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I have an 88 Paso 750 that a previous owner did or had done the airbox removal to K&N filter pod modification. Well, not all the needed parts were swapped. The velocity stack (airhorn as called in the parts manual) is missing so the bike runs like complete crap. Does anyone know of a place to get one? I have searched all over the net...craiglist,ebay, used parts locators....and so on. Any help would appreciated.

Thanks ,
Jason

Know nothing about Webers but could these fit:
http://www.webcon.co.uk/shop/shopexd.asp?id=10365

The spares I have Gert measure 43mm

Tamburinifan....That link has some cool stuff on it but, I don't know if I can adapt the airhorns from the IDF carbs. I am fairly handy at modifying things but in todays wounderful economy I don't have the "extra" to test parts.
Higgy... the spares you say measure 43mm... are they stock? Is 43mm the OE size?

yup, stock and old but that's what they measure. I measured the inside diameter of the rubber, not the manifold jfyi

btw its off a 906 I believe

Hi Jason, Don't forget that the plastic air filter lower case ,if removed formed an extension of the velocity stack of about 20 mm.What I did when modifying my spare air filter case was to trim it to the same shape as the velocity stack .I think that it also restricts the air flow somewhat as it sits down inside the top cover of the weber a mm or two.The k&n then sits on top of the modified air filter case,and the velocity stack sits on top of this before the lid goes back on the k&n.

The plastic air filter case also had a number of holes for venting the idles,emulsion tubes,etc. to the vents on the velocity stack,so I thought that it was a good idea to retain it rather than throwing it away.

I don't think that it is a real big job to fabricate a velocity stack with the extra 20mm of length added in, it would just be a small rectangle of aluminium (about 4mm plate) with the four stud holes to match the weber top cover and vent holes and ventury holes bored in it with 2 stacks welded on.

The base plate of the k&n would then sit straight on the carby top cover,with
the vents venting inside the k&n and the velocity stack bolted on top.

The main things to watch out for would be that the stacks matched the inside diameter and height of original,and that they slipped down inside that little rebate around each ventury hole in the top cover. This is important because the ventury and air corrector holes come very close together at this point,and if the air correctors were trying to draw air from a vacuum source.................
It frightens me just thinking of the tuning issues.

If you decide to go down this avenue let me know and I will post precise measurements of original spec. regards Jay.

You're looking for the air horn for the Weber? Like this one?
Where are you and what Weber do you have. The one in the lower part of the picture is from a 44dcnf

What else you missing?

Ya higgy thats the one. As far as I know the airhorn (and spacing for airbox lower case) is the only thing I need . The carb is a 44DCNF-110-7J and I'm in Houston Texas which is about 45-50ft above sea level. And ridiculously hot already this year.

jayh... great info if I go that route I will definitely be hitting you up for more info. I have been following your Weber What if? tread. Excellent work my friend, excellent work.

Don't forget that the plastic air filter lower case ,if removed formed an extension of the velocity stack of about 20 mm.What I did when modifying my spare air filter case was to trim it to the same shape as the velocity stack

you mean this ?


Jason, if you need it you can have it. I kept it from my first airbox I had modified for the Mikunis.

G.

I have a spare I can send you but it will be a while as I am on the road for the next 6 months.....or so.

paso750 wrote:

Don't forget that the plastic air filter lower case ,if removed formed an extension of the velocity stack of about 20 mm.What I did when modifying my spare air filter case was to trim it to the same shape as the velocity stack

you mean this ?


Jason, if you need it you can have it. I kept it from my first airbox I had modified for the Mikunis.

G.

Thanks G. I think it would work great with the airhorn I found at pierce manifolds.... I hope it is the right height . A Ferrari site said installed height on their 44DCNFs is 1.5".

Pierce also has the optional screen for the top of that stack. I modified my stack to fit it

with some cutting and grinding two days ago it looks like this now. I`ve sent you a pm.


G.

WOW!!! G. that looks great..... good work...PM sent

jayh..... I am getting the bottom section of the airbox from G. and the measurements that Pierce Manifolds sent me for the airhorn are 45mm tall x 40mm ID x 62mm OD. The air filter measures 85mm tall,95mm x 150mm oval. So that will leave me with an air gap of 40mm on the top and 33mm on the sides (16.5mm each side). I think that should be plenty for proper air flow.....what do you think?