906 carb question

[Rock]

DISCLAIMER:

I tried to search this topic before posting this q. If I missed the thread where this is answered please let me know and I'll buy the beer......

The question:

Webber Vs. Mikuni Vs. Dell


I am leaning towards a Dell orto conversion on the following basis with the Dell's I can loose the fuel pump. Am I wrong? is the webber and the fuel pump better? I am humbly asking the opinion and suggestion of the forum.

Also what size Dell would anyone suggest?

Thanks
Rock

[higgy]

Any carb with a power jet circuit like the delorto or the mikuni will work better than the weber which does not have a power jet. Of course they need to be jetted properly.

[ducbertus]

i've owned a 900ss "90.
ya, those ones with the crappy Webers.
after I got rid of id I was told that the problem with those Webers was a lack of a good fuel pressure regulator in the fuel system.
so, before you switch to an other carburator, try this. Because these carburators ain't so bad.

ducbertus

[Rock]

Fuel pressure regulator, that is an option I over looked......Thanks

will check that out....

[higgy]

Rock,On the 906 you can get by just fine without a regulator. If you must have one get the proper holley 12-803b or 12-804 and be sure to mount it properly. The biggest 2 problems with the weber are it has no method of dealing with barometric changes and parts are becoming hard to get.. There are ways around this but all require at the very least a willingness to change jetting to suit the season. If you don't want to fiddle I suggest you go with the mikuni. 38mm flat slides from a monster are not to hard to find nor are the intake manifolds you will need. cables and such will be a little harder jetting can be had almost anywhere they have mikuni in stock..Forget the delOrto's more trouble than they are worth and parts are silly in their cost when you can find them
Me personally,I like to tinker and the weber suits me just fine,but there are days when I think about the mikuni set I have layin around in a box...when those hot summer days just won't go their merry way

[romus]

I have another discussion topic called "Trying to understand the Weber (Weber-air/coils/fuel)". ie associated issues need new coils a

I figure one thing about the 906 is that there are some issues, but they can be addressed - and that makes the bike have soul. Likewise, Webers have soul, so I am sticking with mine, accepting the need to change the jetting and the process involved in that. Higgy has a class on getting the Weber Jetting right if you decide to stick with the Weber. He is taking the time to sort out the best jetting options. When I have finished I will also know that (for a medium to hot sea level climate)

I guess it is about interest and time - so if less time to sort it out maybe the mikuni is what I would do too.

A holley regulator makes sense to get the recommended ~3psi served to the weber, because it fits at the return line position, which is important. The other way that I am trying it is fitting a new non pulse fuel pump and restricting the return line.

[Rock]

Yep,

I have too much time on my hands so I'm over thinking things. Thanks for the info.

Won't be doing anything yet. just collecting info

[Finnpaso]

Weber function better in 906 than in 750 Paso. I have played in my 750 Paso with original Weber, then with 40mm Dellortos(too big for "not tuned" 750cc engine) and at least changed to Mikunis... satisfied now....

[persempre907]

at least changed to Mikunis... satisfied now....

Why didn`t Dellortos work well enough???
Ciao


P.S. Now, I`m in Czech Republic, where they sell a lot of Koskenkorva from Finland (both "normal" and peach).
Pity, I can`t bring some bottle to Italy (on the plane, unfortunaltely, no liquid in the hand baggage)

[higgy]

answered your own question they are Delorto's

[ducinthebay]

40mm Dellortos are too big for the 750, but seem to work well on the 900 motor.

The way I see it:
Stock Weber - If your bike is basically stock and you want to preserve it, then do the mods with jets and pressure regulator. If you have a 900, it will work better than the 750 motor. A big plus is that you keep the stock air box.
Dellorto - 36 for 750, 40 for the 900 - For those who fancy the classic hot rod spirit of the bike. If you get them right, they run well. In the mean time, they will belch, spit, cough, and your garage will always smell of gasoline. All in the charm. Accelerator pumps are fun.
Mikuni - off of the stock SS or Monsters - For those that just want the thing to run right. Maybe not as much top performance, but plenty of performance everywhere else, like Saturday morning when you stop for coffee and a lot of people are ogling your bike. Cheap on e-bay, lot of jet kits available.
Keihin FCR - Best performance and characteristics of all. Great carb, but also high price. Expect to pay $300 - $400 each. Then you need to get manifolds and cables and a new throttle. (2 cable) If you are totally obsessed with performance, this is the carb, but then again, why are you riding a 20 year old motorcycle? Do you really want to spend a lot of time at redline on an old bike?

I have Dellortos on my bike now, but mostly because it came with them. Spent a lot of time jetting them, and still not entirely happy. I do get 115mph on a backroad, and that seems to be enough. If I had to do it over again, I would opt for the Mikuni path and just call it good.

Cheers,

[higgy]

"The way I see it:"

Pretty much says it all

[persempre907]

answered your own question they are Delorto's

Sorry,
I guess my English is too bad, so I don`t have understood .
No matter, they are Dellorto.



Ciao

[higgy]

dellorto delotro it all leaks fuel and wipes out pump brackets, Weber was an improvement any way you look at it.

[jomo]

Sorry I have to reveal the truth.

I have a 906 with original Webber. I bought it 3 years ago and it runs perfectly. I don't know what the previous owner has done but it seems perfect in every way except for one........my other 906 has 40mm Dellortos. Yes they are a bit fiddly, yes I have tried to rejet them, yes they are not quite right, yes I should get it Dyno-tuned.

Would I go back to the Webber or anything else? No way!!! The Dellortos are awesome with the extra power and the induction sound through the K&N air filters is worth all the little problems. It pulls a genuine 225kph with wife on the back (the 2 mates with the Jap bikes were reading 240 but my front Bridgestone 130/70-16 fixes speedo error). I have it tuned a bit better now and would expect 230 or a bit better. That's around 140Mph. If you are not getting that speed out of the bike it is probably jetted too lean on the main jets.