weber what if ?

[Brutus]

Sounds like you need a valve adjustment and a new spring for your sprag while you are at it. 4x is too much adjust your idle jet

Higgy, I don't quite understand what you mean with sprag and spring. The throttle valves have been cleaned and refitted and seem to function ok. You know what your setting is on de idle screw and air bypass screw? tx.

[jayh]

Sounds like you need a valve adjustment and a new spring for your sprag while you are at it. 4x is too much adjust your idle jet

ROFL

yes 4 turns is 1 1/2 further than I would have expected,and indicates a larger idle jet could be used,but if its running alright let it be.

Just watched your youtube clip, sounds good,but you will have to ride it hot to decide if all is good.

Did my ohlins last year,just ordered a seal kit through my local bike dealer,and he supplied me with a photocopied spec sheet and correct weight oil,still going well.I posted some info on the rebuild,it is a little tricky in one spot but otherwise fairly straightforward. J

[higgy]

the grinding noise when you hit the starter,eventually it won't start at all. It is a simple job when done early,just requires a new spring for the sprag clutch. Sprag clutches with good springs don't make any grinding noise

I also hear at least one valve clakin. If you have one loose you got one tight. Loose not so bad if corrected tight is asking for trouble...first sign of a loose closer is a high speed missfire

2 to 2.5 turns on the idle screws when the jet is sized properly

[Brutus]

Sounds like you need a valve adjustment and a new spring for your sprag while you are at it. 4x is too much adjust your idle jet

ROFL

yes 4 turns is 1 1/2 further than I would have expected,and indicates a larger idle jet could be used,but if its running alright let it be.

Just watched your youtube clip, sounds good,but you will have to ride it hot to decide if all is good.

Did my ohlins last year,just ordered a seal kit through my local bike dealer,and he supplied me with a photocopied spec sheet and correct weight oil,still going well.I posted some info on the rebuild,it is a little tricky in one spot but otherwise fairly straightforward. J

Tx. I'll find out soon enough when the rear shock is done. Found your info on http://forums.ducatipaso.org/viewtopic. ... lit=ohlins. Btw sprag clutch is done a couple of thousand miles ago. Used a bearing from a mini cooper (late 60's model). Only the outer ring needs approx 0,5mm of milling. Don't have any problems since. The heads have been overhauled in the last couple of weeks. Valve clearance is ok.

cheers! Léon

[Brutus]

Gents, got the paso back on the road today. Overhauled weber / clutch / Hel brakelines / adjustment front sprocket / overhauled heads / some repairs on dash etc etc. Drives like a maniac !! Response on the throttle is amazing compared to the situation before. Only thing I've to solve is the stumble around 2500-3500 rpm and a little adjustment on the stack of plates from the clutch. It isn't perfect yet, but I'm getting there.
Léon

[jayh]

Try the stock 57 idle jets and see if that helps.I'm not sure why your 56's need to be opened so far ? J.

[Brutus]

Try the stock 57 idle jets and see if that helps.I'm not sure why your 56's need to be opened so far ? J.

I'll do that. Did I mentioned earlier that I run with an oval K&N filter and open exhausts?
Léon

[jayh]

Yes I'm aware of your air filter and exhaust,I run exactly the same (conti cans & oval K&N).
First try 57 idles.If you still have to unscrew your mixture volume screws a long way,something else isn't right.

The size of the idle jets effects how quickly you run out of fuel during the transition phase to main jets.
They also supplys fuel to the idle circuit.Confusing name for these jets really as I consider their job as a fuel supply to the idles, of secondary importance to their role of getting the overlap mixture during transition right.

It doesn't really matter how many turns it takes to get the engine idling properly,1/2 turn or 5 turns,
but if it takes more than 2 1/2 turns to tune the idles ,this is an indication that you may not have enough fuel being supplied to cover the transition hole further up the rev range.Best way is to try
and see.

If you go to big on Idles,you will get a lot of popping and backfiring on the over-run.

Leaving the idles alone and going one size larger on mains may also fix the problem,or a combination of both.I'd leave the Air Correctors alone for the time being.

Also running iridium plugs helps. J.

[Brutus]

Yes I'm aware of your air filter and exhaust,I run exactly the same (conti cans & oval K&N).
First try 57 idles.If you still have to unscrew your mixture volume screws a long way,something else isn't right.

The size of the idle jets effects how quickly you run out of fuel during the transition phase to main jets.
They also supplys fuel to the idle circuit.Confusing name for these jets really as I consider their job as a fuel supply to the idles, of secondary importance to their role of getting the overlap mixture during transition right.

It doesn't really matter how many turns it takes to get the engine idling properly,1/2 turn or 5 turns,
but if it takes more than 2 1/2 turns to tune the idles ,this is an indication that you may not have enough fuel being supplied to cover the transition hole further up the rev range.Best way is to try
and see.

If you go to big on Idles,you will get a lot of popping and backfiring on the over-run.

Leaving the idles alone and going one size larger on mains may also fix the problem,or a combination of both.I'd leave the Air Correctors alone for the time being.

Also running iridium plugs helps. J.

