SU carburettors 1935 Derby 31/2

Arthur Farrow · Posted: Sat Apr 24, 2021 4:07 pm Post subject: SU carburettors 1935 Derby 31/2

Hello I'm new to the club and totally new to this (or any) forum!!

Should there be oil in the dashpots of the carbs? I cannot see any reference to it in technical manual

Thanks. Just checking over the old bus prior to a 100 mile run tomorrow

John Robins · Posted: Sat Apr 24, 2021 4:56 pm Post subject:

The handbook for my R-type says use Viscosity 10 oil, then names some no longer available products. Don’t see why thin modern type engine oil wouldn’t be OK, it’s always done well for me.

Did you get that skid lid off George Formby? He drove Bentleys as well as riding George Shuttleworth’s Speed Demon!

https://www.rideapart.com/news/246809/no-limit-1935-moto-movie-review/

Cheers
John

Martin Webster · Posted: Sat Apr 24, 2021 5:04 pm Post subject:

The Mk VI handbook stipulates viscosity 10 oil so I use 3 in 1 which works well.

Christopher Carnley · Posted: Sat Apr 24, 2021 5:14 pm Post subject:

If you read the DBTM closely, you will find that there is no oil damping arrangement, so no oil should be introduced under the screwed top.

The only oiling is when the instrument is serviced, then a 50/50 mix of paraffin and 3 in1, should be wiped onto the piston extension.

Arthur Farrow · Posted: Sat Apr 24, 2021 5:42 pm Post subject:

Thanks very much Christopher....I suspected as much...no oil in the top under the screwed cap.

I know post war SU's take oil (like my old MG ) but that is a totally different animal

When I done maybe I could write an idiots guide!!

John Robins · Posted: Sat Apr 24, 2021 6:05 pm Post subject:

I’ll join you!

Cheers
John

Christopher Carnley · Posted: Sun Apr 25, 2021 8:03 am Post subject:

We have all been there,John.

Like the London Cabbies, get the "Knowledge".