The past few days/weeks were spent sanding and correcting the two main airbox parts.
When they were finally finished a polyester finishing coat was applied. This paraffin containing coat gets very hard. As it`s thick as yoghurt the layer becomes rather thick and as it`s applied with a brush the result is a slightly wavy surface. This stuff which is like a gel coat dries transparent but rather flat.
Reason enough to spend some more days sanding the surface (again) evenly w/o sanding through the finishing layer. (This was done only on the outside) Due to the paraffin contents of the polyester coat the surface had to be sanded meticulously until the very last shiny spot was gone otherwise a clearcoat wouldn`t stick. The efforts paid off as after spraying two layers of glossy clear coat the result now looks like this:





Of course that was no rattle can spray but applied with a compressor and paint spray gun, but it`s a standard 25l compressor one can find in any home depot. The only requirement is that it needs to be able to keep 4-5bar constant air pressure.
The spray gun came with it as a set and is a very basic one with a 1.5 jet which sprays rather rich as usually one would use a 1.0-1.3 for something like this. Once the air/paint mixture and the spray pattern are properly setup on the spray gun it`s not very difficult to paint without any bleeding even though it`ll take a little practice.

I then started making a new lid as the old one wouldn`t fit anymore. Meanwhile I began to modify its rear section as this would otherwise hit the contacts of the tank floater.






As the temperature dropped to only 12-15°C with some occasional rain I currently can`t continue. Luckily the next days sun should return ...

G.

How's the weber coming G ? Any progress?

One fine looking Paso
You should get yourself a writeup in a publication

Well, in the past two months not much happened to the Paso. After a day of heavy work digging dirt I started having pain in one foot which later put me in bed for almost 2 weeks as the sciatic nerve struck me. There was no sitting or standing. The pain can hardly be described. The MRI showed a slipped vertebral disc as the reason for all which I`m still having trouble with today.
Meanwhile I had gotten my friends Elefant here as the air intake should be modified but as usual I couldn`t keep my hands of it and made also numerous modifications incl. a custom airbox I`m still working on. So each night when I quit working I look like a colombian druglord covered in white dust from all the cutting and grinding of the parts I made.

The only thing I did is doublecheck if all main bolts were torqued correctly and put the Weber on the Paso.

As a bonus for working on the Elefant I got a Scottoiler which is already on the bike now.


To finish up the installation of the Weber I installed an underpresure fuel pump of a Yamaha TRX850 (the one on the left is the one of a Monster/SS)


I had the bike running last year with the Mikunis and it ran just fine from the start. About two weeks ago I fired up the Paso with the Weber and she started up nicely. Idling was just fine and not rough. The carb only had a basic setup and everything about the engine is new so that was actually suprising.
Negative though that after about 10min or so the oil temperature rose so much I stopped the engine. It was steaming.

The engine would stall as soon as you touched choke and if shut off after running it would not accept any throttle to restart. Idle and idle mixture screws would not be responsive which I`d guess is from incorrect jetting. As a starting point I used the one of the Limited models.
I tried again today after connecting my Twinmax sync tester and also the lambdameter but I was not able to get any proper setting. There are no air leaks. I sprayed starting aid spray on the inlet manifolds etc to see if it would revv up but it didn`t.


http://www.twinmax.de/prtmx.html

I was thinking the engine ran rich at the beginning, then I thought it may infact run lean as I had it running w/o the airbox and the engine has big valves etc. Meanwhile I`m back to thinking she`s running rich as that`s what the lambdameter is showing so I ordered 50 and 55 idle jets today (I`ve got 60s now). I hope one of them brings me in a range where the adjustment screws react properly.
Getting the bike to idle below 1.000 rpm was really difficult. With a few lightened engine parts idle has to be raised or it will be rough. Throttle response though is amazing no comparison to what it was before as is the sound over 2.500rpm. I`m just hoping it`s within legal limits. It`s also amazing that there was and is no single miss oder backfiring at all.
I have to admit I`m disappointed although it was very likely that with all the engine mods the standard jetting would not work.

This was in the fuel lines when I bought the bike. Is this a fuel pressure regulator ?


The next days again there`s no time for the Paso as the Elefant will be picked up friday. I won`t be able to finish it until then so I`m getting it back later which keeps the Paso as second priority and riding season is coming to an end. A pity as there`s finally light at the end of the tunnel...

