially closing off the venturi, effectively makes the air inlet smaller and "cures" that.

What think?

JB

 

Thanks for the info.

40 mm CV carb. Stock carb on my 05 Dyan Super Glide.

If the fuel in the float bowl was too low - i.e. float set really low - then that would be a lean condition from what i read. I've levelled the float, the needle is sitting properly (tested by blowing) - and I've raised the fuel level in the bowl (making it richer) but fuel still overflows.

But man - it runs well with the choke/enricher out that itty bitty little bit. Maybe tomorrow it'll make more sense....

doh.

thanks.

 

Actually, the choke on a stock CV40 carb is not a choke as described above but an enrichener. It does NOT restrict the throat of the carb. It controls the position of the enrichener valve. As the enrichener (labeled choke) is pulled, the valve richens the fuel/air mixture (allows more fuel into the engine). The amount of air is unchanged. The result is somewhat simlar...richer mixture. The difference is that with an enrichener, your adding more fuel...possibly more than your engine can burn. This can lead to fouled plugs and bad gas mileage among other things and is why it should be used sparingly.

I agree with JBaker...it sounds lean.

I'd suspect an intake leak causing the lean condition (or maybe another vac leak).

 

Let this fellowdo his thing onit, I bought a new never usedCV40 off ebay, sent it in to him to rework.
The original carb was puking through the air cleaner, flat spots, leaking gas.
His work is flawless and guaranteed.
http://www.harleydavcvcarbrebuild.com/

 

Problem solved. It was - as often they are - stupid. this was after 2 mechanics could not find the problem though!!! The gasket was blocking the vent hole on the face of the carb. The 3 screws were going in but the hole on the brace to allow the venting was blocked by the gasket.

Once I openned up the hole... bingo - no need for Clutch/enricher. Idles nicely. Not one backfire / pop or spit. Full power through all the throttle.

sweet. Thanks all for the help.

 

Thats great !
That has gotten me also in the past.