450... Which carb???

[john jupiter]

Ive read of some carb setups for 450's and there are some monsters out there with carbs up to about 40mm. Disconnected pumpers, etc, etc but im thinking this might be overkill for what im going to doing with the bike
..
Most of my riding is going to be through spirited twisties in the country... Im looking for easy starting, power through the entire rev range and a performance upgrade over the stock vhb29 that i cant seem to get my scrambler to run on.
I like the look of the older carbs, but wouldnt mind getting a brand new one either.. Not going to be doing any porting, maybe a cam if i can find one over the summer or in the fall...

WHAT WOULD YOU GET???

[MotoMike]

32 works well on mine. someon had installled an Amal 932 on a home brew manifold in which they matched the carb throat to the inlet port in the cylinder. Took a bit of sorting but Jon Pegler, a member here recommended jet and needles sizes that had it running spot on with easy starting, smooth idle, good pull all through the rev range. Of course we don't expect too much from a 25 horse bike.

I think a really big one would have you falling on your face when you crack it open. Nigel Lacey mentioned to me that he uses Amal's exclusively for his race bikes and swears by them.

good luck
Mike

[machten]

I'm told a Dellorto PHF32 is a good carb to run on the Desmo 450's and you can use a 750 GT or Sport manifold to bolt it straight on (not sure about that for scrambler frame), although I can't say I've seen a problem with the VHB 29. I use the stock VHB29 on my 74 MKIII 450 with a stock sillentium muffler and pod air filter and it starts, idles and pulls well. I actually took off an Amal carb that was on it as it was hard to start.

A few weeks ago I rode a friends 450 shotgun which has about 4000 original km on it. It is totally stock other than having a short "conti style" muffler and pod filter fitted and it went like a train. It easily accounted for a stock 74 750 Sport off the line. (I know cause I was on the Sport at the time!)

Kev

[Jordan]

32 works well on mine. someon had installled an Amal 932 on a home brew manifold in which they matched the carb throat to the inlet port in the cylinder. Took a bit of sorting but Jon Pegler, a member here recommended jet and needles sizes that had it running spot on with easy starting, smooth idle, good pull all through the rev range.

Can you please let me know the jetting for the 450/932 ?
I had a widecase 250 with an Amal 930 - one of the best running bikes I've had.

Jordan

[MotoMike]

Jordan
I'll look as it should be here in one of my earlier posts. feel free to search if you like, I think the title will be appropriate to the topic.

Found it.

see Jon Pegler's post 4th down from the top on the first page.

viewtopic.php?f=3&t=330

[Teckhardt]

I am also planning a carb upgrade in the future on my 450.

It would be great if we can collect all the 450 carb info in one place - here

carb model & size
jetting
needle position
what sort of manifold was used (pics would help for custom stuff)
any porting etc.


My setup is stock 450 SCR: (based on memory - will update)

carb model & size: Dellorto VHB29AD 29MM
jetting: 130 main / 50 pilot
needle position: V7 needle middle position
what sort of manifold was used (pics would help for custom stuff): stock manifold
any porting etc.: nada

[Jordan]

Found it.

see Jon Pegler's post 4th down from the top on the first page.

viewtopic.php?f=3&t=330

Thanks Mike.

Jordan

[DewCatTea-Bob]

By: machten...
" I'm told a Dellorto PHF32 is a good carb to run on the Desmo 450's "

____ I can confirm that, as I've used a 32mm 'pumper' from a 860GT, on my 450Mk3D with fine results !


" you can use a 750 GT or Sport manifold to bolt it straight on (not sure about that for scrambler frame), "

____ I'm afraid that this is unfortunately not exactly true... The GT-manifold cocks the carb at a strange angle,, and while the Sport-manifold holds the carb at a normal-angle, it would place the left-side top of the PHF-body near 10mm within the back-bone tubing, unless rotated to near 1-o'clock (of otherwise vertical), fine for when parked on side-stand (and without stock-tank) though.


Dukaddy-DUKEs,
-Bob

[john jupiter]

I have a PHBH30 AS on its way from dellorto uk. Will post jetting specs when it arrives.

[DewCatTea-Bob]

" I have a PHBH30 AS on its way "

____ Hope it comes with a suitable manifold ! _ Otherwise, I wish you luck getting it fitted to your otherwise stock Duke !


Hopeful-Cheers,
-Bob