450 carb jets

[graeme]

Can anyone tell me what jets work best on a 450 with a standard squar slide please.
This is what's in it now,
Main 140
Needle jet 265 M
Needle V7
Idle/pilot jet 50
Starting jet 65
Slide 7454-40
Float height 26mm from the flat carb base to the lower edge of float.

Thanks
Graeme

[machten]

Hi Graeme,

I used the following config on my 450 in Europe between 400m and 2800m altitiute and it worked very, very well...(at the highest 150m it started to struggle, but it wasn't worth fiddling with for those rare conditions). It started first kick most times with choke, idled immediatley with choke turned off and pulled very well. My bike was a 74 450 MK3.

Model Year Dell'Orto Type Size Needle Main Jet Idle Jet Slide Needle position Needle Jet
450 Mark 3 1969-74 VHB29AD 29 V7 135 50 60 2 260T

I pulled the the plug (B7HS) out for a look just for interest twice over five weeks - lovely light brown colour and it went straight back in both times.

Kev

EDIT: Desmos are marginally different. Not sure if yours is a desmo...kev

[graeme]

Thanks Kev, yes RT desmo. Standard valves etc
Using a BPR7HS the plug is very black dry soot, so too rich.
Baffled muffler, K&N type filter, unleaded 98/95, at sea level.
I did make a velocity tube close to the original but a little longer.
Only done a few miles and runs like shit.
Suspect faulty ignition, but I want to remove all other possibilities and the carb is the other suspect item.

Graeme

[Jordan]

Have you seen page 4 of the Supplement to Work Shop Manual for singles? It has specs on various 450 models, including Desmos but not specifically RT.

Jordan

[DewCatTea-Bob]

By: machten...
" Model Year Dell'Orto Type Size Needle Main Jet Idle Jet Slide Needle position Needle Jet
450 Mark 3 1969-74 VHB29AD 29 V7 135 50 60 2 260T "

____ I suspect that Kev was probably somewhat dismayed with the outcome of exactly how his word-spacing above had finally became displayed within his post...
__ Listing-presentations like that above on our-forum (as with many other forums), must often leave the writer/presenter frustrated because when his edited-wording has become 'posted', THEN his chosen/intended margin-spacing (which was somewhat of an effort to get all logically laid-out), has become IGNORED, (thus-then leaving such list-presentations in considerable disarray [in POSTed-mode] ) !
__ This much undesired issue occurs because,, although while within EDIT-mode, the writer's chosen spacing remains as expected, once it has become 'posted', ALL (consecutive)- spacing then gets reduced to merely-just one-single/individual 'spacing' (which obviously destroys all the intended helpful spacing which had been expected by the post-writer) !
However the original chosen spacing is not totally lost, as returning-back to EDIT-mode or going to 'QUOTE' mode will then bring-back the posting to include the original spacing as it was left to be.
But in this case presented by machten/Kev, I suspect that HE was using a wide-screen monitor,, cuz as seen on MY std.screen, (while his spacing has been returned [within QUOTE-mode] ), it unfortunately still doesn't display his upper & lower lines (of designations & listed-values) in a straightened-out/logical manor.
So, (since no VERTICAL-spacing is ever ignored once posted [on our forum] ), in order to have such listings TURN-OUT in a most logical/straight-forwardly readable manor, ya then have to list such stuff in the same manor -(vertical, [not horizontal] ) as Graeme has used to present HIS listing.
So when Kev's data is redisplayed in that more-useful manor, it then sensibly appears post-displayed as follows...

Model - 450 Mark 3 ............ 450 R/T
Year - 1969-74 .................. 1971-72
Dell'Orto Type - VHB29AD ...... (same)
Size - 29mm ..................... (same)
Needle - V7 ....................... V 7/II
Main Jet - 135 ................... (same)
Idle Jet - 50 ...................... (same)
Slide - 60 ......................... (same)
Needle position - 2 .............. bottom
Needle Jet - 260T ............... 265 T

____ For any of those of you who may have noted & wondered why I-myself -(DewCatTea-Bob) always add unconventional/extra (space-holding) typing/marks (such as: - ; _ ; __ ; ____ ), to my forum-posts,, ya should now understand that it's all included & intended to make my posted-writings more logically-straight and easier for the reader to more sensibly decipher & follow (compared to posted-writings by others who leave that extra mental-work for the reader to decipher/figure-out).


____ I've added (below)an alternative data-pic to the one posted by Jordan.


Enlightened-Cheers,
-Bob

[machten]

So when Kev's data is redisplayed in that more-useful manor, it then sensibly appears post-displayed as follows...

Thanks for correcting that Bob. I recall this "space and tab stripping" problem now that you have mentioned it. I'll use your format in future.

Kev

[graeme]

Thank you all,

Do VHB 29 carbs all have the same slide?
Do they have different "cut always" to use a term I'm familiar with?
This slide is 7454-40, its drop down piece is 4mm.
Slide cutaway makes a significant difference to a PHF, PHM so I assume to a square slide too?

Graeme

[Jordan]

There's only one size 60 listed (6mm). But some have a hole in entry face.

Jordan

[graeme]

Is the 60 written where my slide is 7454-40 they are -60. ?

[machten]

There are several sizes. I have slides stamped with (and only this) 40, 60 or 80 on the top of the slide reflecting 4mm, 6mm and 8mm cutout (no holes).

Ian Gowanloch (ebay id italspares) has some new original period 60's at a very fair price - Despite research, I couldn't find them new anywhere else in the world. I got one from him a few weeks ago, so I assume he still has them. The cutout size makes a huge difference - if you're not using a 60 slide then the rest of the jetting/atomiser/needle setup is anyone's guess (or at least those with better knowledge than I...but I'd speculate the greater vaccuum of a 40 would draw more fuel and restrict air leading to a much richer scenario!)

Kev