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crossflow spitting oil from carbs


RICHCAT7

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Hello anyone out there can advise on the oil that i seem to get deposited on RHS wing

and also on screen when doing long durations at about 70 mph, gets a bit messy when wipers go on !

K&N filters have not been over oiled either.

substance is a light treacle colour

Around town i do not get any deposited, engine is fresh and healthy otherwise.

Any pointers would be much appreciated, Regards Richard.

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Rich, I had a weber flooding problem just as you describe, I adjusted balance, float levels, check valve etc. I also had a blat mail from a chap in Germany with this solution ... it worked for me and thats quite a few years back! *biggrin*

 

The following is Klaus's e-mail to me.

 

Klaus Koenig, Munich, Germany

---------------------------------------------

 

There is another source for the leaking of Weber DCOEs.

This was pointed out to my by Keith, a Weber tuning guru that I met on the

Innovate Motorsport forum.

I repeat this with my own words, but the credits are with Keith...

 

The DCOE has a design flaw, because there is no seal between the auxillary

venturi and the carb housing.

 

The auxilary venturi carrys the venturi that is responsible for delivering

fuel from the main jet.

The auxilary venturi is simly slotted into the carb body and held in place

by the grub screw on the underside of the carb.

Now, the fuel from the main jet is routed from a hole in the carb body into

a matching channel in the auxilary venturi, but there is no seal to prevent

fuel leackage. The seal is supposed to be made by tightening the grub screw,

but you can't overdo it, because otherwise the aux venturi will be damaged.

 

What will happen now, if the seal in not perfect, is that on open throttle,

when the main circuit is active, fuel will leak out of there and collect in

the gap between the aux venturi and the body. Eventually it will dribble out

of there and drop on you battery. This will only happen when the main

circuit is active, therefore on idle, no fuel will drip out.

 

To cure this, you can try to tighten the grub screw a little bit, or your

can try to put some Hylomar between the aux venturi and the carb body. But

be careful not to smear any sealant into the main circuit channel.

 

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Thanks very much for all your idea's , My breathing is all ok, so i am going to do the Hylamar thing and give the air cleaner a good wash through just to make sure.

will also check balance. Off to the garage now !

Thanks again ,Richard.

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Just returned from the garage, having found a couple of loose trumpets and venturies

Stripped them all out cleaned them up ,carefully retightened up venturies turned trumpet clamps round to ensure rampipes were clamped. fitted new foam piperstockins stolen from my sons garage . *biggrin*

instead of my k&n's.

Roadtest Tomorrow 😬

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Mmmm...tis a bit, I have too much invested in a chassis now.

Plus wheel on the wrong side. S3 a bit too small for me.

Plus, I have to chase my dream. *wink*

I have to say, I was very, very, very tempted by Kenny's little crosflow recently. 🥰

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Hi , Sorry for update delay ! Did'nt get out for the roadtest untill today ,Mistake 1.

Fired her up this morning to go to Duxford ,all loaded up Wife,picnic,etc only to find a nasty misfire on acceleration.

Returned to base and proceded to strip down again,What have i done to it *confused*

Fuel delivery seemed ok from pump,so filters off ,trumpets and venturi off, arhhh there,s the problem i mis alligned the venturi dimple when inserting it, thought the dimple screw was located but it was going in to the machined out area next to dimple!

Result no fuel to pot.

Wont do that again .marker pen on end of venturi helped refit.

Back in the car all systems go ,off to Duxford .

No oil was found anywhere on my return, *biggrin*

Just one thing though car seemed jurky at 2500 to 3500 rpm at constant but over 4000 seemed fine, is it too rich ? Thanks for all your help.

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Could be balance between the carbs. At light throttle loads the engine is much more sensitive to air inflow differences.

 

Leaning out tends to result in misfires and spitting from the carbs (especially on light acceleration when the accelerator pump isn't delivering a squirt of fuel); too much fuel gets you banging and popping on the overrun (when you lift off the throttle).

 

Or you could have a misfire due to a weak spark, or low pressure on one or more cylinders. It's difficult to tell without hearing it running.

 

Alex McDonald

Loud, louder, loudest...

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Hi Alex, will check compressions ,think they are ok as engine is very fresh only about 1500 miles since fitting.

coil is new bosch blue 12 v non ballast with aldon ignitor dizzi

plugs seem to be good colour on electrode bar but sooty arround immediate area of electrode

i dont get many bangs when on overun just the odd one.(except after a huge bit of welly) 😬

Think it may be time for the rollers as i am not a tuning person!

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