Author Topic: 93 sp111 phf36d carb sync issues  (Read 945 times)

Offline 93spada

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93 sp111 phf36d carb sync issues
« on: June 14, 2018, 07:03:58 PM »
Hi Folks
We are having problems getting the carbs to sync and stay. Using a dial vacuum gauge. 
Just put on new cables. Cable slack has been adjusted as close as possible.
At idle can adjust both to same and that stays put.
Left carb reacts well thru revs then settles to same reading at idle.
Right carb will occasionally read same as left thru revs after fine adjustment but then shows
too much or too little vacuum thru revs after shutting engine off and restarting.
Some times it seems to change mid revs.
These are original carbs and have 86,000 miles on them.
The rubber sleeves are 2 years old and show now sign of cracks or checking.
Plugged the Digiplex vacuum lines and that did nothing to correct.
Just lengthened the enriching cables and got slack same on them but ran out of patience to test after that.
Any thoughts on what would cause one side to go funky???
Thanks in advance.
Paul


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Offline 93spada

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Re: 93 sp111 phf36d carb sync issues
« Reply #1 on: June 14, 2018, 07:21:42 PM »
PS
*****Saw the trouble shooting post after I posted*****
Yes I did do the google search.
Read everything the search returned on carb sync and the PHF 36 A-B DD, Lean burn, shrouded- un shrouded, Euro. US, German variations.
All very informative as well as entertaining.
That spurred me to look at choke settings.

Paul
PJM

Offline Chuck in Indiana

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Re: 93 sp111 phf36d carb sync issues
« Reply #2 on: June 14, 2018, 08:02:07 PM »
PS
*****Saw the trouble shooting post after I posted*****
Yes I did do the google search.
Read everything the search returned on carb sync and the PHF 36 A-B DD, Lean burn, shrouded- un shrouded, Euro. US, German variations.
All very informative as well as entertaining.
That spurred me to look at choke settings.

Paul

Good idea. Make sure you have some slack in the choke cables, and the little rubber gizmos (technical term) in the plungers are in good shape.
Chuck in (Elwood) Indiana/sometimes SoCal

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Offline ccoli

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Re: 93 sp111 phf36d carb sync issues
« Reply #3 on: June 14, 2018, 11:43:43 PM »
Check float levels and  needle valve. After all these years and miles, I had a needle come apart. Spent days trying to fix electrical issues.
Wisconsin MGNOC Rep
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Offline 93spada

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Re: 93 sp111 phf36d carb sync issues
« Reply #4 on: June 15, 2018, 05:16:54 AM »
Good idea. Make sure you have some slack in the choke cables, and the little rubber gizmos (technical term) in the plungers are in good shape.

Thanks Chuck
There is about 1/8" free play. Unfortunately I used an old throttle cable that we had in stock and the cable to sheath was a little long so any more and it will not open all the way.
The rubber gizmos have permanent denting from the jet but no damage. I was thinking of putting a touch of silicone grease on the gizmo and running it to see if it changed it to eliminate it.
I also pulled the carb top oring and cleaned and re  placed that I also added a touch of grease to that to seal any leaks for a test. We have not put gauges on since the enrich cable adjust of the top seal. Hopefully today.
Paul
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Offline 93spada

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Re: 93 sp111 phf36d carb sync issues
« Reply #5 on: June 15, 2018, 05:28:14 AM »
Check float levels and  needle valve. After all these years and miles, I had a needle come apart. Spent days trying to fix electrical issues.

Thanks ccoli
We set the floats to 18.2mm to within spec before last vac test.. I was having occasional flooding issues on shutdown when hot. So far that seemed to fix that.
The needle and atomizer are both relatively new (1yr) and in good shape.
That reminds me though, I need to change needle clip position back to 2nd notch. Artound home we can get 91 no ethanol. on the road we get 93 w/ethanol weasel piss and it instantly runs like its got water in it. We raise the needle to richen it to get it to almost run ok.
PJM

Offline chuck peterson

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Re: 93 sp111 phf36d carb sync issues
« Reply #6 on: June 15, 2018, 07:31:07 AM »
If I remember correctly, which may be unlikely......... :popcorn:

My phf carbs giave me trouble on a cal 111. The issue came down to a float needle. Unlike the vhb needles, the phf are two parts with a movement to them....mine was intermittent-ingly not moving, making the float........not. Isn't there a tiny spring inside the float needle?

WAG....for free, so it's worth that.....good luck!
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Offline 93spada

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Re: 93 sp111 phf36d carb sync issues
« Reply #7 on: June 15, 2018, 08:42:22 AM »
If I remember correctly, which may be unlikely......... :popcorn:

My phf carbs giave me trouble on a cal 111. The issue came down to a float needle. Unlike the vhb needles, the phf are two parts with a movement to them....mine was intermittent-ingly not moving, making the float........not. Isn't there a tiny spring inside the float needle?