G.

looks like an accumulator G, more for fuel injection than a carb. Accumulators maintain pressure at the injectors when the pump is not running. just a guess

The 50s and 55 idle mixture jets had arrived days ago but I didn`t have the time to try them.
As I had to give up on the Elefant for the moment (about half the tank ran into the crankcase housing due to the Keihins spilling like mad even though the engine didn`t turn once and the fuel pump is an underpressure pump). Ordering new floater needles and seats etc gave me the time today to change the idle mixture screws on the Paso.
I started off with the 50s and after a little fiddling she runs and starts just fine. Still no single backfiring or miss so far. She runs like a sewing machine
Other than with the 60s the lamdameter now displayed something reasonable instead of jumping up and down like mad (it now shows 14,4-14,9:1) and the synchronization was very easy.


Idle mixture screws are out 3,5 turns now (airbox not on the carb).
The engine runs just awesome but it idles high. I can`t get it lower than 1100-1200rpm. I completely removed the throttle linkage but it was slack so that`s not the reason. If I turn the idle screws in I can lower idle but then I`m losing the correct mixture.
I wonder if this`ll change with the airbox on or what other reason there could be. Also currently when you open throttle and close it fast the engine revvs down not as spontaniously as you`d expect it to.
I then tried the 55s but it was noticable that getting a proper setup was easier with the 50s.
Btw, thanks Jay & higgy.

a small video
http://www.box.net/shared/zllixtc7k4sxugn1v5f2

G.

sounds like too much air getting in somewhere G

G. Are the butterflies closing fully back to the idle stop screw ? the accelerator cable isn't too tight ?.You should be able to adjust the Idles right down to nothing with the Idle adjust screw unless the carb is sucking air past the bypass screws instead of the butterflies or as Higgy said you have an air leak somewhere.Throttle shaft maybe,you replaced those bearings from memory ?.A rich mixture has a cooling effect on engine temperatures,so If it was getting hot,and it is definately carb related then you have a lean condition.

You will probably find that the 50 idles whilst good for low speed operation and tuning,will expose a lean hole further up the rev range 4000 - 5000 rpm.They will probably also backfire on the over-run when hot.The most important thing to remember with idle jets is that they also control the amount of fuel available for low speed operation (up to almost 6000 rpm,as the idles have reached their maximum flow and are tapering off,the mains have slowly started,it is this overlap period where the mixture goes lean briefly and you feel a flat spot on acceleration.

There are only 2 ways to cover the lean hole 1) make the main circuit start earlier,raise float,increase main jet size,modify emulsion tube,(but their is a limit to how soon it will start as vacuum is not very high at this stage).or 2) increase idle jet size (to the detriment of low speed operation).A compromise has to be reached between the two.With my earliest starting main jet combination,I found 54 idles too small and 55 idles too big,I opted for the larger 55 size.I realize this is not optimum for idle mixture but this is the compromise of webers. J.

Empathy , simpathy ... to you G. whats left of my sciatic nerve is giving me shit too! not good
I found , with my paso that it ran like crap without the airbox and cover , so much so that I couldnt see the point in trying to tune it with them off

no news on the Paso. It`s on its stands, covered and put away for the winter. I only emptied the carb and fuel lines and filled up the tank to the top to prevent it from rusting.
The Elefant is back at its owner. As we talked about airboxes and glassfibre work in other threads here`re some pics of my last one. It`s not as nice as my own but time was limited and it was more important that it fitted well and is sealed.





This are steering bearing parts from a SS. Does anyone know if the Paso has such a large washer as the one on the right ? I found one in the garage and actually don`t know if it`s from the Paso (can`t see it in the parts catalogue though) or just some part I got with a lot of other Duc parts.


Being cold and wet outside it`s time to take care about other things like prepairing some brake calipers for finally being powdercoated black.

G.

PS: who would`ve thought I`d be the first to pass the 3.000 mark. I was sure it would be Antti.

Gerhard: Such things are really NOT IMPORTANT to me at all... Anyway "everyboby" knows, that I have to concentrate much more to Adventure bikes, not to Paso's... Gerhard is Great guy and he know huge amount of Paso things, so things will be in future in "good hands" here .... Anyway human lifetime is limited, so i have to do still something what i havent had time to do yet with Paso's... I want to go to grave with happy feeling with much more higher experiencies what Paso's (or any Ducati) can offer to me. Hopefully somebody understand my situation....

Don't worry G I'm catchin up fast

I'll see if I have time to break my spare down some more tomorrow.
906 could be different than the 750