Thanks Jay, Really got to understand how the Weber works. Really great stuff to see theory get into practice this way. Btw got iridium plugs allready
I must say the bike really comes alive.. Still some tweaking and maybe it'll run better then my 851.. (with all the electric crap on it)

[jayh]

An increase in idle speed can make your gear changes alot less clunky,if that is the reason that you are fine tuning your clutch.

The only downside to this is the bike tends to idle a bit high when hot (after a good thrashing),but soon returns to 1200 or so rpm within a few minutes of normal riding.

I suggest you play with the idle speed a bit, as it has much to do with the tendency of the engine to miss just off idle as you are taking off,and every time idle jets are changed it needs a tweak as well.

It can really make a difference to the rideability of the bike,and I think that it is the cause of quite a few of the weber issues that people complain of.

I think that some people tune it to get a lumpy idle (I have been guilty of this myself),without realising the other issues that they are creating by doing so. J

[Brutus]

Jay, I've tried 57 idles, closed the air bypass screws, fiddling with the idles screws, even another carb with all the jets/mains etc fitted from the first weber. Not the result I expected. Now I'm running 56 idles again, closed air bypass screws, float level at 45mm, 165mains and 185ac. Runs like hell from 5k. Between 3k and 5k I've got a stumble. Also allot of spitting and banging when the bike starts out cold. Did I mentioned earlier that my paso is the californian type, with a digiplex and some tubing fitted on both sides of the manifold? Furthermore the rubbers between manifold and inlet ducts shows some cracks. No leakage, but can these be replaced with other models..?

[jayh]

Here's one I think ?
http://www.ebay.com.au/itm/DUCATI-UNION ... 43a2e0e889

What did the 57 idles do ?

It is normal for a correctly jetted engine to spit out of the carby,(or misfire),when cold,as the cold engine needs a richer mixture.Use your choke. It should not be doing this once warmed up though ,only for the first 30 - 60 seconds !

I'd check all the ignition and inlet manifold and gaskets for vacuum leaks,as the symptoms you are describing combined with having to open the idle screws so far ,all point toward extra air getting into the mix from somewhere.Throttle shaft maybe ?

My 56 idles are set about 2 1/4 turns. 55 idles 2 1/2 turns.

Yours may differ slightly,but I wouldn't expect much more than 1/4 turn.

J.

[Brutus]

Just did a quick testdrive with 60 idles 165 mains and 185ac. Idle screw set to 2 3/4. The bike reacted better then with the 56 idles. A lean spot around 3,5k and from there on up it keeps on pulling without any hesitation. On the other hand it bangs allot when compression braking. Also it spits a bit below 2,5k.
About the gaskets, I'm really wandering what could be wrong. In the last couple of weeks I overhauled the heads and the weber. Only gaskets I didn't change are the ones between induct and cilinderhead, and the gasket between manifold and weber, see pic below nr23 and nr52.

Also still want to know the difference between the electrical system with digiplex and the one without in relation to the operation of the Weber. I've noticed that the setting of a Weber on an 906 is quite different. Don't know if this is all because of the larger cilinder capacity.

[jayh]

One of the main differences in the webers between the 906 and 750 are the portings inside the carby that effect transition and also the height that fuel overflows out of the auuxillary ventury,(you can't run the 906 float levels on the 750 or fuel will overflow into the barrels).
44dcnf107 750 paso
44dcnf113 750 sport
44dcnf116 906 paso the number should be stamped on the casing.

Check that your chokes are closing properly and no air leaks on throttle shaft.

some popping out of the exhaust on hard decelerations is normal on the weber especially when the engine is fully warmed up and you are really giving it a fistfull.It shouldn't do it when just normally slowing down though.This usually indicates rich on the idle jets.

60 idle jets should be around the 2 turns mark,once again indicating that you may be getting some extra air coming in somewhere ?.

When I had 60 idles fitted,mine popped out the exhaust a lot too.

Are you sure that it is a lean miss and not a rich miss ? J.

[Brutus]

I'm currently running an 44dcnf112. Does it has anything to do with the californian model? Cause there is a digiplex present that is connected to the manifold. One tube from the digiplex that splits in two nearby the vertical head. Then 2 tubes are fitted on either side of the top of the manifold (see nr 49 above for location).

Furthermore I took the inlet ducts off and noticed that one showed a black (burned) area on the side of the inlet of the horizontal head. I could wipe this clean with a cloth and cleaner, so there is one leak. Used a thin gasket and some loctite liquid gasket to seal it. Let it dry for 24h and fired it up yesterday with 56idles, air bypass screws closed and the screw set at 2 1/4. It didn't fire up directly and I couldn't keep it running. Adjusted the screw to 2,75 and 3,25 outwards and there was some improvement. Getting mad overhere.. Idling at 1k it looks like its running on 1 cilinder. Probably need the air bypass screw to get this right. Also it reacts alive when the choke is on. Responds actually great with the choke on. Would like this response without the coke.

Don't really understand what you indicate with leakage at the throttle shaft. I fitted everything as it should be, only adjustment is the new cam. Any advice?

Also I'd like to know if you still use the old gasket between carb and manifold. Thinking of removing this one and use threebond liq gasket instead..

I'll get it right someday!