How to overhaul SU carbs (Specifically HIF4 carbs from a late MGB)
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- Опубліковано 26 сер 2024
- How to overhaul SU HIF4 carbs
I walk you through the process of stripping, cleaning, inspecting and reassembling an SU HIF4 carb off an MGB from start to finish.
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Thanks!
Great video- very helpful. Only constructive advice for those of us following along is at minute 50 when the "deliberate mistake " happens add a comment on screen so audience don't repeat the mistake. You are right about not editing it out though- it's the human side that make your videos watchable.
Brilliant video! Thanks for taking us through the whole process step by step with a really practical approach 👏😎👍
Excellent video, especially for those that disassembled both HIF's at the same time, instead of keeping one assembled while executing a refurb on the other. A special thumbs up for the explanation on this asymmetry of parts on the enrichment cover. Some minor remarks: some prefer checking the centralisation of the throttle by shining a strong light from the other side and minimise the light leaking along the edges and some carbs have an enrichtment exit in the carb throat sticking up, so a cutout on the disk has to be made by filing it in. Initial jetsetting for the best starting position possible is first adjust for top being level with the carb throat and then enrich by two full turns on the mixture screw. PS I never had problems with removing and putting back floats & float needles with the jet and its bimetallic compensator mechanism still in situ 😃
I'm restoring my MGB in this video really helped me. Thank you for your help I very much appreciate it I couldn't have done it without you. One carburetor down one to go.
Glad I could help!
Just starting into refurbing my own 78 MGB GT carbs so thanks for demonstrating how to do it.
You're very welcome. I hope it works out well for you.
excellent video very well explained ,i have a HIF on my harley made by Rivera eng ,had it on there for 30 years still going strong, they are a excellent carby,
Thank you for the thorough explanation. My SU rebuild came with "directions' that covered several models. Your video was quite helpful.
Glad I could help!
Great video, thanks very much. Have a 72 BGT been sitting for years, fuel smells like varnish so the SU’s need a good clean & rebuild. We moved to this house in 2016 so lot of things like brake calipers, clutch cylinder etc.. Car ran great before we moved. Have to flush entire fuel system tho. Engine has aluminum head w/valves & seats for no lead fuel.
Excellent video, helped me a lot overhauling the HIF7 carbs of my Silver Shadow. Thank you so much.
I'm on my second watch of this video cos I'm going to rebuild my hif4 carbs later and it made me chuckle again when you said.. "And give it a little wiggle in the bushes" 🤣 cheers 🍻 Cheers for all the content fella..
Best of luck with the rebuild, mate. Drop me a message if you have any questions!
I rebuilt mine last year, but they are are off again. I didn't pay attention to the linkage positions and I didn't do the float height. I also found one or two little things that might not have helped. Seals not correctly pushed in, locking washer not secure. One of the large nuts not tight. One of the butterfly split screws is broken. I didn't get new butterflies in my SU kit, must check that out. Cheers Ross.
Very good video. Highly recommended. Thank you.
Very informative video, really enjoyed watching.
Thanks! It was a nice job to do, just being able to sit at the bench.
Ive got a Classic Mini with a HS4 carb,with regard to the throttle spindle bush replacement,its worth doing as during a frosty damp morning a few years ago,i was overtaking a bus on a duel carridge way,i was at about 65mph,after i had passed the bus i came to the end of the duel carridge way,after it was a straight road followed by a sharp right hand bend up a hill,so as i approached the bend,i took my foot off the throttle but the revs didnt drop,i fact they still increased!! I thought the cable might be stuck but no,it was free and the bend was coming up fast!! Luckly,there was a lay-by at the bottom of the hill so i switched the ignition off and coasted in to the lay-by!! When i opened the bonnet up,all i could see was a very large knob of ice on the throttle spindle position!! After using de-icer on it,the throttle worked fine!! I had to do the de-icer every few miles that day!!!! Luckly,i had a friend who machined the body and made some bronze bushes to fix it. There was only about 1mm movement on the shaft to the body,but it was enough to cause it to pull the freezing damp air in and cause it to freeze it in the open position!!!!!