WAG....for free, so it's worth that.....good luck!

You are correct!!!  :bow:
The PHF needle has a spring inside. I did just put in new on both carbs. Also adjusted the floats to within spec. When done I checked the movement and it was free and easy. I will check again just in case on assembly it got sticky.
Thanks
Paul
PJM

Offline sdcr

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Re: 93 sp111 phf36d carb sync issues
« Reply #8 on: June 15, 2018, 10:03:32 AM »
I have similar carbs on the Le Mans III. Over the past few years, I have replaced about 4 needle valves in the PHF 36's. Not sure if it's from the quality of gas we have in Pa., or they just wear out.

You are correct!!!  :bow:
The PHF needle has a spring inside. I did just put in new on both carbs. Also adjusted the floats to within spec. When done I checked the movement and it was free and easy. I will check again just in case on assembly it got sticky.
Thanks
Paul
John

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Online canuck750

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Re: 93 sp111 phf36d carb sync issues
« Reply #9 on: June 15, 2018, 10:37:10 AM »
I have Dellorto PHF 36 on my Laverda and they were stock on the 77 Le Mans I just sold. The set on the Le Mans were clean and after a long ultrasonic bath they functioned fine. The ones on my Laverda will not respond to hours of ultrasonic cleaning and the idle is intermittent and they stumble. I have given up on saving them and am ordering a new pair from Columbia Car and Cycle in Canada through Wolfgang Haerter he can beat the price of a similar set on Ebay out of the USA and jet them properly as well as supply manifolds (new Dellorto manifolds will not fit the old style). I replaced every internal brass part on the Laverda set and still they won't run correct, plus the wear between the body and slide can not be rectified without sleaving and new carbs are cheaper than fixing the old set.

Wolfgang has been servicing Dellorto's for over 30 years and has had several of the PHF carbs that have blocked pilot jet passages that will not clear even with ultrasonic cleaning. He tells me he has even cut apart a PHF 36 to find the blockages and reports the tiny pilot passage ahs blocked more form oxidation than anything else and they are often irreparable.

Nothing more annoying than investing a lot of money in a restoration to fight old worn out carbs.
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Offline 93spada

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Re: 93 sp111 phf36d carb sync issues
« Reply #10 on: June 16, 2018, 08:28:55 AM »
I have similar carbs on the Le Mans III. Over the past few years, I have replaced about 4 needle valves in the PHF 36's. Not sure if it's from the quality of gas we have in Pa., or they just wear out.

Thanks John
Ill try new needles. The ones in there now have been in and out so many times maybe they got beat up. There cheap enough.
Paul
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Offline 93spada

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Re: 93 sp111 phf36d carb sync issues
« Reply #11 on: June 16, 2018, 08:43:12 AM »
I have Dellorto PHF 36 on my Laverda and they were stock on the 77 Le Mans I just sold. The set on the Le Mans were clean and after a long ultrasonic bath they functioned fine. The ones on my Laverda will not respond to hours of ultrasonic cleaning and the idle is intermittent and they stumble. I have given up on saving them and am ordering a new pair from Columbia Car and Cycle in Canada through Wolfgang Haerter he can beat the price of a similar set on Ebay out of the USA and jet them properly as well as supply manifolds (new Dellorto manifolds will not fit the old style). I replaced every internal brass part on the Laverda set and still they won't run correct, plus the wear between the body and slide can not be rectified without sleaving and new carbs are cheaper than fixing the old set.

Wolfgang has been servicing Dellorto's for over 30 years and has had several of the PHF carbs that have blocked pilot jet passages that will not clear even with ultrasonic cleaning. He tells me he has even cut apart a PHF 36 to find the blockages and reports the tiny pilot passage ahs blocked more form oxidation than anything else and they are often irreparable.

Nothing more annoying than investing a lot of money in a restoration to fight old worn out carbs.

Thanks Canuck
I hope they are not toast. that would be an expense I could do without (Guzzi Content!! / Cheap or frugal).
I have not googled it but, do you have the specs for the ID and OD on the barrel and slide?
That was one of our thoughts that the slides are loose.
If I cant get them set up right I will check out Columbia this winter.
Is there any way to test the idle passage flow?? We are lucky and can get non-ethanol fuel
around here so hopefully that will help keep the passages clean.
Paul
PJM

Offline Chuck in Indiana

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Re: 93 sp111 phf36d carb sync issues
« Reply #12 on: June 16, 2018, 08:51:57 AM »
Quote
Nothing more annoying than investing a lot of money in a restoration to fight old worn out carbs.

This. When I was putting the Aero engine together, I thought 36s would be about right. Milich said he'd sell me a set of the Goddess only knows how used ones for $400. The Kid got me a set of new ones for a little over $500. Guess which way I went? Naturally, it started right up, and I haven't had the first issue in over 11K miles now.
Chuck in (Elwood) Indiana/sometimes SoCal

02 Scura RC
87 AeroLario
79 G5
95 Skorpion tour
 
I think senility is going to be a fairly smooth transition for me..

