Carb Maintenance

[RJF_70]

Been Tinkering a bit this afternoon and noticed the carb chamber needed a bit of oil both sides, Haynes manual says top up to filler line but as far as I can see there is no filler line? Also is there any maintenance needed for the float chambers as doesn't mention this in the manual?
Cheers Rich..

[Toledo Man]

Just top up the dashpot to the top of the piston that the plunger goes into. It doesn't matter too much if you put a bit too much in because the screw cap has a smale hole so any excess will be forced out when the piston goes up. My recommendation is to use ATF but any oil that is thinner than engine oil will do. One of my Club Triumph friends used a mix of 20W50 engine oil and 3-in-1 type oil in his racing Spitfire in his dashpots (he was running the 1500 lump with the SU HS4s at the time). The reason for using a thinner oil is to improve response when the piston moves up when the throttle is opened.

[RJF_70]

Have topped the oil up in the pots, but wondered if there was any maintenance needed for the other chamber / float pots?
Cheers Rich..

[Toledo Man]

If the car is running fine then you don't have to do anything else.

[RJF_70]

Ok great , 1000 miles since I got her and running fine.
Cheers Rich..

[cliftyhanger]

I would say use engine oil.
Too thin an oil lets the piston rise too quickly, which means there is less enrichment during acceleration (SU carbs are more complicated than they look. When you accelerate the piston moves down, this gives more vacuum over the jet and enrichens the mixture. The fact the needle gives a weaker mixture with the lower piston is trumped by the vacuum)

[geeksteve]

I tended to use whatever was nearest. I've used ATF, 3in1, 20w50... There probably is a small difference but it's nothing that I noticed/concerned me. I can tell you that "bugger, forgot to put oil in the dashpots" is quite noticeable though

Steve