Carb sync?

[jim.cox]

Got the Ducati staring, running, idling and restarting reliably over the weekend :)

The carb rebuild has definately helped sort the starting and plug fouling.

But it is still just a little rough and stumbles slightly off-idle.

Its not fueling quite evenly

Does anyone have any experience with carb sync, guages, etc they would care to share?

[pete376403]

Did you ever see the long thread that OddDuck posted about his efforts with a Ducati? I dont know if he was ever successful in getting it to where he wanted it. Was a while ago
https://www.kiwibiker.co.nz/forums/showthread.php/178552-Winter-Layup-1995-Ducati-900-Supersport

[husaberg]

Got the Ducati staring, running, idling and restarting reliably over the weekend :)

The carb rebuild has definately helped sort the starting and plug fouling.

But it is still just a little rough and stumbles slightly off-idle.

Its not fueling quite evenly

Does anyone have any experience with carb sync, guages, etc they would care to share?

I will bite Jim What sort of Duke is it? What carbs does it have....

[jim.cox]

I will bite Jim What sort of Duke is it? What carbs does it have....

Its an MHR with Dellortos.

I'm nowhere near the engineer that Old Duck is.

But I think I can improve the running further and was wondering if syncing the carbs would help.

[Kickaha]

Its an MHR with Dellortos.

I'm nowhere near the engineer that Old Duck is.

But I think I can improve the running further and was wondering if syncing the carbs would help.

From my own experience with both a Darmah and MHR with Dellortos yes it will, I had the same off idle stumble

[jim.cox]

From my own experience with both a Darmah and MHR with Dellortos yes it will, I had the same off idle stumble

So how did you do it? - someone good around town? bought guages? - if so what sort? or?

[jellywrestler]

So how did you do it? - someone good around town? bought guages? - if so what sort? or?

some people have the ear for it with for v twins, find someone who knows the generation of bike is a start
also actually think what the person needs to know, ie a ducati is not enough, it could be anything from single to four, injected etc, give them the info, mileage helps so they know if they are looking at worn parts too.

[Grumph]

Where are you for a start. I've still got the gear and have been doing it for lierally decades in ChCh.

[jim.cox]

Where are you for a start. I've still got the gear and have been doing it for lierally decades in ChCh.

I'm in Chch.

Would you be prepared to give lessons?

Happy to make it worth your while.

[Kickaha]

So how did you do it? - someone good around town? bought guages? - if so what sort? or?

Phil Sutton did both of mine, he's worked on Bevel twins for decades, made a very noticeable difference, dunno if he's still working on them

[husaberg]

Where are you for a start. I've still got the gear and have been doing it for lierally decades in ChCh.

You also willingly put dellorto carbs onto bikes:laugh:
If mike was alive he would want me to recommend these.....not that he likely cared about the off idle cough.
https://mikunioz.com/shop/tm38-twin-mikuni-flatslide-kit-ducati-860-900-desmo/?v=13b249c5dfa9
this is 667 NZD

[Grumph]

PM sent. + 3 characters

[jim.cox]

Not satisfied with some rough running, I've been wanting to give the MHR's carbs a wee tune-up.

Thought if anyone was going to look at them, it better be me.

So I finally get back to the back of the garage this weekend and drag the bike out.

The plan was to change the fuel, give the carbs a tickle and go for a ride.

Even with fresh fuel she did not start too easily, idled ok, but the acceleration just was not quite right.



Think I might have fond the source of the problem....

351843

To loose one adjustment screw is a misfortune, but two is just plain careless

Had to take the Suzuki for a squirt to stop the screaming inside my head

[F5 Dave]

I-I love the colorful clothes she wears
And the way the sunlight plays upon her hair
I hear the sound of a gentle word
On the wind that lifts her perfume through the air

I'm pickin' up . . . .

She's giving me. . .

Good, good, good,. .

[kawaaiguy]

I wlll generally bench-set the butterflies on carbs, Just a visual to see the plates are ~1/3 over the pilot holes.
Air pilot screws get set 2.5 turns backed off "nipped up"
On a 4 cyl you balance two pairs, then bring the two pairs together with the middle adjust.

Once she runs, and is warm, then you really need a manometer. Drill and tap somewhere upstream from the carbs for a nipple.
A couple of yards of brewery hose (8mm clear plastic) is good. 1/2 fill with 2 toke oil; connect each end to a cylinder, keep the tube upright and lower than the carbs; the different vacuums will show up pulling the oil up one side or the other. Tweak carb screws to balance.
Even numbers of cylinders help, not sure how you'd balance 3.

