906 carb tuning

ducatipete · Post by **ducatipete** » Thu Feb 15, 2007 10:19 pm

Have rebuilt my weber carb, modified the accelerator pump cam profile (LHS)and fitted a fuel regulator. As my 91 bike has only done 9600 miles I wish to continue using the weber, like the rest of the bike, it looks like new. Have made a temporary petrol tank using a metal petrol can, so have full access to carb while its running.Is the idle speed controlled by single threaded screw throttle acting on throttle cable cam/linkage lever on carb or by adusting the 2 air bypass screws? plan to use a motorcycle gunsons color tune to set mixture plus exhaust co meter, any tips? will this be enough?. The bike is not smooth at speeds below 30 mph, but appears alright at higher speeds. Weber info says idle circuit controls mid range fuelling too. And finally how do you measure the float height? regards Pete

Post by **paso750** » Thu Feb 15, 2007 11:37 pm

Pete,
have you checked the workshop manual in the download section?
You`ll find the adjustment procedure there.

G.

ducatipete · Post by **ducatipete** » Fri Feb 16, 2007 7:48 pm

Thanks, just having problems downloading the manual

ducatipete · Post by **ducatipete** » Sat Feb 17, 2007 7:46 pm

Getting there, what is the C0 level for a 906 PASO

Finnpaso · Post by **Finnpaso** » Sat Feb 17, 2007 8:10 pm

..... :laugh: :laugh: :laugh: .... Where the hell U need to know such???? :laugh: :laugh: :laugh:

ducatipete · Post by **ducatipete** » Sun Feb 18, 2007 11:31 am

Need CO reading as have a exhaust gas analyser, want to to get carb setting as close as possible to std setting before using the colortune, its at 3.5% at the moment

Finnpaso · Post by **Finnpaso** » Sun Feb 18, 2007 1:11 pm

If U use gas analyzer, then REMEMBER close another muffler pipe with some stuff, like just right size wood, that it DONT TAKE air backwards from that pipe !!!! NEED to do so, if U want put analyzer to exhaust output. I have seen, what happens, if that is not done: There is some "pumping effect", what cause wrong display to analyzer. Such have happened to me.... If U tune same time, then U have to wait some mins, that analyzer start to function. That have some delay and remember adjust little by little. Anyway i dont trust so much to such analyzers. That function much better, if U put Your bike to Dyno and then adjust it little by little, then You can maybe find best adjustments, but surely much harder job with Weber, than with adjustable injection, like P7 with some adjustable FIM eprom, what U can remap in dyno with FIM software/pc...

ducatipete · Post by **ducatipete** » Sun Feb 18, 2007 2:46 pm

thank you finnpaso, will take advice regarding blocking the other muffler when gas probe is being used

Finnpaso · Post by **Finnpaso** » Sun Feb 18, 2007 7:58 pm

Simply some wood, etc. to end of another muffler and lambda probe to another muffler end. But remeber, that analyzer measurement is conclusion of BOTH sylinders. Better, if U can weld connectors for lamda sonds to BOTH headers, about 15-20 cm from cylinder heads, where is RIGHT temperature for "normal" lambda sond. I have welded connectors for both 750 and 907 and they NEED to be there, if You put your bike to very good dyno. U dont know difference between sylinders adjustments, if u have only one lambda.... SIMPLE, as U see!

ducatipete · Post by **ducatipete** » Fri Jul 20, 2007 6:35 pm

Help!!! my weber book says the lower screw on the carb(@45 degrees to carb) is the air bypass screw and the upper one is the mixture screw, the 906 manual says the lower one is the mixture screw the upper one is the air screw!!! which is correct. When using the exhaust analyser the bottom screw seems to be the one to adjust for CO levels

Post by **paso750** » Fri Jul 20, 2007 6:39 pm

btw CO level according to Ducati Germany
http://www.box.net/shared/eovf78q2dg
is max. 4,5% (idle at 1.100-1.300rpm)
G.

Post by **paso750** » Fri Jul 20, 2007 7:11 pm

the Paso manual should be correct
http://forums.ducatipaso.org/viewtopic. ... icle&sid=9
the diagonal screw is the idle mixture screw that of course will effect CO%.

Irritating that the Paso user manual names the air screw "slow running adjustment screw".

Finnpaso · Post by **Finnpaso** » Fri Jul 20, 2007 7:56 pm

If U want to adjust Ducati engine working "best way", then U have to adjust IDLE mixture close 4-5% !!!! I have heard this from very many guys, who have worked with Ducati engines.... Many cars use 1% in idle, but thats "nothing"... :laugh: Ducatis are NOT "cars"... :funny:

ducatipete · Post by **ducatipete** » Sat Jul 21, 2007 7:32 am

Thanks everybody will have another go on saturday...
To help my carb tuning I have removed the Ducati tank and used a metal 5 litre petrol can and soldered an outlet and return pipes to it, and strapped this to frame, this gives me plenty access to the carb screws. Also fitted 2 front mini indicators to each side of the headlight, so I can use the bike on the road, without any bodywork so I can easily check my spark plugs for colour changes during tuning...

ducapaso · Post by **ducapaso** » Sat Jul 21, 2007 4:40 pm

You're doing a very good job!

Althought, I had no good result until I built my own vacuum balancer and had a complete tuning of the balancer

All my experience, is posted in 750 f.a.q digest, available for any skilled mechanic

have a nice work, and...

906 carb tuning

906 carb tuning

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