SU carburettor tuning - Part 1 - The Basics

This video is part 1, tuning a SU carburettor. It takes you through the theoretical basics of tuning and some very specifics of the SU. I am using a HIF 38 and 44, however the methods apply to all types with small differences. Assembly and basic verifications, including baselining are part of the baseline video. In part 2, we apply the theory in practice by an actual tuning exercise. If things are nor clear in this video like the drop test, then please watch the SU baseline video on my channel. Enjoy

[@grayfool]

At last! A well explained video with tests and measurments to prove the statememnts. Thank you very much. You have obviously put a lot of work into this.

[@D3Sshooter]

Glad it was helpful!

[@classicminidiy]

No surprise here, great video, and super high quality. Thank you for making such an in-depth video on this.

[@D3Sshooter]

Glad you enjoyed it!

[@brianparkinson1594]

Great explanation with super illustrations on the mystics of the SU!

[@D3Sshooter]

Thank you kindly!

[@IngeBall]

What a nice start on a tuesday!

[@D3Sshooter]

Enjoy!

[@tomtomed1]

Incredibly professional! Can't believe you only have 30k subs. Thanks for uploading!

[@D3Sshooter]

Thanks for watching!

[@chuckayuey]

You put so much work into your videos... and it is appreciated. I have a little brick called Checkered and you have inspired me to get back out in the garage. I look forward to watching the second video.

[@D3Sshooter]

That is awesome Jason, Thanks for the comments

[@axelpieper2754]

Your videos are the best on youtube! Your explanations are very comprehensive. The way you present is is extemely educational and professional! Thanks for putting in all this wirk and please continue to educate us to service our vintage cars. AX

[@D3Sshooter]

Glad you like them!

[@allthingsmaine4514]

I really enjoy your videos, you are very gifted in your ability to teach a subject in a way that truly makes sense. Thank you so much.

[@D3Sshooter]

You are so welcome

[@jimmielmholt]

As always very professional layout and explanation.

[@D3Sshooter]

Glad you liked it!

[@gshort4707]

Love these technical tutorials. KZbin is full of "dumbed down" videos so this one is a rare and refreshing change. Graham

[@D3Sshooter]

Thank you...

[@mgbsandotherstuff2982]

Excellent explanation, I have learned that I need to understand how things work before I just dive in and try to adjust thing blindly. Thanks

[@D3Sshooter]

Thank you for the comments.

[@aussieboganbloke2244]

Awesome video... Helped me out alot with tuning my carburetor on my daughters and my own motorcycles..,very simple design...turns out the jets were plugged in both from our last ride and the needle in my bike was bent... I counted the turns in before i removed them... Absolutely awesome chanel mate.. Great content and easy to understand...

[@D3Sshooter]

Glad it helped

[@wadeeb]

excellent videos! these are the videos we need!! thank you so much

[@D3Sshooter]

Thanks for the comments

[@CotswoldParagliding]

Great video! Thank you

[@D3Sshooter]

Glad you liked it!

[@reesw1821]

Excellent video, lots of information. Thanks.

[@D3Sshooter]

Glad you enjoyed it!

[@andymiddleditch3855]

Very well made video, very informative and very useful.

[@D3Sshooter]

Glad it was helpful!

[@baioszisimos3367]

Perfect waiting for part 2

[@D3Sshooter]

Coming tonight

[@bshnabel]

Just excellent

[@D3Sshooter]

Thanks for the comments

[@cyrussataravalla6731]

Ma786sai Dua bless you a tremendous video. My Rolls-Royce Spirit 1982 has the HIF7 SU carbs which are running TOO RICH. The car runs beautifully but every few months the plugs go sooty black, and some even wet. I want to WEAKEN the mixture

[@alejandroforbes4037]

Thanks a lot for your videos which are helping us a lot ! I cannot disassamble the neddle from the piston because it is blocked, could you please give me the good method ? I have already put a lot of wd40 but no success ! Thanks in advance !

