carb settings vhb30 750s

[peerfleuren]

Last week I did a ultrasonic cleaning of my VHB carbs, after that I revised them using the proper revision set. Now the bike is running way to rich. I tried adjusting the idle and tried the needle (V3) in lower position. The only thing I altered was putting a new o-ring in the pilot mixture screw as it was in the revision set. There was no O-ring before.
Normally I would use a Colortune plug to sort out the settings, but they are completely sold out at the moment.
Any suggestions or comments?

Peter
the Netherlands

 

[Haggis]

Hi Peter
Did you change the float height? Either deliberately or by accident.

 

[peerfleuren]

Hi Peter
Did you change the float height? Either deliberately or by accident.

no I didnt and checked before I put them back together.

 

[martymoose]

Could be lots of things, but i would check the chokes first

 

[MarnixSFC]

There was no O-ring before.

VHB carbs have no o-ring on the pilot mixture screw. That’ll make quite a difference.

Marnix

 

[peerfleuren]

thnx Marnix,

thought so but both Konstanz and dellorto parts shop have them in their revision set for the VHB, this afternoon I removed them. didnt have the chance to have a proper run jet...

 

[peerfleuren]

Could be lots of things, but i would check the chokes first

thanx Marty I checked and rerouted the chokecable, seemed ok

 

[Laverda SF]

I've ran the Delortto VHB 30A mechanical square slider (open mouth ) for something like 45 years on my 70 SF SF0 - Love them Carbs because they don't ware out; however, they are susceptible to exhaust changes Vs main jets and the rubber cross-over Intake Manifold has to be solid - The hose tend to collapse - Use Hydraulic grade.

Use Rust Check RED to clean and lubricate them Carbs.

I was never far off 8000rpm with a Breganzie twin - That's walking !

Open Mouth - You hear me - No Air Filters or Velocity Cones - Change your oil every season - Common Truckers grade 15w40 Diesel - Rotella, Delvac - I preferred Shell Duron if you can find it !

Enjoy your 69 750S - Not many can - Ask Wolfgang - The 69 Breganzie 750S is his Pride Ride !

 

[peerfleuren]

problem solved... Marnix was right, after a check up I took out the pilot screw o-rings and put the needles back in the middle position. She runs like she should.
thanks for your thoughts and tips.

 

[Paul Marx]

My S was running very rich off idle. I finally sorted it by going down to 45 pilots.
I had opened up the intakes from 27mm to 30mm though.

Paul

 

[martymoose]

Rode the sf2 to work today, awesome! I'm still running 55 pilots, 130 mains, might drop to the 50's, see how it goes.

 

[piranha-bro2]

Rode the sf2 to work today, awesome! I'm still running 55 pilots, 130 mains, might drop to the 50's, see how it goes.

130???!!! You sure, Marty? That's 10 or 15 lower than any stock SF I've ever worked on. Or are you running 8:1 CR?!

 

[martymoose]

I had 140 mains, running rich, dropped to 130, but only running back and forward to work due to lockdown, still plenty of pull, i havent looked at the plug colour yet. With the 140's, it was very sooty.

 

[martymoose]

I had the two 50 pilot jets sitting on the shelf, knocked one of them off, fell on the floor, gone! Spent 5 minutes on my knees, gone. Bugger.

 

[piranha-bro2]

You must be cranking that baby on the way to work and back to be hitting the main jet, Marty

Maybe modern fuels relates to a 10 drop in main? Dunno. I found with mod fuels that plug colour is a totally different beast than it was in leaded days. Reading plugs used to mean something back then.

 

[Haggis]

I'm on 45 idles, plus a 0,4mm shave increasing the cutaway height, BUT my SF does have soft cams in it, so don't read too much into it.

 

[MarnixSFC]

I had 140 mains, running rich, dropped to 130, but only running back and forward to work due to lockdown, still plenty of pull, i havent looked at the plug colour yet. With the 140's, it was very sooty.

Needles and needle jets still in good condition?

Marnix

 

[Andy]

I had the two 50 pilot jets sitting on the shelf, knocked one of them off, fell on the floor, gone! Spent 5 minutes on my knees, gone. Bugger.

Check in your socks…

 

[martymoose]

Hi Marnix, probably not! Looked ok to the naked eye, should have forked out for new bits, see what Santa brings me