Dellorto symptom

[77gears]

Hi Everyone,
Strange symptom while tuning carbs on 1000s. 36 PHF Carbs have been rebuilt and balanced. Fine when warm.

The symptom is with the chokes. They have new choke pistons. It will never idle on choke but..... when i gently pull up the left choke cable.. the idle comes up. If I do the exact same thing on the right side, you can hear the intake air chugging and it stalls or pops like it is lean. What is weird is that it seems like it is letting in more air when the cable is tensioned??? Should be less air.

Notes: No vac leaks, has all new Dellorto parts, o rings, gaskets, accel pumps and carbs are clean.

Any ideas?
Many Thanks,
Peter

[guzzisteve]

Did you sync the chokes, makes a difference. If you want it to idle w/chokes on you need something like a #60 or close to what the idle jet # is as the jet #

[jacksonracingcomau]

My guess spark or mech issue
Swap carbs, see if issue follows carb or cylinder

Or leakdown test and ignition ohaul / timing set.
Duff lead or plug ?

[Idontwantapickle]

Those are not chokes but enrichening circuits. What you describe is most likely the result of a clogged jet to that circuit. It is the one that the rubber surface of the plunger blocks when completely seated. When you open the circuit you are adding air but no fuel.
The circuit works by bypassing the throttle and all other jetting and adding both fuel and air needed for the cold engine.
Clean the jet and passages and all will be well. A clean carb is a happy carb!!

Hunter

[Idontwantapickle]

I will add one more thing. This type of circuit works best when the cables are adjusted properly so that the plungers open fully allowing enough air to pass when the �choke� lever is pulled. There is a tendency (and I have done this) to leave a LOT of slack in those cables just to be sure they stay closed. But this arrangement will make the engine hard to start cold and can flood the engine or foul the plugs due to the distorted mixture supplied by the partially opened plunger.
If any of you have 40mm pumpers this is easy to check as the plunger is in a separate part and can be removed and observed for correct operation.
It may sound complicated but in the end if the carb is clean (I know, I said that already) and adjusted properly your riding experiences will be much better!

Hunter

P. S. If you�re nearby just come on over and I�ll help you.

[77gears]

Brilliant. Thank you guys. Will check all of that later today.

Enrichment, not choke... interesting.. like my old japanese two stokes (if it ain't smokin'... its broken)

I carefully cleaned all of the jets but i remember that I was using an external fuel tank that I later found had contamination in it. I now have a proper aux fuel tank on an IV stand which works great. Much better that the old man soup can hanging off the handlebar and spilling everywhere.

Thanks again guys. Stay tuned... might have another question as I go. 

Best,
Peter

[77gears]

Ok.. Update and a question or two.
I took out the choke piston. Removed the bowl and starting jet. All clean but I cleaned and blew out the passages.
Went to balance the choke cables and realized that I ....

need clarity on choke lever. There are two ball detents.. one in the off position and one is about 10-20 degrees from that which the book says is the cold start position. However... you can pull the lever all of the way to the handlebar controls. Is this supposed to go that far? Do people do that? Crank it all of the way back past the detent?

The other problem is that the choke cable adjusters are almost all of the way out and the cables still have at least 3mm play.
Is there a second adjustment in the splitter?  Maybe the wrong cables for this model?

It is a friends bike that I am working on, and everything is going great except for this enrichment issue, so I appreciate your helping me finalize it.  It is a beautiful stock 1993 1000S US model with the 36PHFs.

Many Thanks for any wisdom or advise. Headed out for a systems check.. She is fun to ride. Very Italian feel.

Peter

[guzzisteve]

Yes, my SP3 had same set up. Had to be real cold out to pull it all the way back.  You can leave the play, just put on a set of carb sticks so they slurp the same and make sure they have play w/closed. Check your orings too, might be a tiny one on the top and a fat one on the jet that fits in the well in bowl.

[77gears]

Brilliant... Thank you guys. Works like a dream.. put in some #60 jets (and made sure the chokes were perfectly synced) . Starts up with choke on.. nice clean high idle.. responds to throttle on full choke. No coughing, spitting or smoke or loading up. Really grateful for the help.
Guzzi Steve, you mentioned the smaller choke jets.. so thank you. It was way too rich before. Easy to change, fixed the issue.. Brilliant.
Can't wait to have another problem so I can ask you guys.. haha
Best,
Pete