There's also a method of "reading" spark plugs by cutting out the ignition while riding. I've never had to do that so not sure how correct it is but could be worth searching up.

TL:DR? Slap a turbo on it.

[Oldknowallprik]

Got the Ducati staring, running, idling and restarting reliably over the weekend :)

The carb rebuild has definately helped sort the starting and plug fouling.

But it is still just a little rough and stumbles slightly off-idle.

Its not fueling quite evenly

Does anyone have any experience with carb sync, guages, etc they would care to share?

You can set each throttle plate by eye, just
use a magnifying glass and tweak them to identical
position over the tiny pilot-hole, yeah pretty much 1/3rd
of the tiny hole exposed and they're balanced sweet.
The now twelve thousand dollar-each manometers and vac gauges
which do the exact same thing or the thirteen thousand dollar bill for
a motorcycle shop to do it for you can be saved to buy two new motorcyle tyres,
as long as they're not the "special top of the range" motorcycle tyres which are
now about sixteen thousand dollars a pair. Thanks motorcycle industry corporate CEO's..

[husaberg]

https://www.aliexpress.com/item/1005003304596539.html


$16

people used to use wire...

[Laava]

I just did my Ducati with a home made manometer, 3m of clear hose filled with cooking oil. Cheap as and dead accurate. Connecting to the inlet stubs is the bit that has to be done carefully. It is the last thing you do after all float levels set and jets etc are clean and clear.

[SaferRides]

https://www.aliexpress.com/item/1005003304596539.html


$16

people used to use wire...Have you got one?

Sent from my SM-S906E using Tapatalk

[Laava]

https://www.aliexpress.com/item/1005003304596539.html


$16

people used to use wire...
I bought a set of these gauges but found they were not calibrated the same as each other. Was however very useful to have the jetted connector stems to hook my oil filled hose up to! Absolutely dead on!

[pete376403]

I bought a set of these gauges but found they were not calibrated the same as each other. Was however very useful to have the jetted connector stems to hook my oil filled hose up to! Absolutely dead on!

I also bought a set of the gauges, pretty basic and the adjustment valves wouldn't be out of place in a fish tank filter system. I've got a nice Magneihelic gauge that was used to set vacuum on a large IBM printer, has two ports so can do vacuum to 150mm H2O, or pressure to 15 psig, just need to make a manifold with shutoffs for each cylinder so it can service each of the carbs. One of these days I'll get on to it Gauge is a bit like this one https://www.fishpond.co.nz/Kitchen/Dwyer-Magnehelic-Series-2000-Differential-Pressure-Gauge-Range-0-380cm-WC/0128030294753?utm_source=googleps&utm_medium=ps&utm_campaign=NZ&gclid=CjwKCAjw9J2iBhBPEiwAErwpeYwbm7Ag2DFXRo8P52P9 vEXdLVP61AFnPZjVuUUybMTP4zfYGFDg0hoCwg0QAvD_BwE

[SaferRides]

I bought a set of these gauges but found they were not calibrated the same as each other. Was however very useful to have the jetted connector stems to hook my oil filled hose up to! Absolutely dead on!They may just need calibrating, that's if they can be adjusted. I am tempted to buy one just for the hardware!

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[Laava]

They may just need calibrating, that's if they can be adjusted. I am tempted to buy one just for the hardware!

Sent from my SM-S906E using Tapatalk
No they are cheap shit. However the connecting tubes have been on a few bikes now

[husaberg]

No they are cheap shit. However the connecting tubes have been on a few bikes now
silly question but couldn't you just use one gauge and swap it around between them it would remove the variability?



i remember these old ones that went directly on the throats of cars.

here is one
353004


This professional style carb carburetor carburettor syncrometer is a must for any VW engine tuner Fits most dual carb setups and does not restrict air flow Rubber end is between 40mm and 50mm diameter Easy to read gauge allows for precision synchronizing of both carburettors for smooth idling and maximum performance See our other listings for adapter tubes to suit various carbs

https://www.trademe.co.nz/a/motors/car-parts-accessories/volkswagen/listing/4102733559

Most gauges do have adjustability as do thermometer's

[husaberg]

this is in NZ appears to use hg or other liquid manometer or similar
https://palmside.co.nz/products/manometer-4-column-and-pouch

It looks like a Morgan tune system.
https://www.carbtune.com/