Offline John Croucher

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Re: 93 sp111 phf36d carb sync issues
« Reply #13 on: June 16, 2018, 10:27:03 AM »

Remaining "exactly the same" on both sides at all throttle openings and engine speed should not be the goal.  Close is acceptable.  How close, there is a specification somewhere.  Maybe someone can share it.  1 pound of mercury indifference is acceptable on a set of Mikuni's per their tuning guide.  You did not mention how much they get out of balance. 

Offline Rough Edge racing

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Re: 93 sp111 phf36d carb sync issues
« Reply #14 on: June 16, 2018, 10:46:14 AM »
 There's no guarantee that both carb slides are identical, especially the slide cutaway which has an effect on slow speed airflow. Remove both slides and compare them side by side...I have found that sometimes the slide cutaway needs a slight re profile with a file so they both match...It's been my experience that even air flow at small throttle openings makes V twins run nicer in town...
 You may also want to try an airflow meter rather than trying to balance manifold pressure...I use this one on two cylinder bikes.. But it may or may not fit on a Guzzi situation?

   I use this one made in Germany for about 50 bucks on Ebay...Try to avoid the Chinese knockoff...

     
I ride junk, some of it actually goes fast

Offline 93spada

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Re: 93 sp111 phf36d carb sync issues
« Reply #15 on: June 17, 2018, 08:24:50 AM »
This. When I was putting the Aero engine together, I thought 36s would be about right. Milich said he'd sell me a set of the Goddess only knows how used ones for $400. The Kid got me a set of new ones for a little over $500. Guess which way I went? Naturally, it started right up, and I haven't had the first issue in over 11K miles now.

I have to assume you went with new (non-Guzzi content!!)
I'll keep dinking around for the summer then see.
It still runs OK.

Paul
PJM

Offline 93spada

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Re: 93 sp111 phf36d carb sync issues
« Reply #16 on: June 17, 2018, 08:30:45 AM »
Remaining "exactly the same" on both sides at all throttle openings and engine speed should not be the goal.  Close is acceptable.  How close, there is a specification somewhere.  Maybe someone can share it.  1 pound of mercury indifference is acceptable on a set of Mikuni's per their tuning guide.  You did not mention how much they get out of balance.

Thanks John.
They would not stay where put. We would adjust to same +/- and then shut down and they would need to go in the opposite direction on restart. I don't remember how much difference when they went out. Probably going to try again this am so ill make notes and maybe some pics.

Paul
PJM

Offline 93spada

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Re: 93 sp111 phf36d carb sync issues
« Reply #17 on: June 17, 2018, 08:36:35 AM »
There's no guarantee that both carb slides are identical, especially the slide cutaway which has an effect on slow speed airflow. Remove both slides and compare them side by side...I have found that sometimes the slide cutaway needs a slight re profile with a file so they both match...It's been my experience that even air flow at small throttle openings makes V twins run nicer in town...
 You may also want to try an airflow meter rather than trying to balance manifold pressure...I use this one on two cylinder bikes.. But it may or may not fit on a Guzzi situation?

   I use this one made in Germany for about 50 bucks on Ebay...Try to avoid the Chinese knockoff...

     

Good ideas.
I'll look at the slides this morning. Never knew that. Thought they would be cast the same. They are Italian though!!!.
I saw that meter when googling the issue. That looks like $50 well spent.
Thanks
Paul
 
PJM

Offline Rough Edge racing

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Re: 93 sp111 phf36d carb sync issues
« Reply #18 on: June 17, 2018, 09:42:45 AM »
Carburetors primarily meter fuel in response to air flow.... Compare the slide cutaways by placing the slides together .Take measurements and or make a template...Slight differences do affect air flow and if you feel up to it, use a half round file to make them identical as possible...A bigger cutaway leans the low speed mixture so thread carefully and only match the small cutaway to the larger one...If they are the same, then look elsewhere...
 
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Offline 93spada

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Re: 93 sp111 phf36d carb sync issues
« Reply #19 on: June 17, 2018, 08:02:01 PM »
Carburetors primarily meter fuel in response to air flow.... Compare the slide cutaways by placing the slides together .Take measurements and or make a template...Slight differences do affect air flow and if you feel up to it, use a half round file to make them identical as possible...A bigger cutaway leans the low speed mixture so thread carefully and only match the small cutaway to the larger one...If they are the same, then look elsewhere...

Thank You!!!
Rode today instead of screwing with it.
May have to work (bummer) tomorrow so maybe not then either.
Soon though. trying to get it well sorted for a trip to the pacific north west!!!
Thanks again.
Paul
PJM

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