[@vintage76vipergreenBeetle]

👍 You should do video on tuning Weber's carburetors,IDF's

[@D3Sshooter]

Great suggestion! I have done the DCOE's

[@vintage76vipergreenBeetle]

@@D3Sshooter Yes,the DCOE Weber's are a little different, but will do. Thanks for making the videos. I just finished watching those Weber's videos.

[@user-xs6zg4jl2s]

Hi Sir, I just found out and watched your videos excellent! I'm a bit confused here. You say here that advance ignition should be set before tuning the carbs, but then in your video ' ignition timing', that fuel mixture should be correct before strobing? Am I misunderstanding something? Thank you.

[@D3Sshooter]

Thank you, yes always set your ignition timing correct before adjusting the carbs. that is the start, then adjust the mixture on idle and listen to the engine, measure the AFR if you can and or use a colortune... or just listening to the engine. Once that is done you can retune your ignition with small changes as the burnrate of the fuel/air mixture might have changed and more or less advance is needed. I always adjust for the max advance on idle , but do not allow pinging of the engine. Everything hangs together and relates on an engine... Have a look on the video on adjusting the webers on acceleration and main circuit on my playlist for the webers. There you see what `i mean with the burn rate of fuel and how that relates to ignition advance

[@renato3225]

Hi, could you please show the tuning of carburettors of an old MG TC. 1946 ? Many thanks

[@D3Sshooter]

If I come across one I wil

[@HiroshanFernando]

if the carburetor throttle flap worn out, does it affect the Air Gas ratio & tuning.

[@D3Sshooter]

Yes i does much depending where its worn, if it leaks air through the axle then you are having a vacuum leak and it starts to run lean, in all cases it will result in a leaner mix

[@emmajacobs5575]

Just one point to add - the biased spring loaded needles were introduced on some later HS type carbs before HIF ones. My 1974 MG Midget has them. Excellent video as usual, otherwise.

[@D3Sshooter]

Thanks for the info! and that is a bit strange that the HS has it. What type do you have ?

[@emmajacobs5575]

@@D3Sshooter mine’s twin HS2 carbs on a 1275 A series engine.

[@notajp]

I believe the HS2’s I have on my 74 Spitfire has them as well, however it’s not the stock setup. It originally had the single Zenith.

[@D3Sshooter]

Mark's Mini Garage that is good to know. Thank you. I will need to remember that

[@D3Sshooter]

Emma Jacobs thank you

[@ajd5363]

Man you look like Paul Weller from the Jam!

[@minimoe2008]

Where did you get the graph chart from the circle one in specific?

[@D3Sshooter]

Thanks for the comments, well that is something you need graph yourself based on the information in the SU needle catalogue.

[@minimoe2008]

@@D3Sshooter Ahh okay, It looked like an excel program so I thought it was something where you plug in the needle number and it plots it on a chart. Similar to the other link you had on the previous video. Thank you sir.

[@D3Sshooter]

minimoe2008 , indeed you can use xl plugin the data snd add a grapht to excel in radarview

[@DavidUKesb]

Hello. Is there any special way to fit a new fixed needle or do you just put it in flush and tighten the screw? Thanks

[@D3Sshooter]

Just put it flush ( for an articulated needle) and make sure it points/leans in the correct direction ( either to the engine or airfilter, there is an etched mark on the birdge of carburetor)

[@DavidUKesb]

@@D3Sshooter Thanks for that. Not sure what you mean by leans in correct direction though. If fitted correctly doesn't needle point straight down?

[@D3Sshooter]

@@DavidUKesb David, the needle sits in an angle that is what I mean with a biased or leaning needle. That is only for those carbs with a biased needle ( spring inside the insert). The needle can lean forward or backward... most of the time its leaning towards the air intake side. So the needle does not sit straight. If yours does , then its not right or you have carburetor with a NONE biased needle and then it sits straight. In that case you will need to center the jet itself

[@DavidUKesb]

@@D3Sshooter Many thanks. My needle is fixed which is why I was confused!.

[@D3Sshooter]

@@DavidUKesb No problem, good luck