Flatsides carbs on Le Mans

[BaronRouge]

Hi folks! I'm fed up with my oem phf36 Dell'ortos, and I'd like to swap for a pair of 38TM Mikuni's ... Has anyone already did It? I've tried to find informations using the "search" , but can't find anything...
(Hope you 'll understand my broken english.)

 

[Moto-Uno]

Being thoroughly pleased with the Dellorto's I have on my kitted Le Mans 2 I'm curious what is driving you to
Mikuni's ? The Mikuni's are fine carbs usually , but you might be spending a long time jetting them to your
bike ! Peter

 

[BaronRouge]

Being thoroughly pleased with the Dellorto's I have on my kitted Le Mans 2 I'm curious what is driving you to
Mikuni's ? The Mikuni's are fine carbs usually , but you might be spending a long time jetting them to your
bike ! Peter

Hi Peter!
What drives me to Mikuni's is f.... huuuuge consumption:there's a hole in my tank, she drinks like a fish,but it's not water, it's good gas, and the prices are rising up these days...So I dunno: if she has a carburation issue or what, but I realized that she drinks 10liters per 100 kilometers!!!! Whatever city or highways,country roads, 10l/100km!!!!
I run KeihinFCR's on my 93' 900SS Ducati, and those carbs turned a nice bike to a really cool grunty bike: torque,power, and less consumption:5l/5,4l/100km...
I know a Guzzi engine is not the same architecture, but I wanna give those flatslides a try.

 

[john zibell]

Hi Peter!
What drives me to Mikuni's is f.... huuuuge consumption:there's a hole in my tank, she drinks like a fish,but it's not water, it's good gas, and the prices are rising up these days...So I dunno: if she has a carburation issue or what, but I realized that she drinks 10liters per 100 kilometers!!!! Whatever city or highways,country roads, 10l/100km!!!!
I run KeihinFCR's on my 93' 900SS Ducati, and those carbs turned a nice bike to a really cool grounty bike: torque,power, and less consumption:5l/5,4l/100km...
I know a Guzzi engine is not the same architecture, but I wanna give those flatsides a try.

Sounds like you are jetted really rich. My MkV with 40s delivers close to 50 mpg. Check all your settings against the original owner's manual or service manual for your bike. If someone removed the stock air box then some changes from stock are needed, but someone set her way too rich.

 

[BaronRouge]

Sounds like you are jetted really rich. My MkV with 40s delivers close to 50 mpg. Check all your settings against the original owner's manual or service manual for your bike. If someone removed the stock air box then some changes from stock are needed, but someone set her way too rich.

Yeah,sure,you should see the plugs:black as hell,not greasy, but full of dry kinda soot... it's strange ,cuz that bike was setted(7 years ago) by a well well known mechanics, a very cool and humble french Guzzi guru named Daniel GOUTAL, and he knewed those bikes....
Anyway, she runs way richer....and as a dumbass as I can be, I put Nology Hot wires before setting this issue, so I am now mixing the problems ....gonna go back to former ignition cables and set those carbs before changing anything...
But I will put those TM's in a way or another!

 

[Moto-Uno]

For reference , my Le Mans 2 has a 90mm big bore kit with Wiseco pistons , 40 mm Dellorto's , a Megacycle 620 camshaft
and Bub large diameter header pipes and LaFranconi style mufflers ! It's been dyno'd years ago at 70 rwh . I also get 20km
to 22 km per liter . Something on your bike is way out of spec . If your bike was set up for racing and jetted accordingly , that
might explain your horrible fuel consumption . We also pay a lot for fuel and that's one of the reasons I'm still riding my Le Mans
instead of my 2018 Eldorado ( it's thirsty ) . Peter

 

[BaronRouge]

For reference , my Le Mans 2 has a 90mm big bore kit with Wiseco pistons , 40 mm Dellorto's , a Megacycle 620 camshaft
and Bub large diameter header pipes and LaFranconi style mufflers ! It's been dyno'd years ago at 70 rwh . I also get 20km
to 22 km per liter . Something on your bike is way out of spec . If your bike was set up for racing and jetted accordingly , that
might explain your horrible fuel consumption . We also pay a lot for fuel and that's one of the reasons I'm still riding my Le Mans
instead of my 2018 Eldorado ( it's thirsty ) . Peter

Hi Peter!
No,the bike wasn't definitely setted for races, It's a daily rider, as any of my bikes (ain't got no car)...and I dunno if she runs like that since 2013 as I have to admit that she worked perfectly and I don't check my plugs every day ; the price of gas made me worrying about consumption,then I realize she was so thirsty ....gotta fix that before installing those Tm's anyway.

