Carby set up

A

Aroundtoit

New member
Hello fellow laverdaristas
Finally the bucket of bits is empty( well almost!)
And all the bike is back assembled into
One unit so after months I got to go for
a ride , all the bits from red are on and I'm
In a much happier place!!!!
I did fully strip the carbs and rebuild
and now it is running really rich( I used
a full tank from ocean reef to bindoon
return( About 150km)
Anyone out there who can assist with this final
tune to get the best out of her! Or know someone
Happy to travel and donate to bar or pay
to get it done
Cheers
Nig
 
My bike used to gobble fuel at an alarming rate when I first got it. From a full tank, it would go onto reserve at about 130km.

The PO (nice guy but a lousy engine tuner) had over-jetted it to buggery, so it was running way too rich. I did a dyno session to get the jetting somewhere near optimum. Went from 135 mains (Dellorto) to 120 and dropped the needles a notch which improved power and reduced fuel consumption marginally. But by far the most effective bit of tuning was to dial in the cam timing (PO had fitted 4C cams with A11 sprockets). After that it would run a lot better and hit reserve at around 210km.

The next big jump in efficiency was when I fitted Mikuni carbs. It's not making any more power than with the Dellortos, but I'm now hitting reserve at around 260km and fuel mixture is still OK on the dyno.

Cam
 
check float hight and also that the float valves do really close! To high float hight or not closing float valves => fuel runs into the inlet channel and mixture is way to rich.

Easy check is if you

-open petcocks until no bubble appear anymore in the fuel hose
-close the petcocks
-take off the fuel hoses
-drain the fuel out of the hoses
-put a cub under the central float bowl screw
-open the screw and let all fuel drain into the cub
-measure what amount of fuel is in the cub
-drain the cub completely and repeat with 2nd and 3rd carb
-now re-install the fuel hoses, hold all 3 floats up so that they close completely, open the petcock on one side and see if fuel runs out of one or more of the carbs. if so, float valves are the fault.

I think to remember the amount of fuel in one float chamber should be 57ml +/-1 but am not 100% sure.

After that, you need to check if floats are 18,5 mm +/-1 from the sealing surface of the float chamber when the float valve actually fully closes. You can do that with a U-formed piece of metal/alloy and the same method as when you checked the floats for if they are closing. If you make the U so that one side is a bit shorter (the side that goes against the carbs sealing surface) and the other one is a bit longer (reaching below the float) and you set the two upper surfaces to 18,5mm, you will see if the float acutally closes or not at 18,5mm. If not, the float level is set to to high => to rich. If it closes before the U-piece touches the carbs sealing surface, your setting is to low => to lean

U-Piece should look like this:

_________________
I
I                          between top of the upper and top of the lower "leg" it should be 18,5mm
I
I
I_____________________________

HTH
 
Mario, at Thunderbikes, is ya Dell'O man in da west.  but ya've heard that before ay?
http://www.thunderbikes.com.au/shop/24-carburettors-fuel-supply

old carbs;  get some new needles & jets (atomizers) from Mario, & 'av a word to the bloke.  i reckon Mario knows stuff.
& as Lothar says,  float levels & valve shut-off is a must to get setup correctly.  but i don't bother with all that measuring stuff (of fuel volume).  just read the Dell'O manual, look & observe & pay attention to the detail.
& don't leave ya fuel taps on.  ever !!
cheers,  Mark

<edit>  & i like to set the float position closer to 18.5 mm, rather than 17.5 mm.  i.e.  the level is 1 mm lower.
& the carb shown in fig.13 ain't got a pumper, so ya gotta take the pumper housing off, or hang the carb over the edge of a block, or bench top.
floatlevel-4.jpg



 
& Nig old mate.  'av a look at ya chokes.
the choke farken plungers just luv to bleed a bit of fuel when ya not looking.
all outer cables need 'noticeable' slack in 'em.  the #1 left cable can be da culprit.  & get some new plungers from Mario.

of course,,  ya fuel consumption may have absolutely nothing to do with the Dell'Os.  coz wot could possibly go wrong ay!  ;)
Mark
 
well Lothar,  ya doing better than me.  reckon ya German language looks just like a lot of chaotic alphabetical farken soup !!

but, me 2 younger niece 'av studied German & tell uncle that it's all logical & makes a lot of sense.  yea right??  :o
no,,  they didn't grow up in da cane fields. 
maybe a bloke should give Italian a go.  the food was good.
Mark
 
well - there is a lot of logic in the german language - if you forget about the exceptions...  :D

Italian is at least as difficult as latin. It takes years to be able to say at least some sentences the right way...
 
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