Yikes! Sounds like you had a lucky escape there. Carb icing is a massive problem on air-cooled VWs because of the pressure drop over the long manifold. With these carbs, I was confident that the wear was minimal after changing the throttle spindle. If I had any doubts, I would have changed the bushes.
@@Endfloat I thought the same till i had a real close look!!!!Never had it before(Ive had a Mini on and off for nigh on 45 years!!!!!LOL)or since!! Not a good expeirience!!!! At least with an older carbed car you can "switch" of and coast,no power steering or ECU to worry about!!!! Newer vehicles pose a different solution!!!!! Keep up the good work,i enjoy your videos!!!!
Great video demistifying this job I need to do, thank you.
lovely explanation, thank you well done
Up the Dubs. Good stuff.
Well done. I especially appreciate how you don’t edit out your human-ness…like when you installed the jet assembly before the needle and seat, and had to double back and correct yourself. Exactly the kind of thing that I’d do…and that many people would have removed from their videos. I’ve always believed that people learn from their mistakes. I don’t fully trust people who claim to never make mistakes. I always wonder if they really know what they’re doing?
PS. Some folks like to use 90 wt gear oil in the damper pots (vs engine oil,) the idea being that the extra viscosity slows the piston’s movement enough so that at throttle tip in the mixture is richened slightly. This is supposed to act as a momentary enrichener, like an accelerator pump. I’ve tried it and can’t really tell too much difference, if any at all…but, I offer it up to you for what it’s worth.
Thanks. Yeah, I try to be the everyman, and include my mistakes. I'm not a professional, just a have a go hero. With respect to the oil, I might try different oils and see what works best. I might even do a video on it! I've heard others saying that 3 in 1 oil is good too, which is the opposite to what you're saying.
Good video I need to do my hif carbs thank you
You're very welcome! I hope my video helps!
So which rebuild kit seems to be the goto for most.
Great video.I’m halfway through….looks like I need to drill out that pesky screw…never done that before….I’d best checkout another UA-cam video to see how it’s done! Thanks
Just take your time and you'll be grand.
This helped me immensely but my kit has 2 extra washer gasket things I haven’t figured out where they go
I think I had a couple of spares too. So long as you have one either end of the throttle shaft and one for the choke valve, then you should be alright.
Great video mate, really simple yet helpful. So followed it and the Carbs are back on with no leaks and the MG starts, however, only on choke. Going back to your video the jets were put in flush “for now” and assume they need adjusting. I’ve looked through your other videos and couldn’t find one for tuning and adjusting carbs. Do you have one and if not what do I need to do next to tune the carbs after the overhaul?? Thanks in advance.
Have a look at my more recent videos where I tuned up my brown MG. Same carbs.
Can you tell me once more what default position is for the jet?
Level with the "bridge" that goes across if I remember correctly.
I've seen mention of getting rid of the popet valves on the butterfly do you have an opinion on that?
I've done it in the past because it allegedly makes for easier tuning and removes a point of failure. The new throttle plates I got for a pair of carbs I rebuilt didn't have the poppet in them.
Nice - very helpful. Thanks! Question: Shouldn't the throttle shaft be oiled a little when reassembled? Or no?
A little Vaseline would help, and won't harm the seals.
I screwed in my seat, just like the gentleman in this video did, and it sheared right off. Now I gotta get the threaded brass part out of the carburetor. It shouldn't be hard as it wasn't even tight yet!!? So be careful 😉
I wonder was it perhaps a defective part that you got. Certainly shouldn't have broken too easily.
@@Endfloat Hello Endfloat. How ya doin'? That could well be the case my friend. Turns out the ones that were in the car may be okay, so I will reuse them. I already put them back in (and they didn't break). The ones on the car use a needle with a square cross-section, Viton tip, and a spring loaded "dimple" that makes contact with the float, whereas the new needle was triangular in cross-section, Viton tip, and no spring on the side that comes in contact with the float. I'm guessing the triangular one allows fuel to pass faster. I'm not sure of the function of the spring-loaded end. I can't imagine that the float actually can overcome the spring force. Thanks for commenting !
I think the left carb is very shiny!!!! 😂 Ahem... 👀