 

[Nordicnorm]

As a fairly easy test, try dropping your needles one notch (raise the clip one notch on the needles). That will lean the low to midrange out. As a daily rider you spend a lot of time in that range of carburation. It should give you a good indication of what is going on.
Please don't dump those Dellortos, unless you dump them in my back yard!

 

[BaronRouge]

As a fairly easy test, try dropping your needles one notch (raise the clip one notch on the needles). That will lean the low to midrange out. As a daily rider you spend a lot of time in that range of carburation. It should give you a good indication of what is going on.
Please don't dump those Dellortos, unless you dump them in my back yard!

Hi!
Thanks for the tip! Gonna try It tomorrow!!!

 

[Moto-Uno]

If you get a chance , tell us what jets it has in it , plus float level . Looks like a Le Mans 3 in your picture .
Is this the bike ? Any other mods ? Peter

 

[BaronRouge]

If you get a chance , tell us what jets it has in it , plus float level . Looks like a Le Mans 3 in your picture .
Is this the bike ? Any other mods ? Peter

Hi Peter! That's the Le Mans 3 I'm talkin'bout! Definitely stock, except a complete Mistral line, BMC air filters, Dyna3 electronic ignition, EME regulator, Tarrozzi fork stabilizer and rearsets...
Wich carbs are you talkin, for the jetting? Tms?

 

[Moto-Uno]

I'm running the 40 mm Dellorto's that were available as part of their performance kit decades ago . They came with
looney rich racing jetting , useless on the street . Here's what's in mine now ( remember the mods)
#62 idle jet
3/50 throttle slide
K-3 Needle , lowest setting + .020" spacer under needle
AB266 needle jet
155 main jet
And YMMV a lot from this setting , and as mentioned earlier I still get 20 to 22 km / liter
The low speed I adjust when up to temp , highest idle speed and richen about 1/2 turn out .
Jets are pretty reasonable and accessible . And check those choke rubbers and cable free play
Peter

 

[john zibell]

I'm running the 40 mm Dellorto's that were available as part of their performance kit decades ago . They came with
looney rich racing jetting , useless on the street . Here's what's in mine now ( remember the mods)
#62 idle jet
3/50 throttle slide
K-3 Needle , lowest setting + .020" spacer under needle
AB266 needle jet
155 main jet
And YMMV a lot from this setting , and as mentioned earlier I still get 20 to 22 km / liter
The low speed I adjust when up to temp , highest idle speed and richen about 1/2 turn out .
Jets are pretty reasonable and accessible . And check those choke rubbers and cable free play
Peter

You may want to adjust idle mix a bit differently. Once warmed up, turn mix screw in (leaner) until a bit of stumble, then out 1/2 turn.

 

[SimonD]

Before adjusting anything, particularly anything that can’t go out of adjustment by itself, you might want to check the air filters are clean & clear.

 

[BaronRouge]

Before adjusting anything, particularly anything that can’t go out of adjustment by itself, you might want to check the air filters are clean & clear.

Sure! It has been done....and, in fact , my slides were totally worn!!! a pair of new slides and I guess a big part on the heavy consumption mystery will be solved!!!

 

[Barnapkin]

Do these varbs have emulsion tubes? I know on my 900SS that is a common wear item. bikes slowly gets richer and richer until it is hard to start.

 

[BaronRouge]

Do these varbs have emulsion tubes? I know on my 900SS that is a common wear item. bikes slowly gets richer and richer until it is hard to start.

Hi! Emulsion tubes? Is it something special like on some PWK Keihin carbs ,like a charger? I think every carbs got emulsion tubes...or it's a misunderstood for emulsion jets,sorry , english is not my common language!

 

[Barnapkin]

The tube is what the needle slides within. if the needle rubs, it will slowly wear the tube's inner cylinder shape to an oval. Once oval you lose fuel management - bike gets richer.

 

[BaronRouge]

The tube is what the needle slides within. if the needle rubs, it will slowly wear the tube's inner cylinder shape to an oval. Once oval you lose fuel management - bike gets richer. View attachment 27441

AAAhhh,ok, It does definitely make sense!!!

 

[john zibell]

The tube is what the needle slides within. if the needle rubs, it will slowly wear the tube's inner cylinder shape to an oval. Once oval you lose fuel management - bike gets richer. View attachment 27441

If you look at DelOrto manuals it is called the atomizer, and they come in different sizes. For your flat tubes it appears they are also sized. I wish the terminology was consistent.